Electrical Planning

Main Electrical Service

Contractor Selected — SLS Electric LLC

Quote: $4,610 (200A service + 50A generator plug)

_[Content redacted for privacy]_

Status: ✅ Complete (2026-04-17 final invoice). All SLS scope wired, terminated, and energized: 200A panel, underground feeder, interior/exterior GFCI outlets, soffit wafer lights, entry-door light switch, 50A generator inlet. Passed inspection. All remaining electrical work is DIY — contractor re-engagement reserved for challenging tasks only. Details: Quote Summary | Contractor Records

Service Specifications: 200A Wire, 100A Connection

Panel: 200 amp breaker panel in garage (mounted on plywood with wireway) Feed Wire: 200A capacity (2/0 AWG copper or 4/0 AWG aluminum) Initial Connection: 100 amp breaker at house main panel House Panel Location: SW corner basement, west wall

Future-Proofing Strategy:

100A service provides plenty of capacity for all current garage needs

200A wire installed now future-proofs for potential upgrade

If house upgrades to 400A service, garage can upgrade to 200A by changing breaker only

Cost difference for wire is minimal vs. digging new trench later

Existing House Panel Documentation

Photo documentation of the house main panel (2025-12-02) provides baseline reference for electrical contractor discussions:

Panel Interior (Open) — Full panel view with deadfront open showing circuit layout, breaker positions, and inspection stickers
Inspection Stickers — Close-up of mechanical, plumbing, and electrical inspection approvals (Permits: M305565, P2256472, 2006 electrical)
Panel Label & Legend — Factory data label with bus rating, breaker specs, and circuit legend showing available space for 100A feeder breaker
Panel Exterior (Closed) — Wide shot showing panel mounting, work clearance, and conduit routing pathways

Panel Specifications (from photos)

Manufacturer: Eaton / Cutler-Hammer 200A residential load center

Available Space: Top-left position suitable for 2-pole 100A breaker

Existing Inspections: Final mechanical (3/28/05), plumbing (3/30/05), electrical (3/27/06)

Work Clearance: Meets NEC 30” width requirement

Scope of Work — Contractor vs. DIY

SLS Electric (Licensed Electrician — $4,610):

200A panel installation in garage (mounted on plywood with wireway) — ✅ panel installed
Underground feeder from house to garage (trenching + conduit + wire pull) — ✅ trench complete 2026-03-24
2x 1” conduits run from house to garage underground — ✅ installed (unexpected scope addition; enter house at NW corner junction boxes, merge into single 2” conduit through garage floor)
Eaton BRPSF225 225A lug block kit staged at house panel for feeder connection — pending
50A generator inlet (Reliance CS6375, exterior-mounted) — ✅ installed 2026-03-31
Exterior weatherproof GFCI outlet — ✅ installed 2026-03-31
Interior GFCI convenience outlet near panel — ✅ installed and wired 2026-03-31
Front soffit recessed lights (3x wafer lights) — ✅ installed, wired, and energized 2026-04-17
Light switch at entry door — ✅ installed and terminated 2026-04-17 (controls soffit lights)
SLS final invoice received 2026-04-17 — 2026-04-17 - SLS Electric - Final Invoice.pdf
Breakers installed in 200A panel — ✅ 2026-03-31
2x 1” conduit penetrations foamed at house basement wall — ✅ 2026-03-31

Owner (DIY) — All Interior Electrical:

All 120V branch circuits (perimeter, workbench, ceiling/door, lift bay, mechanical room) — 🔄 in progress; rear wall 16” perimeter circuit energized 2026-05-25 (first DIY branch circuit live)
All 240V dedicated circuits (lift, compressor, welder/plasma, EV/auxiliary)
UPS distribution circuit with orange outlets (UPS Strategy)
Interior lighting installation and wiring (18x LED fixtures across 3 circuits)
Smart home integration (Shelly relays, motion sensors, Home Assistant)
Loft subpanel feeder and all loft/apartment circuits (future)
Network wiring (Cat6A, smurf tubing, patch panel — see Network Planning)
Fume extraction and ventilation circuits

DIY Install Progress:

The north wall hosts two separate 20A perimeter circuits, each with its own GFCI lead device:

✅ North wall 16” floor-line circuit — ENERGIZED 2026-05-25. Multiple 2-gang boxes at 16” AFF chained with 12-2 NM-B. GFCI lead is a single device in a workbench-height (~46” AFF) 2-gang at the east end of the north wall, near the loft stairs — deliberately raised above the standard 16” AFF because the planned rolling tool cabinets at that section would block any floor-level outlet. Second slot in the GFCI 2-gang is intentionally empty (no duplex installed yet); it will be retrofit later in series with the rest of the 16” AFF chain. 20A BR breaker landed in the garage panel. First DIY branch circuit live.
✅ North wall workbench-height circuit (~42–46” AFF) — ENERGIZED. Separate 20A circuit from the 16” floor line, with its own GFCI lead. Receptacles completed, panel-side pull done, 20A BR breaker landed; energized in a session prior to 2026-06-19 and RT250-verified 2026-06-19 (first + last outlet read correct). 5 workbench-height 2-gang boxes total on the north wall (one is the 16” circuit’s GFCI lead raised near the stairs; the rest are on this workbench-height circuit).
✅ West wall 16” perimeter circuit — ENERGIZED 2026-06-19. Boxes at 16” AFF (no workbench on this wall, so entirely floor-line); receptacles installed, romex pulled back to the panel, 20A BR breaker landed, energized and RT250-verified 2026-06-19 (first + last outlet correct).
✅ GFCI / wiring verification (2026-06-19): tested the first + last outlet of every energized circuit with a new Klein Tools RT250 GFCI outlet tester — wiring correct in all cases; TEST-button GFCI trip times 0.08–0.09 s (well within UL 943). The ceiling-light circuit (no GFCI) was checked for correct wiring only. A full every-receptacle test + photo pass is planned before drywall (see To-Do).
🔄 Tidying pass deferred — wires from 2026-05-25 are routed but not yet stapled to studs; labeling and detailed circuit-position photos also pending.
🔄 Wire slack at panel intentionally left long — see Conduit Routing Decision below.

Vehicle-bay lighting circuit (dedicated 20A) — rough-in started 2026-06-07 (Uncle Ed + Chris helping):

✅ Three ceiling-light boxes installed — one per bay, for the front-to-back 5-fixture runs (see Zone 1 layout).
✅ Cable run to the stairwell-bottom switch box (the 3-way location near the loft stairs).
✅ First 5-fixture chain hung and tested off an extension cord — works perfectly. It’s over Bay 3 (east/lift bay). These fixtures double as construction lighting for the remaining build (see construction-phase lighting strategy). Note: fixtures are clip-mounted (two single-screw clips each), not chain-suspended — they pull down and reinstall quickly, so the run was put up now for interior-work lighting and will come down for ceiling drywall, then go back up.
✅ 3-way switching complete & energized 2026-06-19. 12/3 run from the stairwell 3-way to the entry-door 2-gang box (which already holds the SLS exterior-soffit switch + the 2026-04-22 Shelly); bay-light 3-way switch installed there. As-built differs from the original plan: the home run lands at the stairwell box (not the entry-door box), and the bay + stairwell lighting share one branch circuit (plenty of headroom — ~6A of LED load). Energized on a temporary 20A breaker; a 15A replacement is on order (HD WK29485567) and becomes required once the 14/3 stairwell run is added (14 AWG ≤15A, NEC 240.4(D)). The 12/3’s white is re-identified as a switched hot (NEC 200.7(C)(2)). Per the switch topology, the bay-light Shelly lives in the stairwell box (constant L+N); the entry-door switch is a 3-way input. Diagram + box photos: 3-way diagram, stairwell box, entry-door box.
✅ All three bay runs hung 2026-06-19 — 3 rows × 5 = 15 Barrina fixtures; initial garage lighting complete. Switched together on the garage-floor 3-way; bright enough Conor called it “like being flashbanged.” See all-15-lit photo.
See Timeline 2026-05-25, Timeline 2026-05-26 (morning-after documentation), Timeline 2026-06-07 (ceiling lights), May 25 photo set, May 26 photo set, and June 7 photo set for the install record.

North-wall workbench layout context (clarified 2026-05-26):

Workbench: central section of the north wall, equidistant from both garage bays
Rolling tool cabinets: against the same north wall, east of the workbench, near the future 2-post lift and the loft stairs
Loft stairs: on the east side of the garage, starting at the back/north and turning south to ascend
West wall: intentionally all 16” AFF — no workbench planned on this wall

Reset locations for future troubleshooting:

16” AFF floor-line outlets misbehave → reset at the raised GFCI 2-gang near the loft stairs (east end of north wall, ~46” AFF)
Workbench-height outlets misbehave (once energized) → reset at the workbench-height circuit’s own GFCI (a different box on the same wall, in the workbench section)
West wall outlets misbehave (once energized) → reset wherever the west wall circuit’s GFCI lead lands (TBD when that circuit is built out)

Conduit Routing Decision — Kneewall vs. Up-to-Rafters

Status: 🔄 Under evaluation (2026-05-26)

The new rear-wall circuit’s panel-side feed was deliberately left with extra wire slack so the routing choice for all first-floor branch circuits stays open. Two options:

Option A — Inside the kneewall (current path): Cables run along the long edges of the garage behind the kneewall, dropping to the panel through the wall cavity. The kneewall area is excellent for cable routing, and this is the default.
Option B — Up-to-rafters via conduit: Bundle all first-floor branch cables into a single conduit run up to the rafters, then drop into the panel. Pros: tidy, protects cables, easier future re-pulls (especially if Romex is replaced with stranded THHN in EMT or PVC later); separates branch wiring visually from the structural framing.

Additional constraint: a second conduit will be needed later for the future loft 100A subpanel feeder (see Second Floor Subpanel). Whichever option is selected, the routing plan should accommodate both runs in advance so the rafter penetrations / kneewall paths only have to be opened once.

Photo reference: panel-side wire slack.

Circuit Labeling Plan

Status: 🔄 Sharpie pass complete; Brother P-touch purchased 2026-06-05 — printed labels before insulation

Cables and panel breakers were not labeled at install time (label maker was misplaced as of 2026-05-26). The interim plan:

Sharpie pass within 1–2 days of energization while context is fresh — mark each Romex at the panel end (circuit name / area) and at the lead box of each chain. Acceptable as a temporary measure since the panel is open and accessible.
Proper printed labels before any insulation, vapor barrier, or drywall goes in. Sharpie marks fade and rub off; printed labels survive long term and pass inspection cleanly.

Update 2026-06-05: A Brother P-touch PT-D210 has been purchased for this task, replacing the misplaced unit. This is the tool the Wire & Box Labeling Convention designates for in-box wire/cable labels. The bundle’s standard laminated cassettes handle flat coverplate/box labels; order TZe-FX231 (½” Flexible ID) for wrapping round NM-B cable before the labeling pass. (The convention originally specced TZe-SL self-laminating tape — corrected to TZe-FX231 on 2026-06-05, since the SL line is industrial-printer-only and won’t fit the PT-D210.) Printed cable + breaker labels still need to be applied over the interim Sharpie marks before any insulation goes in.

Both passes are owner-DIY and tracked in To-Do. A printable labeling cheat sheet is available to post in the mechanical room.

Why this split: SLS handles the service entrance, generator hookup, and exterior work that require licensure, utility coordination (DTE), and permitting. All interior branch circuit work is owner-installed following NEC code. Interior work will be inspected per local requirements.

Service Route:

Separate underground trench from house SW corner to garage foundation
Enters garage through 2” PVC conduit in mechanical room
Additionally, 2x 1” conduits run from house NW corner to garage (underground), entering house basement through block wall and terminating at exterior junction boxes; on garage side these merge into single 2” conduit through floor into panel area
See Trench 1: Electrical Service (RED arrow path) for detailed routing
Photo documentation: Garage panel with conduits, House exterior junction boxes, House basement conduit penetrations

Installation Requirements:

Licensed electrician required
Permit and inspection required
NEC compliant burial depth (18”-24” depending on wire type/protection)
Proper grounding and bonding per code
THWN-2 or XHHW-2 conductors in conduit, or direct-burial rated cable

Exterior Penetration Sealing (Owner Follow-Up)

SLS’s exterior scope included several wall-penetrating boxes (NW-corner Cat6/spare junction boxes, 50A generator inlet, GFCI outlet) mounted directly to lap siding. SLS applied spray foam from the interior at each penetration (basement-side, before the conduits disappear into the block wall) — that is the primary air seal and insulation at the conduit penetration. The exterior side was left open and is owner follow-up: its purpose is narrower — blocking wind-driven rain from being forced behind the siding at the top and sides of each box.

Three-sided caulk rule — do NOT seal the bottom

Vinyl/composite siding is intentionally not watertight; it is a drained cladding. Sealing all four sides of an exterior box creates a water trap: any incidental moisture that gets behind the box or siding loses its escape path. Always leave the bottom edge unsealed so water can drain out. In a textbook assembly, a flashed mounting block or flanged penetration integrated to the hidden WRB handles the primary exterior water control; this exterior bead is only a secondary rain deflector. Seal the top and both sides only.

Sealant (paintable hybrid polymer or elastomeric — must flex with vinyl-to-PVC movement):

OSI Quad Max — primary recommendation; hybrid polymer, paintable, white color-matches siding, excellent adhesion to PVC and vinyl
Sashco Big Stretch — acrylic elastomer, water cleanup, paintable, very high movement capability
DAP Dynaflex Ultra — acceptable budget alternative

Avoid:

Pure silicone (GE Silicone II, etc.) — doesn’t bond reliably to vinyl siding, not paintable, fouls any future touch-up
Plain acrylic latex caulk — won’t hold up on a joint that moves seasonally

Procedure (per box):

Trim any excess interior foam protruding at the exterior flush with a utility knife once cured
Wipe the joint with denatured alcohol; allow to dry
Apply a shallow surface bead across the top of the box-to-siding joint and down both sides
Tool the bead with a wet finger or caulk tool for a clean profile
Do not pack the cavity full or try to seal to a hidden layer; this bead should adhere to the exposed box and siding only
Leave the bottom edge unsealed (or at most a tiny weep gap) to allow drainage
Let cure per product label before rain exposure (typically 24 hours skin, 7 days full cure)

Why not a siding mounting block? The textbook install is a flanged mounting block (Arlington InBox, TAPCO) set under the siding course before the box is mounted, providing a flat flashed surface. Retrofitting one now means pulling siding courses off the north wall, which isn’t warranted for a few already-installed boxes. 3-sided caulk is the correct pragmatic answer at this stage.

WRB vs. vapor retarder: for this exterior detail, the relevant hidden layer is the exterior WRB/drainage plane, if present, not an interior vapor barrier/vapor retarder. The caulk does not need to contact a vapor barrier.

Boxes to treat:

NW corner Cat6 house-side junction box — see Cat6 box photo (2026-04-19)
NW corner spare/future-fiber conduit body (adjacent to the above)
50A generator inlet (Reliance CS6375) — see NW corner exterior boxes overview
Exterior GFCI outlet
Any other wall-penetrating box SLS installed — walk the house perimeter before starting

Checklist:

Walk perimeter and catalog every SLS exterior box/penetration — stage:: 7
Trim protruding interior foam flush at exterior — stage:: 7
Purchase sealant (OSI Quad Max white, 1–2 tubes) — stage:: 5
Apply 3-sided caulk bead (top + both sides, bottom open) at each box — stage:: 7
Photo-document sealed boxes for future reference — stage:: 7

Outlets & Wiring

GFCI protection for all 120V garage outlets.
NM-B (Romex) allowed in finished walls; keep 1.25” from stud face or use nail plates.
Heights: 12–18” typical; 48” above floor for workbench runs.
Provide extra circuits for tools and future loads.

NM Cable Support & Securing (NEC 334.30)

Reusable reference for stapling/securing NM-B (Romex) on exposed runs across framing — applies to every DIY branch circuit, not just the first.

The two numbers that govern it (both NEC 334.30):

Support at intervals ≤ 4½ ft (54”). This is the hard maximum spacing between securing points.
Secure within 12” of every box (334.30) — or within 8” at a plastic single-gang box with no internal cable clamp, which is the 314.17(C) Exception: a clampless single-gang nonmetallic box ≤2¼”×4” needs no cable clamp provided the cable is fastened within 8” of the box measured along the sheath. Most plastic single-gang boxes have no clamp, so assume the 8” figure at outlet drops. This catch is a common DIY inspection miss: the long run gets stapled perfectly and the staple right at the box gets forgotten.

Mapping to truss/stud spacing (24” OC framing):

Staple cadence	Spacing	Compliant?
Every framing member	24”	✅ Yes (overkill, always safe)
Every other member	48”	✅ Yes (≤ 54” max)
Every 6 ft	72”	❌ No — exceeds the 4½ ft limit

So on 24” OC framing, every other member satisfies code; every 6 ft does not.

Running parallel along a member vs. draping over the tops (perpendicular):

Along a face (cable runs parallel to one stud/chord): every-other-member is fine — the run is already pinned to a flat plane.
Draping over the tops (cable runs perpendicular, crossing each truss/joist top edge): prefer stapling at every crossing. A cable laid over the narrow top edge wants to slide sideways and sag between supports; pinning each high point keeps the run tight and from migrating. You can’t seat a staple on the top edge itself — drive the staple into the side of the member just below the top, capturing the cable where it rolls over. Keep each span snug (don’t leave big dips), and route over wood, clear of any truss connector plates (toothed metal gussets) so the cable can’t chafe on a plate edge.

Vertical runs in a stud bay. The ≤4½ ft rule (NEC 334.30) applies to the whole length of the cable, not just horizontal stretches — a riser up a wall needs intermediate staples too. The within-8” staple at the box is only the first securing point; do not leave the rest of the riser hanging loose. Run the cable against a stud (something to staple to) and add a staple to the stud face/side every ≤4½ ft up the bay. Example: a ~16”-to-~11’ riser (~9.5 ft of travel) gets the box staple, one at mid-height (~5–6 ft), and one near the top before it transitions to the trusses. Keep staples back so the cable stays ≥1¼” from the stud’s front edge (NEC 300.4(D) for cable run parallel to framing), or add a ≥1/16” steel nail plate where you can’t — the riser is in drywall-screw territory. Where a riser instead passes up through bored holes in plates/studs, the holes must be ≥1¼” from the edge (NEC 300.4(A)(1)) and, spaced ≤4½ ft apart, the framing itself is generally accepted as the support (AHJ-dependent); a surface riser still needs actual staples.

Support both legs of a bend. Where a horizontal run turns to drop down a wall, secure it on both sides of the corner (a staple before the bend and the within-8–12” staple at the box) so the cable isn’t supporting its own weight at an unsupported turn.

Staples: plastic insulated staples (or listed straps/cable ties) sized for the cable — e.g. ½” for a single 12-2/14-2. Seat them firm enough that the cable can’t slide under the staple, but not so hard they deform the jacket. Plastic staples lower the pinch risk vs. metal.

Physical-damage protection (NEC 334.15(B) generally; 334.23 → 320.23 in attics): NM cable must be protected from physical damage where exposed (334.15(B)). In accessible attics/roof spaces, 334.23 points to 320.23, which sets the trigger: where the space is reached by permanent stairs or a ladder, guard strips (or conduit) are required for cable run across the top of floor joists and within 7 ft of the floor on the face of framing; where the space is not so accessible (scuttle-hole only), protection is required only within 6 ft of the scuttle hole. The practical test is whether the cable could be stepped on or have storage set on it. A closed, non-storable cavity (e.g. a kneewall triangle boxed in by web bracing at every truss) does not trigger guard strips even when the cable drapes over the tops, because the space can’t be disturbed. Don’t drill or notch engineered trusses to route cable — that’s a building-code/manufacturer restriction (IRC R802.10.4: trusses can’t be cut, notched, or altered without the design professional’s approval), not an NEC rule; surface-mount and staple instead.

Code references (NEC section numbers stable across 2017/2020 editions — the editions Michigan has adopted; 314.17(C) is renumbered to 314.17(B)(2) in the 2023 NEC):

Claim	Code section
Secure ≤4½ ft apart and within 12” of every box; applies to the whole cable length (risers included)	NEC 334.30
8” securing at a clampless single-gang nonmetallic box (≤2¼”×4”), measured along the sheath	NEC 314.17(C) Exception
≥1¼” setback from edge for cable run parallel to framing, else ≥1/16” steel nail plate	NEC 300.4(D)
≥1¼” setback for bored holes through studs/joists, else steel plate	NEC 300.4(A)(1)
Protect exposed NM cable from physical damage	NEC 334.15(B)
Attic guard-strip trigger (7 ft if stairs/ladder access; 6 ft of scuttle hole otherwise)	NEC 334.23 → 320.23(A)
Don’t cut/notch/alter engineered trusses without design-professional approval	IRC R802.10.4 (building code, not NEC)

Applied: rear kneewall run (2026-06)

First outlet line behind the south kneewall — trusses run N–S, cable drapes E–W over the top chords through a closed triangle (web bracing at every truss, not usable for storage). Plan, end to end:

Riser from the ~16” outlet box up to ~11’ (~9.5 ft): staple to the stud at the box (within 8”), at mid-height (~5–6 ft), and near the top before the transition — three points, ≤4½ ft apart, kept ≥1¼” back from the stud edge.

Top bend: support both legs where the riser turns across the truss tops.

Over the trusses: plastic staples at every truss (side of chord, just under the top edge), snug spans, clear of metal plates.

No running board needed (non-storable cavity).

Outlet Protection Strategy

Workshop Safety Consideration: In a metal-working and automotive environment, loose metal parts (bolts, sockets, brackets, metal shavings) pose a risk of bridging outlet contacts, especially behind cabinets and shelving where they may not be immediately visible.

Required Protection:

Tamper-resistant (TR) outlets throughout garage (NEC required for all 120V 15A/20A receptacles)
TR outlets have internal spring shutters that prevent single-prong insertion
Provides baseline protection but doesn’t prevent two metal objects bridging both contacts

Additional Protection for Blocked Outlets: When cabinets, shelving, or equipment block access to outlets:

Simple outlet caps/plugs - Inexpensive (~$5 for 36-pack), easy to remove, prevents debris and accidental contact
Blank cover plates - For permanently blocked outlets, replace receptacle with blank plate (still accessible by removing one screw)
Weatherproof in-use covers - Spring-loaded hinged covers for occasionally-accessed outlets in high-debris areas

Best Practices:

Stock spare outlet caps in the shop to protect outlets as layout evolves
Label blocked outlets on circuit schedule for future reference
Inspect behind shelving periodically for any metal debris near outlets
Consider weatherproof covers for outlets near metalworking zones (welder, grinder, plasma cutter areas)

Procurement:

Recommended Simple Outlet Caps (easy removal, bulk packs):

JOOL BABY 32-Pack - $6-8 (Home Depot) - Best for local pickup, perfect quantity
Safety Innovations 50-Pack - $10-12 (Amazon) - Best value per cap, Prime shipping
Idea Safety 40-Pack - $8-10 (Amazon) - Mid-size option, good reviews
Dreambaby 24-Pack - $5-7 (Lowe’s) - Smallest pack, in-store pickup

For High-Risk Metalworking Areas:

AIV Locking Outlet Covers 6-Pack (AIV Inc.) - More secure for plasma cutter/grinder/welder zones

Weatherproof While-In-Use Covers (for high-debris areas):

Recommended Products:

TayMac MM410C Clear In-Use Cover - $8-12 each (Amazon, Lowe’s) - Best for workshop, clear polycarbonate, horizontal/vertical mount
Commercial Electric Metal While-In-Use Cover - $16 (Home Depot) - Metal construction, extra durability
Commercial Electric Extra Duty In-Use Cover - $12-15 (Home Depot) - 16-in-1 configurations, very versatile
BELL Self-Closing Duplex Cover - $6-8 (Home Depot) - Budget option for lower-risk areas

Which Outlets Need In-Use Covers:

High Priority (metal debris/sparks):

Welder/Plasma outlet (50A 240V NEMA 6-50) - Use TayMac MM410C or Commercial Electric Metal
Workbench outlets near metalworking (3-4 outlets) - Use TayMac MM410C clear covers
Air compressor area outlets - Use TayMac MM410C (compressor stays plugged in)
Lift bay support outlets (2× 20A near columns) - Use Commercial Electric Extra Duty (16-in-1 for versatility)

Medium Priority (general debris): 5. Perimeter outlets in fabrication zones - Use BELL self-closing or TayMac as budget allows 6. Ceiling/door run outlets - Consider for cord reels exposed to airborne debris

Budget Estimate:

6-8 TayMac covers @ $8 - 12 e a c h =$ 48-96
2-3 Commercial Electric heavy-duty @ $12 - 16 e a c h =$ 24-48
Total: ~$75-150 for complete high-risk area protection

Other Items:

TR outlets: Specify in electrical materials order

Main Floor Outlet & Circuit Layout

120V general-purpose circuits

Perimeter runs (4× 20A): Each wall gets its own GFCI-protected 20A circuit with receptacles every ≤6’. Expect ≈22 floor-height duplexes so any bay can power tools without cord trees.
Workbench runs (2× 20A): Dedicated 20A circuits serving 5–6 duplexes at 48” AFF along the main bench/toolbox wall plus two outlets under-counter for fridge/chargers. Keeps benchtop tools isolated from bay loads.
Ceiling/door run (1× 20A): Feeds the 3 garage door openers, the front-wall (south door-wall) outlets, and camera/sensor outlets. Overhead shop lights are NOT on this circuit (own dedicated 20A — see Vehicle bay lighting below), and the cord reels were split off to their own 20A on 2026-06-22 (see Cord reels below) — so a tripped opener and, especially, a high-draw tool on a cord reel cannot cascade across these loads or darken the bay lights while working under a raised vehicle. A GFCI breaker for this circuit is on hand (2026-06-22). Detailed breakdown:
- Garage door openers (3×): Ceiling outlets near each opener for factory power cords (plug-in, not hardwired). Openers draw ~5A briefly when running, <1A idle. Using factory cords maintains serviceability and manufacturer warranty.
- Front-wall (south door-wall) outlets (4× 2-gang = 8 receptacles): Dual-gang duplex boxes on the door wall at standard height — (1) between the entry door & Bay 3, (2) between Bay 3 & Bay 2, (3) between Bay 2 & Bay 1, (4) near the west corner. Useful for leaf blowers, car vacuums, battery chargers, and general bay-front tasks. (Boxes not yet installed as of 2026-06-22; count grew from the earlier 2–3× estimate.)
- Camera/sensor outlets: Low-draw security and automation devices.
- Total estimated load: Well under 20A even with simultaneous use — openers run briefly and front-wall outlets are typically light-duty. (The high-draw wildcard — the cord reels — was moved to its own circuit on 2026-06-22, see Cord reels below.)
- GFCI protection: GFCI breaker at panel (not GFCI outlet) — the first outlet in the chain is ceiling-mounted, so breaker-based protection avoids ladder access for reset. Breaker on hand (2026-06-22).
- Wiring topology: Ceiling run with wall drops — run 12/2 NM-B along the ceiling through the 3 opener boxes (across the front of the ceiling), then drop down to the front-wall outlets from the nearest ceiling box. Minimizes wire runs through the open joists. Outlet count on this circuit: 3 GDO + 4 front-wall (2-gang) + camera/sensor ≈ 8–9 boxes on one 20A breaker, well within load.
Cord reels (1× 20A dedicated — split off the ceiling/door run 2026-06-22): Ceiling outlets for 2 retractable cord reels, positioned between the garage doors near the center of the garage (one between Bay 1 ↔ Bay 2, one between Bay 2 ↔ Bay 3). Each between-bays reel swivels to serve both adjacent bays equally, and the reel’s typical 25–50’ cord clears all of either bay easily — prevents extension cords across the floor. Put on their own 20A GFCI circuit so a high-draw tool on a reel (shop vac, compressor, grinder, charger ≈ 10–15A) gets the full circuit and can’t trip the opener/front-wall circuit; reasoning parallels the 2026-04-23 bay-lighting split. Boxes mounted 2026-06-22 (reel box photo); wiring + reels later. Future flexibility: if more reel coverage is ever needed (e.g., a 4th bay-specific reel for the lift area), a wall-mounted cord reel can plug into any of the planned perimeter outlets (every ≤6’ on all 4 walls) — no ceiling re-rough required. Decision 2026-05-24 trimmed this from 3× to 2×: with 3 bays there are only 2 between-bays positions geometrically, and a third reel directly over one bay would drop a cord on the parked vehicle rather than alongside it. See cord-reel split rationale. Routing (decided 2026-06-22): run via the kneewall chase — do NOT drill the loft floor framing. Those members are attic-truss bottom chords (IRC R502.11.3 prohibits drilling truss members without engineer approval). Take the home run up into the kneewall chase, travel length-wise there, then drop into a single truss bay and run parallel to the chords to each box (feed each box from within its own bay). See routing rationale.
Vehicle bay lighting (1× 20A dedicated): Powers the nine overhead LED shop lights in three linkable groups of three (360W / 3A total — huge headroom on a 20A breaker). Three ceiling outlets along the bay centerlines (one per bay); first outlet in each group takes the factory plug-in cord, and the other 2 fixtures in the group daisy-chain off it via factory link cables. Position each lighting duplex at the depth-midpoint of its bay (~12’ from the front in a 24’-deep bay) — this puts the single 3-fixture chain over the middle-to-rear of the bay (where the vehicle parks and the lift is used) and preserves the rough-in option to double the lighting later to 6 fixtures per bay by plugging a second linkable chain into the unused half of the same duplex, extending in the opposite direction. Two chains × 3 fixtures each from one centered duplex covers ~80% of the bay depth evenly, no additional rough-in needed. Split off from the ceiling/door run on 2026-04-23 to isolate overhead lighting from opener, cord-reel, and front-wall loads — a nuisance trip on those circuits must not darken the bay while the 2-post lift is raised. See Interior Lighting (Main Garage Floor) for fixture layout and 2026-04-23 — Vehicle Bay Lighting Split to Dedicated Circuit for rationale.
Lift-bay support (1× 20A): Two WR duplexes, one near each lift column, for diagnostics lights/fans separate from the lift’s 240V feed.
Mechanical/server convenience (2× 20A dedicated): Two circuits serving the mechanical room. Defined loads (clarified 2026-06-07):
- Rack/network circuit (1× 20A): Dedicated 20A at the structured-media/rack location feeding the network switch, PoE injector/switch (cameras + WAPs), and NVR. This is the previously-vague “server rack circuit.” UPS-backed — the rack is the natural #1 load on the centralized UPS, so its outlet should be one of the orange UPS outlets (see UPS Strategy). Cross-ref Network Planning.
- Boiler/pump control circuit (1× 20A): Feeds the Navien boiler (~15A 120V) and mechanical-room controls. Reserve one labeled spare outlet on this circuit adjacent to the boiler as a contingency for an external circulator pump — only energized/used if the post-insulation Manual J shows the NCB-E’s internal pump is inadequate for the slab loop length (~1A wet-rotor circulator). Cross-ref Boiler Installation Components §4 (Hydronic Side).
- Note — low-draw mechanical loads use a general-purpose receptacle (no dedicated circuit): the central vacuum motor (RIDGID HD1400, ~6A intermittent) and the water softener control head (<1A standby) plug into a nearby general-purpose receptacle (a mechanical-room or adjacent perimeter outlet) rather than dedicated circuits — confirmed sufficient given their low/intermittent draw. Keep the ~6A vac motor off the boiler/pump control circuit so it can’t interact with boiler controls; label whichever outlet it lands on so it’s traceable on the panel schedule.
UPS distribution circuit (1× 20A dedicated): Feeds centralized rack-mount UPS in mechanical room; UPS output powers dedicated orange-colored outlets at server rack, 3D printer station, workbench, and future loft office. DIY installation. See Approach B Centralized UPS Distribution — “Orange Outlet” Strategy.
Pressure-washer outlet (1× dedicated GFCI): Dedicated GFCI-protected circuit at the Bay 3 / mechanical-room wall for a wall-mounted pressure washer (voltage per chosen unit — 120V/20A typical, 240V for hot-water units). Rough in during framing. See Wall-Mounted Pressure Washer.

Total: 9 general-purpose 20A circuits (≈30 outlets, including the dedicated vehicle-bay lighting circuit added 2026-04-23 and the dedicated cord-reel circuit split off 2026-06-22) plus two dedicated 20A circuits in the mechanical room, all balanced across panel legs. (Authoritative breaker count now lives in the Panel Schedule below.)

Minor conveniences (added 2026-06-07)

From the 2026-06-07 completeness pass — small adds that are cheap now, costly to retrofit:

Dedicated shop fridge/freezer circuit (RECOMMEND): Give the shop fridge/freezer its own 20A circuit instead of sharing the workbench circuit (supersedes the “two under-counter outlets for fridge/chargers” sharing note in the Workbench bullet above). NEC 210.8(A) still requires GFCI for garage receptacles — use a single self-test GFCI receptacle so a downstream tool fault can’t quietly kill the fridge, and a tool nuisance-trip doesn’t spoil food. Keep the chargers on the workbench circuit.
Additional exterior WP GFCI outlets ×2 (RECOMMEND): Beyond the single SLS exterior GFCI, add ~2 weatherproof, in-use-covered GFCI outlets — one on the opposite side wall, one toward the driveway/apron — for landscaping, running an EV cord under a door, outdoor pressure-washing, and seasonal lighting.
Ceiling air-filtration outlet (RECOMMEND, cheap): A switched ceiling receptacle for a hanging shop air filter (Corvette-restoration sanding/grinding dust). Tap a ceiling/lighting circuit; control via its own switch or a Shelly/HA so it can run on a timer after dusty work. Not its own breaker. Selected unit (2026-06-08): WEN 3417 — 556/702/1044 CFM 3-speed, 5-micron + 1-micron filtration, IR remote + programmable timer (pairs with the Shelly), 2-yr warranty, ** $320.99 * * . S i ze df or t h e 9, 600 c u - f t g ro u n df l oor (1044 CFM \approx 6.5 ai rc han g es / h r) . C h ose n o v er t h e J ET A FS - 1000 C ($ 659.99, same airflow, 2× price) and POWERTEC AF1044 ($186.85 but currently unavailable, 1-yr warranty) per the project’s “Buy Cheap, Upgrade When Proven” philosophy. A 400-CFM hobby unit (e.g. WEN 3410) would be undersized for the full bay.
USB power at the bench — via plug-in hub, not in-wall (DECIDED 2026-06-08): Skip in-wall USB receptacles. Instead, ensure standard 20A duplex outlets at workbench height and power an Anker USB power hub (multi-port USB-C PD + USB-A desktop charger) from one of them — the owner already runs several of these in the house and they work well. Rationale: a plug-in hub is trivially upgraded as USB standards evolve (PD revisions, higher wattage, new connectors), whereas an in-wall USB module is fixed at install-era specs and is the part most likely to fail. No special receptacle needed here — just confirm bench-height duplex coverage (already planned).

Product picks (researched 2026-06-27 — USB-only desktop GaN chargers, ≥100W USB-C PD for laptop charging): Two-tier plan to fit the “buy cheap, upgrade when proven” philosophy across several shop locations — one capable anchor at the main bench, a cheap repeatable unit everywhere else. (Charger prices swing hard with promos; MSRP is the anchor, sale price is “if you catch it.” All prices as of late June 2026.)
- Bench command center → Anker Prime 200W 6-Port (A2683) — 4× USB-C + 2× USB-A, 100W single port, two ports can do 100W simultaneously. USB-A covers older shop gear (battery chargers, flashlights, headlamps). ~ $80 a t A nk er (MSRP$ 104; Amazon floor ~$56). Six ports = laptop + phone + tablet + a couple tool-battery chargers off one brick. (Anker page · price history)
- Repeatable satellite unit (loft office desk, individual bays) → Anker Prime 100W 3-Port (A2688) — 2× USB-C + 1× USB-A, genuine 100W single port, foldable plug (no captive cord dangling off a bay outlet). ~ $40-50 (MSRP$ 70). Buy 2–3×. (Anker page)
  - Value alternative: UGREEN Nexode 100W 4-Port (90736B) — same 100W capability + an extra USB-C for ~ $15 l ess ($ 33–50), but off the Anker ecosystem the house standardizes on.
  - If a spot routinely charges laptop and phone together: Anker 737 GaNPrime 120W 3-Port (A2148) — 120W total gives headroom so the laptop at 100W doesn’t starve the phone. ~$55–85.
- Phone/small-device-only corners (media/karaoke area — no laptop) → Anker 543 65W 4-Port (A2046) — slim, adhesive-mountable, $39.99. ⚠️ 45W max single port — not for laptop charging; phones/tablets/headlamps/Eneloop chargers only.
- Rejected as overkill: Anker Prime 250W 6-Port w/ LCD (A2345, ~$130–150) — its 140W single port targets 16″ MacBook Pro / 140W laptops; unnecessary for a standard ~65–100W laptop.
Battery-backup egress light at the stair/exit (RECOMMEND, modest): An integral-battery LED fixture at the stair landing / service-door exit for power-outage egress. Complements the already-resilient stair-light circuit (which keeps the stair lit if the loft loses power) by also covering a whole-garage outage. Selected unit (2026-06-08): Lithonia ELM2L M12 — UL 924 dedicated emergency fixture, two aimable LED heads, hardwired 120/277V, auto-on at power loss, 90-min battery (meets NFPA 101 / OSHA). ** $37.28/ e a o n A ma zo n * * (c h e a p er t han Ho m eDe p o t^{'} s [$ 49.97](https://www.homedepot.com/p/Lithonia-Lighting-Contractor-Select-ELM-120-277-Volt-Integrated-LED-White-Emergency-Light-Fixture-with-Battery-ELM2L-M12/305568847)). Since the landing already has a normal stair light, a dedicated emergency-only fixture is the cleaner fit than a double-duty unit. Alternative if you’d rather the landing’s main light itself be battery-backed: Commercial Electric WR484040EFL — 4-ft 4000-lm wraparound that runs as everyday light + 90-min backup, $145.

Quantity & placement (2026-06-08): Install two units — one at the stairwell landing, one above the service door (the two egress points). Note the ELM2L is a single fixture with two aimable heads on one body, so each location needs its own unit.

Wiring (constant hot, ahead of the switch): Connect each fixture’s line lead to the constant (unswitched) hot of the lighting circuit serving that area — not a switch’s load/output terminal. (The service-door unit can tap the always-on leg the electricians already ran above the door, which feeds the line side of the exterior-light switch + exterior plug; the stairwell unit taps a constant hot from the stair-light feed on the vehicle-bay lighting circuit, ahead of the stair switch.) Why constant hot: a UL 924 unit continuously monitors the normal supply and only switches to its battery when that supply actually fails — wire it to a switched leg and it would nuisance-activate (and cycle the battery) every time someone turns the lights off. This also satisfies NEC 700.12’s intent that the emergency unit monitor the area’s normal lighting circuit. Locate each unit so its push-to-test button / charge LED is reachable for the monthly 30-second test. If the tapped leg is downstream of a GFCI (exterior plug), a GFCI trip will also activate the light — harmless.

240V / dedicated loads

2-post lift: 30A 240V circuit with local disconnect between the PEX-free pads in bay 3. Spec verified against the leading candidate (BendPak GP-9LC): 208–230 VAC, 1-phase, ≈23A draw; manufacturer requires a 25A-minimum time-delay breaker/fuse on a dedicated circuit. The 30A / NEMA 6-30 / 10-3 build covers it with margin. Power unit ships with a pigtail and must be wired by a licensed electrician. See Lift — Electrical and the manuals in Manuals.
Air compressor: 30A 240V circuit in the corner feeding the planned manifold/piping system.
Welder / plasma: 50A 240V (NEMA 6-50) receptacle along the bench wall for welding, plasma cutting, or blasting equipment noted in the design docs.
EV / auxiliary: 50A 240V (NEMA 14-50) receptacle centered on the back wall between bays for auxiliary loads (welder overflow, large equipment, etc.). EV charging consideration: This receptacle can support Level 2 charging via any EVSE rated up to 40A continuous (50A circuit × 80% = 40A max), delivering ~30 miles of range per hour. However, a second NEMA 14-50 on the front wall between garage doors would be more practical for EV use — allows charging inside any bay and running a cable under a door to charge in the driveway. Front wall receptacle is a future addition; panel has capacity. Interim EV charging: The exterior weatherproof GFCI outlet provides Level 1 (120V/20A) at ~4-5 miles of range per hour — sufficient for overnight top-ups. Note: Do not use the generator inlet (Reliance CS6375) for EV charging — it is a power inlet, not an outlet, and is interlocked with the utility feed.
Mini-split outdoor units (×2): Two dedicated 240V branch circuits to the shared rear-wall pad — one per condenser. Each gets its own breaker and outdoor disconnect sized per MrCool 5th Gen nameplate. Garage system (18k single-zone Hyper-Heat) is fed from the main panel. Loft system (21k 2-zone, 9k+12k) is fed from the loft subpanel — see Second Floor Apartment Subpanel ✅ CONFIRMED for subpanel sizing rationale. Two-system topology decided 2026-05-14 — see 2026-05-14 — Mini-Split Topology: Two Separate Systems (Single-Zone Garage + 2-Zone Loft).
Generator inlet: 50A 240V weatherproof NEMA 14-50 inlet with interlock as described in the backup power plan.

Ventilation / Fume Extraction Circuits

Fume extraction blower (loft): Dedicated 20A 120V circuit for inline fume extraction blower serving loft workstations (resin printers, soldering, airbrushing). Junction box location in loft ceiling near planned exhaust penetration. See Fume Extraction Strategy.
Paint booth exhaust: No dedicated circuit. Occasional automotive painting uses a portable window-mounted exhaust fan powered from existing front-wall outlets. See Decisions Log — Paint Booth Exhaust for rationale.
Ceiling outlet for dust collection (optional): 15A 120V for future ceiling-mounted cyclone separator or dust collector if upgrading from shop vac approach.

All 240V circuits pull through the embedded conduits shown in the slab photos, leaving space for future additions.

Dedicated Loads & Future-Proofing

Car lift — verified for the GP-9LC candidate: 208–230V 1-phase, ≈23A, 25A-min breaker (30A circuit planned). See note under 240V / dedicated loads.
Air compressor (dedicated 240V circuit as needed).
Welder receptacle (e.g., 50A 240V), EVSE rough-in, server rack circuit.
Two mini-split outdoor units, each on its own dedicated breaker: garage system fed from main panel, loft system fed from loft subpanel. Both condensers share a single rear-wall pad. Indoor heads do not require dedicated breakers (powered from the outdoor unit per MrCool 5th Gen wiring).
Panel sizing: 200A panel with 100A feed provides ample capacity for all loads (see Main Electrical Service above).

Panel Schedule / Circuit Directory

Single source of truth for every breaker in the garage 200A panel. Fill the CKT # column from the panel directory as each circuit is landed; keep this table in sync with the in-panel directory label and the labeling cheat sheet. Status key: ✅ energized · 🔄 in progress · ⬜ planned · ⏳ future.

⚠ Confirm actual panel space count before committing to all future circuits

This schedule assumes the garage Eaton BR panel has enough spaces for everything below plus the future 2-pole loads. Read the panel’s space count off its label on the next visit (e.g., 40-circuit / 20-space-with-tandems vs. a true 40-space) and record it here. The pole tally below shows the active build is comfortable, but the future 2-pole loads (SPD, loft 100A feeder, 2nd-240V stub, 2nd EV receptacle) are what could make slots tight. Mitigations if tight: tandem (half-height) breakers where the panel/circuit allows, mounting the SPD as an external unit that doesn’t consume slots (verify model), and the loft 100A subpanel offloading all loft circuits off the main panel.

120V branch circuits (1 pole each)

CKT #	Circuit / area	A	Breaker	Wire	Status
__	North wall 16” floor-line outlets	20	GFCI (lead device)	12/2	✅ 2026-05-25
__	North wall workbench-height outlets	20	GFCI (lead device)	12/2	✅ 2026-06-19
__	West wall 16” outlets	20	GFCI (lead device)	12/2	✅ 2026-06-19
__	Ceiling/door (3 openers, 4 front-wall 2-gang, sensors)	20	GFCI breaker (BR120GF, on hand)	12/2	⬜ (boxes mounted 2026-06-22)
__	Cord reels (2× ceiling, between bays)	20	GFCI	12/2	⬜ (boxes mounted 2026-06-22; split off ceiling/door 2026-06-22)
__	Vehicle-bay lighting + stairwell light	20→15	std (Shelly at loads)	12/2 + 12/3 (+14/3 stair)	✅ 2026-06-19 (bay lit; temp 20A → 15A pending; stairwell light TBD)
__	Workbench outlets A	20	GFCI	12/2	⬜
__	Workbench outlets B (also feeds workbench task lighting)	20	GFCI	12/2	⬜
__	Lift-bay support (outlets + lift-bay lighting)	20	GFCI	12/2	⬜
__	Mechanical — rack/network (PoE, NVR; UPS-backed)	20	std	12/2	⬜
__	Mechanical — boiler/pump control (+ circulator contingency outlet)	20	std	12/2	⬜
__	UPS distribution (feeds orange outlets)	20	std	12/2	⬜
__	Pressure washer (Bay 3 wall)	20	GFCI	12/2	⬜
__	Dedicated shop fridge/freezer	20	GFCI (self-test)	12/2	⬜ (added 2026-06-07)
__	Rear & side security lighting (LV cabinet)	15	std	14/2	⬜
__	Smoke/CO/heat detector interconnect (garage chain only — bridged to house via HA, not wired between buildings)	15	std	14/3	⬜ (added 2026-06-07)
__	Interior GFCI convenience near panel (SLS)	20	GFCI	12/2	✅ 2026-03-31
__	Exterior GFCI outlet (SLS)	20	GFCI/WR	12/2	✅ 2026-03-31
__	Exterior soffit lights (SLS)	15	std	14/2	✅ 2026-04-17
__	Additional exterior WP GFCI outlets (×2, side + driveway)	20	GFCI/WR	12/2	⬜ (added 2026-06-07)

Shared, no separate breaker: workbench task lighting (on Workbench B), lift-bay lighting (on Lift-bay support), and the switched ceiling air-filter outlet (tap a lighting/ceiling circuit). The central vacuum motor and water softener ride a general-purpose receptacle (see mechanical-room note above), not their own breakers.

240V / dedicated loads (2 poles each)

CKT #	Load	A	Receptacle / type	Wire	Status
__	2-post lift (Bay 3, local disconnect)	30	NEMA 6-30 / per lift	10/3	⬜
__	Air compressor (mech-room corner)	30	NEMA 6-30	10/3	⬜
__	Welder / plasma (bench wall)	50	NEMA 6-50	6/2 †	⬜
__	EV / auxiliary (rear wall between bays)	50	NEMA 14-50	6/3	⬜
__	Mini-split — garage (18k Hyper-Heat)	per nameplate	hardwired + disconnect	per nameplate	⬜
__	Generator inlet (Reliance CS6375, interlocked)	50	NEMA 14-50 inlet	6/3	✅ 2026-03-31
__	Whole-panel SPD (Eaton CHSPT2ULTRA)	30 (2-pole feed)	panel-mount SPD	factory leads	⏳ pre-drywall
__	Future: loft 100A subpanel feeder	100	feeder	per feeder	⏳
__	Future: 2nd 240V stub (welder/EV/dust)	TBD	capped stub	pull later	⏳
__	Future: 2nd EV receptacle (front wall)	50	NEMA 14-50	6/3	⏳

† Welder is 6/2, not 6/3 — intentional. A NEMA 6-50 is a 2-hot + ground device with no neutral, so 6/2 w/ground is code-minimum and correct. Don’t “fix” this to 6/3. (The EV 14-50 does carry a neutral, so it stays 6/3.) See the wire reference below for the full rationale.

240V Wire & Cable Reference

Wire size is set by two things, not just amperage:

Amperage → gauge (copper): 20A → 12 AWG · 30A → 10 AWG · 50A → 6 AWG.
Receptacle → neutral → conductor count: NEMA 6-xx outlets (6-30, 6-50) are 2-hot + ground with no neutral → 2-conductor cable (e.g. 10/2, 6/2). NEMA 14-xx (14-50) carries a neutral → 3-conductor cable (6/3). (“10/2 w/G” = 2 insulated conductors + a bare ground.)

Cable per circuit (decision 2026-06-20 — see 2026-06-20 — 240V Branch Wire Sizing (Gauge + Neutral) & Conduit Wire-Method Flag):

Load	Amps	Receptacle	Cable (NM-B)	Neutral	Note
Mini-split (garage)	~20 per nameplate	hardwired	12/2 w/G	No	Verify MrCool nameplate MCA/MOCP before buying
2-post lift	30	NEMA 6-30	10/3 w/G	spare	Future-proofed: spare neutral lets a later 14-xx swap with no re-pull (cheap at 10 AWG)
Air compressor	30	NEMA 6-30	10/3 w/G	spare	Same future-proofing rationale
Welder / plasma	50	NEMA 6-50	6/2 w/G	No	Code-minimum — 6/3 is much pricier at 6 AWG and the neutral would never be used
EV / auxiliary	50	NEMA 14-50	6/3 w/G	Yes	14-50 requires the neutral
Generator inlet ✅	50	NEMA 14-50 inlet	6/3 w/G	Yes	Installed 2026-03-31

Product links (Southwire NM-B, Home Depot — buy length to suit each run):

12/2 — same stock as the 120V circuits
10/2 (if any 6-30 run is done without the spare neutral): 50 ft · 250 ft
10/3 (lift, compressor): 50 ft
6/2 (welder): 50 ft
6/3 (EV): 50 ft · by-the-foot

⚠ Confirm wire method for the slab-conduit runs before buying

The 240V home runs pass through the embedded slab conduits. NM-B (Romex) is not rated for wet locations (NEC 334.12), and conduit in or under a slab is generally a wet location (NEC 300.5 / 300.6) — those segments may require THWN-2 individual conductors instead, with NM-B used only in the open stud walls. THWN-2 also pulls through conduit far more easily than jacketed Romex. If THWN-2 is needed, pull individual 12 conductors (2 hots + neutral where required) plus a separate green EGC sized per NEC 250.122 (#12 for 20A, #10 for 30A and 50A). 6 AWG THWN-2 is sold by-the-foot at Home Depot.

Confirm whether the embedded slab conduits are a wet location (in/under slab) — decides NM-B vs THWN-2 for the 240V runs before ordering wire. — stage:: 5

Pole-count tally (capacity check)

120V (1-pole): ~18 active/planned (incl. the cord-reel circuit split off 2026-06-22) + 2 new minor (fridge, detectors) ≈ 20 single-pole slots
240V (2-pole): 6 active loads + SPD = 7 × 2 = 14 slots
Active subtotal: ≈ 34 slots
Future 2-pole: loft feeder + 2nd-240V + 2nd EV = 3 × 2 = +6 slots → ~40 total

A 40-circuit panel covers the active build (≈34) comfortably, but the future 2-pole loads now push the projected total to ~40 — essentially full — so the space-count confirmation and the mitigations above (tandems, external SPD, loft-subpanel offload) matter more than before. Action: confirm the panel’s actual space count and record it here (open item, see warning above and To-Do).

Second Floor Apartment Subpanel ✅ CONFIRMED

Inspector Guidance (January 27, 2026)

Building inspector confirmed the subpanel approach and provided guidance:

Recommended: Install separate subpanel upstairs so future tenant can reset their own breakers

DIY allowed: Homeowner can self-install if space is used as general-purpose first, then converted to apartment later

If immediate apartment: Would require licensed electrician due to dwelling unit codes

Strategy: Use loft as general bonus room initially, convert to apartment later = DIY installation permitted

See Inspector Visit Notes for full inspection summary.

Confirmed Electrical Plan

Main Floor (Workshop/Garage):

All outlets, lighting, lift, compressor, welder, etc. → Main 200A Panel
This is the primary workshop electrical system

Second Floor (Loft/Future Apartment):

All outlets, lighting, future HVAC → Dedicated 100A Subpanel
Subpanel located in loft, accessible for tenant breaker resets
Future-proofs for apartment conversion without rewiring

The second floor is planned for a future rental apartment. A dedicated subpanel on the second floor allows tenants to reset their own tripped breakers without requiring access to the main garage workshop.

Electrical Topology

House Main Panel (200A)
       ↓
   100A feeder
       ↓
Garage Main Panel (200A) ← Workshop, lift, compressor, etc.
       ↓
   60-100A feeder
       ↓
Apartment Subpanel (2nd floor) ← Tenant-accessible for resets

Subpanel Sizing

Option	Capacity	Best For
60A subpanel	Adequate for typical apartment loads	Small apartment, mini-split on separate circuit
100A subpanel	Extra headroom for future expansion	Electric range, electric dryer, or growth potential

Recommendation: 100A subpanel with 20-24 spaces provides flexibility for future needs and costs marginally more than 60A.

Circuit Protection Requirements (Dwelling Unit)

Rental apartments have different code requirements than garages. Dwelling units require AFCI protection for most living spaces.

Room/Area	AFCI Required	GFCI Required	Breaker Type
Bedrooms	Yes	No	AFCI
Living room	Yes	No	AFCI
Kitchen (general)	Yes	Yes (near sink)	Dual function
Kitchen (countertop)	Yes	Yes	Dual function
Bathroom	No	Yes	GFCI
Laundry	Yes	Yes	Dual function
Hallways/closets	Yes	No	AFCI

Note: Dual function breakers (AFCI+GFCI) are ideal for kitchen and laundry circuits where both protections are required. Unlike the garage floor where motors can cause nuisance AFCI trips, apartment circuits have typical residential loads that work well with AFCI protection.

Panel Location Requirements

Tenant accessible: Hallway closet, utility closet, or similar location within apartment
NEC working clearance: 30” wide × 36” deep × 78” high minimum clear space
Not in bathroom or clothes closet (NEC restriction)
Coordinate with floor plan during framing phase

Feeder Routing

Run feeder from garage main panel up to second floor
Rough-in conduit during framing — much easier/cheaper than retrofitting later
Coordinate chase/penetration location with floor plan and stair layout
Typical feeder: 4 AWG copper or 2 AWG aluminum for 100A subpanel

Construction-Phase Early Circuits (Pull-Forward)

Decision 2026-06-25 — install the subpanel ahead of schedule

The loft summer work push happens while the loft is uninsulated and brutally hot. Rather than run long extension cords from the main-floor circuits for temporary cooling, install the 100A loft subpanel + feeder early and rough three branch circuits now. Each doubles as a permanent loft receptacle later, so nothing is throwaway. See Temporary Construction-Phase Cooling (Uninsulated Loft) for the cooling plan these circuits feed.

All three are fed from the loft subpanel (consistent with the “all loft circuits originate at the subpanel” architecture above — do not feed them from the main garage panel). Each is 20A / 120V, 12/2 Cu w/ ground, GFCI-protected (construction-phase temporary/wet-use envelope; dwelling-grade AFCI / dual-function applies later once the loft is a finished living space, per Circuit Protection Requirements (Dwelling Unit)).

#	Circuit	Location	Construction use	Permanent use
1	Dormer A/C #1	Receptacle at south dormer #1	One window A/C unit	Normal loft receptacle
2	Dormer A/C #2	Receptacle at south dormer #2	Second window A/C unit	Normal loft receptacle
3	Construction / tool	Central, or near the top of the stairs	Tools, chargers, lights, fans, vacuum	Convenience / maintenance receptacle

Why this is low-cost: the materials are already on hand — 1,000 ft spool of 12/2, spare 20A GFCI receptacles, 4-5 spare 20A breakers, extra boxes (all new). The incremental cost of pulling these three circuits while the subpanel goes in is minimal, which is what makes moving the subpanel up in the schedule worthwhile.

Subpanel grounding reminder: in the loft subpanel the neutral and ground bars must be kept separate (not bonded together) — the #1 DIY subpanel mistake. The feeder is a 4-wire run (2 hots + neutral + ground).

Metering & Energy Monitoring

The apartment subpanel is the natural choke point for measuring all upstairs energy use — every loft circuit passes through it. Clamping current transformers (CTs) around the two hot conductors of the 100A feeder gives total upstairs kWh, real-time draw, and historical trends. This parallels the Flo water-monitoring strategy for the mechanical closet: cheap, smart, Home Assistant-integrated, with a future upgrade path for revenue-grade tenant billing.

There are three tiers worth planning for. Tier 1 is the day-one install; Tiers 2 and 3 are upgrades that become worthwhile if the loft is rented.

Tier 1: Whole-Subpanel Monitoring (Day One)

Two CTs on the feeder hots inside the subpanel enclosure, reporting to a wall-powered hub. This gets you 90% of the value: total upstairs draw, kWh totals, peak detection, and tenant-vs-workshop breakdown when paired with main-panel CTs.

Product	Cost	Notes
Emporia Vue Gen 3	~$150	Recommended. Two 200A CTs on feeder + up to 16 smaller CTs for branch circuits if you ever want per-circuit. No subscription. Native Home Assistant integration via emporia-vue HACS or MQTT. WiFi or Ethernet. Mounts inside the subpanel enclosure.
Shelly Pro 3EM	~$130	DIN-rail mount, 3-phase capable (overkill for split-phase but harmless). Excellent HA/MQTT integration. Cleaner install if you have DIN rail; otherwise Emporia is easier.
Sense Energy Monitor	~$300	ML-based device disaggregation (“your dryer just turned on”). Whole-panel only via 2 CTs. No subscription, but accuracy of disaggregation is hit-or-miss and HA integration is unofficial. Skip in favor of Emporia unless you specifically want device fingerprinting.

Recommendation: Emporia Vue Gen 3, installed at the same time as the subpanel. Provides immediate visibility for the workshop-as-bonus-room phase, then doubles as tenant usage tracking after conversion.

Tier 2: Per-Circuit Breakdown (Optional Upgrade)

Add Emporia’s 50A CTs to individual breakers inside the subpanel — water heater, mini-split, range, dryer, lighting. ~$15/circuit. Useful for diagnosing tenant complaints (“AC is running constantly”, “electric bill seems high”), identifying a runaway load, or proving out which circuits dominate the apartment’s load profile. Up to 16 channels per Emporia hub, so a fully-instrumented 100A subpanel fits in one device.

Tier 3: Revenue-Grade Sub-Billing (Apartment Conversion)

For legally billing the tenant in Michigan, you generally want a revenue-grade meter rated ANSI C12.20 (Class 0.5 or 1.0 accuracy). Emporia/Sense are ±2% and not certified for billing — they’re fine for usage visibility but not for line-item invoices the tenant can dispute.

Product	Cost	Notes
Leviton Series 2000 Submeter with VerifEye display	$300–500	Purpose-built for tenant submetering. ANSI C12.20 Class 1.0. Wall-mount display shows kWh totals for billing. Simple, proven.
eGauge Pro	~$700	Pricier but combines monitoring + revenue-grade billing in one device. Web UI, Modbus, popular for ADUs and granny flats. Eliminates the need for a separate Tier 1 monitor.

You can run both an Emporia (for HA/live monitoring) and a Leviton (for the legal billing record) simultaneously — they don’t conflict. The Leviton goes in line with the feeder; the Emporia CTs clamp around the same conductors. Total Tier 1 + Tier 3 cost ~$450–650.

Tenant Billing Approach Comparison

Approach	Tenant Billing	Notes
Subpanel only (no monitoring)	Included in rent	Tenant usage on landlord’s bill; no usage data either
Subpanel + Emporia (Tier 1)	Included in rent	Landlord sees usage; can adjust rent based on actuals; not for itemized billing
Subpanel + Revenue meter (Tier 3)	Tenant pays separately or itemized	Defensible kWh totals; required in some jurisdictions for rental sub-billing
Separate utility-owned meter	Tenant has own utility account	Highest legal clarity; requires Consumers Energy/DTE coordination + meter base on exterior; significant cost

Action: Before apartment conversion, confirm with Clare building department and Consumers Energy whether sub-billing from a private meter is permitted, or whether a utility-owned meter base is required. Michigan rules vary by utility and jurisdiction.

Recommended Strategy

Spec the rough-in for both Tier 1 and Tier 3 now (cheap), install Tier 1 on day one (~$200), defer Tier 3 until apartment conversion is imminent. This mirrors the Flo strategy for water and avoids spending on revenue-grade hardware until there’s actually a tenant to bill.

Rough-In Checklist ⚠️ DO BEFORE INSULATION/DRYWALL

Critical Timing

These items are 10x easier now while walls are open. Once insulation and drywall are installed, routing conduit and wire becomes much more difficult and expensive.

Subpanel Feeder Rough-In

Determine subpanel location — Choose accessible spot in loft (hallway/utility area, NOT bathroom or closet). Must have 30”W × 36”D × 78”H clear working space. — stage:: 3
Plan feeder route — Map path from main panel location up to loft subpanel location (e.g., mechanical room ceiling → floor penetration → subpanel) — stage:: 3
Install conduit — Run 1¼” EMT or PVC from main panel area to subpanel location. Pull string for later wire pull. — stage:: 3
Mark floor penetration — Fire-stop penetration through floor assembly per code — stage:: 3
Install subpanel backing — Mount ¾” plywood backing at subpanel location (24”W × 30”H minimum) — stage:: 3

Apartment Energy Monitoring Rough-In

These items make Tier 1 monitoring (Emporia) installable on day one and keep Tier 3 (revenue meter) a low-friction future upgrade. See Metering & Energy Monitoring for the strategy.

Spec subpanel enclosure with extra interior depth — Choose a NEMA 1 indoor enclosure with at least 4” of gutter space (top/bottom or side) so CTs can clamp around feeder conductors and an Emporia hub fits inside without crowding breakers. Many “compact” subpanels are too tight. — stage:: 3
Pull Cat6 to subpanel location — Run from network closet/equipment rack to within 12” of the subpanel. Terminate to a keystone jack on a low-voltage plate adjacent to the subpanel. Used for wired Emporia/eGauge connection (more reliable than WiFi inside a metal enclosure) and any future Modbus revenue meter. — stage:: 3
Install 120V duplex outlet within 3 ft of subpanel — Powers the energy monitor’s 5V wall-wart and any future revenue meter display. Must be on a circuit not fed by the apartment subpanel itself (otherwise tripping the main feeder kills the monitor that diagnoses the trip). Source from main garage panel. — stage:: 3
Reserve straight feeder length inside subpanel — Leave at least 6” of straight conductor on the feeder hots inside the subpanel enclosure (after the main lugs/main breaker, before the busbar split). Allows future revenue-meter CTs to clamp on cleanly without re-pulling feeder wire. — stage:: 3

Loft Circuit Rough-In

Plan outlet locations — Determine outlet placement based on potential apartment layout (bedrooms, living area, kitchen, bathroom) — stage:: 3
Run outlet boxes — Install electrical boxes at planned outlet locations while walls are open — stage:: 3
Run lighting boxes — Install ceiling boxes for light fixtures — stage:: 3
Rough-in bathroom circuit — Dedicated 20A GFCI circuit for bathroom — stage:: 3
Rough-in kitchen circuits — Two dedicated 20A circuits for kitchen countertop receptacles (if planning kitchen) — stage:: 3
Loft mini-split circuit — Rough-in dedicated 240V circuit from loft subpanel to shared rear-wall pad for the loft 21k 2-zone outdoor condenser (separate from the garage system’s circuit, which originates at the main panel). Include outdoor disconnect at pad. — stage:: 3
Loft transfer-fan circuit — Branch a 15A 120V circuit off the loft general-lighting circuit to feed all transfer-fan locations (bathroom + 2-3 speculative future office / 2nd bedroom / closet locations). Each fan <0.5A; combined load is trivial. At each fan location: single-gang box at sleeve location + switch-leg to a wall box for a future Leviton DT160 countdown timer. Wire all boxes now; leave un-used ones capped with blank plates until rooms emerge. See Loft Door-Closed Comfort for the air-pathway hub rationale. — stage:: 3
Loft ERV pre-rough — 120V outlet — Pull a dedicated 15A 120V circuit (or branch off loft general-lighting) to a capped outlet box at the planned ERV unit location (central ceiling area of loft). Leave capped/blank until ERV unit is purchased and installed (deferred 5+ years per 2026-05-15 — Loft ERV Pre-Rough Now, Install Later). — stage:: 3

Home Theater Infrastructure Rough-In

Install recessed floor box — 2-gang recessed floor box under planned couch position (Side 1: 120V duplex, Side 2: low-voltage plate). UL-rated, GFCI if required. See Floor Outlet. — stage:: 3
Rough-in 15A dedicated circuit — From loft subpanel to floor box for couch power and shaker amp. Same panel phase as equipment rack circuit. — stage:: 3
Run 1.25” ENT smurf tube — From equipment rack area to floor box (low-voltage side) for AV signal routing. Install pull string. Do NOT run 120V in same conduit. See Smurf Tube (ENT) — AV Signal Routing. — stage:: 3

Documentation & Coordination

Discuss with SLS Electric — Coordinate subpanel feeder with main service install; they may want to pull feeder wire at same time — stage:: 3
Photo document rough-in — Photograph all conduit runs and box locations before insulation covers them — stage:: 3
Confirm metering requirements — Check with Clare building department if separate meter required for future rental — stage:: 3

Feeder Specifications

Item	Specification	Notes
Feeder wire	4 AWG copper THWN or 2 AWG aluminum	4-wire: 2 hots + neutral + ground
Conduit	1¼” EMT or Schedule 40 PVC minimum	Allows easy wire pull
Subpanel	100A, 20-24 spaces	Siemens, Square D, or Eaton recommended
Breaker at main panel	100A 2-pole	Feeds the subpanel

Subpanel Grounding — Common DIY Mistake

In a subpanel (unlike the main panel):

Neutral and ground bars must be SEPARATE (not bonded together)

Ground bar bonds to panel enclosure

Neutral bar is isolated/floating

Requires 4-wire feeder (2 hots + neutral + ground)

This is the #1 mistake DIYers make with subpanels. If bonded incorrectly, neutral current can flow on ground wires creating shock and fire hazards.

Backup Power & Generator Integration

As-Built Configuration (2026-03-31)

Inlet: Reliance CS6375 50A 240V NEMA 14-50, exterior NW corner of garage Backup scope: Whole-property — generator backfeeds the garage subpanel, which feeds the house through the always-live garage-to-house feeder Safety mechanism: Procedural — operator must manually open the house 200A main breaker before connecting the generator. There is no mechanical interlock kit at either panel. Procedure: See Generator Operating Procedure for the step-by-step sequence (printable version available)

As-Built Topology

The installed configuration is a hybrid of the originally-considered options:

Inlet at garage (the location originally described as “Option B”)
Whole-property backup (the scope originally described as “Option A”), achieved because the garage feeder from the house is always live — backfeeding the garage panel pushes power back through that feeder into the house panel
No mechanical interlock kit was installed at either panel. Steve (SLS Electric) was specific that grid isolation depends on the operator opening the house main breaker before energizing the inlet

Why this matters for operation: The interlock is only as good as the procedure. Skipping the “open house main first” step would backfeed the utility grid — a life-safety hazard to lineworkers. The procedure document must be available at both the house main panel and the generator location.

System Components (As-Installed)

Generator Inlet:

Reliance CS6375 — 50A 240V NEMA 14-50 weatherproof inlet box
Location: Exterior NW corner of garage
4-wire connection (Hot A, Hot B, Neutral, Ground)
Installed: 2026-03-31 by SLS Electric (Steve)

Garage Panel Inlet Breaker:

Dedicated 2-pole 50A breaker in the garage 200A subpanel
Normal position: OFF (only switched ON when generator is connected and house main is open)
This is the breaker visible at the top of the garage panel, currently labeled for the generator inlet

House Main Breaker (Procedural Disconnect):

Standard 200A main breaker in the house service panel
Functions as the grid-isolation device during generator operation
Must be opened BEFORE the garage inlet breaker is closed

Natural Gas Integration:

Natural gas quick-connect port at garage (installed with gas service)
Allows tri-fuel generator unlimited runtime during extended outages
Generator stored at garage, runs on natural gas during outages

Generator (Owner-Supplied):

Portable tri-fuel inverter generator with NEMA 14-50R outlet
Outlet has a 120V/240V selector — must be set to 240V for this installation
Reason: backfeeding a split-phase residential panel requires both legs 180° out of phase; 120V mode bonds both legs to the same phase and would put 240V loads at 0V while overloading the neutral

Operating Procedure Summary

Full procedure with hazard callouts: Generator Operating Procedure

Sequence (high-level):

Open the house main breaker (200A) — this isolates the property from the grid
Verify the garage inlet breaker is OFF
Position generator outdoors with adequate ventilation, connect to natural gas (or fuel)
Connect the 50A cord from generator outlet to the garage inlet (CS6375)
Set generator voltage selector to 240V
Start the generator and let it stabilize
Close the garage inlet breaker to energize the panel
Reverse order when utility power is restored: open garage inlet breaker → stop generator → disconnect cord → close house main breaker

Future Upgrade Path: Permanent Standby Generator

Infrastructure supports future upgrade to a permanent standby unit (Generac, Kohler, etc.)
Upgrade would replace the procedural lockout with an Automatic Transfer Switch (ATS) at the house service entrance
50A circuit adequate for most residential standby generators
Natural gas connection already in place
Inlet conduit and panel space support permanent installation
Design goal: Avoid ripping out and redoing electrical work during upgrade

Design Notes

Procedural interlock requires disciplined operator behavior — the operating procedure document is part of the safety system, not optional reference material
Backfeed to utility is prevented only by the house main breaker being open; verify this every time before energizing the inlet
Generator must be set to 240V, never 120V — see voltage rationale above
See Backup Generator Plan for generator specifications and tri-fuel runtime planning

Interior Lighting (Main Garage Floor)

Comprehensive Plan: See Interior Lighting Plan for complete specifications, product recommendations, and shopping list.

Overview

Total Fixtures: 18× 4ft LED shop lights (5000K, 4000-5500 lumens each)
Total Illumination: 72,000-99,000 lumens (75-100 lumens/sq ft)
Mounting: 9 flush-mount (vehicle bays) + 9 suspension-mount (workbench/lift area)
Technology: Linkable LED fixtures to minimize electrical runs

Circuit Assignment

Circuit 1: Vehicle Bay Lighting (1× 20A dedicated)

9 fixtures in 3 linkable groups (3 ceiling outlets)
Flush-mounted in rows between parking bays
Load: 360W (3A @ 120V)
Dedicated 20A circuit — not shared with the ceiling/door run (split 2026-04-23; see 2026-04-23 — Vehicle Bay Lighting Split to Dedicated Circuit)

Circuit 2: Workbench Task Lighting (1× 20A)

6 fixtures in 2 linkable groups (2 outlets)
Suspension-mounted 36-48” above work surfaces
Load: 240W (2A @ 120V)
Shares workbench circuit with outlets

Circuit 3: Lift Bay Support Lighting

3 fixtures (2 flush overhead + 1 suspension near columns)
Load: 120W (1A @ 120V)
Shares lift-bay support 20A circuit

Total Lighting Load: 720W (6A @ 120V) distributed across 3 circuits

Smart Controls Integration

Vehicle Bays: Motion sensor + Shelly relay (auto-off energy savings)
Workbench: Manual control via Shelly relay (work mode, no auto-off)
Lift Bay: Manual or lift-activation tied control
Home Assistant Scenes: “All On”, “Work Mode”, “Bay Mode”, “Away”

Outlet Requirements

3× ceiling outlets for vehicle bay flush-mount groups
2× workbench-height outlets for suspension-mount groups
1× lift area outlet for task lighting
All outlets on appropriate circuits per zone

Coordination Notes

Coordinate fixture placement with compressed air line routing
Maintain clearance from mini-split indoor units
Ensure overhead lights clear 2-post lift when raised
Locate ceiling joists before installation (see compressed air actions)

Product Recommendation

Barrina LED Shop Lights (20-pack, $199.99)

4ft, 40W, 5500 lumens, 5000K daylight
Linkable up to 6 units, dual-mount capability
See Shopping List for full product options

Installation Reference

See Interior Lighting Layout Diagram for detailed fixture placement, spacing, and mounting specifications.

Exterior Lighting (Soffit)

Recessed LED soffit lights above garage and entry doors; use IC/wet-rated fixtures.
Provide neutral in switch box; plan Shelly 1/Plus 1 smart relay integration.
Motion sensing via hardwired PIR(s) to Shelly SW input (parallel) or wireless sensors via Home Assistant.
Consider splitting soffit lighting into 1–2 circuits for flexibility and load.
Coordinate junctions, drip loops, and sealant for weatherproofing.

Front Motion Sensor (added to existing soffit circuit)

Decided 2026-05-02 — see 2026-05-02 — Front Motion Sensor Architecture and the full design at Front Motion Sensor.

No new circuit. RAB STL360 PIR mounts at center of front soffit; L/N tap from existing soffit circuit at the soffit junction box.
Pre-drywall rough-in (stage 3): pull 22/4 shielded alarm cable from front-soffit-center junction box back to the LV cabinet via smurf tube. PIR’s load-out signals the LV cabinet’s Shelly Plus i4 input; HA orchestrates the existing Shelly 1PM Mini Gen 4 relay.
PIR does not wire to the existing entry-door Shelly’s SW input. That Shelly is in toggle mode with HA controlling the relay independently of switch position; parallel-wiring a PIR there has hidden failure modes. Centralized I/O via the LV cabinet is the clean architecture.

Rear & Side Security Lighting (separate from soffit)

Decided 2026-05-02 — see 2026-05-02 — Rear & Side Security Lighting and the full design at Rear & Side Security Lighting.

One additional 15A 120V circuit feeds the LV control cabinet (see below); the cabinet then distributes to 4× wall packs and powers the sensors. Connected load is <70W (4× 13W wall packs + Shelly Pro 4PM + HDR-15-12 + 2× BXS-AM + 1× Shelly Plus i4 for front PIR); the dedicated breaker is for fault isolation, not amp capacity.
Low-voltage control cabinet (NEMA 1, ~24-module, hinged) mounted adjacent to the main 200A panel (or at the smurf-tube convergence point). Houses Shelly Pro 4PM, Mean Well HDR-15-12 (12V DIN PSU), Class 2 fuse block, and 12V terminal blocks. Sized for future 12V/control device expansion (front motion controller, 24V PSU, ESPHome boards, energy monitoring). NEC 725.136(D)-compliant mixed-voltage construction: separate gland plates, slotted wireway duct, ≥0.25” separation between Class 1 and Class 2 conductors.
This cabinet is intentionally NOT inside the main 200A panel — the residential load center is listed as a branch-circuit distribution panel and adding control equipment violates its UL listing.
Pre-drywall rough-in (stage 3):
- Backing board (¾” plywood) at LV cabinet location.
- Short 14/2 home run from main panel to LV cabinet via EMT/ENT.
- From LV cabinet, 14/2 MC branches via smurf tubes to each of 4 wall pack locations (above each rear/side window).
- 22/4 shielded alarm cable from LV cabinet via smurf tubes to each of 2 BXS-AM center-mount positions (one per wall).
This circuit is separate from the front soffit circuit — different architecture (curtain PIR + full-cutoff fixtures), different control device, different HA zoning model.

Switch Topology & Smart Relay Placement

Decided 2026-04-20 — see 2026-04-20 — Interior Lighting Switch Topology. Stairwell circuit decided 2026-06-07 — the stair light shares the vehicle-bay lighting branch (garage main panel), not the future loft subpanel; see Decisions Log 2026-06-07 and the Circuit column below.

Design principle: 3-way only on walk-through paths

Physical 3-way switching is reserved for locations where you actively walk between switches (entry → stairwell, top → bottom of stairs). Task lighting (workbench, lift bay) uses single-pole switches at the point of use — you’re at the station when you need those lights, so a remote switch adds wiring complexity with little ergonomic benefit. Whole-floor “all on/off” is handled via Home Assistant scenes through the Shelly relays, not via physical gang boxes at the entry.

Per-zone switch + relay plan

Zone	Load	Switch	Circuit (panel)	Shelly Model	Shelly Location
Vehicle bay lights (walk-through)	360W / 3A	3-way: entry door + stairwell bottom	Dedicated bay-lighting 20A (garage main)	Shelly 1PM Mini Gen 4	First switch box (entry side) or fixture box
Workbench lights	240W / 2A	Single-pole at workbench	Workbench 20A (garage main)	Shelly 1PM Mini Gen 4	Behind the switch
Lift bay lights	120W / 1A	Single-pole near lift controls	Lift-bay support 20A (garage main)	Shelly 1PM Mini Gen 4	Behind the switch
Stairwell light	<120W / <1A	3-way: top + bottom of stairs	Shares bay-lighting 20A (garage main) — decided 2026-06-07; not the loft subpanel	Shelly 1PM Mini Gen 4	Fixture box (load side)
Loft main lighting	TBD	Single-pole at top of stairs	Loft subpanel (future)	Shelly 1PM Mini Gen 4	Behind the switch
Exterior soffit	<120W / <1A	✅ Single-pole at entry (installed by SLS 2026-04-17)	Soffit (garage main, SLS)	✅ Shelly 1PM Mini Gen 4 (installed 2026-04-22)	Behind the existing switch

Model default (decided on install 2026-04-22): All garage lighting Shellys will be 1PM Mini Gen 4 wherever load allows — replacing the Plus 1 / Plus 1PM rows in the table above. Rationale:

Fits any box. The Mini Gen 4 is the shortest front-to-back module in the Shelly lineup; fits behind a toggle in a standard-depth box and trivially in any fixture/load box.
Power monitoring on every circuit. Every zone gets per-circuit kWh data for essentially no cost delta vs. the non-PM Plus 1.
Load headroom is ample. The Mini Gen 4’s 8A max clears every planned lighting zone with 2.5× or better margin — largest zone is the vehicle bays at 3A. The only scenario where a larger relay would be needed is if a zone is ever consolidated or repurposed for a non-lighting load above 8A, which is not in the current plan.

Reserve the larger Plus-line relays for any future circuit that does exceed 8A (a consolidated “all lighting” trunk, a large resistive heater, etc.). See the install photo at First Shelly Install - 2026-04-22.

Why hardwired 3-way for the stairwell

Stair lighting must work without Wi-Fi or Home Assistant — descending dark stairs is a life-safety hazard, not an inconvenience. Traditional 3-way wiring with a Shelly at the fixture gives you always-works physical control plus smart integration (remote shutoff from the office, automations, per-circuit power monitoring via the 1PM Mini Gen 4).

Stairwell light circuit — shares the bay-lighting branch (decided 2026-06-07)

The stair light is powered from the garage main panel on the dedicated 20A vehicle-bay lighting branch — not the future loft subpanel. Full rationale in Decisions Log 2026-06-07; the short version:

Egress lighting must not depend on the power of the space being evacuated. Feeding the stair from the garage main (a different source than the loft subpanel) keeps it lit if the loft loses power — the circuit-level extension of the hardwired-3-way principle above.
Effectively a garage light (stairs open to the floor, no door until the top), trivial load (<1A), and simplest at the box — the 12/2 home run already at the stairwell-bottom 2-gang feeds both 3-ways from one source.
Per-circuit monitoring is preserved — the stair’s own Shelly at its load meters the stair independent of the bay-light Shelly.

Future-apartment future-proofing — smurf tube + 12/3 to the landing

If the loft is ever converted to an apartment with its own exterior door + steps to the current landing, the tenant-facing stair-light switch will need to move into that new entry space. During pre-drywall, run ¾” smurf tube (ENT) from the stairwell-bottom 2-gang up to the landing and pull a 12/3 through it (leave a pull string + generous service loops; terminate both ends in accessible blank-covered boxes per NEC 314.29).

Why conduit + 12/3 rather than just burying a cable now:

Conduit stays re-pullable. The apartment isn’t laid out yet, so the switch’s exact location/config is a guess — conduit lets you pull something different later without opening finished walls. A cable buried in the wall only solves the one guess.

12/3, not the 12/2 spool. A relocated switch most likely wants 12/3 — to support a 3-way (extra traveler) and/or a smart switch, which needs a neutral at the box per NEC 404.2(C). Pre-running 12/2 risks sealing the wrong cable in the wall.

No box savings to “just running cable.” A de-energized cable can’t dead-end in a wall (NEC 314.29) — it needs the same accessible covered boxes at both ends either way.

Per NEC 210.25(B), a shared/landlord stair stays on a house (garage main) circuit — exactly where this sits — so only the switch location moves at conversion, not the circuit source. Tracked in To-Do.

3-way wiring pattern with Shelly

PANEL ─┬───(12/2)──▶ [Switch Box A] ──(12/3 traveler)──▶ [Switch Box B] ──(12/2)──▶ [Load Box + Shelly 1PM Mini Gen 4] ─▶ Fixture
       │                  │                                      │                              │
       └─ hot              └─ 3-way toggle                         └─ 3-way toggle                 └─ Shelly switches the load
                              (SPDT)                                   (SPDT)                         SW input tied to common
                                                                                                      so toggle state = smart state

The two toggle switches route the “hot” path as a conventional 3-way; the Shelly interrupts the load leg at the fixture and mirrors toggle state via its SW input. If Wi-Fi goes down, the switches still work normally. See the wiring reference image in [[Email Imports/2026-04-20 - Shelly - Wiring Reference Screenshot.png|Shelly behind-switch wiring reference]].

Installation requirements

12/3 NM-B between 3-way switch boxes (two 3-way circuits: vehicle bays + stairwell) — 12 AWG required because the shared lighting circuits are 20A
12/2 NM-B from panel to first switch box, and from second switch box to load (already covered by the 1,000’ 12/2 spool)
Standard-depth boxes are fine at switch locations — the 1PM Mini Gen 4 is the shortest Shelly module and tucks behind a toggle without a deep box. Oversize only if you’re also cramming multiple cables + wire nuts into the same gang.
Neutral required in every switch box — Shelly relays need a neutral reference even when mounted at the load
Toggle switches: Standard residential 20A 3-way toggle (Leviton CS320-2W or equivalent), $4-6 each

Amp load verification

All circuits sit well under the Shelly 1PM Mini Gen 4’s 8A rating:

Largest 3-way circuit: 3A (vehicle bays) — 2.6× Shelly headroom
Stairwell: <1A — essentially no load concern
All zones combined under Home Assistant “All On”: 6A — still fits a single 20A circuit if ever consolidated

Wire & Box Labeling Convention

Adopt before installing the first box

Pick one convention and apply it consistently from box #1. Retrofitting labels onto already-installed wiring is the most common cause of “what is this wire?” mysteries — second only to no labels at all. Spend 30 minutes setting the standard now and the entire rough-in is documented as it’s built.

Tooling

Two label-making tools are on hand; each has a clear role:

Tool	Media	Best Use
Brother P-touch PT-D210 (multi-line)	TZe-FX231 (½” / 12mm Flexible ID, black on white, laminated)	Wire and cable labels inside boxes. Flexible-ID tape is the correct media for round NM-B: a specially formulated adhesive sticks to itself when wrapped, and the lamination resists abrasion, moisture, and UV. Water-resistant and rated for wire wrapping/flagging. Plain flat labels lift off PVC sheathing within a few years. (TZe-FX221 ⅜”/9mm available if a narrower label is wanted on smaller cable.)
Brother P-touch PT-D210	Standard laminated TZe-231 (½”, came with the bundle)	Flat, durable labels — box exterior / coverplate IDs, faceplates, parts bins. Laminated so it survives, but not for wrapping round cable (use TZe-FX for that). Overlaps with the DYMO’s flat-surface role; use whichever is loaded.
DYMO LabelWriter 450	LW Multipurpose (30336) and Address (30252)	Flat-surface labels only: panel directory cards, breaker face labels, box exterior labels on framing/drywall, faceplate labels, Shelly relay cover labels, drawer/parts-bin labels. Do not apply DYMO paper labels directly to wire jackets — paper adhesive does not bond reliably to PVC and will not survive 20 years.

Why not self-laminating (TZe-SL) tape?

An earlier draft of this convention specified TZe-SL self-laminating cassettes (the clear wrap-over-printed-text design). That tape is not compatible with the PT-D210 — the TZe-SL line is industrial-printer media (P-touch EDGE 500/700/900 and Desktop 800/900 series) and its smallest width is 24mm, wider than the PT-D210 can feed. For a consumer PT-D210, TZe-FX flexible ID tape is the correct wire-wrap media and is what’s specified above.

Media status:

✅ Colored vinyl electrical tape — already on hand. Owner purchased a 9-pack: red, orange, black, white, brown, yellow, blue, grey, green. This palette covers every banding role in the convention below with several colors held in reserve for future expansion. Same rolls were originally bought for extension-cord length/owner coding — the wire-banding convention here takes precedence; extension-cord coding can use any subset of the colors that don’t conflict (e.g., grey/black/brown are all unused for cord-length coding in typical conventions).
✅ Brother P-touch PT-D210 — purchased 2026-06-05. Bundle included one ½” (12mm) laminated TZe sample plus three ½” laminated TZe cassettes (standard black-on-white). The PT-D210 feeds TZe tape up to ½” (12mm) — confirmed compatible.
⏳ TZe-FX231 flexible ID tape — pending order. This is the wire-wrap tape for in-box cable labels (½” / 12mm, black on white). The bundle’s standard laminated tape works for flat coverplate/box labels but is not flexible enough to wrap round NM-B reliably long-term. Order 1–2 TZe-FX231 cassettes before the labeling pass. (Originally specced as TZe-SL self-laminating — corrected 2026-06-05; SL tape is industrial-printer-only and not PT-D210 compatible.)

What every cable label must show

Every NM-B cable entering or leaving a box gets a self-laminated label with three pieces of information:

Circuit number — matches the panel directory exactly (e.g., CKT 22)
Direction — IN (from upstream) or OUT (to downstream)
Source or destination — upstream box ID, downstream device, or function (e.g., from PANEL, to B-15, to BAY-1 LIGHTS)

Multi-line label format (P-touch):

CKT 22
IN from B-14

CKT 22
OUT to BAY-3 LIGHTS

CKT 14/16 MWBC
IN from PANEL

Place the label on the cable sheath 1–2” from where it enters the box — visible after wire-nutting and devicing, not buried under the bundle.

Conductor color-coding within the box

NEC mandates white for the grounded (neutral) conductor and green/bare for the equipment ground. For everything else, adopt this convention and apply it across the whole garage so any box opened in the future tells the same story:

Conductor function	Phase tape band	Notes
Constant hot (line, Leg A)	None — bare black conductor	Standard 120V hot from panel; the bare black wire is itself the identifier
Switched hot (load)	Red band, ~1” from device end	Distinguishes the switch leg from the constant hot
Traveler (3-way)	Blue band, both ends	Both travelers banded — color identifies the pair
Shared neutral (MWBC)	Yellow band, both ends	Plus written `MWBC` label on the cable jacket
UPS-protected hot	Orange band	Mirrors the orange-outlet convention in Critical Circuit UPS Strategy
Leg B / Phase B (240V circuits)	Brown band, both ends	Identifies the L2 conductor on 240V multi-pole circuits and the subpanel feeder — helps when balancing loads across legs
Re-identified white wire used as hot	Black band on the white conductor, both ends	NEC 200.7(C) requires re-identification when white is used as an ungrounded conductor (typical in 12/2 switch loops)
Low-voltage / Class 2 cable jacket	Grey band on the cable sheath	Distinguishes Cat6, alarm, sensor, and ESPHome wiring from line-voltage NM-B at a glance — useful in mixed-voltage runs and at the LV control cabinet
Equipment ground	None — bare copper or green insulation as supplied	Green tape reserved for re-identifying a conductor as ground in rare retrofit scenarios; bare copper is standard
White	Not used for banding	No useful function — invisible on white neutrals, ambiguous on colored hots

Apply bands by wrapping ½” colored vinyl tape twice around the conductor. Bands must be visible without disturbing the wirenut.

MWBC handling (NEC 200.4 + 210.4)

Multi-wire branch circuits get special treatment because they have hidden failure modes (a lost shared neutral puts 240V across 120V loads):

Both hots must be on a handle-tied 2-pole breaker or a true 2-pole breaker — required by NEC 210.4(B) for any MWBC supplying receptacles, switches, or fixtures sharing a single yoke
Shared neutral must be grouped with its hots at the panel — wire-tie the neutral to its two hots inside the panel cabinet (NEC 200.4(B))
Cable label reads CKT 14/16 MWBC (both circuit numbers, in the order red leg / black leg matches the panel)
Shared neutral conductor: yellow band at both ends, inside every box and at the panel

Box and location numbering

Every electrical box gets a permanent ID so the panel directory and as-built can reference it precisely:

Format: B-NN (sequential, no zero-padding) — e.g., B-1, B-2, B-37
Marked twice: Sharpie on the framing stud next to the box during rough-in (drywall covers it later but it survives until then), and a DYMO label on the inside of the cover plate after finishing
Recorded in the circuit schedule alongside the room/wall location (e.g., B-14: N wall workbench, 48" AFF, CKT 22)

This lets the panel directory say CKT 22: B-14 → B-15 → B-16 (N wall workbench outlets) rather than vague descriptions like “north wall outlets.”

Special-purpose labels

Beyond the standard cable label, these scenarios need extra identification:

Scenario	Label content	Where applied
Dedicated 240V circuit	`30A 240V — LIFT` or `50A 240V — WELDER`	Cable + disconnect/receptacle face
Critical-load (UPS) circuit	`UPS — orange outlets only`	Cable + faceplate (DYMO)
MWBC	`CKT 14/16 MWBC — handle-tied`	Cable (P-touch) + breaker face (DYMO)
3-way traveler run	`3-WAY: B-22 ↔ B-23`	Both cables in the run
Shelly relay SW input (separate switch loop)	`SHELLY SW INPUT`	On the small-gauge wire
Outdoor / wet location	`WET`	At box entry — flags need for WP boxes, gaskets, in-use covers
Smurf tube / ENT future pull	`LV — empty — 2026` or `LV — 1× Cat6`	Tape label on both ends of the tube

Panel-side documentation

The panel directory is where wire labels prove their value. Print a directory card on the DYMO with one row per breaker:

1    20A    CKT 1    Perimeter outlets — N wall (B-1 → B-7)
3    20A    CKT 3    Perimeter outlets — E wall (B-8 → B-13)
5    30A    CKT 5    2-post lift (240V) — B-30 mech room disconnect
...

Update the directory the same day any new circuit is energized. A panel with stale or vague labels is functionally an unlabeled panel.

Photo documentation step (before drywall)

Open every box, fan out the labeled cables so all labels are readable
Photograph with the Pixel — frame the box ID on framing (B-14) and all cable labels in the same shot
File to pictures/YYYY-MM/ per the standard naming scheme; create the paired .md description noting box ID and circuit(s)
After drywall and finishing, re-photograph each box with cover plate labels visible — these become the “what’s behind this plate” reference decades from now

Per-box checklist during rough-in

Box marked B-NN on adjacent framing in Sharpie — stage:: 3
Every entering cable wears a P-touch self-laminated label (circuit #, IN/OUT, source/destination) — stage:: 6
Switched hots, travelers, MWBC neutrals, and UPS hots banded with the correct color tape — stage:: 6
Cable label oriented so it’s readable after wire-nutting — stage:: 6
Photo taken before wire-nutting and before drywall — stage:: 6
Box ID and circuit assignment recorded in the circuit schedule — stage:: 6

Procurement & setup tasks

~~Purchase colored vinyl electrical tape (9-pack: red/orange/black/white/brown/yellow/blue/grey/green)~~ — already on hand
~~Purchase a P-touch label maker~~ — Brother P-touch PT-D210 purchased 2026-06-05 (feeds ½” TZe tape; came with 4× standard laminated ½” cassettes)
~~Confirm the purchased P-touch model accepts the planned tape~~ — PT-D210 takes TZe up to ½”; wire-wrap tape corrected to TZe-FX231 (TZe-SL self-laminating is industrial-only, not PT-D210 compatible)
Order 1–2× TZe-FX231 (½” Flexible ID) cassettes for in-box cable labels — order:: Electrical Materials Order — stage:: 5
~~Print a “labeling cheat sheet” and post it in the mechanical room~~ — see Electrical Labeling Cheat Sheet (print the HTML in printable/ and post; color codes + label format + box numbering)
Start the circuit schedule spreadsheet (or markdown table) keyed by box ID before first box is wired — stage:: 3

Actions

Priority: Subpanel Rough-In (Before Insulation)

Determine loft subpanel location — Plan based on potential apartment layout — stage:: 3
Run subpanel feeder conduit — 1¼” conduit from main panel to loft before walls close — stage:: 3
Install subpanel backing board — ¾” plywood at subpanel location — stage:: 3
Rough-in loft electrical boxes — Outlets and lighting locations while walls open — stage:: 3
Coordinate with SLS Electric — Discuss subpanel during main service install — stage:: 3

Main Floor Electrical

Draft circuit schedule with estimated loads. — order:: Electrical Materials Order — stage:: 3
Lay out receptacle heights and locations (workbench, tools, doors). — order:: Electrical Materials Order — stage:: 3
Coordinate conduit path between house and garage for low-voltage. — stage:: 2
Add soffit lighting circuit(s), neutral in switch, and optional sensor conduit to plan. — order:: Exterior Lighting Order — stage:: 5
Add fume extraction blower circuit (20A 120V) to circuit schedule — loft ceiling location. — stage:: 3
~~Determine paint booth exhaust circuit requirements~~ — Decided 2026-04-30: portable window-mounted fan, no dedicated circuit. See 2026-04-30 — Paint Booth Exhaust Portable Window-Mounted Not Fixed.

References

Chat summary: Chat Reference
Interior lighting: Interior Lighting Plan; Interior Lighting Layout Diagram
Soffit lighting: Lighting; Garage_Soffit_Lighting_Summary
Fume extraction: Fume Extraction Strategy
Home theater: Home Theater Plan; Home_Theater_Seating_Bass_Shaker_Plan

Procurement

Shopping list (120V): Electrical Shopping List — 120V Install
Shopping list (240V): Electrical Shopping List — 240V Install
Order: Electrical Materials Order
Index: Orders Index

Garage Construction Project

Explorer

Electrical Planning

Main Electrical Service

Existing House Panel Documentation

Scope of Work — Contractor vs. DIY

Conduit Routing Decision — Kneewall vs. Up-to-Rafters

Circuit Labeling Plan

Exterior Penetration Sealing (Owner Follow-Up)

Outlets & Wiring

NM Cable Support & Securing (NEC 334.30)

Outlet Protection Strategy

Main Floor Outlet & Circuit Layout

120V general-purpose circuits

Minor conveniences (added 2026-06-07)

240V / dedicated loads

Ventilation / Fume Extraction Circuits

Dedicated Loads & Future-Proofing

Panel Schedule / Circuit Directory

120V branch circuits (1 pole each)

240V / dedicated loads (2 poles each)

240V Wire & Cable Reference

Pole-count tally (capacity check)

Second Floor Apartment Subpanel ✅ CONFIRMED

Confirmed Electrical Plan

Electrical Topology

Subpanel Sizing

Circuit Protection Requirements (Dwelling Unit)

Panel Location Requirements

Feeder Routing

Construction-Phase Early Circuits (Pull-Forward)

Metering & Energy Monitoring

Tier 1: Whole-Subpanel Monitoring (Day One)

Tier 2: Per-Circuit Breakdown (Optional Upgrade)

Tier 3: Revenue-Grade Sub-Billing (Apartment Conversion)

Tenant Billing Approach Comparison

Recommended Strategy

Rough-In Checklist ⚠️ DO BEFORE INSULATION/DRYWALL

Subpanel Feeder Rough-In

Apartment Energy Monitoring Rough-In

Loft Circuit Rough-In

Home Theater Infrastructure Rough-In

Documentation & Coordination

Feeder Specifications

Backup Power & Generator Integration

As-Built Topology

System Components (As-Installed)

Operating Procedure Summary

Future Upgrade Path: Permanent Standby Generator

Design Notes

Interior Lighting (Main Garage Floor)

Overview

Circuit Assignment

Smart Controls Integration

Outlet Requirements

Coordination Notes

Product Recommendation

Installation Reference

Exterior Lighting (Soffit)

Front Motion Sensor (added to existing soffit circuit)

Rear & Side Security Lighting (separate from soffit)

Switch Topology & Smart Relay Placement

Design principle: 3-way only on walk-through paths

Per-zone switch + relay plan

Why hardwired 3-way for the stairwell

Stairwell light circuit — shares the bay-lighting branch (decided 2026-06-07)

3-way wiring pattern with Shelly

Installation requirements

Amp load verification

Wire & Box Labeling Convention

Tooling

What every cable label must show

Conductor color-coding within the box

MWBC handling (NEC 200.4 + 210.4)

Box and location numbering

Special-purpose labels

Panel-side documentation

Photo documentation step (before drywall)

Per-box checklist during rough-in

Procurement & setup tasks