If your wiring job is in the United States, Mexico, or Venezuela, most likely it has to comply with the National Electrical Code (NEC). This is a hefty volume containing over 900 pages of carefully worded regulations pertaining to all residential, commercial, and industrial wiring installed in jurisdictions that have adopted the Code—which is to say that they have enacted it into law. No matter what type of electrical job you're performing, the NEC is a great resource to consult.
Current edition of the National Electrical Code
The NEC is administered by the National Fire Protection Association (NFPA), a non-governmental organization that also issues documents concerning electrical and other safety issues. On its own, the NEC has no legal standing. It is offered up for states and municipalities to enact as they see fit into law, with or without cuts, additions, or changes. Besides legal jurisdictions, private organizations such as insurance companies and all sorts of builders use NEC guidelines to ensure that the work does not contain hazards.
The NEC explicitly states that it is not an instruction manual for untrained persons. It focuses strictly on electrical safety, particularly from the standpoint of the twin demons of electrical fire and shock, although other hazards are addressed as well. For example, a length of improperly secured conduit could fall, injuring a passerby.
As mentioned, the NEC is lengthy and packed with technical information. However, there is good news: it is sensibly worded and impeccably organized so that individuals with knowledge of the basics can quickly find information relating to the job at hand and apply it as needed. The best professional electricians keep a copy of the NEC in shop or vehicle and refer to it on a daily basis.
NFPA issues a new edition every three years, often with extensive revisions. It is the key reference for electrician licensing exams, which are usually open book, and electrical inspectors invariably make use of it.
In most jurisdictions, homeowners are permitted to perform wiring on their primary residences. Typically, this may not be done on second homes or rental properties, and certainly a developer is not permitted to do unlicensed electrical work on buildings under construction. Every homeowner who is serious about protecting lives and property should have a copy of the NEC and refer to it as needed.
An example of an NEC Article
If you want to get a feel for the kind of distinctions that are characteristic in the Code, turn to Article 100, Definitions. Here are the first three entries:
- Accessible (as applied to equipment). Admitting close approach; not guarded by locked doors, elevation, or other effective means.
- Accessible (as applied to wiring methods). Capable of being removed or exposed without damaging the building structure or finish or not permanently closed in by the structure or finish of the building.
- Accessible, Readily. Capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to actions such as to use tools, to climb over or remove obstacles, or to resort to portable ladders, and so forth.
The classic example of a location that is accessible but not readily accessible is the area above a suspended ceiling, where individual panels can be easily replaced, but where a portable ladder would be required.
Throughout the NEC, various types of equipment, such as entrance panels, are required to be readily accessible, or such as live terminals are required to be not accessible.
By Guest Columnist David Herres