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#94837 - 08/15/05 07:26 PM Physical protection  
George Little  Offline
Joined: Jan 2004
Posts: 1,489
Michigan USA
We have an inspector in our area who wrote a violation quoting 334.15(B). The installation involved installing NM cable horizontally through the studs in an unfinished garage. The inspector wanted the wiring to go up and over instead of around the garage at about 3 feet above the floor. What is the opinion of this forum?

I told him to count his belssings because I didn't think plastic NM cable boxes were Listed for use in exposed wiring. Seems like this came up a few years ago at an IAEI code panel and a UL guy made a point of this.

George Little

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#94838 - 08/15/05 07:55 PM Re: Physical protection  
George  Offline
Joined: Feb 2002
Posts: 375
I would suggest protection is necessary.

#94839 - 08/15/05 08:13 PM Re: Physical protection  
walrus  Offline
Joined: Jul 2002
Posts: 680
Bangor Me. USA
If he ran the NM up and over and then down would he need protection for the portion that came down??. The original description would pass in Maine without a doubt.

#94840 - 08/15/05 08:28 PM Re: Physical protection  
luckyshadow  Offline
Joined: Jan 2005
Posts: 307
Maryland USA
Go into my garage and you will see romex running through the wall studs at about 3' off the floor. Inspector had no problem with it. Is this a local "code" thing or is the inspector pushing his own ideas on you ?

#94841 - 08/15/05 09:30 PM Re: Physical protection  
gfretwell  Offline

Joined: Jul 2004
Posts: 9,124
"Physical damage/protection" always seems to be a local decision.
"Subject to physical damage" is always a subjective question. [Linked Image]

Greg Fretwell

#94842 - 08/15/05 09:31 PM Re: Physical protection  
e57  Offline
Joined: May 2003
Posts: 2,876
Around here NM and MC for that matter, is subject to damage <8'AFF. In fact we do alot of corrections on exactly that type of work. It's obvious of the hazard when you walk in to do the work, and find all kinds of things hanging on it. Like crowbars, boxes stuffed into the stud-bays, and once, a kayack tied to it. Even above 8', we pipe it unless it is planned to be rocked.

As far as Code goes, "protected from physical damage where necessary", is pretty subjective, and lends alot to the AHJ.

As for the boxes, as you mention,
314.17 (C) Nonmetallic Boxes and Conduit Bodies.
Nonmetallic boxes and conduit bodies shall be suitable for the lowest temperature-rated conductor entering the box. Where nonmetallic boxes and conduit bodies are used with open wiring or concealed knob-and-tube wiring, the conductors shall enter the box through individual holes. Where flexible tubing is used to enclose the conductors, the tubing shall extend from the last insulating support to not less than 6 mm (1/4 in.) inside the box and beyond any cable clamp. Where nonmetallic-sheathed cable or multiconductor Type UF cable is used, the sheath shall extend not less than 6 mm (1/4 in.) inside the box and beyond any cable clamp. In all instances, all permitted wiring methods shall be secured to the boxes.
Sounds like the boxes need clamps for NM....

Mark Heller
"Well - I oughta....." -Jackie Gleason

#94843 - 08/16/05 12:53 PM Re: Physical protection  
Alan Nadon  Offline
Joined: Mar 2005
Posts: 399
Elkhart, IN. USA
You forgot to read the exception that followed the rule. "...where the cable is fastened within 8 inches..."
An AHJ could argue that the box is not IN a wall but it would be a weak case.
I would approve the installation.

Cheap, quick fix: nail scrap lumber, insulation board, particle board, etc. around the wall to cover the NM.

If it was easy, anyone could do it.

#94844 - 08/23/05 08:57 AM Re: Physical protection  
Mvannevel  Offline
Joined: Mar 2003
Posts: 29
Hesperia, Michigan, USA
I'm not sure where your area is at George (I believe you're in Michigan too), but it's come up in mine as well. I personally have always allowed it and will continue to do so. 334 permits NM for exposed and concealed work. I doubt that where run through bored holes around the perimiter of a garage, it's any more subject to physical damage than it is where it's run through bored holes in floor joists in a basement. How many times have you seen the lady of the house use those cables to store clothes from on hangers? In fact, if you think about it, it's probably more likely to be damaged where it's stapled down the side of a stud. As stated earlier, "subject to physical damage" is a rather subjective phrase.

#94845 - 08/23/05 12:21 PM Re: Physical protection  
SolarPowered  Offline
Joined: Jul 2004
Posts: 625
Palo Alto, CA, USA
... and find all kinds of things hanging on it. Like crowbars, boxes stuffed into the stud-bays, and once, a kayack tied to it.

How many times have you seen the lady of the house use those cables to store clothes from on hangers?

I don't think I'd call that, "Subject to physical damage." I'd call it, "Failure of foolproofing, due to development of a better fool." [Linked Image]

#94846 - 09/02/05 06:48 PM Re: Physical protection  
tom25  Offline
New Member
Joined: Sep 2005
Posts: 5
What is the difference with NM cable installed in bored holes within the floor joist in an exposed basement ceiling.

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