Isolating a windmill inverter

[tedge]

I've been discussing this in the contracting forum, but wanted to test the NEC legality of it here.

Situation:

I'm installing a standby generator in a home. I will use an auto-transfer switch to isolate the generator from the grid. The wrinkle is that the house has a grid-tied windmill inverter. I've ascertained that the inverter cannot run while the generator is running for various reasons. I've also found out that the inverter senses the utility AC through the output circuit which is landed on a 2-pole 60A breaker in a sub-panel in the house.

My proposed solution:

Install a relay in the output circuit which will close the circuit with utility power and open it without it, even if the generator is running. I would run a circuit (240v w-grnd) from the transfer switch to a relay with a 240v coil in the house, breaking the output circuit of the inverter.

Is it legal to approach it this way? Again, the entire system will be isolated from the grid by the transfer switch for the generator.

 

[Rockyd]

Good time to call a meeting with your POCO as the utility wants to be addressed of "potential backfeed", regardless of how infinitely small the potential is.

Second, the city inspection department maybe interested. Then again, it maybe decided on what side of the meter you are on. Then it's back to the utility...

 

[tedge]

I will definitely inform all interested parties of my proposal.

Poco up here has no problem with generator installs when done to code. The transfer switch will be installed before the meter (service disconnect rated switch) so they will be involved.

There is no municipal inspector for this area, so a State guy will have to be called.

Just looking to not waste anyones time if I'm not thinking this through correctly.

 

[Buck Parrish]

Won't you need a manual disconnect before the transfer switch?

 

[tedge]

Actually, you're right. I'll have to change the house mounted meter to a pedestal mounted meter disconnnect to meet the poco requirements. They won't allow a switch before the meter. Then the transfer switch will be non-service rated and after the meter.