Electrical conduit for PV system in exterior wall
Electrical conduit for PV system in exterior wall
(OP)
Hello,
I'm working on a plan to install 4kW, 1-phase, 240VAC, grid-tied, micro-inverter based, Photo-Voltaic System no a rooftop in a multi-unit residential building. I wanted to inquire if it is an acceptable practice to run the AC cables from the rooftop junction box to the PV AC Disconnect on the buiding's exterior wall, in EMT conduit installed inside the building's exterior wall. Exterior wall cladding work is also planned around the same time, so I wanted to inquire if it is acceptable to run the EMT conduit inside of the exterior wall.
This work is conducted on an existing building, so going through the attic and ceiling space of the building is not an option. Another alternative could be installing the EMT conduit from the rooftop junction box on the surface of the exterior wall. I'd appreciate your comments/suggestions on the best practice to install the EMT conduit from the rooftop junction box to the PV AC disconnect on the exterior wall. Also, is rigid EMT conduit preferable or flexible, galvanized steel conduit?
Thank you.
I'm working on a plan to install 4kW, 1-phase, 240VAC, grid-tied, micro-inverter based, Photo-Voltaic System no a rooftop in a multi-unit residential building. I wanted to inquire if it is an acceptable practice to run the AC cables from the rooftop junction box to the PV AC Disconnect on the buiding's exterior wall, in EMT conduit installed inside the building's exterior wall. Exterior wall cladding work is also planned around the same time, so I wanted to inquire if it is acceptable to run the EMT conduit inside of the exterior wall.
This work is conducted on an existing building, so going through the attic and ceiling space of the building is not an option. Another alternative could be installing the EMT conduit from the rooftop junction box on the surface of the exterior wall. I'd appreciate your comments/suggestions on the best practice to install the EMT conduit from the rooftop junction box to the PV AC disconnect on the exterior wall. Also, is rigid EMT conduit preferable or flexible, galvanized steel conduit?
Thank you.






RE: Electrical conduit for PV system in exterior wall
Regarding "rigid emt", there is no such thing, nor is there flexible emt. Flexible metallic conduit (galvanized or aluminum) is not acceptable in wet locations including where exposed to rain, however flexible liquid tight conduit is. Exposed runs of any distance are best done in a non-flexible raceway such as emt, galvanized rigid, or aluminum rigid conduit.
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Me wrong? I'm just fine-tuning my sarcasm!
RE: Electrical conduit for PV system in exterior wall
RE: Electrical conduit for PV system in exterior wall
Bends can and should be used to deal with this type of stuff, as well as the problems of cumulative expansion and contraction of the raceways and conductors.
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Me wrong? I'm just fine-tuning my sarcasm!
RE: Electrical conduit for PV system in exterior wall
Is there a maximum vertical drop length after wich bends should be used, something like a rule of thumb?
RE: Electrical conduit for PV system in exterior wall
Rule 12-120
Appendix B; Notes on 12-120
Table 21
Also;
12-516 Protection for cable in concealed installations (see Appendix G)
Other options are Rigid PVC Conduit, NMD or AC cables with a junction box to transition to a wiring method suitable for exposed locations where the cable exits the wall.
Best to talk to a local residential Electrical contractor. He will know the most cost effective method that is acceptable to the local AHJ.
Bill
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"Why not the best?"
Jimmy Carter
RE: Electrical conduit for PV system in exterior wall
EMT should be fine in the application you describe. My only concern would be if it is a high traffic area, I would reccomend RMC for the bottom section.
JFPE