MC in ENT

[LarryFine]

If they insist, what about installing a metal box inside of a larger plastic box, terminate the ENT in the plastic box so the MC goes directly into the correct position in the metal box.

Do they even make plastic 4-11/16" boxes?

Seriously, if they back up the weird request, ash which wiring method should terminate in the KO's. :-?

 

[winnie]

I can see ways in which this is reasonable, and ways in which this is insane.

Picture a totally standard installation using MC. You have runs of MC going from a panel to various junction boxes, device boxes, etc. You also have MC running from one JB to another, etc.

Between termination points, the MC is supported, by being attached to the structure.

If this support is provided by having NMC sleeving which goes from one termination point to the other (with say 6" of gap so that you have room to work), then this is probably a pretty sane installation. Extra work, but it means that you can pull out a length of MC and install a replacement, without moving anything else.

Or, as another poster pointed out, the NMC could be required for feeders, but not for branch circuits.

Or, this could be a totally insane requirement for a complete raceway system installed inside another raceway system, with dual boxes and other insanity

-Jon

 

[Twoskinsoneman]

Do the requirements for a complete raceway or conduit apply when the ENT is not being used as part of the physical structure through which an approved cable assembly is being run? This is akin to a section of conduit being used for physical protection...but what I am envisioning is not a _short_ section as per 300.12 exception.

IMHO if ENT used in this fashion is 'invisible' to the NEC (meaning that it is mechanical structure, but not an electrical component), then good design would still dictate following a number of the raceway rules (conduit fill, bends between pull points, support, etc.)

-Jon

When re-reading this post I got to reading and found 300.15 (c) which seems to indicate that if a short run of coduit is used for protection it has to have fittings on the ends but doesn't have to be ternminated.

When you run direct burial out of the ground through a protective conduit, do you put a fitting on the end?