mc in plastic boxes

[peter d]

Still no reply from bridgeport now why doesnt that surprise me. Typical new england.

You're more than welcome to stay on Long Island.

 

[nolabama]

330.40 - well i dont know yet - im waiting with baited breath for the ul listing from mr cow to find out what ive been doing wrong lately - i have used rigid couplings to transition from carflex and pvc for some time - i may be wrong with that - but i do know you will not use an mc connector in the back of that particular box

 

[Pierre C Belarge]

And that is certainly false statement by Carlon.

Here is a PVC box covered by 314.3, it happens to be a cantex.

Is adding a KO to this box a UL violation?

Or was the above box manufactured not to be used?

Or are the rules different for smaller boxes and if so where is that explained?

314.3 applies to all non-metallic boxes not just single gang device boxes. :smile:

I am not sure why you have said it is a false statement. Maybe you could contact the manufacturer for more info first.


The standards set forth that manufacturers are required to follow may be the reason for the manufacturers response.

I asked multiple questions to Carlon about plastic boxes, lets see what they have to say when I get the response back.

 

[nolabama]

cant wait - im thinking now this whole install from today is botched :-?

 

[LarryFine]

The pvc in that box is probabbly 1/4 " thick making it difficult to find a connector that has threads long enough to reach the other side of the connector.

You could always use the Carlon box adaptors that pass through the box wall from the inside and glue into a coupling.

 

[RJohnsonMasterElectrician]

I beleive you have to use a grounding bushing if you use mc in a plastic box, and then try to wrap the wire around point of connection

 

[Buck Parrish]

I beleive you have to use a grounding bushing if you use mc in a plastic box, and then try to wrap the wire around point of connection

Why ground a plastic box?

 

[peter d]

Why ground a plastic box?

You have to bond the armor of the MC cable somehow if you happen to terminate it in a plastic enclosure.

 

[Buck Parrish]

You have to bond the armor of the MC cable somehow if you happen to terminate it in a plastic enclosure.

Yeah I thought of that. But then I realized they must have it bonded on the other end.:smile:
Or we're useing AC cable is that the one with the bare aluminum?
I guess it wouldn't matter.

I guess MC is normally bonded by the connectors. Never gave it much thought.:wink:

What are you doing up so late any how?

 

[peter d]

Yeah I thought of that. But then I realized they must have it bonded on the other end.:smile:

True, if it was bonded at one end it wouldn't need to be bonded again. But since I don't know what's on the other end, then it needs to be bonded in the plastic box.

What are you doing up so late any how?

Just wasting my life away.

 

[M. D.]

Well a dead end with internal connections works for me if plastic box to plastic box ,.. but the duplex with 2 MC and a plastic box doesn't cut it . The bond is external .

 

[M. D.]

Wait a minuet,...

SINGLE-GANG BOX
A box nominally 2-1/4 by 4 in. or smaller is intended for one or more nonmetallic sheathed cables to enter through a single or multiple stage knockout opening.

http://database.ul.com/cgi-bin/XYV/...n=versionless&parent_id=1073991695&sequence=1

 

[M. D.]

FWIW ,I just spoke to Brian at Arlington ,.. asked if I could use the one box with M.C. ,.. the answer was an unambiguous no listed for N.M only. He said the pull tests are not the same for NM and MC,. Nm being 25 and MC being 75 pounds ,.. He also said that UL would not even allow them to test that box for mc or conduit.

edit to add;
As someone posted a while ago ,.. they do have a metal version available

 

[steelersman]

You have to bond the armor of the MC cable somehow if you happen to terminate it in a plastic enclosure.

why? the armor isn't a ground.

 

[peter d]

why? the armor isn't a ground.

Because the armor is metallic and must be bonded. It makes no difference that it isn't a "ground." It has to be bonded for the same reason we have to bond all metallic non-current carrying parts.

 

[steelersman]

Because the armor is metallic and must be bonded. It makes no difference that it isn't a "ground." It has to be bonded for the same reason we have to bond all metallic non-current carrying parts.

seems kind of overkill

 

[peter d]

seems kind of overkill

Following the code is overkill? It only had to be bonded once at one end of the other, but it still has to be bonded.

 

[steelersman]

Following the code is overkill? It only had to be bonded once at one end of the other, but it still has to be bonded.

well yeah. Alot of things in the code are overkill.

 

[peter d]

well yeah. Alot of things in the code are overkill.

Well, this is not one of them. So you're suggesting it's ok to leave a metallic part of a wiring method unbonded? Especially something like the jacket of MC cable which could easily become energized?

 

[steelersman]

Well, this is not one of them. So you're suggesting it's ok to leave a metallic part of a wiring method unbonded? Especially something like the jacket of MC cable which could easily become energized?

I've never used MC in Plastic boxes for one. But if I ever did I would imagine that the other end would be connected in a metal box therefore being bonded at the other end. But this makes me wonder, is an MC connector connected to a metal box which is grounded an approved method for bonding?