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Joined: May 2005
Posts: 41
My brother-in law pulled in some direct burial cable to his well a couple of months ago, about 1500' to the well. The pumped stopped running and he thought it went out, but checked and he had 97 volts instead of 230 V. He apparently has two of the conductors 'leaking' - he says there is about a 4 on his continuity tester. Is there any instrument that helps find an underground location of a bad insulation spot? He would like to repair it instead of pulling it all out again - said it was really tough - I don't know what kind of wire it was (I do commercial) he calls it quadraplex (I get) but direct burial, but he pulled it in PVC. He is about 300 miles from me.

Joined: Jul 2002
Posts: 8,432
Likes: 3
Something doesn't sound right here,
Where exactly in the system is the 97V he is measuring?
If it's at the supply end of the cable, I'd suspect a faulty contactor or the like.
What controls this pump?, if it's got a pressure switch on it I'd make sure that the pressure switch has been wired correctly.
Failing that, the pump unit should be pulled up and checked, it may have something jammed in the impeller.
I would suggest that the cable be meggered between all cores and a continuity test done on each core before pulling the cable run out.
What I usually do before installing any cable is megger and continuity test the drum of cable before installation and then test the cable again after installation.
It's not unusual to get a bad reel of cable from the factory.

Last edited by Trumpy; 11/08/07 12:17 AM. Reason: Typo
Joined: Aug 2002
Posts: 402
A very expensive piece of equipment called a time domain reflectometer (TDR) can tell you the exact distance from one end of the cable to the fault.

Joined: Jun 2004
Posts: 202
Originally Posted by Last Leg
he says there is about a 4 on his continuity tester.

4 ohms or 4k ohms?

Joined: Oct 2005
Posts: 40
Hello LastLeg,
The situation could be a bunch of things. Here at the forum we do our best to picture it in front of us. You said he gets 4 on his multimeter in continuity mode/OHMS. I would think you would get a reading like that if you were reading 3000 feet of conductor with an ohm meter. 1500 feet one way and back. They cant be leaking to earth if it in pulled in PVC like you were saying. It could to other conductors(short). I would disconnect the well pump and disconnect it at the panel (both sides). Get a megger and meg the conductors to ground and each other to see if you even have a problem (then worry about location of a fault). I dont know your brother-inlaw, but you never know if he undersized his wire from the initial install to compensate voltage drop, especially when we are dealing with 3000 feet. The well pump could have burned up from an undervoltage to the motor after a long period of time. Was there correct voltage verified with a digital meter at the pump before the pump was put online. Just check the amp rating on the pump and do the math to verify correct wire size. I hope some of my suggestions help. Good Luck Man

Brian Gibbons
Joined: Jul 2004
Posts: 9,770
Likes: 14
Does he see 230v with the motor disconnected?
What size wire did he run?
If he decided #12 was fine for a 3/4hp pump (~10a) he would drop 57 volts at FLA ... but I doubt it would ever get it spinning. I guess it might have run for a while until something burned up. LRA might drag that down to 97v.
Have him try it with a couple c9 or c6 christmas tree lights wired in series and see what he gets.

Greg Fretwell
Joined: Jun 2007
Posts: 301
gfretwell is correct.
Measure the voltage at the end of the run (pump) with the pump disconnected. If he has 240 or close I would bet the wire is way to small for the distance. The pressure switch or other controlling device should be located at the pump so I doubt he has problem there. But it's possible he is single phasing the pump, either with a bad conductor (not likely) or a bad controller ie: presure switch or starter.
He needs to do a voltage drop calculation, since it is in PVC it is not likely the conductors are damaged. No mention here in the post of any breaker trips either.

Can you imagine how he got that flat cable pulled that distance. He must have used his He may have ruined the flat cable during the enormous pulling strain. Mabe a 90 or two? I hope not. Does he have any pull boxes. If so check all connections.

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