Silent Knight wiring issues

[Joel P]

I reciently wired a building with 12/2 fire wire and the tech that is trimming it out says that almost all of the cable ties from romex staples are too tight and causing shorts. I know for a fact that when I put them on hand tight that they did not break the insulation, but when I told this guy that he said that I dont know about fire wire and that if the tie is too tight then it can cause a short without breaking the insulation.

What is he referring to? I know that if you stretch or flatten the copper out in a wire that is a problem but I know that this is not the case with my wiring.

Any help to understand what he is even talking about would be appreciated

Joel

 

[TwinCitySparky]

12/2 ? Are you sure it wasn't 18/2 ?


The firewire I have installed has a very tough jacket and insulation. I would see for myself what the guy is talking about.

 

[Joel P]

Yes it was 12/2 since the runs are very long. It is a Cosco size warehouse.

Ill be out there tomorrow to see this first hand, but he said that the insulation was not broken and the securing means were too tight. How can this be a short if he says that? This is what is confusing me. I just wanted to make sure that I have all of the information about securing fire wire before I go on site tomorrow.

If it is not broken and the conductors are not touching can their still be a short like he is saying there is?

 

[nhfire77]

I've seen it happen. The zip ties are crushing the conductors together, possibly against the metal staple.

I have seen zip ties too tight and when you start you play with the cable the short goes away, but then you are left with the where question. Its almost certain it will come back eventually.

I'm not saying its this in your case, but it is possible.

You may have to start ringing out each leg of each circuit.

 

[MisterCMK]

I've seen it happen. The zip ties are crushing the conductors together, possibly against the metal staple.

I have seen zip ties too tight and when you start you play with the cable the short goes away, but then you are left with the where question. Its almost certain it will come back eventually.

I'm not saying its this in your case, but it is possible.

You may have to start ringing out each leg of each circuit.

I've seen the same thing. I had a short on the signature loop of an EST2 that ended up being where the wire was pinched with staples. I've also seen where guys have really reefed on the cable when installing it and split the jacket and dinged it up with tie-wraps when strapping it up. Gotta start checking the loops.

 

[Joel P]

Ill start checking for sure. So is the idea that the insulation of the individual conductors may have a split in it from the zip ties pulling the cable into the staple? This would be the only way that I could see a short happening right?

Thank you for all your input.

Joel

 

[tpepperl]

Not necessarilly pulling the wire onto the staple. More likely squeezing the wires together inside the jacket and splitting the insulation around each wire.

I have seen this if the wire was installed when it was too cold out and the isulation becomes brittle and splits under pressure.

 

[Rob454]

Tell the guy to pull out his meter and start checking for shorts or ground faults. Im thinking its more his trim than your wiring. Unless you smash the bejesus out of that romex staple or missed and whacked the wire with a hammer i doubt its the wiring

 

[mivey]

Other contractors could have been banging into your cable as well and pulled it against the staple.