Is 6 AWG copper overkill for a 50 amp circuit?

No. It is the size you need when terminations are limited to 60 °C (55 A in Table 2), and it is also the usual upsize for voltage drop: at the Rule 8-102 default of 40 A on 240 V, 6 AWG copper reaches about 55 m before passing 3%, against about 35 m for 8 AWG.

What size wire for a 50 amp subpanel in Canada?

The same as any 50 A feeder: 8 AWG copper or 6 AWG aluminum with 75 °C terminations (6 Cu / 4 Al at 60 °C), a neutral if 120 V loads are supplied, and a bonding conductor of at least 10 AWG copper or 8 AWG aluminum from Table 16. Size up for distance using the tables on this page.

What load do I use for voltage drop on a 50 A circuit in Canada?

Rule 8-102 uses the connected load when it is known, otherwise 80% of the overcurrent device rating, which is 40 A for a 50 A breaker. The limits are 3% for a feeder or branch circuit and 5% total from the supply side of the consumer's service to the point of use.

What size bonding wire for a 50 amp circuit in Canada?

10 AWG copper or 8 AWG aluminum, from the CEC Table 16 row for overcurrent devices rated over 30 A up to 60 A (Rule 10-616). A 30 A circuit needs 12 AWG copper or 10 AWG aluminum.

How much can a 50 amp breaker carry continuously?

Under Rule 8-104, a continuous load on a breaker not marked for 100% continuous operation is limited to 80% of its rating, which is 40 A on a 50 A breaker (9.6 kW at 240 V). That is why a 40 A Level 2 EV charger is usually installed on a 50 A circuit.

What Size Wire for 50 Amps in Canada? CEC Chart, Distance in Metres

8 AWG copper or 6 AWG aluminum for a 50 A circuit or subpanel under the Canadian Electrical Code (Table 2 and Table 4, 75 °C column), or 6 AWG copper and 4 AWG aluminum where terminations are limited to 60 °C. Below: why 8 AWG copper sits right on the line at 50 A, wire size by distance in metres under Rule 8-102, max run lengths at 120/240, 208 and 600 V, the Table 16 bonding conductor and how much load a 50 A circuit carries.

CEC data notice: CEC values were checked against public summaries of CSA C22.1:24, not the code book itself. Conduit and conductor areas use NEC Chapter 9 data, and some aluminum kcmil ampacities are unverified. Confirm against the CEC edition and provincial amendments adopted where you work.

Quick answer: wire size for a 50 A breaker in Canada

Minimum conductor for 50 A, not more than three conductors in a raceway or cable, 30 °C ambient.

Conductor and termination rating	Minimum size	Ampacity
Copper, 75 °C (terminals marked 75 °C)	8 AWG	50 A (Table 2)
Copper, 60 °C (unmarked equipment rated 100 A or less)	6 AWG	55 A (Table 2)
Aluminum, 75 °C (terminals marked 75 °C)	6 AWG	50 A (Table 4)
Aluminum, 60 °C	4 AWG	55 A (Table 4)

Why 8 AWG copper is a borderline answer at 50 A

8 AWG copper is rated exactly 50 A in the 75 °C column of Table 2, with no margin, and 40 A in the 60 °C column. Rule 4-006 treats equipment rated 100 A or less that is not marked with a termination temperature as 60 °C, so if the breaker, the panel or the equipment at the far end (a range, EV charger, welder receptacle or hot tub disconnect) is unmarked, the minimum becomes 6 AWG copper. Any derating for more than three conductors (Table 5C) or a hot location (Table 5A) also pushes 8 AWG below 50 A, because there is no headroom left.

CEC Table 2 (copper) and Table 4 (aluminum), not more than three conductors, 30 °C ambient.
Size	Cu 60 °C	Cu 75 °C	Cu 90 °C	Al 60 °C	Al 75 °C	Al 90 °C
10 AWG	30 A	35 A	40 A	—	—	—
8 AWG	40 A	50 A	55 A	35 A	40 A	45 A
6 AWG	55 A	65 A	75 A	40 A	50 A	55 A
4 AWG	70 A	85 A	95 A	55 A	65 A	75 A

The 90 °C rating of T90 or TECK90 (55 A for 8 AWG copper) does not raise the circuit rating: the conductor is used at the termination column, at least for the first 1.2 m from the termination. The 90 °C value is the starting point for correction factors, covered on the CEC Table 2 chart.

Wire size for 50 amps by distance (metres, 240 V)

Smallest size that keeps a 120/240 V single-phase run at or under the Rule 8-102 3% limit. The 40 A columns use the Rule 8-102 default for an unknown load (80% of a 50 A breaker); the 50 A columns are for a known full load. The table starts at the 75 °C minimum (8 AWG copper, 6 AWG aluminum).

One-way run length. 3% drop (7.2 V) at 240 V, conductor resistance at 75 °C.
Run	Cu, 40 A	Cu, 50 A	Al, 40 A	Al, 50 A
10 m	8 AWG	8 AWG	6 AWG	6 AWG
15 m	8 AWG	8 AWG	6 AWG	6 AWG
20 m	8 AWG	8 AWG	6 AWG	6 AWG
25 m	8 AWG	8 AWG	6 AWG	6 AWG
30 m	8 AWG	6 AWG	6 AWG	4 AWG
40 m	6 AWG	6 AWG	4 AWG	4 AWG
50 m	6 AWG	4 AWG	4 AWG	3 AWG
60 m	4 AWG	4 AWG	3 AWG	2 AWG
75 m	4 AWG	3 AWG	2 AWG	1 AWG

If your terminations are limited to 60 °C, start at 6 AWG copper or 4 AWG aluminum instead:

60 °C terminations, 40 A load, 3% at 240 V.
Run	Copper	Aluminum
30 m	6 AWG	4 AWG
50 m	6 AWG	4 AWG
60 m	4 AWG	3 AWG
75 m	4 AWG	2 AWG
90 m	3 AWG	1 AWG
110 m	3 AWG	1/0 AWG

Example: a 50 A subpanel in a garage 25 m from the main panel, load not yet known. Rule 8-102 says to use 40 A. 8 AWG copper reaches 35 m at 40 A and 6 AWG copper reaches 55 m. In aluminum, 6 AWG reaches 33 m and 4 AWG reaches 53 m. The 5% total limit includes the service conductors and the branch circuits after the subpanel, so leave room for them.

Maximum length at 50 amps by wire size

The longest one-way run, in metres, before each size reaches the drop shown. Three-phase columns use the √3 formula and are resistance-only figures.

Copper

Size	240 V, 40 A, 3%	240 V, 50 A, 3%	240 V, 40 A, 5%	208 V 3-ph, 40 A, 3%	600 V 3-ph, 40 A, 3%
8 AWG	35	28	59	35	103
6 AWG	55	44	93	55	161
4 AWG	89	71	148	89	257
3 AWG	111	89	186	112	323
2 AWG	141	113	235	141	408
1 AWG	178	142	296	178	514
1/0 AWG	224	179	374	225	649

Aluminum

Size	240 V, 40 A, 3%	240 V, 50 A, 3%	240 V, 40 A, 5%	208 V 3-ph, 40 A, 3%	600 V 3-ph, 40 A, 3%
6 AWG	33	27	56	33	98
4 AWG	53	43	90	54	155
3 AWG	68	54	113	68	196
2 AWG	85	68	143	86	248
1 AWG	108	86	180	108	313
1/0 AWG	136	109	227	136	393
2/0 AWG	172	138	287	172	498

For your exact load and length, use the Canadian voltage drop calculator or the Canadian wire size calculator, which checks ampacity and Rule 8-102 together.

Bonding conductor for 50 amps

Bonding conductor (Table 16, Rule 10-616): 10 AWG copper or 8 AWG aluminum for an overcurrent device rated over 30 A up to 60 A, which covers 50 A.
Neighbouring rows: devices up to 30 A need 12 AWG copper or 10 AWG aluminum; devices up to 100 A need 8 AWG copper or 6 AWG aluminum.
Upsized conductors: if you upsize the circuit conductors for voltage drop, confirm with your inspector whether the bonding conductor must be increased under the edition adopted in your province.

How much load can a 50 amp circuit carry?

System	At 50 A	At 40 A (80%)
120 V single phase	6.0 kW	4.8 kW
240 V single phase (120/240 V)	12.0 kW	9.6 kW
208 V three phase (120/208 V)	18.0 kW	14.4 kW
600 V three phase (347/600 V)	52.0 kW	41.6 kW

Balanced load, unity power factor. Rule 8-104 limits a continuous load on a breaker not marked for 100% continuous operation to 80% of its rating, which is 40 A on a 50 A breaker. The amps to watts calculator handles power factor.

Common 50 A circuits in Canadian homes

Level 2 EV charger: a charger set to 40 A output is a continuous load, so it needs a 50 A circuit under the 80% limit. Many chargers can be set lower (32 A on a 40 A circuit) if the panel calculation is tight.
Electric range: ranges are commonly on a 40 A or 50 A circuit; follow the range nameplate and installation instructions for the breaker size, then size the wire from the table above.
Subpanel in a garage or shop: a 50 A feeder at 240 V gives 12 kW; size up for the run length using the distance tables.

CEC vs NEC for 50 amps

The raw ampacities in CEC Tables 2 and 4 match NEC Table 310.16 for these sizes, so the 75 °C answer (8 AWG copper, 6 AWG aluminum) is the same in both countries. The differences: voltage drop is mandatory in Canada under Rule 8-102 instead of an informational note, the code works in metres, bonding conductors come from Table 16 instead of NEC Table 250.122 (both give 10 AWG Cu / 8 AWG Al at 50 A), and provinces adopt different editions of the code. For the US version, with NM-B cable, 14-50 receptacle and range tables, see wire size for 50 amps (NEC). For larger Canadian circuits, see 60 amps and 100 amps.

Sources

VRI Electrical, Cable Ampacity Tables – CEC / CSA C22.1 (Tables 2 and 4)
CSA Group, CEC Section 8 excerpt (Rules 8-102, 8-104)
Electrical Industry News Week, Guide to the CE Code, Section 4 (Rule 4-006)
IAEI Magazine, Application of Rule 4-006
Hongbin Li, Bonding conductor size, CSA C22.1:24 Table 16
Conductor resistance: NEC Chapter 9 Table 8 values at 75 °C, converted to metres

What Size Wire for 50 Amps in Canada? (CEC)