What Size Wire for a 100 Amp Service?

This entry was updated on December 14, 2023 by Kevin Pommells

What Size Wire For 100 Amps

A #2 AWG wire is needed for a 100 amp service. This wire is used when the run between the breaker panel and the electrical load (such as an air conditioner) is long, like in large commercial buildings. A #4 AWG wire can be used if the distance between the breaker panel and the electrical load is less than 50 feet.

Where is 100 amp service used?

Here are some of the places where 100 amp service is used:

Mid-size homes and apartments
Older homes with a limited number of appliances
Detached garages
Workshops
Agricultural facilities
Temporary power at construction sites
Subpanels and circuit breaker panels in residential, commercial, and industrial buildings

100 amp service is a very common type of electrical service, and you can find 100 amp subpanels everywhere.

A certified electrician is necessary for handling these types of amperages and wiring.

Want to know the wire sizes of other amperages? Visit some of our other pages below.

Types of Copper Wires For A 100-amp Service Panel

THHN/THWN-2 and XHHW-XHHW-2: Ideal for conduits, THHN/THWN-2 suits diverse conditions, while XHHW-XHHW-2 offers heat and sunlight resistance.
USE-2 RHH RHW-2: Tailored for underground service entrance, it resists sunlight and moisture for reliable outdoor use.
Copper SER (Service Entrance Cable): Popular for panels and subpanels, ensure proper ground wire sizing for effective grounding.
Type MC Cable: With protective armor, it's conduit-free, providing flexibility and added protection in various applications.
UF-B Cable: Suited for underground and direct burial, it insulates against moisture, eliminating the need for conduit in outdoor installations.

Is copper wire safer than aluminum wire?

These two types of wires are similar in resistance and can be used interchangeably with no ill effects, though aluminum will cost less due to its lower material costs.

Copper Wire: Rated at 100 amps and can carry anywhere between 80-95 Amps of continuously loaded current. Copper wire is more expensive than aluminum wire, but looks nicer when strung together on poles.

Aluminum wire: Rated at 100 amps and can carry between 94-105 Amps of continuously loaded current. Aluminum wire is less expensive than copper wire, but looks uglier when strung together on poles.

Conclusion

To conclude this blog post, you have learned that #2 AWG is the perfect 100 amp wire size. Also, aluminum wiring is a viable option for houses where copper prices are high, but the superheat requirement of aluminum wire limits it's use in some cases.

Thank you so much for reading this article on Aluminum Wire Vs Copper Wire For 100 Amp Service, hopefully you found it helpful and informative.