🔌 What Size Wire for a 30 Amp Breaker in Canada?
The short answer
Start with 10 AWG copper NMD90 for an ordinary 30 A circuit. A TT-30 RV receptacle is 120 V, while a typical dryer or water-heater circuit is 240 V; that voltage difference changes long-run sizing.
The verified 60°C column supports #8 aluminum at 35 A, so aluminum is included. Confirm the conductor type, terminals, and equipment listing in the Canadian Ampacity Check tool. Ampacity Check tool.
Distance changes the answer — and Rule 8-102 is mandatory
Minimum size at the full 30 A and at or under the mandatory 3% voltage-drop limit. Distance is one way; the calculator also rejects any size that fails ampacity.
30 A at 240 V — dryer or water heater
| Material | 15 m (50′) | 30 m (100′) | 46 m (150′) | 61 m (200′) | 76 m (250′) |
|---|---|---|---|---|---|
| Copper | 10 | 8 | 8 | 6 | 4 |
| Aluminum | 8 | 6 | 4 | 4 | 3 |
30 A at 120 V — RV TT-30
| Material | 15 m (50′) | 30 m (100′) | 46 m (150′) | 61 m (200′) | 76 m (250′) |
|---|---|---|---|---|---|
| Copper | 8 | 6 | 4 | 3 | 2 |
| Aluminum | 6 | 4 | 2 | 1 | 1/0 |
Common Canadian 30-amp jobs
Dryers, water heaters, RV park receptacles, baseboard heat, and some mini-split circuits commonly land near this rating. Use the equipment nameplate when it gives a different circuit requirement.
Worked example: 30 A RV receptacle at 30 m (100 ft)
At 120 V, our verified calculator selects #6 copper (26,240 circular mils): 2 × 12.9 × 30 × 100 ÷ 26,240 = 2.95 V, or 2.46%. The 240 V table is smaller because the same volts lost are half the percentage.
Related
30-amp wire size FAQ
- What size wire for a 30 amp RV plug in Canada?
- A TT-30 RV receptacle is 120 V. Start with 10 AWG copper NMD90 at ordinary distances, then use the 120 V table or calculator for the actual one-way run.
- Can 12 gauge wire handle 30 amps in Canada?
- No. CEC Rule 14-104 caps 12 AWG copper at a 20 A overcurrent device for ordinary circuits, so it does not pass a 30 A ampacity check.
- What size wire does a 30 amp dryer use in Canada?
- Start with 10 AWG copper NMD90 for an ordinary 30 A dryer circuit. Check the appliance instructions, termination rule, and distance before installation.