Cable damage inside conduit 3

[eigenk]

A contractor ran cable in conduit on a project. The outer sheath had so many tears in it after the cable pull that we were concerned that the underlying layer of insulation was also damaged - it appears they did not use pulling compound. The company offered to Meg test which they did successfully. We later learned that cable passes the meg test even with blatantly exposed copper showing from the insulation and we do know there was at least one case where they did damage the insulation and had exposed copper. Ought we accept the meg test result and accept
the cable or should we fight to have the cable replaced? It will certainly become litigatious if we refuse to accept.

 

[dpc]

If you can see significant visual damage to the outer jacket, then the cable was damaged during installation and should be rejected, removed, and replaced. It doesn't matter what the insulation resistance is. There is no electrical test that will guarantee that there will not be problems in the future.

Don't let the contractor get away with dictating the conditions for the acceptance of the cable, and don't let him scare you with threats of lawsuits. If you haven't yet paid him for this part of the work, then don't. If you have, then see if there is still some retainage and hang onto that.

If possible, have a field engineer from the cable manufacturer come out and give an opinion.

Read the General Conditions of your contract. If this is standard construction contract, you should have a solid case for replacing the cable. In fact, in the standard EJCDC and Federal General Conditions, if the Contractor refuses to remove the defective work, I believe the Owner can hire another contractor to do the work under Force Account and then bill the original contractor.

Good luck and let us know how it turns out.

 

[busbar]

I'm not real current on contract verbiage, CSI or otherwise, but would tend to side with dpc on using cable-manufacturer information for determination of installation acceptability. It would seem likely that reasonable installation procedures have not been exercised.

[Given 600V-class cable] aside from visible copper exposure, the cable jacket is an integral component of cable insulation, and visible scarring of the outer layer alone should likely be cause for rejecting the installation. Is it possible that manufacturer’s quality-assurance or NRTL listing/labeling standards could be applied to the finished assembly? Maybe the cable could be shown to have been subject to stresses beyond what published/standard values intended or evaluated for the cable insulation.

Also, if NEC applies and if any portion of the raceway is underground or outside, or passes through a temperature gradient, it does not seem possible that condensation or water impingement could be prevented for any reasonable length of time, making the installation unacceptable.

 

[jbshep]

I would not accept the installation based on your brief description.
You have not revealed the voltage, cable type or cable insulation material. These are critical parameters.
A partial discharge test or even a high voltage "proof" test would be more revealing.
The cable manufacturer will have a recommended test procedure for new cable at the time of sale; your cable should pass these same tests after initial installation.
Incorrect installation, particularly too much tension or side wall pressure will cause damage that will not be revealed by any tests but will cause premature failure at some future time (shortened life).
If you know the cable has been subjected to excessive tension, trauma or side wall pressure (a result of excessive tension around bends)then, in my opinion, you have just cause to reject the installation.
J. B. Shepherd, P.E.,

http://www.brad.shepherd.com

 

[abeltio]

Quick test to reject the megger... fill the conduit with water, seal with putty and megger again. If insulation is damaged it will fail miserably.
HTH
Saludos.
a.

 

[eigenk]

Thank you for responses. I have a meeting with the contractor tomorrow and will use the inputs provided.

 

[MMurphy]

Do not accept it!! I have had cable that meggered ok experience intermittent shorts to ground.Eventually the cables inside a motor junction box were found to have some of the insulation worn away by rubbing against an ungrommeted hole. It was found that the magnetic field around the cable when operating the motor caused the cable to move enough to touch the case.

 

[busbar]

Maybe the crew was out of pulling lube and hoped no one would notice?

[tt][sub]<There is the old axiom, “It’s better to say your sorry than ask for permission.”>[/sub][/tt]

 

[abeltio]

eigenk,
What happened???
If you have a couple of minutes post the results of your meeting willya?
gracias.
a.