DeFreitas Enterprises
Member
- Location
- Chelmsford, MA, USA
What's up everybody. Been a while since I posted but haven't had any crazy designs until now.
I have a client in Western MA who is getting a (55) panel, 19.525 kW DC, 16.2 kW AC install (LG 355 Mono-X! panels and Enphase IQ7+ microinverters).
He wants battery backup, and I was able to convince him to wait a little longer for the battery technology to develop further. I have my eyes set on Enphase's IQ8 technology, but it keeps getting delayed.
Never the less, we will be using microinverters, so the battery backup needs to be AC coupled. There are no DC strings to intercept since everything is 240Vac off the roof.
I am planning on adding a critical loads / backup panel, which will also act as the solar subpanel for the (4) 20 amp branch circuits. I want to have everything set up for the battery backup, and only have to add in the inverter and battery, or Enphase's batteries, whichever technology we go with.
Here are my questions / concerns:
It is looking like I will need a very large panel, possibly a 200 amp subpanel for this application. 80 amps for the solar branch circuits, maybe 60 amps for a 10 kW inverter for the battery circuit, and all the critical loads (maybe another 60-80 amps). This is leaning me towards a 200 amp subpanel.
I have never wired a 200 amp subpanel off a 200 amp MSP. I do not want to do a lineside tap, since we would in theory be at risk of overloading the conductors coming in for the 200 amp service. I have not made note of their size yet, but I will next time on site.
My electrician seems to think we will be able to use a 200 amp breaker like any other subpanel install, but I think he may be mistaken here. I can't imagine the size of the terminals to accept the proper sized wire for 200 amps. I have only seen 100 amp breakers, never anything higher.
I am hoping some of y'all can help guide me through this. I will be having a professional electrical engineer stamp and approve my design, since our install is above 15 kW AC this is a requirement here in National Grid service territory. He seems pretty unfamiliar with all this residential backup technology so I wanted to look elsewhere for assistance.
Thanks in advance and solar on my friends.
-Alex DeFreitas
I have a client in Western MA who is getting a (55) panel, 19.525 kW DC, 16.2 kW AC install (LG 355 Mono-X! panels and Enphase IQ7+ microinverters).
He wants battery backup, and I was able to convince him to wait a little longer for the battery technology to develop further. I have my eyes set on Enphase's IQ8 technology, but it keeps getting delayed.
Never the less, we will be using microinverters, so the battery backup needs to be AC coupled. There are no DC strings to intercept since everything is 240Vac off the roof.
I am planning on adding a critical loads / backup panel, which will also act as the solar subpanel for the (4) 20 amp branch circuits. I want to have everything set up for the battery backup, and only have to add in the inverter and battery, or Enphase's batteries, whichever technology we go with.
Here are my questions / concerns:
It is looking like I will need a very large panel, possibly a 200 amp subpanel for this application. 80 amps for the solar branch circuits, maybe 60 amps for a 10 kW inverter for the battery circuit, and all the critical loads (maybe another 60-80 amps). This is leaning me towards a 200 amp subpanel.
I have never wired a 200 amp subpanel off a 200 amp MSP. I do not want to do a lineside tap, since we would in theory be at risk of overloading the conductors coming in for the 200 amp service. I have not made note of their size yet, but I will next time on site.
My electrician seems to think we will be able to use a 200 amp breaker like any other subpanel install, but I think he may be mistaken here. I can't imagine the size of the terminals to accept the proper sized wire for 200 amps. I have only seen 100 amp breakers, never anything higher.
I am hoping some of y'all can help guide me through this. I will be having a professional electrical engineer stamp and approve my design, since our install is above 15 kW AC this is a requirement here in National Grid service territory. He seems pretty unfamiliar with all this residential backup technology so I wanted to look elsewhere for assistance.
Thanks in advance and solar on my friends.
-Alex DeFreitas