NEC TABLE 310.16
amps.title
amps.subtitle
| AWG | Copper (amps.subtitle) | Aluminium 75 °C | ||
|---|---|---|---|---|
| 60 °C | 75 °C | 90 °C | ||
| 14 | 15 | 20 | 25 | — |
| 12 | 20 | 25 | 30 | — |
| 10 | 30 | 35 | 40 | — |
| 8 | 40 | 50 | 55 | 40 |
| 6 | 55 | 65 | 75 | 50 |
| 4 | 70 | 85 | 95 | 65 |
| 3 | 85 | 100 | 115 | 75 |
| 2 | 95 | 115 | 130 | 90 |
| 1 | 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 |
電線径計算ツール
アンペア・電圧・距離を入力 — 許容電流と電圧降下の両方を満たす最小ゲージを算出。
推奨サイズ
—
—
- 負荷側電圧
- —
- 電圧降下
- —
- Ω (片道)
- —
- 代表アンペア (NEC)
- —
- 決定要因
- —
How many amps can 12 AWG wire handle?
NEC Table 310.16 rates 12 AWG copper at 25 A (60 °C), 30 A (75 °C), 35 A (90 °C). For overcurrent protection the NEC limits residential 12 AWG circuits to a 20-amp breaker.
How many amps can 14 AWG wire handle?
NEC rates 14 AWG copper at 15/20/25 A for the 60/75/90 °C columns; residential branch circuits are protected at 15 A.
What size wire for 30 amps?
10 AWG copper is the standard choice for a 30-amp circuit (rated 35 A at 75 °C and allowed at 30 A by NEC 240.4(D)).
What size wire for 50 amps?
8 AWG copper (50 A at 75 °C). For aluminium, 6 AWG is the equivalent choice.
What wire for 100-amp service?
A 100 A residential service typically uses 4 AWG copper or 2 AWG aluminium, subject to NEC Table 310.12(A) service sizing.
Does voltage drop depend on length?
Yes — voltage drop is proportional to length. A 12 AWG circuit that is fine at 30 ft may drop too much at 120 ft; use our wire size calculator to check both limits.