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Breaker Size for Spaces and Spares

Posted on February 21st, 2019. Last updated on June 14th, 2023.

Q: How do I change the size of space/spare breakers on panels?

A: The size of spaces and spares is based upon your settings in the Wire Sizing command.

Spaces and spares default to the smallest breaker that has Standard Branch Circuit checked.

For example, if the smallest breaker with Standard Branch Circuit checked is 20 A, your panels will use 20/1 spaces and spares. If you check Standard Branch Circuit for a 15 A breaker, your panels will use 15/1 spaces and spares instead.

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