Here are two seemingly conflicting “correct” answers. I can only think that the “Sub-Panel” descriptor makes the difference?
Can anyone help me out? I am losing confidence in going through these test questions.
Thanks JJ. So, to be clear, if it is a single wire (conductor), then secured 8" above panel and if it is the entire 3-wire cable, then 12 inches before?
Matt, some general rules:
- cables entering a panel (or other enclosures) need to be secured to the panel
- individual conductors have to be protected by something like a conduit, you cannot just run them like you can NM (romex) cable.
For the most part, only a GEC would be entering a panel without some sort of raceway.
Having said that, NM cables need to be secured within 12 inches of an enclosure or 8 inches if the cable is not secured where it enters the enclosure – this mostly applies to plastic electrical boxes that don’t clamp the cable. Here is the exception where you don’t have to secure the cable to the enclosure:
1 Like
Thanks Simon!
The first question should say cable not conductor for the reasons Simon mentioned. Also there is no such thing as a retainer bushing in the NEC. Whomever wrote the question should use the proper terminology not slang words. What is a retainer bushing?
3 Likes
It’s that bloody thing, you know, the one you stick into the box and it holds the cable in place 
1 Like
So if we substitute NM cable connector for retainer bushing how do they get the 12" answer in question #2? Are they referring to 312.5(C)Exception?
No, I don’t think so. I believe both questions are about the single exception where it’s a plastic outlet box without a clamp and otherwise 12 inches is the answer. All NM cables entering an enclosure through means of a knockout (without use of a raceway of any kind) must be secured to the enclosure. I’m not aware of any exceptions to this rule other than the one I posted. Therefore, both questions are improperly worded and have incorrect answers. As I noted in the other thread from a day or so ago, many of these questions are improper/incorrect and have been this way for years.
3 Likes
Correct. And generally denied by people in charge.
1 Like
I didn’t either but that’s about as close as you can get to an answer that makes any sense since they used the words before the panel in the “correct” answer.