Solar Panel System

[Pettrix]

I might be installing a ground mounted solar panel system in a year or two. I am building a house/garage now and pulling power to the site. It will be a 400 amp service with an exterior panel mounted on the garage exterior.

What should I do to prepare for the future solar panel system install? My garage will have a concrete wall so if I need to sleeve a hole, now is the time to do it.

 

[RNeumann]

400a is a lot of power. If it is after the meter (sub panel) you will need 3 wires plus the ground. The 3 main wires in copper THHN (about the smallest wire you can use) will be 500 which is nearly an inch in size! Plus a ground which can be smaller. With all that you are going to need to put conduit in the ground that is 3-4". I'd use sch. 40 pvc with LONG sweeps. You will also need to put a ground in the concrete before you pour. 20' of rebar in the base of the footing that sticks out of the slab/footing near your panel will work- it's called a ufer ground.

If it's a new service with a meter call your utility as they typically want to see what's up and will tell you what they want.

That's a lot of power! In the post meter/sub panel scenario-- Most homeowners could get away with 100-200a and if needed would add a second 200a panel- the wire alone for 400a will come on spools that are truck mounted and will take a winch to pull.

Good luck and google "wire amp chart" and "conduit fill calculator" also look at panels that can have a 400a breaker. That is going to cost a lot as well.

It may be easier to have the utility put a service at your shop and pay for 2 meters- house and shop.

 

[EddieWalker]

I have two 200 amp panels to my house. One panel is in my garage, which feed the garage and all the outlets in the house. The other panel is in my utility room that powers my HVAC system, my electric water heater, and then runs out to my hot tub, RV pad and everything else outside. I forget what sized conduit I used to run the wires up through my slab and walls, but since the walls are 2x4's, it was 3 inches or less.

 

[RNeumann]

Yep 200a is 4/0 THHN aluminum wire (smaller if copper) and with my conduit calculator you would need 2 1/2" PVC. Still use long sweeps.
This is much more reasonable!

 

[nikdfish]

Are you planning on a strictly grid-tied system, battery based or a hybrid? Grid tied could pretty much all be done externally, as that is where you are planning for the main utility breaker location, although it would probably need a weather proof cabinet or shed. Battery or hybrid would mean you need a location for battery installation & conduit for the feeds. Lead acid batteries are typically happier in an area that stays reasonably climate controlled (they lose efficiency when cold) & may require separate ventilation for safety if not sealed.

Nick

 

[techman]

Besides your spool for a feedthrough, the only other prep on a grid tie is to leave a 2-pole breaker space open at the bottom of the panel (furthest from the supply end of the panel).

paul

 

[Pettrix]

400a is a lot of power

That's a lot of power! In the post meter/sub panel scenario-- Most homeowners could get away with 100-200a and if needed would add a second 200a panel- the wire alone for 400a will come on spools that are truck mounted and will take a winch to pull.

Good luck and google "wire amp chart" and "conduit fill calculator" also look at panels that can have a 400a breaker. That is going to cost a lot as well.

It may be easier to have the utility put a service at your shop and pay for 2 meters- house and shop.

I am having 400 amps pulled so that my guest house will have 200 amps and then my future main house will have the other 200 amps. That's why I am having 400 amps brought to the house as it will serve 2 homes.

Will 3" PVC conduit be large enough for the wire pulls?

Can the ground mounted solar system be connected/installed from the OUTSIDE of the garage where the main line feed comes in? Or will I have to gain access to the inside of the garage?

 

[Pettrix]

Are you planning on a strictly grid-tied system, battery based or a hybrid?

It will be grid tied/hybrid but I will NOT be sending power back to the utility company. I will be using the Tesla battery to store power.

 

[prichard]

3" would be absolute minimum. I wouldn't want to pull it. If I had to do 400A I'd pull parallel 250MCM in 3". But I'd go for 2 200A services as suggested previously. 200A meter, breakers, wire, etc are all going to be much cheaper. Around here 200A is max residential meter size. 400 is considered a business service and the monthly charges are even more.

 

[Pettrix]

The utility company will provide the power cable. I have to provide the trenching and conduit. They said 2" conduit up to the house site and then there will be a transformer about 80' from the house and then it goes to a 4" conduit to the house.

The utility company will pull the cable up to the home.