Inverter in basement, good idea or not???

[Beachnut]

We live 3 blocks up from the Pacific Ocean, near Pismo Beach. It is a salt air, fogy, highly corrosive to metal environment. I have signed the Sunrun lease agreement, and am in the phase of waiting for the engineer to come over and lay out the system. I so far have been telling the sales rep. that I wanted the wiring to run through the attic, down to the basement internally rather than externally for more protection. (Metal conduit would rust quickly outside, & i have already installed a pull rope for the internal route). I am also asking them to mount the inverter in our basement, right next to the sub panel for the house. The main breaker / and meter are located just outside the sub panel inside the basement, yet the meter is facing the weather & ocean side of the house, and it takes a beating. Some questions I have about putting the inverter inside are:

1. Can an inverter be a fire hazard? (Anyone ever hear of them catching fire?)

2. How much heat do they produce? (Will it heat up my 15' x 24' basement?)

3. Will adding 30 + feet of wiring diminish output? (It would be a much shorter wiring run externally if they came off the roof, over the eve, down the wall, through the wall into the basement, or even mounting the inverter outside, rather than my proposed internal wiring run.

Thank you for your help an answers!

[Ian S]

In your situation, mounting outdoors in a corrosive environment will require NEMA 4X certification which might limit your choice of inverter. I don't see any problem with mounting in the basement, in fact I think it would probably be ideal. Some inverters can be a bit noisy though. They also produce some heat but I doubt it would be enough to really impact a volume the size of your basement. Someone else can chime in on the power loss in an extra 30 ft of wiring but I doubt it would be significant and could be eliminated with a slightly heavier wire gauge.

[Mike90250]

Some inverters have a distinct 60 cycle hum when running, so mounting it somewhat isolated from shared walls might be good. Maybe build a false wall for it. Fire hazzard - no more than any other appliance.

BUT, your local code agency's may want exterior AC & DC cutoffs, which would complicate the conduits somewhat.

[Beachnut]

Some inverters have a distinct 60 cycle hum when running, so mounting it somewhat isolated from shared walls might be good. Maybe build a false wall for it. Fire hazzard - no more than any other appliance.

BUT, your local code agency's may want exterior AC & DC cutoffs, which would complicate the conduits somewhat.

I am assuming the hum will only occur when the sun is putting out power through the panels, so the hum should not be a problem. Our room is above the basement, but the noise would have to get through the false ceiling in the basement, then through 5/8" x 8" floor slats, 1/2 inch thick oak flooring on top of the slats, then pad and carpet before getting through to the bedroom.

The main shut off breaker for our house is right below the PG&E meter, accessible to the outside. I assume that would kill anything coming from the panels,, right? Wont they run the power off the inverter, into the A/C sub panel that feeds the whole house? Hence power from panels, would have to go back through the main breakers, then spin the meter backwards, and then on into the grid, right?

Thank You for the replies.

[inetdog]

The main shut off breaker for our house is right below the PG&E meter, accessible to the outside. I assume that would kill anything coming from the panels,, right? Wont they run the power off the inverter, into the A/C sub panel that feeds the whole house? Hence power from panels, would have to go back through the main breakers, then spin the meter backwards, and then on into the grid, right?

Thank You for the replies.

When you turn off the grid power, the grid-tie inverter will not have the reference voltage it needs and will automatically turn off. That means that any DC from the panels will not be usable.
But you still need an outside switch to disconnect that DC voltage from reaching the interior of the house or a disconnect at the inverter, depending on NEC version and local regulations.