Is it realistic to have an operational and functioning load center panel (with power supplied only to temporary outlets mounted near the panel), fed by an offgrid solar system, in a half-built residential building?

(The panel would be an outdoor-usable type and would be built and installed as soon as some wall framing was present, the building would then be completed, and the panel would be reworked to provide power to all of the building's circuits as the building was completed.)

Would this require questionable nonsense like having two separate electrical permits? Or is it simply a stupid idea rather than just using a generator or other external power source?

Jurisdiction is the USA, in a rural area where building inspection and permitting is fairly relaxed but still very much a force.

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    Where are you on the planet? (What country?) – Tyson Dec 12 '18 at 10:25
  • USA, in a jurisdiction with fairly light oversight (but which still enforces the NEC) – ikrase Dec 12 '18 at 10:41

If your solar system is large enough to provide power it is legal, sane, and safe. For temporary power all the circuits will need to have GFCI'S, if the panel is exposed to wet conditions you will need a nema 3r type of enclosure (outdoor as you mentioned) the last if not under cover you will not be able to use NMB or Romex wiring it will need to be in conduit and use thhn/ thwn wire. With weather proof boxes , and in use covers. I have seen temporary power using standard breakers and WR rated GFCI outlets this may be a better way to go because the circuit breakers don't have the electronics sealed (I have had to replace GFCI'S in a nema 3r panel in just the last year on one of my temporary power setups).

In my area a temporary power permit is required. If you are only connecting to your own solar system I don't know if I would get a temporary permit, the temporary permit provides an inspection and a green tag so the power company can connect to the panel. If you need more power than your solar can supply then a permit / inspection would be required. In my mind your solar would be the same as running a generator for temporary power and no permit is needed for that.

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    Actually, I'd use UF for temporary wiring in wet/outdoor areas -- conduit isn't really suited for something you'll be ripping up once construction's done :) – ThreePhaseEel Dec 13 '18 at 3:48
  • I would agree but in temp power the wiring still needs protection, it may be tougher for me because of commercial requirements, I have 2 full setups for residential where we drop a temp pole, I also have 3 for the plant locations that we drop 480 to 240 for tools and everything has to be GFCI and conduit to the outlets. Since the temp power is going to end up being inside later I could see an inspector allowing NM but I could not do that , that's why on most jobs we run a generator or set a temp pole. – Ed Beal Dec 13 '18 at 14:14

Since codes are ultimately local, the permitting required would depend on how they do things where you are, there may be an inspection required for temporary power whether it's utility or solar.

As for building the solar power and the main panel first and using them for temporary power during construction - anything's possible but there could be a couple issues.

One of course is whether the solar system supplies and stores enough power. Do you lay everyone off if it rains for a week? Do you need to work after dark or before dawn?

There's also some logistical / safety related issues, you have a little more down time cutting over from temp power to permanent this way. You're going to have to shuffle around some or all of your solar gear from the temp location to the permanent location at some point.

Overall if there's a really big solar system going in anyway, it might be workable, but I really doubt it will be worth the trouble to avoid a portable generator or two and a portable distribution device.

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