Bare ground or insulated, in conduit or not

[48Rob]

I am running 8 AWG cable from my array on an exterior wall, down into a plastic disconnect on the exterior wall with waterproof fittings, then back up through a gland into an unfinished attic, and then as I drop into the finished space downstairs, it will be run in PVC conduit.

Does the entire run (attic, and exterior to/from the disconnect) need to be in conduit, or is it optional? PVC okay or should it be metal?

I also need to run my ground wire from, and to, the same locations. Should it be insulated, or uninsulated in the attic section, and can it be run together with the array cables through the attic?

Rob

 

[glandpuck]

Only Romex can be in the attic without being in a conduit. The ground in Romex will be bare, but covered by the sheath. Wires like THHN should be in a conduit. Your ground wire should also have an insulating jacket when run in the conduits. Bare copper ground wire is okay for outdoors, but you should try to use a green/green-yellow insulated wire in conduit for the ground. In the attic, PVC is okay, outside PVC is okay, wet areas PVC okay. EMT in places like garage.

 

[Mike 134]

ALL DC wiring must be in metal conduit inside a building!!! AC can be whatever your local authority allows. Ground wire should be run inside the conduits.

 

[glandpuck]

ALL DC wiring must be in metal conduit inside a building!!! AC can be whatever your local authority allows. Ground wire should be run inside the conduits.

His original post did not contain information on whether he was running AC or DC current from his array. But you are correct if he is running DC current.

 

[pvgirl]

PV circuits need to be in conduit once they leave the array, the ground wire from the array needs to run with the PV circuits to the inverter, in the same conduit. Metal conduit is required anywhere the circuits are inside the building, note NEC 690.31(D)(1) Flexible Wiring Methods if using FMC or MC cable. If you happen to still be NEC 2017 after the first disonnect inside the buiding you are no longer required to be in metal conduit, but you still need to be in conduit, etc. Ground wire can insulated or bare, it must be at least 6 AWG when ran exposed in the array, but can be reduced to 10 AWG in the conduit run.

 

[48Rob]

Thank you.

Sorry for the omission. I am running D/C.

Is this style flexible metal conduit acceptable?

 

[pvgirl]

Thank you.

Sorry for the omission. I am running D/C.

Is this style flexible metal conduit acceptable?

That conduit is fine for runs inside the building, it can not be used outside.

 

[48Rob]

Thank you!

 

[Siamac]

That conduit is fine for runs inside the building, it can not be used outside.

Why?

So outside use plastic flexible conduit such as this?

https://www.amazon.com/gp/aw/d/B09NNDG19Z?psc=1&ref=ppx_pop_mob_b_asin_title

And inside use the metallic conduit linked above?

Run the PV cable in the conduits to the inverter? Where does disconnect fit and how to transition from plastic to metal conduit?

(I was thinking of putting one plastic disconnect where the panels connect to 8 AWG PV cable, and then another disconnect right before the inverter. But the inverter has PV on/off switch. Does that change anything?)

 

[glandpuck]

Yes. But if you are in USA, then you will do much better at HD, Lowe's, or a local electrical supply like City Electric. Your outside PVC conduit can also be rigid (only the grey PVC for electric) and glued together (only PVC glue for electric). Please watch some youtube videos on flexible metallic conduit, flexible non-metallic conduit, rigid metallic and rigid PVC as well as terminations and making connections. Of importance is being able to drill holes or punch holes into electrical boxes. The dimensions of electric is the inside size. So for a 1" conduit fitting, you would drill a 1+3/8" hole, for a 1.5" conduit, you would drill a 2" hole. 3/4" a 1" hole. There are tables online of what size hole to drill or punch with a kit (amazon).