Wire Size Chart Canada: CEC Table 2 & Table 4

Wire Size in Canada: CEC Table 2 & Table 4 Chart

Copper and aluminum ampacities from CEC Tables 2 and 4 (CSA C22.1:24), 14 AWG to 4/0, with the Rule 8-102 voltage drop check that often decides the final size.

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.

CEC Table 2 (copper) and Table 4 (aluminum)

Allowable ampacity in amperes, not more than three conductors in a raceway or cable, 30 °C ambient.

Size	Cu 60 °C	Cu 75 °C	Cu 90 °C	Al 75 °C
14 AWG	15	20	25	—
12 AWG	20	25	30	20
10 AWG	30	35	40	30
8 AWG	40	50	55	40
6 AWG	55	65	75	50
4 AWG	70	85	95	65
3 AWG	85	100	115	75
2 AWG	95	115	130	90
1 AWG	110	130	145	100
1/0	125	150	170	120
2/0	145	175	195	135
3/0	165	200	225	155
4/0	195	230	260	180

Pick the column that matches the lowest temperature rating among the conductor insulation and the equipment terminations. The 90 °C column is mainly a starting point for correction factors. Values above 4/0 are in the full ampacity chart; aluminum sizes 300, 400, 500, 600, 750 and 1000 kcmil could not be confirmed against a public CEC source.

Table 2 vs. NEC 310.16

For the sizes above, the numbers are identical to NEC Table 310.16, so a US chart gives the same raw ampacity. What differs is the code around it: Canadian cable types (NMD90, TECK90, ACWU90), terminal temperature rules, overcurrent protection limits for small conductors, and provincial amendments. Check those in the CEC edition adopted in your province.

Free air: CEC Table 1

Single copper conductors in free air use Table 1, which allows more current. At 75 °C: 10 AWG is 50 A, 6 AWG is 95 A, 1/0 is 230 A and 4/0 is 360 A.

Then check voltage drop (Rule 8-102)

The CEC makes voltage drop mandatory: 3% in any feeder or branch circuit and 5% total from the supply side of the consumer's service to the point of use. Use the connected load, or 80% of the breaker rating if the load is unknown. A 30 A breaker with unknown load means calculating at 24 A. Run the numbers in the Canadian voltage drop calculator, which accepts metres.

Sources

VRI Electrical, Cable Ampacity Tables – CEC / CSA C22.1 (Tables 1, 2, 4)
SparkShift, CEC Table 2 Ampacity Chart (2024)
CSA Group, CEC Section 8 excerpt (Rule 8-102)

Frequently asked questions

What is CEC Table 2?

Table 2 of the Canadian Electrical Code, Part I (CSA C22.1) lists allowable ampacities for copper conductors, not more than three in a raceway or cable, at 30 °C ambient, in 60, 75 and 90 °C columns. Table 4 is the aluminum equivalent.

Is CEC Table 2 the same as NEC Table 310.16?

For 14 AWG to 4/0 copper and aluminum, the values in public summaries of CSA C22.1:24 Tables 2 and 4 match NEC Table 310.16. The surrounding rules (terminal temperatures, cable types, small-conductor protection, provincial amendments) are Canadian and can change the final answer.

What is CEC Table 1 for?

Table 1 covers single copper conductors in free air, which get higher ampacities than Table 2. For example, 6 AWG copper at 75 °C is 95 A in Table 1 versus 65 A in Table 2.

Does voltage drop change the wire size in Canada?

Often. CEC Rule 8-102 limits drop to 3% in a feeder or branch circuit and 5% total, calculated on the connected load or, if unknown, 80% of the overcurrent device rating. Long runs frequently need a larger conductor than Table 2 alone requires.