How to test for damaged insulation inside conduit?

[J.P.]

Another vote for pulling in new wire. Don't even bother megging it. You already know enough to have a reasonable concern that it is damaged.

 

[Ponchik]

I am sure you will do Mandrel test before you install the new conductors.

 

[GoldDigger]

And if there are plastic sweeps be very careful with pulling speeds and tension while the rope is still in the sweeps.

Tapatalk!

 

[Jon456]

I am sure you will do Mandrel test before you install the new conductors.

We will be doing more than just mandrel tests, I assure you. In addition to brushing and swabbing the conduits, we will be visually inspecting all of them with a camera.

 

[Jon456]

Another vote for pulling in new wire. Don't even bother megging it. You already know enough to have a reasonable concern that it is damaged.

I agree. However, the contractor who did the installation will be financially liable for the repairs, and he's not going to agree to replacing all the wire unless we can prove that it's defective. Hence, the reason for this thread.

Even on the known failures, he's trying to come up with excuses as to why they're not his fault.

 

[Jon456]

So we still need to come up with an acceptable test procedure for identifying how many damaged feeders we have. We do not want to simply pull them all out for visual inspection, because if a set of feeders are good, then we risk damaging them during the R&R. And the installation contractor is not going to take responsibility for redoing any work unless we can prove to him that actual damage exists.

I'd still like to hear any ideas on how to test these wires.

 

[GoldDigger]

So we still need to come up with an acceptable test procedure for identifying how many damaged feeders we have. We do not want to simply pull them all out for visual inspection, because if a set of feeders are good, then we risk damaging them during the R&R. And the installation contractor is not going to take responsibility for redoing any work unless we can prove to him that actual damage exists.

I'd still like to hear any ideas on how to test these wires.

Well, if you have well defined limits which the insulation is supposed to withstand, potentially destructive testing methods stopping short of those limits would seem to be OK. Or does the stress of that form of testing, even short of the failure point, still damage the wire?

Filling the conduits with water prior to testing with a megger should be OK too, since the cable should be rated for a wet environment. Figure out a way to seal the ends to keep from flooding your equipment areas of course.