Code reference library
NEC reference: 97 clause-cited answers
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Code fundamentals
- NEC Table 310.16 ampacity, explained
- The NEC 705.12 120% rule, actually explained
- What wire size for a 100 A sub panel?
- NEC 625: EV charger circuit sizing
- NEC 706: battery energy storage disconnects
- NEC 240.4(D): the small-conductor overcurrent caps
- Voltage drop and the NEC: what's required vs recommended
- NEC 220 standard-method dwelling load calc, worked
- Boat wiring ≠ house wiring: ABYC E-11 vs NEC
- Canadian (CEC) vs US (NEC) conductor sizing — what actually differs
- NEC 690.8: sizing PV circuits (the 125% × 125% chain)
Conductor ampacity
- 14 AWG copper wire ampacity (NEC 310.16)
- 12 AWG copper wire ampacity (NEC 310.16)
- 10 AWG copper wire ampacity (NEC 310.16)
- 8 AWG copper wire ampacity (NEC 310.16)
- 6 AWG copper wire ampacity (NEC 310.16)
- 4 AWG copper wire ampacity (NEC 310.16)
- 3 AWG copper wire ampacity (NEC 310.16)
- 2 AWG copper wire ampacity (NEC 310.16)
- 1 AWG copper wire ampacity (NEC 310.16)
- 1/0 AWG copper wire ampacity (NEC 310.16)
- 2/0 AWG copper wire ampacity (NEC 310.16)
- 3/0 AWG copper wire ampacity (NEC 310.16)
- 4/0 AWG copper wire ampacity (NEC 310.16)
- 6 AWG aluminum wire ampacity (NEC 310.16)
- 4 AWG aluminum wire ampacity (NEC 310.16)
- 2 AWG aluminum wire ampacity (NEC 310.16)
- 1 AWG aluminum wire ampacity (NEC 310.16)
- 1/0 AWG aluminum wire ampacity (NEC 310.16)
- 2/0 AWG aluminum wire ampacity (NEC 310.16)
- 3/0 AWG aluminum wire ampacity (NEC 310.16)
- 4/0 AWG aluminum wire ampacity (NEC 310.16)
Wire size by breaker
- What size wire for a 15 amp breaker?
- What size wire for a 20 amp breaker?
- What size wire for a 30 amp breaker?
- What size wire for a 40 amp breaker?
- What size wire for a 50 amp breaker?
- What size wire for a 60 amp breaker?
- What size wire for a 70 amp breaker?
- What size wire for a 80 amp breaker?
- What size wire for a 90 amp breaker?
- What size wire for a 100 amp breaker?
- What size wire for a 125 amp breaker?
- What size wire for a 150 amp breaker?
- What size wire for a 175 amp breaker?
- What size wire for a 200 amp breaker?
Solar interconnection (705.12)
- How much solar can you backfeed on a 100 A busbar with a 100 A main?
- How much solar can you backfeed on a 125 A busbar with a 100 A main?
- How much solar can you backfeed on a 150 A busbar with a 150 A main?
- How much solar can you backfeed on a 200 A busbar with a 200 A main?
- How much solar can you backfeed on a 200 A busbar with a 175 A main?
- How much solar can you backfeed on a 225 A busbar with a 200 A main?
- How much solar can you backfeed on a 400 A busbar with a 400 A main?
EV charging (625)
- What breaker for a 16 A EV charger? (NEC 625)
- What breaker for a 24 A EV charger? (NEC 625)
- What breaker for a 32 A EV charger? (NEC 625)
- What breaker for a 40 A EV charger? (NEC 625)
- What breaker for a 48 A EV charger? (NEC 625)
- What breaker for a 64 A EV charger? (NEC 625)
- What breaker for a 80 A EV charger? (NEC 625)
- Biggest EV charger on a 30 A circuit
- Biggest EV charger on a 40 A circuit
- Biggest EV charger on a 50 A circuit
- Biggest EV charger on a 60 A circuit
- Biggest EV charger on a 100 A circuit
Dwelling load calcs (220)
- What size electrical service for a 1000 ft² house? (NEC 220 worked)
- What size electrical service for a 1500 ft² house? (NEC 220 worked)
- What size electrical service for a 1800 ft² house? (NEC 220 worked)
- What size electrical service for a 2000 ft² house? (NEC 220 worked)
- What size electrical service for a 2400 ft² house? (NEC 220 worked)
- What size electrical service for a 2800 ft² house? (NEC 220 worked)
- What size electrical service for a 3200 ft² house? (NEC 220 worked)
- What size electrical service for a 3600 ft² house? (NEC 220 worked)
Wire size by distance
- Wire size for 20 amps at 100 feet (240 V)
- Wire size for 30 amps at 100 feet (240 V)
- Wire size for 30 amps at 150 feet (240 V)
- Wire size for 40 amps at 100 feet (240 V)
- Wire size for 50 amps at 50 feet (240 V)
- Wire size for 50 amps at 100 feet (240 V)
- Wire size for 50 amps at 150 feet (240 V)
- Wire size for 50 amps at 200 feet (240 V)
- Wire size for 60 amps at 100 feet (240 V)
- Wire size for 60 amps at 150 feet (240 V)
- Wire size for 100 amps at 100 feet (240 V)
- Wire size for 100 amps at 150 feet (240 V)
- Wire size for 100 amps at 200 feet (240 V)
- Wire size for 200 amps at 100 feet (240 V)
- Wire size for 15 amps at 50 feet (120 V)
- Wire size for 15 amps at 100 feet (120 V)
- Wire size for 20 amps at 50 feet (120 V)
- Wire size for 20 amps at 100 feet (120 V)
- Wire size for 20 amps at 150 feet (120 V)
- Wire size for 30 amps at 100 feet (120 V)
Energy storage (706)
Code text is paraphrased and cited — verify against your jurisdiction's adopted edition and a licensed professional before installation.