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Mounting junction box behind panel to feed wires to panel?

Mounting junction box behind panel to feed wires to panel?

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Old 01-19-18, 09:40 AM
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Mounting junction box behind panel to feed wires to panel?

OK, i have a weird situation here. I am surface mounting a new main panel to the outside of my garage. The only access to install the wiring to the house runs in this panel is by two 2 1/2 inch knockouts on the back of the panel going through the wall into the garage. i am planning on mounting a junction box on the inside of the garage directly behind the panel. The wires would come into the junction box and be secured by clamp connectors then run thru conduit nipples into the main panel to go to the circuit breakers.

Is this to Code?

How else could this be done?

skeeter
 
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Old 01-19-18, 10:32 AM
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How come the panel has to be outside? It sounds like a better place for the panel would be where that junction box was going to be.
 
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Old 01-19-18, 10:50 AM
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Well it doesn't HAVE to be outside but it solves a couple problems. If i place it outside it will be a combo panel with meter, main disconnect and circuit breakers. If i place it inside then i still have mount the meter and main disconnect outside for the POCO to have access. But placing the panel outside does pose another problem. Some of the old run wires will not be long enough to go to the panel outside so a splice will have to be made. I should able to splice those wires in the junction box to extend those wires correct?

skeeter
 
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Old 01-19-18, 11:05 AM
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OK, so your disconnect has to be outside due to local issues; that answers that question. I would still put the panel inside but that's just because I won't want to monkey around with stuff while standing in a puddle of water. Anyway, if these nipples are truly just short nipples then you don't have to derate, but you do still have the 60% fill limit (from memory). That junction box is gonna be sizeable.

In fact, here's what I would do if I _had_ to have some breakers outside: Instead of a junction box inside, I'd just mount a subpanel there and reconnect all the existing house wiring right there. So that way you only have a handful of large conductors going through a single nipple. Large loads like A/C could be run outside in conduit directly to the main panel or whatever is easiest.
 
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Old 01-19-18, 11:39 AM
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Outdoor panels are common in some locations, typically nicer climates. I would not want to trudge through a foot of snow to reset a tripped breaker!

I'd go with your pan, mount a 12x12 or 18x18 junction box inside with nipples between the two. Mark the wires in the junction box for the future, and do whatever splices needed. You can also add a grounding bar and terminate all your grounds to that bar and run a single ground wire from the junction box to the main panel (sized to the largest circuit in the junction box). Neutrals will of course need to pass through and terminate in the panel.

Sounds like an easy solution.
 
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Old 01-19-18, 01:22 PM
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I live in beautiful Southern California, where it hardly never snows, rains only sometimes and the regulations and taxes are higher than the summer temperatures.

core,
Really don't want two panels. if i didn,t mind the added expense and work i would put the panel on the inside and the meter with a disconnect on the outside. Trying to avoid that.

Zorfdt,
Thanks for the confirmation that my plan is sound. As for adding a ground bar i think i'll just run all wires sliced or not thru to the main panel. The spliced wires are only temporary until i can completely replace all the original wiring in the house in stages during remodeling.

Another question,
The newly installed romex coming from the house, do i trim the sheath where it comes into the junction box or where it goes into the outside panel?

skeeter
 
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