Are Canadian wire ampacity tables the same as American ones?

Yes for the 60/75/90°C columns and every shared size shown in this tool. The current CEC Table 2 and Table 4 values are verified identical to NEC Table 310.16. That harmonization does not extend to the CEC's higher-temperature columns, free-air tables, or derating rules.

How many amps can 12 gauge wire handle in Canada?

20 amps on a 20 A breaker for ordinary circuits — CEC 14-104 caps #12 copper at a 20 A overcurrent device, the same as the US rule, even though the 75°C and 90°C columns list 25 and 30 A.

Is NMD90 limited to 60°C like American NM-B?

No blanket cap. NMD90 has 90°C insulation and follows the termination-temperature rule (CEC 4-006): use 60°C for equipment rated 100 A or less or marked for #1 AWG and smaller, and 75°C above that. The limit applies to the first 1.2 m from the termination; the 90°C column mainly serves as the derating starting point.

🔥 Canadian Wire Ampacity Chart — CEC Tables 2 & 4

Verified CEC Table 2 and Table 4 values, with the Canadian rules that control how the columns are used. 🇺🇸 US version

Canadian source: CSA C22.1:24 — Canadian Electrical Code, Part I, 26th edition (2024). The 60/75/90°C columns below are verified from CEC Table 2 and Table 4. Provincial adoption and amendments vary; confirm the edition adopted locally.

The chart

The grid below is CEC Table 2 copper and Table 4 aluminum data . Their 60/75/90°C columns are verified identical to NEC Table 310.16 across every shared size in this tool.

Size	Copper (CEC Table 2)			Aluminum (CEC Table 4)
Size	60°C	75°C	90°C	60°C	75°C	90°C
14 AWG	15	20	25	—	—	—
12 AWG	20	25	30	15	20	25
10 AWG	30	35	40	25	30	35
8 AWG	40	50	55	35	40	45
6 AWG	55	65	75	40	50	55
4 AWG	70	85	95	55	65	75
3 AWG	85	100	115	65	75	85
2 AWG	95	115	130	75	90	100
1 AWG	110	130	145	85	100	115
1/0	125	150	170	100	120	135
2/0	145	175	195	115	135	150
3/0	165	200	225	130	155	175
4/0	195	230	260	150	180	205

Source: CSA C22.1:24, 26th edition (2024). Rule 14-104 caps the overcurrent device at #14 copper → 15 A, #12 → 20 A, and #10 → 30 A regardless of the raw column. Interactive calculator: Ampacity Check.

Which column am I allowed to use? (the NMD90 story)

Same principle as everywhere: use the column of your weakest link (CEC Rule 4-006). Wire insulation may be rated 90°C — NMD90 and T90 both are. Marked equipment uses its marked termination temperature. For unmarked equipment, use 60°C when rated not more than 100 A or marked for #1 AWG and smaller, and 75°C above that. The rule applies to the first 1.2 m and permits a transition beyond it; VoltDrop's calculator conservatively applies the lower limit throughout as a simplified method. Here's the difference from the US that trips up cross-border readers: American Romex (NM-B) is hard-capped at the 60°C column by a blanket rule; Canadian NMD90 is not — it follows the termination rule like any other 90°C conductor. In everyday residential work the answers land in the same familiar places (#14 → 15 A, #12 → 20 A, #10 → 30 A), but the 90°C rating gives NMD90 a better starting point when derating for heat or bundling.

Does voltage change ampacity?

No. A #10 wire carries the same ~30 A at 12 V, 120 V, 240 V, or Canada's commercial 347/600 V. What voltage changes is the sting of voltage drop — 3 lost volts is 1.3% of a 240 V circuit but 25% of a 12 V one. And remember: in Canada the drop limit is mandatory (Rule 8-102).

What this chart doesn't cover

These are base values. Hot environments, countable conductors above three, termination ratings, small-conductor device caps, and continuous loads can lower the usable result. Use the Canadian ampacity calculator for CEC Table 5A, Table 5C, Rules 4-004, 4-006, 8-104, and 14-104.