Service Entrance Calculator
120/240 V single-phase dwelling service or main power feeder, NEC Table 310.12 (2023).
NEC Table 310.12 & Table 250.66
Service Range
100 A to 400 A
Input Parameters
For a 120/240 V single-phase service or main power feeder of one dwelling unit. Other services are sized from Table 310.16. Where the conductors run hotter than 30 °C or with more than three current-carrying conductors, the corrections in Tables 310.15(B)(1)(1) and 310.15(C)(1) still apply.
Grounding electrode conductor from NEC Table 250.66 (values from NFPA's 2020 grounding fact sheet).
Results
200 A, 120/240 V dwelling
Service conductors, NEC Table 310.12
- Copper
- 2/0 AWG
- Aluminum or copper-clad aluminum
- 4/0 AWG
Grounding electrode conductor, NEC Table 250.66
- For 2/0 AWG copper service conductors: copper
- 4 AWG
- For 2/0 AWG copper service conductors: aluminum or copper-clad aluminum
- 2 AWG
- For 4/0 AWG aluminum service conductors: copper
- 4 AWG
- For 4/0 AWG aluminum service conductors: aluminum or copper-clad aluminum
- 2 AWG
Frequently Asked Questions
What size wire do I need for 200 amp service entrance?▼
For 200 A residential service entrance, NEC Table 310.12 allows 2/0 AWG copper or 4/0 AWG aluminum for dwelling services.
What size ground wire for service entrance?▼
Grounding electrode conductor sizing per NEC Table 250.66: 100 A service needs 8 AWG copper, 200 A needs 4 AWG copper, 400 A needs 1/0 AWG copper.