NEC Quiz: Article 406, Part 2 Answers

by Mark Lamendola

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  1. In the general installation requirements, we find 406.4(C) Methods of Grounding. So at first blush, it appears you ground a receptacle. But read more closely. You're connecting it to the equipment grounding conductor (EGC). The EGC is actually a bonding jumper that has, by long tradition, been misnamed a "grounding" conductor. Refer to the Article 100 definitions of grounding and bonding. This confusing misuse of the word "grounding" occurs elsewhere in this Section. At some point in a future revision of the NEC, this will be cleared up. Over the past few Code cycles, the NEC has made huge progress on this issue. Clearly, more progress is yet to be made.

  2. First of all, non-grounding type receptacles don't solve noise problems. It's debatable whether isolated ground receptacles do either, though those are often recommended for such problems. Sometimes, a grounding-type receptacle is used in an old home with a two-wire system. There's no EGC in the cabling, so unless you can run that EGC you don't install a grounding-type receptacle. I've pulled such receptacles out and put the old style back in, because using them without an actual EGC connection can cause safety problems.

    The answer depends upon whether there is an EGC. If an EGC, use a grounding type receptacle. The NEC has a really good solution, for when there is no EGC. Use a GFIC that is marked "No Equipment Ground." See all the rules on this issue in 406.4(D)(1) and (2).

  3. The receptacle must be installed such that the yoke (or strap) is held rigidly at the finished surface [406.5(A)].

  4. The receptacle must be installed such that the yoke (or strap) is held rigidly against the box or box cover [406.5(B)].
  5. The receptacle must be installed such that the yoke (or strap) is held against the cover by more than one screw [406.5(C)]. Alternatively, you can use a device assembly or box cover listed and identified for securing by a single screw.