Roof system connected to remote pedestal.

[electrofelon]

I have a roof mount PV system where it is not possible to get to the panel inside the structure. The feeder come from a pedestal UG and thru the slab into the middle of the house. The meter pedestal is a 200A meter main with spaces after the main and feed thru lugs which is what is serving the house. I am confused about which ways are acceptable to interconnect the PV system to the pedestal. My first though is to run a 100A feeder over and set a panel in the carport (attached to the house) which would also be handy for other stuff. However this gets into two feeders serving the building, 225.30. There doesnt seem to be an exception for a PV system, or does "parallel power production system" cover it? I dont see a definition of "parallel power production system".

What about setting up such that it is in inverter output circuit and not a feeder, would that make a difference?

Code is 2017, and inverter would likely be a string inverter.

 

[wwhitney]

or does "parallel power production system" cover it?

Sounds like it to me. PV is a power production system, and it's operating in parallel with the utility. See the definition of "interactive system" for something that uses similar terms. As well as the discussion of "power production" in Article 705.

How are you going to comply with 705.12(B) at the pedestal? The 2017 NEC doesn't explicitly address feed thru lugs.

Cheers, Wayne

 

[electrofelon]

Sounds like it to me. PV is a power production system, and it's operating in parallel with the utility. See the definition of "interactive system" for something that uses similar terms. As well as the discussion of "power production" in Article 705.

How are you going to comply with 705.12(B) at the pedestal? The 2017 NEC doesn't explicitly address feed thru lugs.

Cheers, Wayne

Yeah certainly makes sense, I just always envisioned something else when reading that section.

Regarding the busbar in the meter main, I dont know how the AHJ treats that here as I have never needed to cross that bridge. One option would be to downgrade the main breaker in the house panel to 150A. Another would be to move the house feed off the main lugs and into a 125 branch breaker (both if load calc allows).

 

[wwhitney]

Another option, which might take care of both of your issues at once, would be to intercept the underground conduit just outside the house, bring the conduit and the feeder up outside the house and back again, and put in a feeder splice and PV disconnect on the outside of the house. Then you get to use the feeder interconnection rules, and there's no question on 225.30. This assumes that the panel in the middle of the house has a main breaker.

Having never tried to do that, not sure how difficult that is in practice. The feeder interconnect could also be at the pedestal, if that's easier.

Cheers, Wayne