Rules Pertaining To Installation Of Type Nm Wire In Attics

Raul no this is not a standard practice and is most likely the result of improper installation of electrical attic wiring.

Rules pertaining to installation of type nm wire in attics.

Nm cable must be supported by framing when running through walls ceilings and floors. A loose cable like in the photo above gets caught in the spring mechanism of a pull down folding ladder at the attic opening and frayed. For this reason the nec has protection requirements for nm cables in an attic. The number and the content of code question of the day submissions concerning the installation of nonmetallic sheathed cable suggests vast differences among or lack of proper inspection of electrical installations using type nm cable as the wiring method.

Damaged cables can cause a short circuit or even worse arcing that will start a fire in the attic. It is a really stiff but flexible wire that will not break and you can feed it through the hole in the attic down the wall and out the place where you intend to put the jack. If this meets code then i will be running attic wiring in this manner from now on. Whenever i do attic wiring i remove the insulation and staple it to the ceiling joist.

I was also under the impression that if wiring is in an attic space that it may need to be derated because it can get very hot up there. The attic wiring should be protected and secured to ceiling joists or other wood structural supports. Most of the wiring in a modern home consists of runs of nonmetallic sheathed cable or nm cable also known by the popular brand name romex. Type nm cable may be installed exposed section 334 10 of the 2002 nec section 336 4 of the 1996 and 1999 nec 1 one or two family dwellings of any height may use type nm section 336 4 2 not including specific locations such as flammable or combustible liquids storage areas or wet locations etc.

It is what all the pros use for pulling wire. Normally the cables carry 10 12 or 14 gauge conducting wires for individual house circuits. I am looking to run several nm 12 2 and 14 2 wires in my attic the entire length of the house. I am trying to do everything to code both for safety and for inspection.

Methods of proper attic electrical wiring. The national electrical code nec outlines specifications for securing nm cable and other electrical wiring.