Work out the minimum standard breaker for a load, including the 125% rule for continuous loads.
How it works
Continuous loads run 3 hours or more, so they count at 125% of their amps. The result rounds up to the next standard rating in Section 240.6.
Before you order
- A breaker protects the wire, so the wire must be sized for the breaker.
- Motors and HVAC equipment follow their own nameplate maximum fuse or breaker size.
- Never put in a larger breaker to stop nuisance trips, since that removes the wire protection.
Common questions
What counts as continuous?
A load expected to run at maximum current for three hours or more, such as lighting or an EV charger.
Why not use exactly the load?
Most breakers are rated for continuous use at 80% of their rating, which is where the 125% factor comes from.