Multiple cables through single knockout

[dnem]

Trevor the question is not about nipples but cable clamps.Be it integral nm clamps or ko clamps.What are they listed as far as capacity goes.I would have to say that if the listing has been tested for one nm cable under each clamp,then to place 2 cable assys. under that same clamp would be a violation of the listing.Since they have only been tested with that one cable under the clamping device.To say if they are strong enough for one then they will be ok for two is a silly argument.Why stop at 2 why not 3 or 4 or 5 if the fit.
Just because there are 4 openings in a 1 gang NM box doesn`t mean that you can put 4 12/2`s and a device in that box.

I disagree with several of your points.

"I would have to say that if the listing has been tested for one nm cable under each clamp,then to place 2 cable assys. under that same clamp would be a violation of the listing."
Using a device in a way that it has not been tested is not a violation. . Lack of testing could be cited by the AHJ as a reason for not accepting it but that doesn't mean that it's a violation of the code. . It's not a violation.

"Since they have only been tested with that one cable under the clamping device.To say if they are strong enough for one then they will be ok for two is a silly argument."
It may be an argument that you wouldn't accept as the AHJ, but it's not a silly argument. . It's a logical argument. . A Romex connector actually has some squeezing pressure to hold whatever is passed thru it. . What kind of holding ability does the nonmetallic box tab have to hold ?Multiple cable entries? ?in a single cable knockout opening? [314.17(C)X] ? . Sometimes the box tab doesn?t even survive the insertion of a single Romex.

"To say if they are strong enough for one then they will be ok for two is a silly argument.Why stop at 2 why not 3 or 4 or 5 if the fit."
Why stop at two ? . That?s what the manufacturers have asked. . That's why they don't stop at 2. . Did you look at the link that Allen posted ?
http://www.aifittings.com/c_19.htm

"Just because there are 4 openings in a 1 gang NM box doesn`t mean that you can put 4 12/2`s and a device in that box."
That depends on the sq" capacity of the box. . But that's not what's being debated right now.

David

 

[dnem]

What I'm saying is that you could put 100 current carrying conductors through a nipple and not worry about derating, so why should there be a concern about derating for multiple cables into a connector.

A nipple isn't restricted bundling. . 334.80 says "bundled" and "thermal insulation or sealing foam" which traps the heat from escaping.

A clamp is more like a 334.80 situation and less like a nipple situation.

 

[dnem]

http://www.aifittings.com/c_19.htm

Even if you had no connector what-so-ever, how do you squeeze 4 14/2 Romexs thru a 1/2" KO ? . Now add a connector of some type. . I don't care what kind of configuration the BT50 is, how does all of that fit thru a 1/2" KO ?

 

[allenwayne]

http://www.aifittings.com/c_19.htm

Even if you had no connector what-so-ever, how do you squeeze 4 14/2 Romexs thru a 1/2" KO ? . Now add a connector of some type. . I don't care what kind of configuration the BT50 is, how does all of that fit thru a 1/2" KO ?

You would be surprised as to what can fit in a 1/2 in ko !!!!!I had an inspector call me a few years ago knowing I was in the area and asked me to come look at something.The piece worker had a bathroom with an exhaust fan and 4 vanity strips and he used the fan as a juction for everything.So there was 1 sw. leg and 4 jumpers in a bath fan !!!! No connector but he did make the splice (don`t know how)So don`t say it can`t be done it has !!!!!!!

 

[infinity]

Trevor the question is not about nipples but cable clamps.Be it integral nm clamps or ko clamps.What are they listed as far as capacity goes.I would have to say that if the listing has been tested for one nm cable under each clamp,then to place 2 cable assys. under that same clamp would be a violation of the listing.Since they have only been tested with that one cable under the clamping device.To say if they are strong enough for one then they will be ok for two is a silly argument.Why stop at 2 why not 3 or 4 or 5 if the fit.
Just because there are 4 openings in a 1 gang NM box doesn`t mean that you can put 4 12/2`s and a device in that box.

I used nipples as an example. David mentioned about derating. My point was that even if you were permitted to put say 10 cables through a connector derating would never apply.

 

[LarryFine]

Even if you had no connector what-so-ever, how do you squeeze 4 14/2 Romexs thru a 1/2" KO ? . Now add a connector of some type. . I don't care what kind of configuration the BT50 is, how does all of that fit thru a 1/2" KO ?

It's not that hard to do. a 1/2" KO isn't all that tight. Remember, it's actually 7/8", and if you divide that by 4, you still get almost 1/4" per 14-2. If you stack four 14-2's flat to flat, they'll fit easily.

Several years ago, I had an inspector dis-allow three 14-2's through a plastic pop-in, so I re-did them with two cables per pop-in, and later checked with Halex. They said only one cable per, so I didn't say anything else to the inspector.

 

[JOEE]

I finally spoke with RACO regarding this. Basically I was told that it's fine to have two NM cables in one priout, as long as the other priout also has a cable in it. He also said that there's nothing official stated from them, because they feel that it doesn't pay to UL relist it. He mentioned that years ago when they were originally listed, the cable pull out test was done at 60 lbs per clamp and now it's down to 25 lbs. Thanks again for everyone's advise.

 

[jonesjax]

T&B 3202 non metalic con

T&B 3202 non metalic con

http://www.tnb.com/ps/fulltilt/index.cgi?part=3202

 

[allenwayne]

I used nipples as an example. David mentioned about derating. My point was that even if you were permitted to put say 10 cables through a connector derating would never apply.

You are correct derating would not apply.But there are no connectors rated for 10 cables.The OP was about how many cables can be used on a listed cable clamp,integral for this post not derating.