What type of wire do I need for a new circuit in my New Brunswick home?
What type of wire do I need for a new circuit in my New Brunswick home?
Choosing the Right Wire for New Circuits in Your New Brunswick Home
Selecting the correct wire type and gauge for a new electrical circuit isn't just about passing a TSANB inspection — it's about safety, performance, and longevity. New Brunswick follows the Canadian Electrical Code (CEC), which specifies exactly what wire types are approved for residential use and which gauge is required for each application.
Wire Types Approved for Residential Use in New Brunswick
NMD90 (Non-Metallic Dry 90°C) — This is the standard residential wiring in New Brunswick, commonly known by the brand name "Romex" (though Romex is technically a US product). NMD90 has two or three insulated copper conductors plus a bare ground wire, all wrapped in a plastic sheath. The "90" means the insulation is rated for 90°C, though the CEC limits its use to 60°C-rated ampacities in residential applications.
- Where to use: Interior walls, ceilings, floors — any dry indoor location
- Where NOT to use: Underground, outdoors, in conduit exposed to moisture, or embedded in concrete
- Cost: $0.80-$2.50 per foot depending on gauge
- Where to use: Underground runs to detached garages, outbuildings, landscape lighting; wet locations like crawl spaces
- Burial depth: Minimum 24 inches (600mm) for direct burial in New Brunswick
- Cost: $1.50-$4.00 per foot depending on gauge
- Where to use: Exposed runs in garages, workshops, basements where cable could be damaged; can be used indoors or outdoors
- Cost: $3.00-$8.00 per foot — significantly more expensive but very durable
- Where to use: Service entrances, long exposed runs, commercial applications, panel connections
- When to choose this: Required when running wire through conduit; gives flexibility to pull exact wire combinations needed
Wire Gauge Selection by Circuit Type
The CEC mandates minimum wire gauges based on the circuit's amperage rating. Using undersized wire is a fire hazard — the wire overheats before the breaker trips.
| Circuit Type | Breaker Size | Minimum Wire Gauge | Common Uses |
|-------------|-------------|-------------------|-------------|
| General lighting | 15A | 14 AWG NMD90 | Ceiling lights, bedroom outlets, hallway outlets |
| General receptacles | 15A | 14 AWG NMD90 | Living room, bedroom, hallway outlets |
| Kitchen countertop | 20A | 12 AWG NMD90 | Counter outlets (minimum 2 circuits required) |
| Bathroom | 20A | 12 AWG NMD90 | Bathroom outlets (dedicated circuit) |
| Laundry | 20A | 12 AWG NMD90 | Washing machine outlet |
| Dishwasher | 15A or 20A | 14 or 12 AWG NMD90 | Dedicated circuit |
| Garbage disposal | 15A | 14 AWG NMD90 | Dedicated or shared with dishwasher |
| Microwave | 20A | 12 AWG NMD90 | Dedicated circuit (if built-in) |
| Electric dryer | 30A | 10 AWG NMD90 | 240V dedicated circuit |
| Electric range/stove | 40-50A | 8 or 6 AWG NMD90 | 240V dedicated circuit |
| Central A/C or heat pump | 20-40A | 12-8 AWG | Depends on unit specs |
| EV charger (Level 2) | 40-50A | 8-6 AWG NMD90 | 240V dedicated circuit |
| Electric water heater | 30A | 10 AWG NMD90 | 240V dedicated circuit |
| Hot tub | 40-60A | 8-6 AWG | 240V GFCI protected |
| Workshop sub-panel | 60-100A | 6-3 AWG or 4-1/0 AL | Feeder to detached building |
Voltage Drop Considerations
For long cable runs — common in New Brunswick's larger rural properties — voltage drop becomes a real concern. The CEC allows a maximum 5% voltage drop from panel to outlet (3% on the branch circuit, 2% on the feeder is the recommended split).
Practical impact: On a 100-foot run at 120V and 15 amps, 14 AWG wire drops about 4.8V (4%) — borderline acceptable. At the same distance and load, 12 AWG drops only 3V (2.5%) — comfortably within limits.
Rule of thumb for New Brunswick homes:
- Runs under 50 feet: Use the standard minimum gauge for the circuit
- Runs 50-75 feet: Consider upsizing one gauge (14→12, 12→10)
- Runs over 75 feet: Upsize one gauge and calculate the actual voltage drop
- Runs to detached buildings (100+ feet): Always calculate and upsize accordingly
Copper vs. Aluminum
Copper is the standard for all branch circuit wiring in New Brunswick residential construction. It's more conductive, easier to terminate, and doesn't have the oxidation issues that plague aluminum.
Aluminum is still used and code-compliant for larger feeders (service entrance cables, sub-panel feeders) where the cost savings are significant. A 100-amp aluminum feeder to a detached garage costs roughly half as much as copper. However, aluminum requires:
- Anti-oxidant compound on all connections
- Connectors rated for aluminum (marked AL-CU or AL)
- Upsizing by roughly 2 gauges compared to copper (e.g., 1/0 aluminum = 3 AWG copper capacity)
Important: The problematic aluminum wiring found in 1960s-1970s New Brunswick homes was branch circuit aluminum (14 and 12 AWG) used for outlets and lights. These smaller aluminum wires and their connections caused fires. Modern aluminum feeder cables (4 AWG and larger) with proper terminations are safe and widely used.
Where to Buy in New Brunswick
Electrical wire is available at:
- Kent Building Supplies — Good selection of NMD90 in all common gauges. Locations across NB.
- Home Hardware — Carries standard residential wire. Good for common gauges.
- Home Depot (Moncton, Saint John, Fredericton) — Wide selection, competitive pricing on bulk spools
- Electrical wholesalers (Rexel, Nedco, Guillevin) — Better pricing on large quantities, full range of specialty wire. Some sell to homeowners with a permit; others are trade-only.
Pricing guidance (2025, approximate):
- 14/2 NMD90 (75m spool): $70-$90
- 12/2 NMD90 (75m spool): $100-$130
- 10/3 NMD90 (30m): $120-$160
- 8/3 NMD90 (15m): $100-$140
- 6/3 NMD90 (30m): $250-$350
Prices have fluctuated significantly with copper commodity pricing — check current prices before budgeting.
Permit Requirements
Any new circuit installation in New Brunswick requires a TSANB electrical permit ($50-$100). This applies whether you're hiring a licensed electrician or doing permitted homeowner work on your own residence. The TSANB inspector will verify proper wire type, gauge, protection, routing, and connections before approving the installation.
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