Maximum # of nm cables through strain reliefs?

[c2500]

I am hunting for the code article (was looking at 2006 IRC, not NEC as NEC is in the truck) regarding the maximum number of NM cables entering a panel through a strain relief. I know that after two through a fire-stopped hole you derate.

IRC/NEC article anyone?


Thanks,

c2500

[stickboy1375]

I am hunting for the code article (was looking at 2006 IRC, not NEC as NEC is in the truck) regarding the maximum number of NM cables entering a panel through a strain relief. I know that after two through a fire-stopped hole you derate.

IRC/NEC article anyone?


Thanks,

c2500

It would be whatever the connector is listed for...

[e57]

These have a pretty useful range: (http://www.aifittings.com/c_9.htm)

1-14/2 to 1-10/2, 2-14/2 to 2-10/2, 1-14/2 and 1-12/2, 1-14/3 to 1-10/3, 2-14/3 to 2-12/3, 1-14/2 and 1-10/2, 1-12/2 and 1-10/2, 1-14/3 and 1-12/3

[George Stolz]

It would be whatever the connector is listed for...
Which would be 110.3(B). ;)

[c2500]

This may be more an inspector oriented question. I as a rule when using metalic strain reliefs in a 1/2 knockout put no more than 2 #12's NM. That is the way I was taught. Anyway, I ran across a 1" knockout that had alot of #12's as well as #6 NM crammed into it (crammed being the operative description, and it passed a rough inspection). So from an inspector standpoint is there some basic guide/chart that you would base a pass/fail on, with regard to metal strain reliefs?

Thanks,

c2500

[stickboy1375]

Anyway, I ran across a 1" knockout that had alot of #12's as well as #6 NM crammed into it (crammed being the operative description, and it passed a rough inspection). So from an inspector standpoint is there some basic guide/chart that you would base a pass/fail on, with regard to metal strain reliefs?

Thanks,

c2500

If that 1" connector is listed for that many cables then you good to go, but if its not then its simply a violation of the manufactures listing... and as george already pointed out 110.3 (B)

[mdshunk]

So from an inspector standpoint is there some basic guide/chart that you would base a pass/fail on, with regard to metal strain reliefs?

No, no basic guidelines. If you're lucky enough to find out who manufactured the connector, then you need to figure out the model. Every manufacturer has different guidelines. Arlington, for instance, puts them online very nicely for us. I printed out their chart to keep with me, since that's the brand I use most. FWIW, I've never seen any job done by anyone failed for too many cables in one connector. I guess it's just too much of a pain to worry about? I took the panel cover off a 10 or 15 year old townhouse the other day, and found every single cable in the panel entering through one 2" connector.

[c2500]

Stickboy,

I am looking for some kind of rule of thumb. Realistically, the packaging for the reliefs is not going to be sitting around. Especially if in an existing house and a home inspector calls attention to the issue. I have read 110.3 and get it, I am just looking for a more generalized answer.

c2500

[iwire]

Which would be 110.3(B). ;)

That is kind of the catch all, but IMO 300.15 is more direct.

'Fittings and connectors shall only be used with the specific wiring methods for which they are designed and listed'.

[stickboy1375]

Stickboy,

I am looking for some kind of rule of thumb. Realistically, the packaging for the reliefs is not going to be sitting around. Especially if in an existing house and a home inspector calls attention to the issue. I have read 110.3 and get it, I am just looking for a more generalized answer.

c2500

sorry I dont have one for you...

[c2500]

Thanks Marc.

[benaround]

May I ask why the use of a strain relief connector on nm cable ? Thanks

[mdshunk]

May I ask why the use of a strain relief connector on nm cable ? Thanks
I think that's what some people call an ordinary romex connector. I've heard it a few times before. When I hear "strain relief" I think more of a Kellems type connector or a connector with a rubber gland inside.

[George Stolz]

FWIW, I've never seen any job done by anyone failed for too many cables in one connector. I guess it's just too much of a pain to worry about?
It is one of the inspection agency's pet peeves around here. But that's not to say they'd catch anything else. ;)

[George Stolz]

That is kind of the catch all, but IMO 300.15 is more direct.
Ahh, but 15 NMs in a 1/2" connector would still be compliant with that section, IMO. It's still NM in an NM connector. ;) :D