Line Side Tap & Islanding

[heimdm]

I am planning to get the feedback on my electricians feedback. For the ATS, my thought was to use a service rated one, that way there is a disconnect switch. My understanding of disconnect requirements if that if you have multiple, they have to be labeled as x of y disconnects such a 3 of 5. I have seen requirements that they all be placed together, so if emergency services finds one, they find them all versus play a game of wack-a-mole.

When functioning normally, the gateway wouldn't be engaged as solar backup, which I will need. So obviously some work to be done on this, as to the gateway the only way to the house would be via the grid (from the gateways perspective).

[PVAndy]

Let’s do simple math. Supply line is 320. Size of the main breaker in Tesla GW should be 200A, based on max current from PWs and solar (current design has it more than 200A but since main breaker protects the buss most likely it is acceptable) so it leaves only 120A for both panels.

I am surprised that electric company would allow residential system of this size. CT(my state) has 20KW limit for residential systems. Interestingly enough combined size of my PWs and solar is more but since PW are not expected to feed the grid while solar is active it passed electric company review. I now see that it is theoretically possible for batteries and solar to feed into the grid at the same time since Tesla has a program with electric companies where Tesla sells electricity from customers batteries, with 80% of payment going to customers and 20% to Tesla.

Just wanted to correct one point. Conn does not limit residential solar to 20kW. $200 Utility Interconnect Application limits to 20kW AC. $500 Fast Track application is limited to 2 MW. We have done many over 20kW residential installs. Several around 60KW

Andy

[PVAndy]

Tesla Gateways do not come with a main breaker. One may be added. We typically install one sized to match service if we have Gateway right after meter. If it's downstream of main usually no main in Gateway

[heimdm]

My cost to Duke Energy for the interconnect, I believe was something like $135. My plan is to add batteries later as net metering lasts for about the next 10 years in Indiana. However, if we are going to replace the existing service disconnects, it probably makes sense to do that when Duke is out swapping the meter for a bidirectional meter.

[Will792]

Just wanted to correct one point. Conn does not limit residential solar to 20kW. $200 Utility Interconnect Application limits to 20kW AC. $500 Fast Track application is limited to 2 MW. We have done many over 20kW residential installs. Several around 60KW

Andy

Thank you for your correction. Somehow I misread generating facility interconnect document and it stuck in my memory. I should have known that since my combined solar + PWs power rating exceeds 20KW and I had to use Fast Track application