Sol-Ark Grid connection options

[wwhitney]

You could add a 200A SUSE enclosed circuit breaker in between the meter and your existing main panel. That circuit breaker becomes the service disconnect and overcurrent device and the only place with a neutral-ground bond. Ideally the load side has double lugs.

Then you run a 200A feeder to your existing main panel from one set of the lugs on the service disconnect. From the other set of lugs you run a 100A feeder tap to your 100A fused PV disconnect. You have a feeder interconnection instead of a supply side interconnection.

Now the 100A feeder for the bypass can run from the main panel to the manual transfer switch through the new service disconnect, the PV disconnect, and the Sol-Ark inverter. Ideally each of those cabinets would be within 24" of conduit run from its neighbors, so that no derating is required.

Cheers, Wayne

 

[PWDickerson]

The split should be after the fused disco for the line-side tap. See hastily sketched attachment. I have drawn a second disconnect (unfused) so you can still power the backup panel from the fused disco and have the inverter de-energized for service.

In that way you can carefully arrange the neutral path so that it follows both the normal path or the bypass path, and there is still only one path for neutral current. Note that if the system is in bypass, the neutral current flowing into and out of the inverter disco and the inverter will cancel and so not create any inductive heating in metal parts. To simplify, I have only shown one line conductor and the neutral conductor.

 

[wwhitney]

On that last diagram, the new "fused disconnect" could instead be a SUSE 100A enclosed circuit breaker. Not sure if that would have any space or cost advantage.

Also, if the POCO doesn't require a PV system disconnect in its own enclosure, the "fused disconnect" and the "inverter disconnect" could be combined into a single enclosure. E.g. a SUSE 200A 4-space panel with a 100A main breaker, a 100A PV disconnect breaker, and a 100A bypass breaker. Physics-wise you only need a 100A bus, but 705.12(B) doesn't have any allowances that recognizes that for busbars with only 3 connections.

Cheers, Wayne