same bored hole, here we go again

[infinity]

Re: same bored hole, here we go again

Originally posted by websparky:
Trevor, I disagree.

The key word is conductors not cables. There is a requirement for a 2" separation from open conductors not cables. They are permitted in the same hole.

This must be one of those "wifes tales".
Look up the definition of "conductor as used in the NEC. Also look at article 310.4. Here is an excerpt:

Where run in separate raceways or cables, the raceways or cables shall have the same physical characteristics. Where conductors are in separate raceways or cables, the same number of conductors shall be used in each raceway or cable.

As you can see, the article 800.52 referenced by david is correct. This means that NM cable does qualify.

This is not a wives tale. A conductor is not a cable. Once a conductor is inside of a cable the assembly becomes a cable assembly or as we commonly call it a cable. A cable and a conductor are not the same thing. The 2" separation required is from conductors not cables.

(2) Other Applications. Communications wires and cables shall be separated at least 50 mm (2 in.) from conductors of any electric light, power, Class 1, non?power-limited fire alarm, or medium power network-powered broadband communications circuits

 

[websparky]

Re: same bored hole, here we go again

Trevor,

A conductor is still a conductor even when it is inside a cable assembly.

The actual code reference that allows this sharing of a hole is what david said in his original answer when you read the exception.

 

[ron]

Re: same bored hole, here we go again

Dave,
The wording "all of the conductors" ... "are in a raceway or in metal-sheathed, metal-clad, nonmetallic-sheathed" seems odd. If the low voltage cable is not considered nonmetallic-sheathed, then how is "all of the conductors" in the nonmetallic-sheathed cable?
What defines nonmetallic-sheathed? Is it only NM type cable 12/2, 14/3 etc or is it any cable that has a non-metallic sheath?

 

[websparky]

Re: same bored hole, here we go again

Ron,
Good point. As for PLFA conductors, I think the answer to that is in 760.55(G)(1) where it says "Either (a)" "or (b)"

Notice that as long as one of them is, the other is OK. Also, the FA conductors must be the approved type.

 

[A/A Fuel GTX]

Re: same bored hole, here we go again

I always thought that the separation was to eliminate induced noise on the communication / video components.

 

[ron]

Re: same bored hole, here we go again

Tom,
No question a good design includes separation for most differing types of circuits. The question being discussed, is whether the NEC requires separation as a minimum.