AC disconnect location

[ian04]

Here is where I am with my solar installation. I have 26 Canadian Solar 260 panels with enphase 215 micro-inverters mounted on a pergola. There are two circuits of 13 panels each and the two enphase cables are routed to a waterproof junction box on the pergola. I'm in the process of finding an electrician to hook the system up to PG and E but would like some feedback as to what to expect. I'm unsure where the AC disconnect should go. My plan is to have the two circuits wired directly into a 100A sub panel with a 20A breaker each. The sub panel is in a farm shed right next to the pergola and easily reached with 10 feet or so of conduit. This is very convenient. However, the sub panel is 75 feet from the main house service (200A) and was installed years ago with #8 copper and protected by a 50A breaker. An electrician has indicated that this is adequate for my solar. The question is where does my AC disconnect go and what size should it be? I just discovered that the utility co. would like it within 10 feet of the main service but will allow exceptions. I'm getting conflicting ideas from local electricians and would like some advice.

Thank you,
Ian04

[ian04]

I should have provided more information. I have a permit from the county for the solar system including the pergola complete with engineering specs. I purchased the solar panels, etc. from Renvu, constructed the pergola, and have completed the solar installation up to connecting to the utility company. My question is should I have an electrician install an AC disconnect between the pergola junction box and the sub panel or between the sub panel and the 200A main service? Or does it matter? The sub panel is 75 feet from the main service.

Thank you.

[solarix]

Well, you have left the troublesome part for last..... Your utility probably wants the disconnect to be located next to the main meter - although they often allow exceptions if you put a permanent map as to where to find the disconnect in an emergency. With two 20A solar circuits, they need to be combined and fed through a 40A breaker into a 200A panel. Using the barn subpanel isn't going to happen.

The average electrician doesn't have experience with backfeeding solar, the average utility doesn't really appreciate losing your revenue - you really need to get a solar installer to help interconnect your system.

[paul65k]

My set-up is very similar to yours. They did not require an AC disconnect as the system is fed through a sub panel through a stacked 20A set of breakers. We simply added placards to the Subpanel indicating that the disconnect was inside the panel and then marked the breakers accordingly. There is also a placard at the meter which only have the single 200A breaker that feeds the subpanel, which in turn feeds the AC units Directly as well as 2 additional sub panels within the 2 separate living areas of the home, and a separate circuit to the shed......they were fine with the breaker functioning as the AC disconnect as long as access to the subpanel was unfettered.

We are not in an area where the subpanel needs to be secured otherwise we could have simply added an AC disconnect just outside of the subpanel............not sure if this helps or if you can provide access to the subpanel easily but it could be worth asking with your local building department.

Good luck!

[ian04]

Thanks for the responses. I just found an electrician who does solar and he pretty much confirmed that I don't need an AC disconnect because my sub panel is accessible. But the placards have to be in the right place. He's going to finish the wiring this week and then hopefully it'll pass the final and start producing power.