Panel Install Orientation Question

I’m new to the training at InterNACHI and have what may be a stupid question. Is it OK to install a main or sub panel with the main breaker at the bottom of the box? If not, why does it matter?

If the breaker handles operate side to side (horizontally) they can be mounted either way unless the panel is marked “TOP” which is a manufacturer’s instruction that must be followed.


If a breaker operates in a vertical manner up must be on.

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What they ^^^^^^^^^^said.

And, welcome to our forum, Stuart!..Enjoy! :smile:

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As mentioned the panel can be mounted with the main CB either at the top or the bottom. The orientation of the CB must comply with NEC 240.81.

Part VII. Circuit Breakers
240.81 Indicating. Circuit breakers shall clearly indicate whether they are in the open “off” or closed “on” position. Where circuit breaker handles are operated vertically rather than rotationally or horizontally, the “up” position of the handle shall be the “on” position.


Thanks Russell,
The one I was checking showed that it was good either way. The inside is a bit of a mess though.

Thanks for the welcome Larry. I think I’ll be using this quite a bit.

Thanks Jim,
Another useful bit of info.

Thanks for the detail Robert.