Detecting low voltage at N1 N2 terminals

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New Member
New Member
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Joined: Wed Feb 24, 2021 4:24 pm

Recently had a short on one of my circuit breakers on the ATS causing It to trip. When I tried to turn the breaker back on, there was a spark on the main 50 amp breaker to the utility panel (50 amp breaker did not trip) and now the ATS switched over to generator power (utility poser is still operational). I reset the 50 amp breaker, everything appeared to normalize but eventually switched back to generator power. Checked the voltage at the breaker and It showed 240v. Then checked at N1/N2 and the voltage there was 90v.

Once again reset the breaker while checking the N1/N2 voltage. Upon reset, the voltage went to 240v but dropped back to 90v after about a minute. Is this indicative of a bad main breaker or could one of the breakers in the transfer switch be causing this.

Please help.
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Joined: Sat Aug 04, 2018 8:46 pm
Location: Clawson, MI

Can you send a picture of the setup you have?

Is the voltage measured anywhere else also showing the drop, or just on the N1/N2 fuses? It could be a bad fuse that is only showing itself when a small load is applied. A tester like a Wiggy (slang for a voltage tester that has a solenoid design inside) would make it show up a little easier since is applies a small load to the circuit when testing, vs a digital meter that doesn't.
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