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.
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 ?
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
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. Alan--Inspector I would approve the installation.
Cheap, quick fix: nail scrap lumber, insulation board, particle board, etc. around the wall to cover the NM.
Alan-- If it was easy, anyone could do it.
Re: Physical protection#94844 08/23/0508:57 AM08/23/0508:57 AM
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.