My question concerns the proper installation of low voltage INTERIOR wiring.

Planning on installing stair lights in the hallways. Drywall will be removed so there is access. Lighting choice is 120V or low voltage. If I use the 120V they would be connected using FMC and a ground wire.

The only thing I see in my 2005 NEC book on low voltage is for recreational vehicles, unless I missed it somewhere:o. Several years’ back, in a kitchen remodel, low voltage under cabinet lights were installed, and they simply ran the wire between cabinets.

If I go with the low voltage, are there NEC codes, or best practice, etc, for running the low voltage wires behind the walls?

Low voltage wiring is now covered by the newly created NEC Article 411, found here at the 2008 edition of the NEC On Line Access: NFPA 70: National Electrical Code® (http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=70&cookie_test=1).

This was created to help with wiring for lighting specifically, so much more popular nowadays, and will refer to Article 725 for details, that has been around for years covering low voltage systems. The relevant codes from 725 were reduced to those needed for lighting, due to the wide scope of 725, and helps to identify this type of system as Class 2.

So, you can use Romex (NM-B), FMC, or a low voltage cable rated minimum Class 2.

Tk- Thanks for the 2008 update. I did reference 725 and other low voltage sections in my 2005 book, but as you stated it's more fully detailed in the 2008 version.

There is NO WAY I'd run low voltage wiring in the walls for lighting. You are forever bound to lo-vo then. At least until you re-wire again.

I would run typical AC wiring and use lo-vo fixtures of that is what pleases you.

Stan,
Good point on the using 120V. Since I'll have the drywall off, it was kind of either/or, as I'll have access to the install the wiring and was just wondering what was easiest to run.

While I'm on the subject, and after reading the 2008 code, it sounds like the current setup of the undercabinet lights is not compliant. The wires to the puck lights appear to be cloth/woven(?) covered, two separate wires (not jacketed) run between the cabinets from the transformer to the lights. No markings on wire so I can't tell if rated class 2. Any thoughts? Replace the current wire with known class 2?