NEC

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lquadros

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1.Let us say we have about 10 TECK 90 cables running together. Each have 3 current catrrying conductors.Do we have to consider it as 30 current carrying conductors and derate it or derating is not necessary? The inspector is saying that we have to separate the cables or derate it.
2.Do we need to separate the power cables from control cables physically to avoid noise and other interference? These cables are installed in liquid tight conduits.
Thanks in advance for your input.
 
Re: NEC

Sorry for the confusion TECK 90 is CSA designation for armoured cable. The cables are being run in a cable tray.
 
Re: NEC

(Teck 90 is similar to PVC jacketed MC cable)
A cable tray is a support system, not a wiring method. Teck itself is a cable wiring method, and in the tray, no seperation is needed from, say low voltage cables. If you used TC then seperation would be required.
Noise and interferece is another issue, beyond the scope of the NEC.
No derating is required for cable trays as in a raceway, but there is a limit on the cross sectional area of the cables in a particular size tray, see NEC Art 692
 
Re: NEC

lquadros,
I notice that you are using TECK 90 cable in cable tray.
Are you asking for a Canadian Electrical Code (CEC), or an NEC answer to your question?

Ed
 
Re: NEC

Hello Ed,
Thanks for jumping in. I am refering to Canadian Eletric Code. I am in Canada. I thought the NEC would help a bit.
But now I have just registerd with "Electric Ed.com" and waiting for a password. I will pose the same question to the Canadian peers as soon as I can.
 
Re: NEC

lquadros,
I am "Electric-ed.com", but I can try to help you here anyway.

If these are power cables (as opposed to signal/control cables), your inspector is correct.

To avoid any de-rating, in a ventilated tray, the cables would have to be spaced more than 1 cable diameter apart. CEC 12-2210(1)
We used to use a short piece of cable as a temporary spacer while ty-wraping the cables to the tray bars.

If the spacing is between 25% and 100% of cable diameter, in a ventilated tray, use the de-rating factors in Table 5D, based on the number of cables. 12-2210(2)

If the spacing is less than 25% of cable diameter, or for any spacing in a non-ventilated tray, use the de-rating factors in Table 5C, based on the total number of current-carrying conductors in all of the cables. 12-2210(3)(Same as if they were in conduit)

Hope this helps,
Ed

[ February 18, 2004, 06:16 PM: Message edited by: Ed MacLaren ]
 
Re: NEC

Ed, Thanks for your help and the introduction of yourself. I just wanted a second opinion of some sort or a way to get around this situation. It seems like we have a problem.
You have great material put together in this forum. My password please.
 
Re: NEC

lquadros,
I don't issue the passwords. That is done by the company that runs the discussion board, and it's a free (ad supported) board, so I can't be too demanding.
When the password doesn't show up, it usually means a registration or e-mail address problem. You could try re-registering.

Ed
 
Re: NEC

Ed
I just reread my post of last nite and it didn't sound to good. :eek:

What I was trying to say is running into someone in here trying to get into your site not knowing who you are. Don't happen to often.

Boy I must of been tired. LOl :D
 
Re: NEC

I am to confused now
( I mean to say too - unlike Hurk ;)
Is this Mike Holt site or Electric Ed site? or both?.
 
Re: NEC

Lquadros, This is Mike Holts site, but along with ED, you will find people here from many sites.

To name a few;

Bill Addiss: ECN
Dave Nix: ELECTRICAL MATTERS
Joe Tedesco: NEC DISCUSSIONS

Roger

[ February 20, 2004, 10:30 AM: Message edited by: roger ]
 
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