I have an few questions, which I have been searching for months. Each time I talked to electricians, OSHA and unions, I get a different answer.
Electricians are installing nonmetallic sheathing cable (NM) for temporary lighting and electric power. The NEC 2002 allows type NM cable to be installed in multifamily dwellings and other structures of Types III, IV, and V construction.
1. If the structure we are building is a type I or type II, can I safely say NM cable can not be used as a temporary electrical system?
The proper temporary installation of NM has been confusing. The nature of construction has many different equipment and hazards, such as scissor lifts,materials such as metal studs and HVAC systems (in the ceilings). Numerous trades working around and near the temporary wiring/lighting. The lighting is moved many times during each phase of construction. The system could be in place for a year before it is removed. The NEC states to protect the cable from Physical damage.
2.How do you protect a NM cable from being damaged in construction.
NEC 527.2(A) states, Other Articles. Except as specifically modified in this article, all other requirements of this Code for permanent wiring shall apply to temporary wiring installations.
Since 334.30 states, Securing and Supporting.
Nonmetallic-sheathed cable shall be 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 (41/2 ft) and within 300 mm (12 in.) of every cabinet, box, or fitting. Flat cables shall not be stapled on edge.
3. Does 334.30 apply to NM cable used in a temporary installation in construction? I have read, NM cable shall be supported from 4.5 feet to 10 feet.
I'm confused with the requirements of splices and maintaining the outer sheathing. 527.4 G) states, On construction sites, a box shall not be required for splices or junction connections where the circuit conductors are multi conductor cord or cable assemblies, provided that the equipment grounding continuity is maintained
with or without the box. See 110.14(B) and 400.9.
If a box is not used and the outer sheathing is striped back, do you need to maintain the other sheathing after making the splice? What I have been seeing is the splice is made with wire nuts.
My concerns are for the safety of ALL workers on site. I feel the NM cable in the above described setting could be very easily cut by metal studs. The splice also could be pulled apart exposing a hot wire and energize a metal studs.
Could you please help use better understand the proper safe installation of NM cable?
Thank you..
Electricians are installing nonmetallic sheathing cable (NM) for temporary lighting and electric power. The NEC 2002 allows type NM cable to be installed in multifamily dwellings and other structures of Types III, IV, and V construction.
1. If the structure we are building is a type I or type II, can I safely say NM cable can not be used as a temporary electrical system?
The proper temporary installation of NM has been confusing. The nature of construction has many different equipment and hazards, such as scissor lifts,materials such as metal studs and HVAC systems (in the ceilings). Numerous trades working around and near the temporary wiring/lighting. The lighting is moved many times during each phase of construction. The system could be in place for a year before it is removed. The NEC states to protect the cable from Physical damage.
2.How do you protect a NM cable from being damaged in construction.
NEC 527.2(A) states, Other Articles. Except as specifically modified in this article, all other requirements of this Code for permanent wiring shall apply to temporary wiring installations.
Since 334.30 states, Securing and Supporting.
Nonmetallic-sheathed cable shall be 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 (41/2 ft) and within 300 mm (12 in.) of every cabinet, box, or fitting. Flat cables shall not be stapled on edge.
3. Does 334.30 apply to NM cable used in a temporary installation in construction? I have read, NM cable shall be supported from 4.5 feet to 10 feet.
I'm confused with the requirements of splices and maintaining the outer sheathing. 527.4 G) states, On construction sites, a box shall not be required for splices or junction connections where the circuit conductors are multi conductor cord or cable assemblies, provided that the equipment grounding continuity is maintained
with or without the box. See 110.14(B) and 400.9.
If a box is not used and the outer sheathing is striped back, do you need to maintain the other sheathing after making the splice? What I have been seeing is the splice is made with wire nuts.
My concerns are for the safety of ALL workers on site. I feel the NM cable in the above described setting could be very easily cut by metal studs. The splice also could be pulled apart exposing a hot wire and energize a metal studs.
Could you please help use better understand the proper safe installation of NM cable?
Thank you..
