Electricians - Help Needed

Factual Questions
1

I’m installing a new subpanel in my garage and as part of the work I’ve got to splice together some 2-ga cable (there’s a long run of 2-ga THHN in metal conduit and another long run of 2-ga Romex and they have to be joined).

The splice is going to be enclosed in a big metal box per code (I live in the SF Bay Area in case there are regional variations).

So here’s my question - how am I supposed to cover each individual splice?

As an example, the white neutral from the Romex gets spliced to the white neutral wire from the THHN in the conduit. Mechanically these two wires are connected using a “Splicer/Reducer” which is basically a little metal block with a hole down its length, you strip about 1/2" insulation from each wire, feed them in from opposite ends, and then there are two setscrews that you tighten down to hold the two wires in place. No problem there except that the metal block is too big for me to put heat-shrink tubing over it (I’ve got 3/4" tubing and that is just a hair to small, which means it’d probably tear when I heat it anyhow).

As far as I can tell it’s a no-no under the NEC to wrap the splice in electrical tape, so what do I use? For smaller wires (10-ga and below) I’d just use wirenuts but I haven’t seen anything like that for bigger wires (for those wondering, 2-ga stranded is about 1/4" in diameter after you strip off the insulation).

Since the work is being done with permits and the splices may well be inspected I want to do this the right way.

Things that I can’t do:

  1. Change the wiring to eliminate the splice.
  2. Depend on the inspector not wanting to go into the crawlspace to check the splices.

Things that I can do:

  1. Pull the splice apart and redo it in place so it’s up to code.

Any licensed electricians know how to do this? I’d be much in your debt!

Thanks!

2

I would use a terminal box.

The terminals are fixed within the box and the box itself it made of an insulating material.

We in the UK call Romex T&E (twin and earth) and we use metric wire sizes so I can’t tell you what capacity the wire is and therefore what size terminals would be needed.

Over here we might use a 40amp terminal box for a garage.

I would recommend that you try to make this box as accessible as you can.

There is no need to splice in the way you describe.

3

Any licensed electricians know how to do this? I’d be much in your debt!

Looks like you answered your own question. Pay the man who knows what he’s doing.