Expanding my grid-tie solar system

[Serina]

I'm installing a grid-tie solar system with batteries and plan to add an electric car later. Can I add more panels after commissioning and how does the utility know if I'm only using extra power and not selling back...I'm wiring for future expansion now, using a string inverter with available extra inputs. Any advice?

 

[Power4Home]

Yep, you can toss in some extra panels later on, but only if your inverter's got the juice for it. The power company keeps tabs on what you send back to them with your net meter. So they'll see any extra power you're feeding into the grid. Just double check your setup complies with their interconnection rules.

 

[Dew762]

Hey idk if you have the kind of solar system that would run through your electrical panel but it matters as well when configuring your solar addition. There should be fused emergency disconnects that’ll be sized to the existing systems wattage those fuses or the entire boxes and fuses will need to be upgraded as well. Then if you have a breaker in the bottom of the electrical panel the size of the panel needs to be verified to insure that the bus bar is rated for that adjustment ( there’s a rating number somewhere on the inside of the cover in watts or labeled something like “imposed amperage”) if not there’s probably taps above the main breaker and all the wire back from the inverter to that tap needs to be corrected to the right size because I guarantee no one upsized that on their own dime. It’ll be bare minimum at best for the existing solar load. And yes the meter cycles backward for hoses with solar systems that have passed inspection they’ll swap the other meters for the solar capable one. If not the power you’re generating will only count up as if you were consuming it, even though you’re actually consuming a net negative. Not an expert but I’ve installed solar systems in a few different possible configurations every day for a couple years but I’ve been an electrician for 8 now and I know how everyone handles things in my region at least largely the country thinks the same terms under the nec besides certain places everyone’s hardwired to carry out the bare minimum and that part about the wire sizing is guaranteed to need replaced possibly the rest too depending on the design/style of yours

 

[_Karrivan]

I'm installing a grid-tie solar system with batteries and plan to add an electric car later. Can I add more panels after commissioning and how does the utility know if I'm only using extra power and not selling back...I'm wiring for future expansion now, using a string inverter with available extra inputs. Any advice?

The utility meter just keeps track of the electricity flowing in and out, so it doesn't care whether the solar energy comes from your original setup or any new panels you've added. If you're generating more power than you're actually using, that extra energy gets sent out to the grid, no matter where it came from.

 

[Dew762]

The utility meter just keeps track of the electricity flowing in and out, so it doesn't care whether the solar energy comes from your original setup or any new panels you've added. If you're generating more power than you're actually using, that extra energy gets sent out to the grid, no matter where it came from.

The meters most people use count for the electrical flow yes. But it can’t read the direction that it flows in so if you consume power or you’re supplying power to the grid the normal electric meter will only ever count up and then the power company charges you for that number