Safe Legal Cable Repair ?

[Johnboy2316]

I have a customer with extreme uv damage to a 750mcm 4 conductor tray cable. With the cost of copper what it is today they really didn't want to hear my recommendation of complete cable replacement. While attempting to tape over the damaged areas ( for a very temporary fix ) I received quite a shock. After retrieving my trusty Fluke 87 I discovered that there was a voltage potential of up to 380v between the wet outer jacket and the cable tray it's laid in. This is a real safety problem. I megged the wire phase to phase and phase to ground and it was between 700 and 1500 M ohms. So it's not shorted but there is definitely an issue with the inner insulation as well if I'm getting voltage with the cable wet. Of course when it dries out you lose the voltage and all is good. However I can't tell my customer to only use their hot mix asphalt plant in dry conditions. I am looking for any input anyone may have. What does the NEC say about cable repairs and what options do I have other than complete cable replacement.

 

[winnie]

My guess is that it is will be cheaper to replace the cables rather than repair them, but a google search for "electrical cable remanufacturing" reveals:

https://www.abl-services.com/pages/products-and-services/power-cable-sales-and-repair/power-cable-repair

I don't work with conductors this size, nor with remaking cables, but apparently services exist....

-Jon

 

[petersonra]

what you are reading with your fluke is probably capacitive coupling and maybe not a hazard at all.

I am not 100% sure, but I think these kind of cables the outer jacket is not really an insulator. Just a physical protective layer. You might be able to just sleeve over it with a suitable sleeving material if it bothers you.

 

[hbiss]

I am not 100% sure, but I think these kind of cables the outer jacket is not really an insulator. Just a physical protective layer.

Looks like TC with the outer jacket damaged?

-Hal

 

[Johnboy2316]

what you are reading with your fluke is probably capacitive coupling and maybe not a hazard at all.

I am not 100% sure, but I think these kind of cables the outer jacket is not really an insulator. Just a physical protective layer. You might be able to just sleeve over it with a suitable sleeving material if it bothers you.

But if it's not an actual stage then why does it shock you when you touch the cable and the tray at the same time ?

 

[Johnboy2316]

Looks like TC with the outer jacket damaged?

-Hal

Yes it is but the internal insulation must be compromised as well because it shocks you and you can read voltage on it when it gets wet

 

[hbiss]

Yes it is but the internal insulation must be compromised as well because it shocks you and you can read voltage on it when it gets wet

Well, I think you answered your own question. Only option is to replace.

-Hal

 

[don_resqcapt19]

The NEC is an installation code and does not address repairs of issues like this.

There is no fix other than replacement and after you replace the cable, you need to install tray covers to prevent this from happening again.