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I have 4 sub panels in my home and I want to move two 20amp breakers from one into another. I want to run #12 Romex from the one panel too the other and use the original panel and just splice each circuit. My question if the neutral stays in the original box can I just move the hot leg

  • So will 1 neutral for the two hot circuits (3 wire Romex) be ok... Or do I need to run two 12-2 Romex – John Raz Jan 30 at 3:07
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You MUST move both the hot and neutral together!

The underlying principle is currents must be equal in each cable or conduit. You can't have a situation where current flows on the hot wire from panel 4 to panel 2, but neutral just ends at panel 2 and takes a different route back to the panel (creating an imbalance in that cable too).

If currents are equal, each wire kicks a large electro-magnetic field (EMF), but the various wires are equal and opposite, so the magnetic fields cancel each other out.
Since currents are not equal, large electro-magnetic fields are kicked up. This will cause eddy current heating, and vibration -> fatigue failure on wires.

Further, neutrals do not have circuit breakers. This is safe, because neutral only handles current for its partner hot wire(s), so they handle the same current and the "hot" breaker protects the neutral. If you return current from a different path, you break that protection, and now the oversubscribed neutral can overload - and no breaker will care.

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No you cannot just move the hot. You must move the hot with the neutral. The ground needs to come from the same panel if there is one. You can splice in the panel and jump to the original panel that would be ok.

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  • I was going to use two wire Romex with the ground but the but if the nuetrsl is in both sub panels why would it matter – John Raz Jan 30 at 1:30
  • These are both sub panels .... When I say original I meant the panel it was originally in just to splice – John Raz Jan 30 at 1:40
  • This is a code requirement , additional connections can create problems. – Ed Beal Jan 30 at 14:14
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NEC 303.3(B) Conductors of the Same Circuit All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors...shall be contained within the same raceway...cable..

The grounded circuit conductor is the neutral.

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  • Ok thanks... So I should be able to use a three wire and would be good to go... – John Raz Jan 30 at 1:49

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