The CMP logs are littered with rejected proposals for this. At this point you'd have do to a peer reviewed study with a worst case arc blast and every combination of 18" nipple would need to be considered, Can I have say a 3" PVC nipple with one 14/2?
and the CMP:
There is no 'cable in a raceway wiring method' your either a cable wining method or a raceway wiring method. A soon as I am a 300.18 complete raceway installation of EMT of FMC wiring method 312.5(C) does not apply.
I would agree with you if 312.5(C) started off "Where cable wiring methods enter a cabinet, . . ."
Of course not worded the best but not as bad as my last post! (but you got what I meant).
Certainly that's the intent. But the meaning under Charlie's Rule should match the intent. Hence a PI is in order.
Which suggests another look at the connector I mentioned in post #7.
It does not need to be required by code to just use a raceway in residential, just lots of people don't think like that, or they pull all the romex then think about the panel later.If the rest of the country would switch to the Chicago Electrical Code, this discussion would go away...that code does not permit cable wiring methods.
I've been saying that for years. It's always the architect who puts it outside because they don't want to figure out where to put it inside, and what do they know about electrical. And it's always in areas where "it's always been done that way". If the NEC prohibited it as they should, it would no longer be a problem. With the increasing use of electronics in breakers, it's only going to create more problems.
This is exactly the kind of thing that the NEC is supposed to be designed to prevent. And yet the code does not read the way they apparently intended it to be used.
I'll reply to myself: UF is allowed in conduit so it is not an issue.
Wayne: How would you propose to secure a cable at a point within the interior of a breaker box? Keep in mind that it's NEMA3 so penetrations are less desirable. I can think of many ways that would be secure, but not necessarily pass inspection. For example, one could epoxy a tie block to the box and tie down to that.
Well, yeah!
Given the intent of the code, then a raceway that is a J Box to a nipple to the back of the box would be fine. But if one runs SER and UF through the nipple, without transitioning to TWHN, then you're back to the "secure" the cable issue, even though it clearly meets the intent of the code and would isolate an arc blast. It seems that the code should be updated to reflect its intent. In fact, the code could state that the purpose of this requirement is to ...
I'd be happy to argue that for SER/UF -- cable clamp -- enclosure -- short nipple -- panelboard cabinet, the SER is secured to the cabinet by transitivity. That is, the SER is secured to the enclosure by a cable clamp; the enclosure is secured to the nipple; and the nipple is secured to the cabinet.
I agree that it is. I am not the expert that most of you are. But I can see why this is likely the most heavily debated provision. I think that expressly stating the intent, limiting the method of securing to a cable clamp that is at the entrance, and expressly stating that entry through a raceway, cable or wire, is permitted, would help to clear this up. Meanwhile, I may consider the unnecessary addition of transitioning to TWHN in the J-Box to avoid rejection.
