Electrical Feeder Size Chart: 100-400 Amps (NEC 310.12)

If you are working with electrical feeders, you are probably acquainted with the electrical feeder size chart. This is an NEC chart (you will find it below) that tells you what size copper or aluminum wire to use for different amp services.

Example: What feeder wire size do you need for 200 amp service? Simple. You just check the NEC feeder sizing table and see that, for 200 amp service, you will need either a 2/0 AWG copper wire or 4/0 aluminum wire.

For adequate feeder sizing, you have to consult the said National Electric Code (NEC) chart. You will find this chart under the NEC Article 310.12 titled ‘Single-Phase Dwelling Services and Feeders’.

Obviously, it’s not all that easy to get your hands on the new 2022 NEC guidebook. That’s why we list the wire sizes for feeders ranging from 100 amp to 400 amp services, in accordance with the NEC 310.12 chart here:

Feeder Sizing Table (100-400A Services, Copper And Aluminum Wire Sizes)

This table is quite easy to use. For example, let’s say you are trying to figure out the feeder wire size for 300 amp service. By checking this table, you can see you will need either 4/0 AWG copper wire or 300 kcmil aluminum wire to provide for a 300 amp service.