Electrical – 6/3 Wire to a 100 amp sub panel, how many breakers

circuit breakerelectricalsubpanel

I have a 100 amp sub panel being fed a 6/3 cable. The main Panel has a two pole 60 amp breakers.

How many breakers can I have, or how many amps can I have? All the outlets/receptacles will be 120v. Can I use twins? What is my limit?

This is for a shed with power tools, fairly light use. I just want lights and 120 volt outlets attached to the Sub panel.

Thanks,
-Greg

Edit please… I'm looking for direct answers, not what I should change. I have 6x spaces can I put 6x 20amp breakers? I had two electricians suggest I can't but wouldn't tell me why.

Best Answer

If you’re thinking about twin breakers, it’s because you got too small a panel. Stop right now before you sink any more work into it, and get a much bigger panel. Spaces are dirt cheap right now, and it’s one place you should splurge.

And it’s fine for the subpanel busing to be much larger than the feed breaker. It’s a safety margin, 130 mph tires are safer than 85 mph tires even if you never drive 85 mph.

Your ability to use twin breaker depends on your local Electrical Code and any requirements it has for AFCI on any breaker or GFCI on 2-pole breakers. Those are not available in double-stuff breakers, so you must plan a full space for each of those circuits. Nowadays that will be most circuits, so I advise to just forget about twins.

Since you will certainly never use all circuits at once at full power, you can put quite a lot in a panel. Having 16 120V circuits would not be unreasonable.

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