500 MCM Cable

[desain86]

Hello All,

Frequent reader, first time poster. I see this has been discussed before to some degree but cannot find an answer.

Just did an install with a Cooper B-Line CT cabinet with 500 MCM cable which the local utility company required for 400AMP service.

For a neat install decided to go out of the cabinet from the back to feed panel board directly behind it.

Utility company inspector came out and is concerned with wrinkles in the 500 mcm cable outer jacket. I haven't even landed on the lugs yet and there is a slight radius to the wire simply from pulling it into the CT cabinet which caused the wrinkles. The inspector is suggesting replacement of wire! When I land to the lugs I am going to have to put a tight bend/ loop.

Is it possible to bend 500 MCM cable without wrinkles to the outer jacket? If so, how do you guys do it? I'm looking at Greenlee Wire Bender but don't see how I can bend the wire without some wrinkles even with that.

I really don't want to have to replace the 500 MCM cable is it industry practice to install 500 MCM without any wrinkles in the outer jacket when you have to make a 90 degree bend or loop or even worse go through an LB?

I am only talking about the thin outer jacket with the cable identification and listings printed on it.

Thanks!

 

[iwire]

I have to assume that you are talking about the thin clear plastic on the top of THHN THWN.

If so that is not really an issue.

 

[desain86]

Thanks for the reply. The outer jacket is not clear, but black and seems to be very similar to the clear I see on THHN! I haven't seen any of the larger supply cables actually having the clear jacket like I see on the 12AWG etc.

 

[Fulthrotl]

Hello All,

Frequent reader, first time poster. I see this has been discussed before to some degree but cannot find an answer.

Just did an install with a Cooper B-Line CT cabinet with 500 MCM cable which the local utility company required for 400AMP service.

For a neat install decided to go out of the cabinet from the back to feed panel board directly behind it.

Utility company inspector came out and is concerned with wrinkles in the 500 mcm cable outer jacket. I haven't even landed on the lugs yet and there is a slight radius to the wire simply from pulling it into the CT cabinet which caused the wrinkles. The inspector is suggesting replacement of wire! When I land to the lugs I am going to have to put a tight bend/ loop.

Is it possible to bend 500 MCM cable without wrinkles to the outer jacket? If so, how do you guys do it? I'm looking at Greenlee Wire Bender but don't see how I can bend the wire without some wrinkles even with that.

I really don't want to have to replace the 500 MCM cable is it industry practice to install 500 MCM without any wrinkles in the outer jacket when you have to make a 90 degree bend or loop or even worse go through an LB?

I am only talking about the thin outer jacket with the cable identification and listings printed on it.

Thanks!

put it in place, hypress or whatever kind of lug you had planned.
megger the finished install, and that should settle the situation.

if it doesn't, and the inspector is still giving you a hard time, get a
milwualkee heat gun, and go to mayday grounding in buena park,
and they sell a 600 volt UL listed heavy wall heat shrink tube by
panduit, that is suitable for direct burial. i think the 1 3/8" size is
what you are looking for. they sell it in 4' lengths i believe.
it is not cheap. nothing mayday grounding sells is cheap.

put that over the offending portion, heat shrink it, and that resolves
the issue for once and all. make sure the ul listing is facing where
the poop can read it.

 

[desain86]

Thanks for the quick responses.

The jacket is not clear, but black. I haven't seen the larger wires with the clear jacket that I see on a 12AWG wire or so.

Don't have a megger, maybe someday. Great to know about the UL Heatshrink from Mayday! As long as it cheaper than cost of replacing 500 MCM, it not expensive, if it comes down to that I hope it doesn't.

 

[roger]

The bottom line is that the jacket, be it clear or black, plays no roll in the insulation value, the jacket is removed for the UL acceptance test.

Here is a excerpt from an old IAEI meeting and Dave is Dave Mercier from Southwire.

When Gil visited us previously, he made a splash by noting that the transparent nylon covering THHN/THWN, while arguably making them sexy compared to THW, is not required to maintain the conductor's dielectric properties. Therefore, if in the course of installation the nylon suffers the odd nick, or unsightly run, or even is scraped off, the conductor is fine so long as the insulation underneath remains intact. Learning this much, we had to have Dave over for more of the story.

Unless conductors are exposed to gasoline or oil, or submerged for an extended period we're talking many months--the nylon covering offers strictly a mechanical protection, Dave explained, with the underlying PVC supplying the dielectric properties as Gil had told us. The nylon actually is stripped away for the UL acceptance test. Therefore, if the nylon is scraped off, but the plastic underneath is intact, an appropriate response usually is "Good; it's done its job," and a green tag.

Roger

 

[masterinbama]

I was taught many years ago, when doing underground splicing of THHN in manholes or vaults to strip the outer jacket back so that your insulating material sealed against the PVC insulation. This was to reduce the risk of water wicking between the layers and compromising your splice.

 

[augie47]

Glad to see you made it from "reader" to "poster"

 

[kwired]

put it in place, hypress or whatever kind of lug you had planned.
megger the finished install, and that should settle the situation.

if it doesn't, and the inspector is still giving you a hard time, get a
milwualkee heat gun, and go to mayday grounding in buena park,
and they sell a 600 volt UL listed heavy wall heat shrink tube by
panduit, that is suitable for direct burial. i think the 1 3/8" size is
what you are looking for. they sell it in 4' lengths i believe.
it is not cheap. nothing mayday grounding sells is cheap.

put that over the offending portion, heat shrink it, and that resolves
the issue for once and all. make sure the ul listing is facing where
the poop can read it.

Then the poop will complain he can not read the original marking on the conductor:happyno:

The bottom line is that the jacket, be it clear or black, plays no roll in the insulation value, the jacket is removed for the UL acceptance test.

Here is a excerpt from an old IAEI meeting and Dave is Dave Mercier from Southwire.




Roger

I have been told the nylon covering is primarily there to give the conductor it's gasoline and oil resistance rating, which what you quoted does support, so the occasional nick in the nylon doesn't hurt unless it is in an application where subjected to gasoline or oil.

 

[GoldDigger]

And if the gas and oil exposure is inside the panel....

Tapatalk...

 

[desain86]

Thanks all, I feel a little better about the wrinkles and hopefully I can talk to the inspector sorting it out as just a misunderstanding on my part. How do you guys feel about tight radius on 500MCM cable. I am talking the same radius you would have to put on the cable to go through a 3" LB? I already went through one 3" LB but am thinking that I will have to make a similar radius on the neutral to land the lug in the CT cabinet. I know im going to end up with a few more wrinkles!

 

[RichB]

Here is a good reference for radius of bend--and the numbers are almost exactly the same for any cable manufacturer

http://www.okonite.com/engineering/bending-ratios.html

 

[steve66]

Thanks all, I feel a little better about the wrinkles and hopefully I can talk to the inspector sorting it out as just a misunderstanding on my part. How do you guys feel about tight radius on 500MCM cable. I am talking the same radius you would have to put on the cable to go through a 3" LB? I already went through one 3" LB but am thinking that I will have to make a similar radius on the neutral to land the lug in the CT cabinet. I know im going to end up with a few more wrinkles!

I don't know exactly how tight you are bending these wires, but LB's usually have a maximum wire size and count listed on them. Just because (4) 500's fit in a 3" conduit doesn't mean they are OK to install in a 3" LB.

You really need to make sure your LB's are made to accomodate the wires that are installed, and make sure you are following articles 312 and 314.28 for distances at pull boxes and terminations. If you follow those, you shouldn't have to bend wires tighter than they are intended to be bent.