Feed 2 sub-panels off one breaker


I have a 225A main service panel. I also have 2 sub-panels with 125A and 200A ratings respectively.

There's a 100A 2-pole breaker in my main panel. I want to feed both sub-panels from that single breaker (all inter-panel wiring, lugs and terminations are good for 100A):

  • Can I run the cable to subpanel #1, replace all the lugs with 2-wire lugs, and leap frog to panel 2?
  • OR, can I have an intermediate junction box with 3-way splices on all 4 wires?
  • OR, am I absolutely required to serve each subpanel from a separate breaker (not illustrated)?

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Best Answer

Since this is fed from a breaker in your main you can do it with both wiring methods but it would be considered a feeder and the wire size would need to be good for 125% of the breaker or 125A the way I interpret the code. If all the loads are non continuous it could be 100% but with all those spaces there will probably be a few continuous loads so better to be safe for the long run.