NEC in the Facility, August 9, 2011

Commonly misunderstood/misapplied terms, part 4.

Commonly misunderstood/misapplied terms, part 4.

Pop quiz: Do explosionproof enclosures protect components from explosions?

Answer: By "explosionproof," the NEC means the enclosure serves as a containment for the explosion. It confines an explosion to its inside rather than protects against one from the outside.

Some other commonly misunderstood terms include:

  • Fitting. A termination isn't a fitting. In a wiring system, a fitting primarily serves a mechanical function rather than an electrical one. A bushing is an example of a fitting. It may also serve an electrical function by preserving electrical continuity of metallic raceway.
  • Garage. It isn't necessarily a place where vehicles are stored. To be designated a garage, it merely needs the realistic potential of serving that purpose (or of being a place where vehicles are sold, rented, repair, exhibited, or demonstrated).
  • Ground. This term has been a source of confusion and friction in the NEC for decades. The NEC definition now is very simply "the earth." The NEC still occasionally uses "grounding" to mean "bonding," but that practice is giving way to this definition.
  • In sight from. This has more meaning than its words indicate. In NEC parlance, it is also 50 ft away or closer.
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