Function of 2 pole 40 amp breaker in main service panel labeled "PV Solar System"

[AntoineX]

I need to replace a breaker for a 15 amp branch circuit - done this before and quite comfortable with it - but now we have rooftop solar, a professional installation, and I don't understand what the 40 amp 2 pole breaker labelled "PV Solar System" does.
Is this where voltage from the inverter feeds into the house?
If I cut off the main breaker (200 amp) is the panel still hot?
Do I need to shut off the PV system at the shut-off box near the inverter to work in the main service panel?
Or turn this "PV Solar System" breaker off to isolate the main panel from the roof top?

I was all set to go when I realized that things were different from what I've been used to!

I should have paid more attention when they were putting the system in, I reckon!

 

[Mattb4]

Is your system grid tie? Not that it makes much difference since it is always a good practice to check circuits dead before working. So turn off both 200a and the 40a. Do a voltage test.

 

[Solar Guppy]

Most likely it is the inverter connection and if you switch off the main, the inverter will stop selling as it is required too and no voltage with be on that breaker. If you want to be extra safe, just toggle the main breaker to off and the inverter breaker to off to do your work with the branch circuit.

 

[Hedges]

If your inverter has a display, look at it before and after turning off main breaker.
As a start to your PV education.

You may want to add grid-backup in the future.
Take a photo of inverter label. That's the first info needed.

And Welcome!

Lancaster - think I got there once or twice visiting a vendor (electronic assembly.)

 

[Hedges]

Ah, Fronius, from 2019.
It likely supports UL-1741-SA frequency-watts, so could be AC coupled to a battery or hybrid inverter.

Looks like Fronius suggests either AC coupling, or a hybrid inverter which would replace existign GT PV inverter.

PV system with battery storage for homes – Fronius Solar Energy

Offer your customers flexible systems for increased independence and energy security with Fronius storage solutions. See for yourself!

www.fronius.com

 

[AntoineX]

Thanks, folks. We'll take a look in the morning!

 

[JBertok]

Keep in mind that your mains coming in from the meter to the 200A main breakers are still going to be hot- even with the 200A breakers open. So when you asked if the "panel will still be hot" the answer is that is that it will be hot unless the utility pulls the meter or shuts down service. That said, and with some experience, it isn't actually required to kill the mains to remove the cover panel, or to de-energize the breaker busses to change a breaker; it is the safest course though. If you are going to shut down the busses, shut off each branch circuit first and then the mains. Reverse to re-energize.

 

[AntoineX]

Understood, thanks.

 

[AntoineX]

Oh, and BTW, our house has something I haven't seen everywhere - a main shutoff where service enters the basement. Bigger than a bread box, large handle on the side. I think I'll leave it alone, since it probably hasn't been touched since the place was built in 1960.