code question

[skidmark]

I saw a panel in a residential house where the electrician had pulled every circuit thru a piece of 2 inch pvc conduit. Isn't this a code violation and where is it in the NEC.

 

[tom baker]

Re: code question

It depends on how it was done. I assume the PVC is a sleeve running into the panel. Prior to the 1999 NEC there was not a method for doing this, the 99 code added a very specific method in 312.2(B) you'll need to look at it carefully.
However, you can still run NM thru PVC conduit if:
Conductor fill observed
Derating for more than 3 conductors
Individually fastened at exit and would have to be from a big j-box or =.

 

[skidmark]

Re: code question

Thank you Mr. Baker. This guy did not observe conductor fill at all and he did not secure any of the conductors, which if I am reading it right is a violation of 334.30 in the 2002 N.E.C. I really would like your interpertation of that code. Thank you.

 

[ryan_618]

Re: code question

See also 312.5 (C)

 

[karl riley]

Re: code question

Also the NM sheath must be run inside the pipe, and the panel must be surface-mounted, as I read 312-5(C).

Karl

 

[ron]

Re: code question

Conductor fill is not an issue if the conduit is for protection only. See Ch 9 table 1 note 2.

 

[eanes]

Re: code question

If I am not mistaken, the pipe (sleeve) can be no longer than 2 ft. I'm sure I'll be corrected if I am wrong on this.

 

[george t. everett]

Re: code question

How do we derate these cables? Is a 3-wire cable counted as 2 current carrying conductors?

 

[tom baker]

Re: code question

Ron, was the conduit installed for physical protection or for ease of installation? I feel as the conduit connects to the panel it becomes a raceway system and note 2 does not apply.
334.30 would not apply.
Only the current carrying conductors are counted for derating, its no different than conduit with THHN, including if the neutral is for discharge lighting.

 

[ron]

Re: code question

The terminology is "complete conduit .... system". If the circuit is not end to end conduit, then an arguement can be made not to follow fill derations.

 

[iwire]

Re: code question

On the ampacity adjustment Factors (derating) you can start at 25 amps on 14 awg and 30 amps on 12 awg.

So you can have 9 current caring conductors before you will run into ampacity adjustment problems, more if you can apply 240.4(B) on the 14 awg.

 

[don_resqcapt19]

Re: code question

Ron,
The exception to 312.5(B) that permits this type of installation requires that the Chapter 9 Table 1 and note 9 be used for the raceway fill. If you are not using this exception, then each cable must secured to the enclosure.
Don

 

[skidmark]

Re: code question

Karl hit the nail on the head. According to 312.5(c) this was a code violation. These circuits were being pulled from the basement up into a flush mounted panel. Kudos to Karl!
Thanks to all for the input!

 

[iwire]

Re: code question

Originally posted by skidmark:
According to 312.5(c) this was a code violation. These circuits were being pulled from the basement up into a flush mounted panel.

How did you expect us to know this was flush mounted and the circuits where from the basement?

Thats why Tom's answer was correct (along with Karls)

By Tom

It depends on how it was done.

Bob

 

[websparky]

Re: code question

Bold type added by me.

2002 NEC
310.15 (B)(2) Adjustment Factors.
(a)More Than Three Current-Carrying Conductors in a Raceway or Cable. Where the number of current-carrying conductors in a raceway or cable exceeds three, or where single conductors or multiconductor cables are stacked or bundled longer than 600 mm (24 in.) without maintaining spacing and are not installed in raceways , the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(2)(a).

 

[ron]

Re: code question

Sorry, I had my head stuck on the conduit fill table, and did not adjust my thinking to # of conductors.