What is the maximum spacing requirement for securing NM-cable (nonmetallic-sheathed cable)?
Friday, June 15, 2018
NM-cable must be secured and supported every 4.5-feet (1.4-meters) by staples, listed cable ties, straps, hangers or similar fittings, or other similar fittings that are designed and installed so that they do not damage the cable. A second requirement is that the cable be secured 12-inches (300-millimeters) of the cable entry into any enclosure, such as an outlet box, junction box, cabinet or fitting. Also, flat cables should not be stapled on edge. Cables that are protected from damage by a raceway do not have to be secured inside the raceway (NEC 334.30).
When the cable is within an accessible ceiling of a one-, two-, or multi-family dwelling that is dropped or suspended, the cable can be run up to 4.5-feet to a connection point of a luminaire (light fixture) or other piece of electrical equipment. So, if luminaires in an accessible ceiling are no more than 4.5-feet apart, the cable can be run from fixture-to-fixture without support or junction boxes [NEC 334.30 (B)(2)].
When the cable is installed through bored holes in studs, the studs cannot be more than 4.5-feet apart and, again, the cable must be supported within 12-inches of a box [NEC334.30(A)]. The hole in a stud cannot be less than 1.25-inches from the face of the stud, or 1/16-inch thick steel plate must be installed to protect the cable from drywall nails or other wall penetrations [300.4(B)(2)].
Also, see our blog post What are the code requirements for NM-cable (nonmetallic-sheathed cable or Romex®) in an attic?
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