Custom Home Service Set up

[Huffman]

I'm building a new home from the ground up. I would like to set up my service configuration for a backup generator system, a future PV system and possibly a battery backup that would work with a PV system and provide power if the utility power went down.

At this point I'm thinking of installing a meter/main with a single 200 amp breaker that would feed a 200 amp sub panel with a generator interlock kit. The PV system and battery backup part of the equation is the part where I don't know what would be the best route. Any suggestions would be greatly appreciated!

 

[Dennis Alwon]

Are you hoping to get power from the solar and the generator at the same time? Not sure about that. I wouldn't rely on solar for when the power goes out but rather as a sell back to the utility.

 

[infinity]

Doesn't the PV system automatically get disconnected when the POCO power goes out?

 

[Huffman]

Are you hoping to get power from the solar and the generator at the same time? Not sure about that. I wouldn't rely on solar for when the power goes out but rather as a sell back to the utility.

what I'm thinking is for now install a generator interlock kit on the main panel so when power goes off I can turn off the main and turn on the generator. Then in the future install a battery system like a powerwall that can be charged from a PV system or from the original generator if I lose power or if I want to power my home off of solar. Basically an off-grid system that's still tied to the grid.

All of this might be over the top, but since I'm starting from scratch it would be nice to install a system that has the most amount of flexibility for whatever they come up with in the future.

 

[Huffman]

Doesn't the PV system automatically get disconnected when the POCO power goes out?

Yes but Tesla claims that their powerwall battery system can work with or without utility power. So if the utility power goes down your home can still be powered by solar panels feeding the power wall. I can't say that I've seen or heard of anyone successfully testing this claim. I also don't know how a system could be designed so that there would be no possibility of back feeding the utility and possibly injuring a lineman.

 

[GoldDigger]

Look for "hybrid" inverter/charger systems that specifically feature "generator support".
Long term vendors of this combo selling in the US are Outback and Schneider (formerly Xantrex).
They include a transfer switch for the utility side and current sensing on the generator connection that will prevent the PV from trying to backfeed the generator when the load plus battery charging is lower than the full PV output.
For more discussion you can search for generator support on PV forums such as solarpaneltalk.com.

Sent from my XT1585 using Tapatalk

 

[Huffman]

Look for "hybrid" inverter/charger systems that specifically feature "generator support".
Long term vendors of this combo selling in the US are Outback and Schneider (formerly Xantrex).
They include a transfer switch for the utility side and current sensing on the generator connection that will prevent the PV from trying to backfeed the generator when the load plus battery charging is lower than the full PV output.
For more discussion you can search for generator support on PV forums such as solarpaneltalk.com.

Sent from my XT1585 using Tapatalk

This is exactly what I was looking for. Thank you for the input!

Now for the bonus round. How would you tie it in to the system/service? I would like to have a meter with a 200 amp single main breaker feeding a 200 amp panel. However I'm thinking that I'm going to have to make it a 200amp service with a 100amp breaker feeding a 200 panel to leave available space for solar on the bus bar.

 

[GoldDigger]

This is exactly what I was looking for. Thank you for the input!

Now for the bonus round. How would you tie it in to the system/service? I would like to have a meter with a 200 amp single main breaker feeding a 200 amp panel. However I'm thinking that I'm going to have to make it a 200amp service with a 100amp breaker feeding a 200 panel to leave available space for solar on the bus bar.

The bonus round is more complicated than that because the transfer switch involved will be built into the hybrid inverter, which has one grid input (AC 1), one generator input (AC 2) and one AC output for your critical loads.
When you do this, you do not require any separate load shedding logic, but you have to manually or automatically limit the loads on AC OUT whether you are on grid or on generator.
For the purpose of connecting to the grid along with grid-only loads and selling power back, you consider the AC 1 connection to be a GTI backfeed, with all that involves in terms of 120% rule, etc. But with the complication that it is sometimes an actual load instead.
There are configuration options that include selling back or not selling back to POCO when the grid is up, and automatically starting and stopping the generator as needed when the grid is down.
These hybrid inverters were often used for supplementing generator use when there never was a grid connection. With current battery costs they do not make economic sense with a grid connection unless you put a high value on "clean" quiet power for long grid outages.

This equation is potentially being changed with the introduction of the PowerWall.

Sent from my XT1585 using Tapatalk

 

[Huffman]

The bonus round is more complicated than that because the transfer switch involved will be built into the hybrid inverter, which has one grid input (AC 1), one generator input (AC 2) and one AC output for your critical loads.
When you do this, you do not require any separate load shedding logic, but you have to manually or automatically limit the loads on AC OUT whether you are on grid or on generator.
For the purpose of connecting to the grid along with grid-only loads and selling power back, you consider the AC 1 connection to be a GTI backfeed, with all that involves in terms of 120% rule, etc. But with the complication that it is sometimes an actual load instead.
There are configuration options that include selling back or not selling back to POCO when the grid is up, and automatically starting and stopping the generator as needed when the grid is down.
These hybrid inverters were often used for supplementing generator use when there never was a grid connection. With current battery costs they do not make economic sense with a grid connection unless you put a high value on "clean" quiet power for long grid outages.

This equation is potentially being changed with the introduction of the PowerWall.

Sent from my XT1585 using Tapatalk

I think at this point I'm going to install a fusible meter/main 200amp feeding a 200 amp panel with a spare conduit from both the main and sub panel to the side of my house where I can put an inverter, generator or battery back. That way I can be able to swap out the fuses to a smaller size if I need to make room for solar. Also i will be able to install the hybrid inverter as an ATS to back feed my sub/main panel. Hopefully this makes sense. When in doubt run a spare.