romex clamps

Status
Not open for further replies.
Not specifically. The best you'll do with the NEC is 110.3(B). If the clamp is only listed for one cable that's all that you can legally use it for.
 
Ditto to what Infinity mentioned. The Arlington 1/2' AND 3/4" "black buttons" will allow you to insert (2) flat cables or (1) round cable. I'm not sure what the Bridgeport metal clamps will allow. It's always best to check the mfr's specs.
 
goldstar said:
The Arlington 1/2' AND 3/4" "black buttons" will allow you to insert (2) flat cables or (1) round cable. ~ It's always best to check the mfr's specs.
Click to expand...

Check again - but they don't do two round cables very well IMO....
 
goldstar said:
Ditto to what Infinity mentioned. The Arlington 1/2' AND 3/4" "black buttons" will allow you to insert (2) flat cables or (1) round cable. I'm not sure what the Bridgeport metal clamps will allow. It's always best to check the mfr's specs.
Click to expand...

Hey goldstar,

Arlington has 1/2' black button connectors :grin:
 
sminor said:
is there a code section that limits the amount of romex cables allowed per clamp?
Click to expand...

If you meant what you wrote, CLAMP, then there is a code section that deals with this indirectly. 110.3(B)

From the UL White Book

METAL OUTLET BOXES (QCIT)





Metallic Outlet Boxes (QCIT)− ​
Continued​







CLAMPS​



Boxes may or may not be provided with clamps. When clamps are provided,





the carton is marked to indicate the type of wiring system or combination
of systems for which they have been tested. The clamps are
marked with the following letters or combinations thereof to indicate that
they are suitable for use with armored cable (??A??): flexible metal conduit
? ??F,?? nonmetallic-sheathed cable ? ??N,?? or flexible tubing (loom) ? ??T.??
Clamps suitable for Type MC metal-clad cable are marked ??MCI?? for
metal-clad interlocking armored cable, ??MCI-A?? for metal-clad interlocking
armor ground cable, ??MCS?? for metal-clad continuous smooth-sheath
cable, and ??MCC?? for metal-clad continuous corrugated-sheath cable. If
suitable for all seven types, the clamp is marked ??ALL.?? Clamps suitable
for nonmetallic-sheathed cable are also suitable for multiconductor underground feeder and branch circuit cable where used in dry locations.
Clamps have been tested for securing only one cable per clamp, except
multiple section clamps are considered suitable for securing one cable​
under each section of the clamp, each cable entering a separate knockout.
 
Last edited:
Of the manufacturer's charts that I've seen for 2-screw 1/2 and 3/4 romex clamps, I have come to one conclusion. If you can physically fit them in the fitting, it's more than likely rated for it.

I still have to smile every once in a while when I open a panel and see that some wise-guy brought 20 romexes through one 2" romex clamp. Makes me wonder if there was ever a "real" inspection.
 
mdshunk said:
Of the manufacturer's charts that I've seen for 2-screw 1/2 and 3/4 romex clamps, I have come to one conclusion. If you can physically fit them in the fitting, it's more than likely rated for it.

I still have to smile every once in a while when I open a panel and see that some wise-guy brought 20 romexes through one 2" romex clamp. Makes me wonder if there was ever a "real" inspection.
Click to expand...

Contradicting yourself a little there my freind?!?!?!? :roll:

Anyway - on the if it fits - its probably rated for it - The 1/2" "Black Button" if you try to get 2 12/3's in it it tears at the insulation and compresses through the jacket - I have even torn the conductor insulation trying to jamb them into them - I gave up - ONE ROUND PER HOLE! Not enough holes - I'll make more....
 
e57 said:
Yes - they do and you can get (2) 12/3's in them - just not very well....
Click to expand...
I agree. If you're using say the newer 12/3 Simpull RX cable it will work fine in the connector. However, inserting two of the older 14/3 and 12/3 round cables into the black button connector does not work well as you pointed out. If you look at the design of the connector you can see how it will hold two (2 conductor) flat cables properly and not allow them to be pulled out. On the other hand, inserting two (3 conductor) round cables may cause damage to the jacket and will not hold properly, irrespective of what the manufacturer says. Just my opinion.
220/221 said:
If they start making them in 2 or 2 1/2 inch I'll be set
Click to expand...
You bet !!! Can't wait until we can slide a 200 amp SEU cable through one of those. Should be a lot of fun :D
 
Pierre C Belarge said:
The clamps are
marked with the following letters or combinations thereof to indicate that
they are suitable for use with armored cable (??A??): flexible metal conduit
? ??F,?? nonmetallic-sheathed cable ? ??N,?? or flexible tubing (loom) ? ??T.??
Clamps suitable for Type MC metal-clad cable are marked ??MCI?? for
metal-clad interlocking armored cable, ??MCI-A?? for metal-clad interlocking
armor ground cable, ??MCS?? for metal-clad continuous smooth-sheath
cable, and ??MCC?? for metal-clad continuous corrugated-sheath cable. If
suitable for all seven types, the clamp is marked ??ALL.??
Click to expand...
A bit of a side bar here but I'm just curious to know this. If you have a metal JB installed with internal clamps that are designed for MC or armored cables and marked as such and you have to install an NMC into the same box, is it acceptable to snap off the rings on that clamp in the field and then use that modified connector to clamp the NMC ?
 
goldstar said:
A bit of a side bar here but I'm just curious to know this. If you have a metal JB installed with internal clamps that are designed for MC or armored cables and marked as such and you have to install an NMC into the same box, is it acceptable to snap off the rings on that clamp in the field and then use that modified connector to clamp the NMC ?
Click to expand...

Just to bust chops, NMC is not really commercially sold "off the shelf", it would most likely be a special order.
But...I knew you most likely meant NM-B cable.

To answer your question, legally no, but it is performed in the field everyday.

Some are using the term "clamp" for romex connectors. The post I presented is for the clamps inside of a metallic box.


All of the conversation we are seeing here is what people do in the field, mostly guess work. The boxes the NM-B connectors come in have the number of cables - sizes of the cable, that are permitted to be installed with that connector. It does not have to be guess work.
 
Pierre C Belarge said:
Just to bust chops, NMC is not really commercially sold "off the shelf", it would most likely be a special order.
But...I knew you most likely meant NM-B cable.
Click to expand...
Good pick-up. Glad to see someone is more awake than I am.;)
 
resistance said:
You miss the joke. Re-read what I wrote.
Hint: 2'
Click to expand...
We didn't miss the joke. The 2' connector is still in the design stage. Now all we need is a 2' knock-out:D
 
e57 said:
Contradicting yourself a little there my freind?!?!?!? :roll:

Anyway - on the if it fits - its probably rated for it - The 1/2" "Black Button" if you try to get 2 12/3's in it it tears at the insulation and compresses through the jacket - I have even torn the conductor insulation trying to jamb them into them - I gave up - ONE ROUND PER HOLE! Not enough holes - I'll make more....
Click to expand...

I thought they called it wire bundling when u put more than 2 wire in a half inch romex conn?
 
Status
Not open for further replies.
Top