ECN Forum Forums Code Related Discussion NEC & other Code issues NM Trough?

So, up t0 30 12-2 type NM cables can be bundled together with no derating required? That just don't sound right!

Not much info available on the web. The product is made by "Speedway Electrical Products". A google search gives _one_ hit; a news blurb saying that Tom Lhota invented the stuff and is selling it direct.

The UL file doesn't say very much.

Ahh, heck with it. UBB doesn't seem to want to parce the long url. Go to www.ul.com and look up file E190378


I presume that if UL tested each of the cables at rated ampacity, at the 40% fill, and that there was no overheating, then derating is not needed...but I see nothing in the guide information that suggests this sort of testing.

-Jon


[This message has been edited by winnie (edited 06-03-2004).]

George and Jon,

Thanks for your help!

My concern is the amount of cables listed as to be acceptable! There sure seems that there needs to be derating because of bundling. At least, I think it is bundling!

If this is not considered bundling, what is??

Where do we "draw the line"?

WebSparky ---

Derating for bundling is very poorly done in the code. It treats conduit in free air the same as conduit in foam insulation and it treats small conduit the same as large conduit.

If a manufacturer of conduit wanted to, he could get UL approval for more accurate derating. This manufacturer appears to have done so. He was smart enough to make his design incompatable with other conduit designs.

Thanks George!

I think I'll call him from the office on Monday to see if he can fax me the UL Listing information.

Thanks for the help!

Dave Nix

George is right. Derating for residential is overblown.
If there is tight packed cables run through tight packed insulation You might just heat up your cables somewhat, but up to 90 degrees centigrade? I doubt it. First we should be looking at the loading on the cable runs in a dwelling. Most are underloaded from the branch circuit rating. Where you are more likely to find wires or cables that should need de rating is in the commercial or industrial setting. I'm sure most of us have run across those way to warm or hot runs of conduit that somebody packed up with too many wires. Especially true where lay in flourescent lights keep getting added to existing circuits. But truthfully have any of you inspectors or fire marshall's out there ever seen a fire start because someone pulled more than 3 runs of romex thru a series of drilled holes? Be honest about your answers now.

What is the name of this product and where can I buy it. Can't seem to find anything on the web. If it is no longer available is there another product that performs a similar function?

thanks