Sheath is too short! Can I finish in EMT?

Question

Gah!! My fat, expensive #4 SE cable going to a subpanel... Somebody stripped the sheath a little too far back. I have tried my darnedest and cannot find enough slack to bring the sheath inside the panel.

So here's my plan. I want to use a 1" knockout to a very short nipple to a 4-11/16 square box, which will be barely an inch from the panel. I want to enter the SE cable into a knockout in the square box, and fit it down properly with a cable clamp. Then run its bared wires through the nipple into the panel proper and to the lugs.

Here's my worry. It is not legal to unsheath a cable and use its individual conductors in place of THHN wire, mainly because those individual conductors are not marked/listed as such. Would this count as that naughty thing, or would it be OK because it is shch a short hop?

Answer 1

Technically it would be a nipple and the code does allow for certain liberties in nipples such as larger fill requirements and no derating of conductors. I wouldn't call a short piece of SE "unsheathing to use as individual conductor". Also consider the alternative, which would be to splice say THWN to the SE. What would be worse? The small piece of SE extended or a splice where you have to leave accessible to maintain the splice, since splices are 80% of all electrical conductor problems.

In short it's all a matter of following code to the letter or the actual intent of the code. Personally I would just as soon reduce the number of splices over any other alternative.

Answer 2

I like the idea of heat-shrink tubing. Runner-up: Install your 1" EMT or GRC nipple say 8" or so long, secure if necessary. Put a rigid coupling on the out end of the nipple; install a 1" NM connector into the coupling. Install SE into the NM connector. This nipple is now simply a sleeve that is being called into a little extra duty. The splice represents a far greater liability than the XHHW run through a short piece of conduit.

Answer 3

If it is very close consider using a Meyer's hub or similar to raise the connector up to 1" away from the panel so it can clamp on the cable.

If it is further away than 1" you could insall a (supported) conduit nipple with the SE connector on the end of it. No need for a J-box. It will be ugly but it will satisfy the Code requirement for physical protection.

Here's my worry. It is not legal to unsheath a cable and use its individual conductors in place of THHN wire, mainly because those individual conductors are not marked/listed as such. Would this count as that naughty thing, or would it be OK because it is shch a short hop?

Actually, they may not be individually marked but they are listed and the cable is marked. Here is an excerpt from the 2015 UL White Book:

SERVICE CABLE (TXKT) SERVICE-ENTRANCE CABLE (TYLZ) GENERAL This category covers service-entrance cable designated Type SE and Type USE for use in accordance with Article 338 of ANSI/NFPA 70, ‘‘National Electrical Code’’ (NEC). Service-entrance cable, rated 600 V, is certified in sizes 14 AWG and larger for copper, and 12 AWG and larger for aluminum or copper-clad aluminum. The cable is designated as follows:

Type SE — Indicates cable for aboveground installation. Both the individual insulated conductors and the outer jacket or finish of Type SE are suitable for use where exposed to sun. Type SE cable contains Type RHW, RHW-2, XHHW, XHHW-2, THWN or THWN-2 conductors. Maximum size is 4/0 AWG copper or 300 kcmil aluminum or copper-clad aluminum.

The exact type of wire would depend on the manufacturer and should be labeled on the packaging and sheath.

Good luck with your project!