Airport circuit

[Elect117]

A rep from S&C tried to sell us a insulation tester than could determine the insulation failure distance (to only a certain degree of accuracy). It didn't work with our set up because our circuits are not grounded.

I don't know if that might help find the problem or if that is just going to tell you that there is a problem. We were looking for a way to test cable's insulation because we temporarily overload them occasionally and they have been in the field for ~30 years.

 

[Hv&Lv]

A rep from S&C tried to sell us a insulation tester than could determine the insulation failure distance (to only a certain degree of accuracy). It didn't work with our set up because our circuits are not grounded.

I don't know if that might help find the problem or if that is just going to tell you that there is a problem. We were looking for a way to test cable's insulation because we temporarily overload them occasionally and they have been in the field for ~30 years.

BI-.35S1 – The Von Corporation

voncorp.com

 

[kwired]

I think it’s actually better. I know with locating faults under pavement, they say to wet the pavement.

Fault finder I use basically detects the point the return current from the faulted conductor to the transmitter electrode is leaking to earth. You kind of need to already have located the path of the conductor just to get you to follow that path when trying to find the fault. The more moisture there is in the soil the easier it is to locate the fault because of increased conductivity for said return current in the soil.

I had one instance where it had been very dry summer and was trying to locate a fault on a direct buried conductor, in sandy soil on top of the dryness . Could not pinpoint where it was. dug up the line in two different best guess locations and nothing was wrong. Seen a hose and sprinkler and decided to set it out in the vicinity of where I suspected troubles. Came back after letting it run a couple hours and found the correct spot pretty much immediately just like the instructions say it should work. Dug it up and that was the right spot.

 

[eagleinthefog]

I'm an Electrician in San Diego. We still have those old 5kv Street Lights. Fault finding is a pain on circuits that are close to 100 years old. And varying cable types across that 100 years!
We commonly start with wiring diagrams to determine where the lights quit working, as a grounded line will still empower lights before the break.
Then, we use a locator such as the VIVAX loc3. It takes practice; but locating open, broken but grounded, or partially grounded (conductor intact, but insulation compromised), it will get you within 18 inches of the fault more often than not.