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#164621 - 06/07/07 09:17 AM Question about metal boxes
EV607797 Offline
Member
Registered: 10/25/06
Posts: 756
Loc: Fredericksburg, VA, USA
Does anybody know what the letters "N" and "T" indicate on Romex clamps with metal boxes? The N is on one side and the T is on the other. I don't think it has anything to do with the manufacturer because I have seen this on several different brands. It's just one of those things that I have always wondered.
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#164636 - 06/07/07 04:28 PM Re: Question about metal boxes [Re: EV607797]
GTE Offline
Member
Registered: 03/26/03
Posts: 48
Loc: Bridgehampton, N.Y. USA
nob & tube
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#164639 - 06/07/07 05:31 PM Re: Question about metal boxes [Re: GTE]
e57 Offline
Member
Registered: 05/27/03
Posts: 2837
Loc: S.F.,CA USA
I'm not one who could bag on spelling... Isn't it Knob & Tube? Nob is a town in Isreal.

Otherwise, I have no idea.
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#164662 - 06/08/07 08:35 AM Re: Question about metal boxes [Re: e57]
Alan Nadon Offline
Member
Registered: 03/10/05
Posts: 398
Loc: Elkhart, IN. USA
The mark is to show what the clamp is listed for. I'm sure the N is for NM cable. Don't know about the T.
Stop at the supply house and look at their box catalogue it will have all the clamps listed. That is where I had to go last time to check on AC cable clamps.
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#165288 - 06/25/07 04:27 AM Re: Question about metal boxes [Re: Alan Nadon]
electure Offline


Member
Registered: 12/24/00
Posts: 4229
Loc: Fullerton, CA USA
From the UL White Book:

"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 nonmetallicsheathed
cable are also suitable for multiconductor underground feeder and
branch circuit cable where used in dry locations."
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#165306 - 06/25/07 09:03 AM Re: Question about metal boxes [Re: electure]
Alan Nadon Offline
Member
Registered: 03/10/05
Posts: 398
Loc: Elkhart, IN. USA
Thank You.
Alan--
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Alan--
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