100 AMP COPPER WIRE SIZE CODE

Typically, a 1″ conduit can fit three #3 THHN wires for a 100A 240V circuit. Running #3 AWG THHN wires through conduit needs to consider conduit fill requirements. A larger size helps compensate for heat buildup in the buried cable. For aluminum, increase to #1/0 AWG underground. For copper wire, the recommended size is #3 AWG based on the 75☌ ampacity. Underground wiring to a 100A breaker should use the proper underground rated wire like USE-2 or UF. Oversize aluminum to #1/0 AWG for better performance. Common insulated aluminum conductors would be #1 XHHW-2 or #1 RHH/RHW-2 for wet locations. This requires #1 AWG aluminum wire to match the capacity of #3 copper.

100 AMP COPPER WIRE SIZE CODE

The code allows aluminum wires for 100A breakers following the NEC one size rule. Optional larger sizes like #2 or #1 AWG can be used for less voltage drop. This gauge handles 100A for installations including wiring in: Copper Wire Sizesįor a 100A breaker, the NEC recommends #3 AWG copper wire. This allows it to be safely run through conduit. THHN wire size for 100 amps would be the standard #3 AWG copper softened with THHN insulation. This high heat-resistant thermoplastic wiring stands up to the elevated temperatures that can occur in a 100A circuit.

THHN Wire for 100 Amp BreakersĪ common wire insulation type used with 100 amp breakers is THHN wire. Oversizing beyond the code minimum is unnecessary and increases expense. Smaller wires may overheat, melt or cause voltage drops.

This wire gauge is sized to safely handle the 100A current and prevent overload conditions from occurring. The National Electrical Code (NEC) minimum wiring size for a 100 amp breaker is #3 AWG copper or #1 AWG aluminum.

100 amp copper wire size