Whole house generator w/ solar

[johnny's]

The solar is not connected to the home. It has it's own meter. Grid feeders come in to tap box. From this point feeders go to solar read meter line side. From tap box to residential meter then to main panel. Installing automatic transfer switch connected to residential meter then load side of switch to main. I believe with this set up no inverters or relays are required.

Thanks
Johnny's

 

[ggunn]

The solar is not connected to the home. It has it's own meter. Grid feeders come in to tap box. From this point feeders go to solar read meter line side. From tap box to residential meter then to main panel. Installing automatic transfer switch connected to residential meter then load side of switch to main. I believe with this set up no inverters or relays are required.

Thanks
Johnny's

No inverters? That makes no sense.

I don't really get what you are trying to do, but the PV system (with inverter(s)) in most cases must be connected on the grid side of the transfer switch so that when the grid is down the house gets power only from the generator and the PV system shuts down. If you want the PV system to run when the grid is down you'll need batteries and a specialized inverter or inverters to deal with them.

 

[Smart $]

.... If you want the PV system to run when the grid is down you'll need batteries and a specialized inverter or inverters to deal with them.

Wouldn't a grid-tied PV system connected to the load side of a generator transfer switch work when POCO power is out?

 

[GoldDigger]

Wouldn't a grid-tied PV system connected to the load side of a generator transfer switch work when POCO power is out?

It might work if the generator output is stable enough and presents a low enough impedance to the anti-islanding algorithms in the GTI.
But it would be a very bad idea since nothing in the system would prevent the GTI from trying to reverse feed the generator when local loads were smaller than the PV output.

If you want the GTI to work with a generator during a grid outage you would need a hybrid system with generator support or an output-modulating GTI with a current transformer on the generator feed. The latter are new on the market from Fronius, among others.

 

[GerryB]

I have seen two solar type installs. One taps the supply side conductors, before the main breaker. A generator transfer switch or interlock kit on the main would not backfeed the street or the solar in this case. The other solar install uses a backfeed breaker in the panel. In this case the generator power would go through that breaker to the solar unless you opened the breaker which is probably what you would want to do.

 

[ggunn]

I have seen two solar type installs. One taps the supply side conductors, before the main breaker. A generator transfer switch or interlock kit on the main would not backfeed the street or the solar in this case. The other solar install uses a backfeed breaker in the panel. In this case the generator power would go through that breaker to the solar unless you opened the breaker which is probably what you would want to do.

In the second case you would want to install a protected loads panel as a sub to the main with the generator connected to the sub and the transfer switch between the main and the sub. The PV would backfeed a breaker in the main and would not be connected to the generator during an outage.

This comes up a lot with folks who get solar and have generators. At first blush they say they want the solar to keep feeding the house during an outage, but when they run the numbers they usually see that it's not worth the expense to set up a system that will do that.