Rules Pertaining To Installation Of Type Nm Wire In Attics

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.

Rules pertaining to installation of type nm wire in attics.

Methods of proper attic electrical wiring. Type nm type nmc and type nms cables shall be permitted to be used in the following except as prohibited in 334 12. For this reason the nec has protection requirements for nm cables in an attic. An attic that is accessible which is defined by the nec as having a permanently installed stair or ladder in place must have protection for any cables that run across the top of the attic floor joists or within 7 feet where they run across the face of rafters or studs.

Charlie trout is moving on to retirement. Nm cable is simply a bundle of individual conducting wires wrapped in a plastic vinyl outer sheathing. They also must be secured within 12 inches of an electrical box that includes a cable clamp or within eight inches of a box or enclosure without a cable clamp. Cables shall not be run on or across.

The lower faces of rafters in attic or roof spaces where the vertical distance. Runs of nm cable must be supported at least every 54 inches. Between the joists and the rafters exceeds 1 m i so where the cable is running under the rafters the rafters have to be 1m above the joists. For the next few months tune in for a best of series of code questions of the day by charlie.

2 multi family dwellings permitted to be of types iii iv and v construction. 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. This edition of code faqs will be the last collection of questions and answers he will provide. Nm cable also commonly known by the common trade name romex is the most common form of electrical wire.

The attic wiring should be protected and secured to ceiling joists or other wood structural supports. If you want to wish charlie the best in his retirement please drop him a note to codefaqs. A new writer will be introduced in january. Raul no this is not a standard practice and is most likely the result of improper installation of electrical attic wiring.