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I have an main circuit breaker panel with a 200 amp breaker and a 60 amp breaker. the main feed comes into top of 200 amp breaker and then 2 wires come out of the bottom of it and into a 60 amp breaker. They then run out of the bottom of the 60 amp breaker and into a subpanel with a 50 amp breaker, 30 amp breaker and 15 amp breaker. I tested the voltage between hot and neutral at the main panel, after the 60amp breaker, and both hots read 120v. But when I test the voltage before the 50amp breaker in the subpanel one hot wire and neutral read 120v while the other hot wire and same neutral read only 25 volts. What could the issue be? I'm pretty sure there is nothing in between, just the wire running between the breakers. Does anyone have an idea about what the issue could be?

The wire is run underground. Direct bury I believe. No conduit. Been there about 20 years.

  • How is the wiring from the main panel to the subpanel run? Individual wires in conduit? Cable in a wall? A buried cable underground? – ThreePhaseEel Mar 28 '19 at 0:55
  • Has there been any excavation activity on your property lately? – ThreePhaseEel Mar 28 '19 at 2:18
  • No there has not – Chris Mar 28 '19 at 2:25
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You most likely have a bad connection of the breaker to the sub-panel bus bar or a loose terminal somewhere. It could POSSIBLY be a bad pole on the 50A breaker, but that's fairly rare in comparison. You MUST address this immediately by the way, because it's a fire waiting to happen.

  • Ran into this problem with an old panel. The metal face of the panel (not the hinged cover, but the face that the breakers poke through) was warped and making contact somewhere in the panel. The end result was very low voltage through most of the house, though I'm not sure exactly why. With the main breaker turned off, I pulled the face out and re-seated it which fixed the problem. – ChrisB Dec 23 '19 at 22:02

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