I have no breaker space in the main 200amp panel. I'd like to set a 100 amp sub panel with its own breaker. Can I connect the sub panel to the main entry lugs on the 200 amp panel?

  • 1
    I'm going to out on a limb here and say no you cannot do that -- the wires and other equipment that feed your main panel are (presumably) sized to handle a 200A load, and if you tap off from that feeder with another 100A breaker, then you could draw 300A from it. Can you move any circuits from your existing 200A panel to the new subpanel to free up space for a new 100A breaker in the main panel?
    – Johnny
    Aug 28, 2015 at 1:42

2 Answers 2


I'll tell you with 100% certainty that you CANNOT do this. Period.

It is a serious code violation and safety issue to have the new 100A feeder be unfused.

  • Does the subpanel need a dedicated breaker just for supplying it, or can it simply connected to the output of the main breaker in the 200amp panel? Seems like as long as the feeder wire to the subpanel is sized for 200amp service this would be OK as long as there's an acceptable way to join that to the main breaker's output. Aug 28, 2015 at 2:44
  • (I ask because my house has basically that setup - but with a 100A main panel and a subpanel with 5 branch circuits. I think the only way to shut off power to the subpanel is to hit the main 100A breaker, so I assume it's connected this way.) Aug 28, 2015 at 2:46
  • Would it be possible to tap the feeder after the service disconnect, assuming of course the disconnect is not the main breaker in the service panel. So for example, if I had a disconnect as part of the meter panel, which then fed a separate panel. Could I tap the feeder between the disconnect and the panel?
    – Tester101
    Aug 28, 2015 at 3:05

You have 2 easy solutions. You can pull two breakers from the main panel, and relocate them to the sub. Or you can replace 4 breakers with half height breakers to make room and free up the connection to the new panel.

  • For what it's worth, the latter is what was done to tie my solar inverters into the panel (and grid) for net metering. (Joe: make Rome? Typo.)
    – keshlam
    Aug 28, 2015 at 2:40
  • The latter is only applicable IF the panel can/will accept them. Not nearly all panels do. Look at the cover for a model. If it is anything like 2020, 3030, 4040 then is CANNOT accept tandem/skinny breakers. Aug 28, 2015 at 11:09
  • The main pannel i have is no longer made cant get breakers any more. The sub pannel would have a breaker witch i would mount next to the main pannel,. I was woundering if i could power the sub pannel breaker with out having a breaker in the main pannel and go derect to the lugs. Aug 29, 2015 at 2:06

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