Huge voltage swings under load - Residential

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James275

New User
Location
Addy, wa
Occupation
Farmer
Three years our system was working well. Simple exterior combined meter and disconnect, about 190 ft from our house. Running service underground using alum direct buriel cables. First, one entire side went down,and then the other side after a while later. Have clear 120 v coming from each power lead, 240 v across at the disconnect. checked at the house, and we were getting 120 v only on one side, one of the hots was 0v, and the other was 120V. Did an Ohm test and indeed all the lines seem fine except for the one with the zero Volts. SO....it looks like a bad alum service feeder. Disconnected it to see if it was affecting the other side, and under no load, i had 120 V. Put a load on it and pow, it went down to 80 V to White, and 120 to Ground. I am stumped. I was going to just replace the one leg that seemed bad, but maybe at the damaged area, there was other damage that wouldn't come to light with my voltage and then OHM Test. I read on another thread how direct burial alum service can be a problem. I feel i am chasing my tail. Clear that one leg is bad, but why would the other side not work properly. Need your help guys! Maybe i should just replace the entire service feeder?
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
So you have a bad conductor in the ground. You have 2 choice IMO, dig up the entire run and replace or get a tracer and dig where the problem is and splice the wire.
This is what I never run cable in the ground....we always install a conduit. One rock and you're digging it up again.

I would call an electrician and get the situation resolved
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
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