new subpanel

pandaman1784

I’m planning on putting in a subpanel into my garage. The subpanel is going to be a 100 amp Square D QO panel. I’ll have 3x #2 THHN wires for the feeders and 1x #4 THHN for the ground. They’ll all be running through 1.25″ RMC.

My question is in regards to my existing panel. It’s a 100 amp Square D QO panel. Is it ok to have a 100 amp circuit breaker in a main panel where the main breaker itself is also 100 amps?

I’m getting some ductwork replaced and the section of drywall that leads from the main panel to the garage will be removed. I figured, this is the best time to put in the necessary infrastructure for future EV charging in my attached garage. the main panel might get upgraded in the future, but that’s much further down the line. For now, I would like a 100 amp circuit breaker feeding a 100 amp main breaker subpanel. Even if I don’t need anywhere near 100 amps in my garage.

Splitpair

pandaman1784 My question is in regards to my existing panel. It’s a 100 amp Square D QO panel. Is it ok to have a 100 amp circuit breaker in a main panel where the main breaker itself is also 100 amps?

Yes that is allowed by Code, you are just limiting yourself to a max continuous load of 100 amp at the main panel.

Also since you are using THHN for the current carry carrying conductors at 100 amps you can use a #3.

By the way the QO panel is one of the best, but keep in mind BB stores like LowesDepot sell QO panels which have plated aluminum main buss’s, that is not a problem unless you move breakers around a lot such as using them as switch’s.