I am owner-builder on a (mostly) new construction project (I say "mostly" because the basement is already finished, but the main floor is being completely replaced plus an addition). I will be doing most of the electrical design and installation myself, although I will have a professional check all of my work at the time they install the new meter panel and connect my new sub panels. I am planning for a future solar array and electric vehicle charger. I was hoping to bounce my plan off some some experts here to be sure I'm on the right path.
I currently have 100A service to the house which is serving a single 100A sub panel in the basement. My plan is to have this upgraded to 400A service at the meter panel outside, which would serve the 100A sub panel in the basement, another 100A sub panel in the main part of the house, a 200A panel for the garage and kitchen addition, and possibly a future sub panel in detached garage. The 100A for the main part of the house will be more than enough, but the garage sub panel is the one I'm questioning. The reason for the garage sub panel is two-fold; for solar back-feed, and to avoid long runs for the multiple 50A and 30A branch circuits from the main panel to the garage and kitchen. I am planning the following branch circuits for the garage sub panel:
- 50A electric car charger
- 30A RV outlet
- 50A double oven
- 50A future induction cooktop (present cooktop will be gas)
- 20A kitchen/pantry small appliance
- 20A island/dining small appliance
- 20A microwave
- 20A refrigerator
- 20A dishwasher/disposal
Finally, I would like to back-feed the solar through this sub panel, which is why I have chosen a 200A panel even though I think 100A would be enough for the above loads.
First question is, does this seem like a wise plan overall or is there a better way to design for future solar? Second, will a 100A feeder circuit be enough given these loads, or should I size the feeder for 150A or even 175A now for current or future loads? If my math is correct, with a 175A breaker in a 200A panel, I could have as much as 65A of solar back-fed to the 400A meter panel, correct? Any advantage to feeding DC from the solar panels back to the meter panel instead?
Any advice will be greatly appreciated!
-Chad
I currently have 100A service to the house which is serving a single 100A sub panel in the basement. My plan is to have this upgraded to 400A service at the meter panel outside, which would serve the 100A sub panel in the basement, another 100A sub panel in the main part of the house, a 200A panel for the garage and kitchen addition, and possibly a future sub panel in detached garage. The 100A for the main part of the house will be more than enough, but the garage sub panel is the one I'm questioning. The reason for the garage sub panel is two-fold; for solar back-feed, and to avoid long runs for the multiple 50A and 30A branch circuits from the main panel to the garage and kitchen. I am planning the following branch circuits for the garage sub panel:
- 50A electric car charger
- 30A RV outlet
- 50A double oven
- 50A future induction cooktop (present cooktop will be gas)
- 20A kitchen/pantry small appliance
- 20A island/dining small appliance
- 20A microwave
- 20A refrigerator
- 20A dishwasher/disposal
Finally, I would like to back-feed the solar through this sub panel, which is why I have chosen a 200A panel even though I think 100A would be enough for the above loads.
First question is, does this seem like a wise plan overall or is there a better way to design for future solar? Second, will a 100A feeder circuit be enough given these loads, or should I size the feeder for 150A or even 175A now for current or future loads? If my math is correct, with a 175A breaker in a 200A panel, I could have as much as 65A of solar back-fed to the 400A meter panel, correct? Any advantage to feeding DC from the solar panels back to the meter panel instead?
Any advice will be greatly appreciated!
-Chad
