Can I install a 225 amp main lug load center "downstream" from my 100 amp external cutoff? I run all gas appliances, I'm looking into gas air conditioning as well... I only want the big panel for the sake of not having a crowded box, and more available circuits than currently allowed in my old 20 space panel.


  • Hello, and welcome to Home Improvement. I'm no pro, but my guess it would be fine. And, you should probably take our tour so you'll know how best to participate here. Jul 13, 2019 at 1:40
  • Is the 100a thing a meter+panel combination, or only a meter+shutoff with a 100A panel that you're replacing? Jul 13, 2019 at 1:47

1 Answer 1


Yes. That is exactly what we recommend.

You can go as large as 42 space for just a few dollars more. Beyond 42 space, the cost gets prohibitive.

There is no problem having the subpanel be of a larger ampacity than the breaker protecting it.

  • Agreed, but do label the incoming supply ie 100A or 150A so people know...
    – Solar Mike
    Jul 13, 2019 at 7:12
  • @SolarMike this shouldn't be that unusual. People ought to be checking service size before provisioning anything big enough to justify recalculating. Available 100A-bus panels don't provide enough breakers for a modern gas house with 100A service, so it almost has to be done. Jul 13, 2019 at 14:17

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