DadBald
Well-known member
- Thread starter
- #1
Here's a summary of my situation. It's still a bit long, so TL;DR at the bottom!
I'm close to pulling the trigger on a solar system for my house. I have 150A service currently, and the solar backfeed maxes out my panel with the 120% rule; but I don't need to change anything yet. I'll have 30A of backfeed. I could probably get away with a 100A circuit for a Lightning 80A charger how it is now. But I'll be maxed out in this scenario.
Adding a Lightning, mostly charging at home, with about as much as I expect to drive annually, I will about double my home electric consumption. So, after 12 months I may double the size of my solar system too, to cover the EV charger usage. This would necessitate 60A backfeed from solar to my electric panel though - similar to a Lightning whole-home backup from my guess. But 60A backfeed would require 300A service to the house. I believe SunRun recommends something like 320A service to the house for the Lightning's home backup function. I think it's just because of the backfeed size and the 120% rule. So this all makes sense.
I may add a second EV charger in the future, upgrade my woodshop subpanel, or, if electrification takes off like some estimates predict, we may swap our gas appliances to electric ones way out in the future. These would all benefit from, or be enabled by, a bigger service feed to the house.
Problem is, I can't find any 300A panels. 400A seems a more available size, but even these are hard to come by for a 1 phase 120/240V 3-wire panel. I found one for $500, but main breakers for it are around $1500, and regular 15-20A breakers for that panel are $50. With 30 breakers, you can see the cost is becoming astronomical pretty quickly.
An alternative would be to go for a 225A panel, which is the biggest that seem to be commonly available for residential. The 120% rule would allow 270A on the bus - if I put in a 200A main breaker, it gives me up to 70A backfeed. So my future solar plans of 60A backfeed could work with this configuration. My biggest concern here is whether I could do 2 EV chargers plus home A/C and whatever other loads I have from my woodshop and the wife and kids inside on the 200A main breaker. Yes, my cars will almost certainly charge overnight... but I guess I can't guarantee on a weekend with a lot of driving we won't have both cars charging during the day with the A/C running in the summer. My electrician said this would certainly be pushing the limits, but it doesn't necessarily violate any codes. I agree it might be worth a shot. I just really don't want to spend all this money upgrading service to 225A and realize later I need 300 or 400.
Materials costs for 225A service and main panel replacement will end up being less than half the cost of 400A. I'm getting about $3-4000 just for the panel and breakers for 400A. I'm guessing $1500-2000 would do it for 225A materials.
So - does anyone have any suggestions here? Should I spring for the 400A service for future-proofing? It seems excessive, but if I need it later I'll be thankful I did it now. Prices are only going up, and I get to bundle it with my solar project for basically 26% off through the federal tax credit by doing it now.
TL;DR - Contemplating upgrading to 225A or 400A electric service to my house. Future plans may involve two 100A circuits for EV chargers, plus A/C, a woodshop, and other misc house loads. Depending on the climate regulations, we may switch appliances to electric in the future (on natural gas for now).
I'm close to pulling the trigger on a solar system for my house. I have 150A service currently, and the solar backfeed maxes out my panel with the 120% rule; but I don't need to change anything yet. I'll have 30A of backfeed. I could probably get away with a 100A circuit for a Lightning 80A charger how it is now. But I'll be maxed out in this scenario.
Adding a Lightning, mostly charging at home, with about as much as I expect to drive annually, I will about double my home electric consumption. So, after 12 months I may double the size of my solar system too, to cover the EV charger usage. This would necessitate 60A backfeed from solar to my electric panel though - similar to a Lightning whole-home backup from my guess. But 60A backfeed would require 300A service to the house. I believe SunRun recommends something like 320A service to the house for the Lightning's home backup function. I think it's just because of the backfeed size and the 120% rule. So this all makes sense.
I may add a second EV charger in the future, upgrade my woodshop subpanel, or, if electrification takes off like some estimates predict, we may swap our gas appliances to electric ones way out in the future. These would all benefit from, or be enabled by, a bigger service feed to the house.
Problem is, I can't find any 300A panels. 400A seems a more available size, but even these are hard to come by for a 1 phase 120/240V 3-wire panel. I found one for $500, but main breakers for it are around $1500, and regular 15-20A breakers for that panel are $50. With 30 breakers, you can see the cost is becoming astronomical pretty quickly.
An alternative would be to go for a 225A panel, which is the biggest that seem to be commonly available for residential. The 120% rule would allow 270A on the bus - if I put in a 200A main breaker, it gives me up to 70A backfeed. So my future solar plans of 60A backfeed could work with this configuration. My biggest concern here is whether I could do 2 EV chargers plus home A/C and whatever other loads I have from my woodshop and the wife and kids inside on the 200A main breaker. Yes, my cars will almost certainly charge overnight... but I guess I can't guarantee on a weekend with a lot of driving we won't have both cars charging during the day with the A/C running in the summer. My electrician said this would certainly be pushing the limits, but it doesn't necessarily violate any codes. I agree it might be worth a shot. I just really don't want to spend all this money upgrading service to 225A and realize later I need 300 or 400.
Materials costs for 225A service and main panel replacement will end up being less than half the cost of 400A. I'm getting about $3-4000 just for the panel and breakers for 400A. I'm guessing $1500-2000 would do it for 225A materials.
So - does anyone have any suggestions here? Should I spring for the 400A service for future-proofing? It seems excessive, but if I need it later I'll be thankful I did it now. Prices are only going up, and I get to bundle it with my solar project for basically 26% off through the federal tax credit by doing it now.
TL;DR - Contemplating upgrading to 225A or 400A electric service to my house. Future plans may involve two 100A circuits for EV chargers, plus A/C, a woodshop, and other misc house loads. Depending on the climate regulations, we may switch appliances to electric in the future (on natural gas for now).
Sponsored
