A switch up… Electrical Installation issues
We have a little DIY work adding a switch to some lighting.
Exposed Type NM cable (or what many call Romex) must closely follow the surface of the building or structure per Sec. 334.15(A).
NM cable (Nonmetallic-sheathed cable/Romex) must be protected from physical damage.
This can be either by rigid metal conduit (RMC), intermediate metal conduit (IMC), Schedule 80 PVC conduit, Type RTRC-XW conduit, electrical metallic tubing (EMT), guard strips, or other means approved by the authority having jurisdiction (AHJ) [334.15(B)].
When installed within a raceway, the cable must be protected from abrasion by a fitting installed on the end of the raceway [Sec. 300.15(C)].
If Type NM cable is installed in a metal raceway, the raceway isn’t required to be connected to an equipment grounding conductor (EGC) [Sec. 250.86, Exception No. 2 and Sec. 300.12, Exception].
If Type NM cable is installed at angles with joists in unfinished basements and crawl spaces, it’s permissible to secure cables containing conductors not smaller than two 6 AWG or three 8 AWG conductors directly to the lower edges of the joists. Smaller cables must be installed through bored holes in joists or on running boards.
Type NM cable installed on a wall of an unfinished basement or crawl space subject to physical damage must be protected in accordance with Sec. 300.4, or be installed within a raceway with a nonmetallic bushing or adapter at the point where the cable enters the raceway, and the NM cable must be secured within 12 in. of the point where the cable enters the raceway.
Then we have securing of the cables.
334.30 Securing and Supporting
Nonmetallic-sheathed cable shall be supported and secured by staples, cable ties, straps, hangers, or similar fittings designed and installed so as not to damage the cable, at intervals not exceeding 1.4 m (4½ ft) and within 300 mm (12 in.) of every outlet box, junction box, cabinet, or fitting. Flat cables shall not be stapled on edge.
Sections of cable protected from physical damage by raceway shall not be required to be secured within the raceway.
Simply draping the cable over air ducts, rafters, timbers, joists, pipes, and ceiling grid members is not permitted, except where fished as allowed in 334.30(B)(1).
Two-conductor NM cable (or other flat configurations) is prohibited from being stapled on edge (that is, with its short dimension against a wood joist). When stapled in this manner, two cables are usually placed side by side under the staple. If the staple is driven too far into the stud, damage to the insulation and conductors could occur. See 300.4(C) for support requirements of cables through spaces behind panels designed to allow access.
(B) Unsupported Cables.
Nonmetallic-sheathed cable shall be permitted to be unsupported where the cable:
(1)Is fished between access points through concealed spaces in finished buildings or structures and supporting is impracticable.
(2)Is not more than 1.4 m (4½ ft) from the last point of cable support to the point of connection to a luminaire or other piece of electrical equipment and the cable and point of connection are within an accessible ceiling.
So there we have it.
If you find any errors or have additional information that would expand on any code, building standards or manufacturer requirements please let me know.
NCW Home Inspections, LLC is a Licensed Washington State Home Inspection service located in Wenatchee Washington serving Chelan County, Douglas County, Kittitas County, Okanogan County and Grant County Washington and the cities of Wenatchee, Leavenworth, Cashmere, Oroville, Cle Elum, East Wenatchee, Quincy and many more…
Your Wenatchee and Chelan Professional Real Estate, Home and Structural Pest Inspection Service
Coordinator & Instructor- Fundamentals of Home Inspection- Bellingham Technical College
Former WA Home Inspector Advisory Licensing Board
www.ncwhomeinspections.com 509-670-9572
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