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I have a 4 wire 220v circuit coming from my main box with the power running through a 2 pole 20 amp circuit breaker. I now need 2 110v circuits near that 220 line. I want to put in a load center where I break off the 2 110v circuits from the 220 and run that power through a 2 pole 15 amp circuit breaker. In code? Sound safe?

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  • So you do need to keep the 220v line? I assume it uses #12 wire? What loads do the circuits need to handle because 20A probably isn't a lot to go around if this even is allowable.
    – JPhi1618
    Commented Apr 8, 2019 at 15:44
  • What are the loads on these circuits. The original is still in use? Or your repurposing the 20 amp wire? If repurposing why not just down grade the original breaker? Your question as written doesn’t tell enough of the story. Please use the edit button and update the question rather than comment.
    – Tyson
    Commented Apr 8, 2019 at 17:49

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Yes, you can change this branch circuit into a feeder. Feeders supply subpanels.

Note that feeders do not supply branch circuit loads, which means your existing 20A load will need to be added to this subpanel, weird though that may be.

So your new subpanel will need: 2 spaces for a 2-pole breaker for existing 20A/240V load, and 1 space x 2 for the 120V/15A circuits. They don't need to be on a 2-pole breaker, unless they share a neutral.

Now, they do make 2-space/4-circuit panels, but those rely on "double-stuff" breakers which are obsolete because they do not support AFCI, which has been required on most circuits since NEC 2014. Also, some panels do not make the special breaker you'd need (double tied quadplex). Because of all this, you need to plan a full space for each circuit. Beyond that, you may also want expansion room. Here's what you need in a panel.

  • Bus rating >= 20A. (This won't be a problem)
  • Main breaker is required if this is in an outbuilding. Must be >= 20A
  • Main breaker optional otherwise. Must be >= 20A
  • Spaces >= 4 (often marketed as >= 8 circuits)
  • Accessory ground bar (not included in every panel) *

A 6-space/60A is fine. A 40-space/200A is fine. Whatever you have lying around.

You must separate neutral and ground in the subpanel.

You attach the existing 12/3 cable to the ground bar, neutral bar, and 2 main lugs or main breaker.

Fit a 20A 2-pole breaker in this panel, and run cable to your existing load.

Fit either a 15A 2-pole breaker, or two 15A single breakers. Attach your 120V loads there.

Neutral and ground go on separate bars. Make the neutral wire long enough to reach the breaker, as this will be required for any future AFCI/GFCI installation.

*. Actually in your case, because of the very small size of the panel, you can simply wire-nut all neutrals together and have no neutral bar at all. That lets you re-task the bar in the panel to be the ground bar. No accessory ground bar needed! This would not work with plug-on-neutral panels.

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  • Great answer - I wondered if there was a minimum wire size for a feeder. Depending on the loads this still might not be a very useful panel, but cool to know it's possible in the right situation.
    – JPhi1618
    Commented Apr 8, 2019 at 19:36
  • The 220v circuit is breakered at the main box. I have to do it again? The 20 amp circuit's expected load is 10 amps - 12 momentary (2hp 3 phase motor). The 110v circuits are barely an amp (led lights).
    – Kevin Doney
    Commented Apr 9, 2019 at 14:43

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