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Mike, Master Electrician
Category: Electrical
Satisfied Customers: 1425
Experience:  Licensed Master Electrician - OnQ Certified Data Voice Audio Video Installer
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Underground power line going to water well. Aluminum wire.

Customer Question

Underground power line going to water well. Aluminum wire. 120 ft distance. . 240 volts across two terminals of breaker. only 150 volts at pump. checked individual. approx 130 volts from neutral to one leg. 40 volts from neutral to other leg. what would cause this. is there a way to find out where the problem is. is there any solution other than laying a new feeder from the breaker to the well.
JA: How long has this been going on? And how severe is the problem?
Customer: I might add that with nothing hooked up at the water well end, the breaker tripped after a few minutes. With no load does this indicate a short between the two feeders or what.
JA: Do you plan on doing the work yourself?
Customer: Probably not. I am capable as far as knowledge, but I havent decided if I want to do it or not. It depends on the cost of someone else doing it.
JA: Anything else we should know to help you best?
Customer: Thats all I have. two legs, one full power, one low voltage and the breaker trips with nothing hooked up. I was told that a lightening strike can cause that to happen. I might add that the feeder comes out of the ground in a 2 inch conduit about 10 ft from the pumphouse, makes a big loop and goes right back into the conduit and on to the pumphouse. I thought that might act like a lightening rod. I checke voltage at the top of the loop to see if the problem was between the breaker and loop or between the loop and the pumphouse. Unfortunately, checking at the loop, I got the weird voltage readings. which are the same as at the pumphouse.
Submitted: 2 months ago.
Category: Electrical
Expert:  Kevin replied 2 months ago.

Hello and welcome to Just Answer. My name is ***** ***** I will be happy to assist you with your electrical question.

1) Disconnect the wires at the pump and take another voltage measurement under a "no load" condition.

2) Across the 2 hots, you should measure approx 240 volts. From each hot leg to the neutral, you should measure approx 120 volts.

3) Also measure from the neutral to a ground wire and it should measure 0 volts or possibly a little more.

4) Sounds like there is a faulty neutral termination or splice somewhere on the circuit?

Expert:  Kevin replied 2 months ago.

1) Is the pump casing properly grounded and bonded back to the ground rod near the main meter socket area of the home?