I am replacing my main breaker panel and want to add a cutoff breaker inline before the new panel. To do so I will need to lower the new panel about a foot. The problem is that the sheathing on the 14/3 feeder wiring does not extend down the wires into the panel. It has been stripped off and stops right at the bottom of the cable clamps. The wire above the new lower main panel would have the hot, neutral and ground wires exposed above the top of the panel where the sheathing stops. Is it acceptable to run these wires inside stubs of conduit coming out of the top of the new main panel? I'd rather not have to wire nut new Romex onto all the runs above main panel and have them secured in junction boxes.
Can't do it. There must be at least 1/4" of sheath past the cable clamp. No cable clamp.
Also there are painful limits on number of jacketed Romex cables in conduit. You can't just cram 'em in.
Only if you put a junction box at the top of the conduit
Fit a junction box there, then use a less-than-2-foot run of conduit called a "nipple".
Consolidate all the grounds into a single ground wire (of the largest size) that you carry through the conduit. If you use steel boxes and EMT conduit (if indoors) or Rigid conduit (if outdoors), then the conduit itself carries the ground, and you can terminate at the junction box itself (get a box with a raised nub for the ground screw).
Given that all your cables are 14/2, each cable splice takes 8 cubic inches (2" x 4 wires), and you lose another 4 cubic inches for all cable clamps and all grounds. That means:
- A 4" square box takes 2 splices
- A 4-11/16" square box takes 4 splices
- A 6"x2" box takes 8 splices
- A 6"x4" box takes 17 splices
"But I'm not splicing! I'm rolling the individual Romex conductors right on through to the panel!" Yeah, that's not allowed by Code because those individual wires are not rated for conduit use. You're meant to splice to another wire type (THHN). I don't seriously expect you to do that... however I want to make sure you already have the cubic inches in the junction box, in case you get flagged and are forced to do them. If you don't have to replace the junction box, then you could do it one pair at a time and not get too confused. Otherwise, what a mess!
One thing you really must do, in any case, is bundle/group your wire pairs/triples. You can't simply have a spew of blacks and a spew of whites raining down from the conduits. You have to mark, in the main panel, which hots go to which neutral. That's as easy as wrapping the pair/triplet with electrical tape positioned so it'll be visible in the main panel.
As mentioned, grounds can be consolidated in the junction box to a single wire (of the largest size), and if metal, can simply be pigtailed to the box itself.
This may be moot, though. Outside may be mandatory
The upcoming NEC, 2020, has only been adopted by one state (Mass.) AFAIK. Once your state adopts it, you must put the disconnect outdoors. Mind you, all the existing houses are grandfathered, and aren't required to retrofit a disconnect... but even under grandfathering, any step must be in the right direction. Once NEC 2020 is adopted in your state, the disconnect will have to be outside. Word to the wise: get that permit pulled soon if you want it indoors.
Put the cutoff outside, at the meter socket
I can understand wanting a cutoff ahead of your panel; this is a very nice thing to have, as it makes servicing the actual panel a snap compared to the more conventional configuration where the service disconnect is in the main panel with always-hot service entrance conductors coming in from a separate meter base.
The solution, though, isn't to try to wedge another thing in inside the house. Instead, the better place to put it is outside, next to the meter, as that positions you quite nicely for compliance with the 2020 NEC's emergency-disconnect requirements, and also allows you to accomplish this relatively inexpensively using a device called a meter-main or Combination Service Entrance Device (CSED). Note, though, that the installer of this will have to run a full four-wire feeder from this new cutoff to the existing panel, and they also may have to relocate the termination of your Grounding Electrode Conductor into the new meter-main from where it lands right now. Finally, before you go shopping for new hardware, you'll need to consult your utility's service equipment rules, as utility requirements for metering equipment can be somewhat idiosyncratic.