Can I install a transfer switch to make solar power during an outage

Today a potential client asked me if I could install a transfer switch for him so when the grid went down in a storm or whatever, his solar system would be able to make power for him. He lives in a coastal town and everyone still has Sandy fresh in their minds. Unfortunately, I had to tell him, no or actually, yes, I can install a transfer switch no problem but the inverters are required under Underwriters laboratory certification to shut down within 10 milliseconds after losing the grid so it wouldn’t do what he wanted. It’s a safety consideration so you are not putting power out on otherwise dead lines.

That said, there are solutions to this issue which require the installation of batteries and an additional device to great a “micro-grid” so the inverters can be tricked into turning back on. It becomes either a necessity issue-medical problem or computer that can’t go down, etc- or an economic issue; do you lose the grid often enough that it’s worth an extra $1.50- $2.00 per watt plus the on going maintenance and battery replacement cost (5-7 years, just like a car) to not lose power.
There is also the issue of how much power you want to have in an outage. There is a central inverter out there that has a 15A outlet built in and is able to do all of the above if all you need is 15A of power during daylight hours. That is enough to run a sump pump or gas heater or refrigerator and for some folks that is a perfect fit. If you need more power then you need to step up to batteries, etc.
A more cost effective solution, assuming lose of the grid is a relatively rare event is to buy a generator and have the proper electrical modifications made so you can run critical loads with it. Again, you would need to identify your power needs during an outage to properly size the generator and make the necessary modifications. Also, if you need it to start up automatically (say, when you are not at home to manually start it) when the grid stops, the cost goes up.
I told him I could help him with any of the above; adding backup power is a multi-faceted decision which requires some professional input.

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