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NEC requirements for Fireman Switch and RSD's?

oldryder1973

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May 17, 2020
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I am in the design stage for a ground mounted grid tie solar system. I've seen that RSD's are required for roof mount solar but have been unable to determine if they are required for a ground mount system. Doesn't seem like they would be needed if the inverters were mounted on the PV structure.

The inverters I am using have a DC disconnect. Presently my plan is to locate the inverters inside to shelter them from the MN weather extremes but I can see where that might make the Fireman Switch/RSD's a requirement.

thx to anyone taking the time to offer advice.

mark in MN
 
I am guessing they might want a disconnect at the meter. If I remember correctly RSD is not need for ground mounts (I would think they might be required because they still back feed the house....Isn't RSD built into your inverter?)....they word these codes so they are so nice to understand....that was sarcasm.

I put a disconnect at the ground mount and at the meter on my install. They are cheap if AC and you can get them with fuses. Because solar can have power flowing in both directions in the feed lines there really need to be fuses/breakers at both end of those wires.

These codes for solar are changing so much in the last 10 years that I would ask which NEC version they are using and then check it out of you local library. You power company might also have a say in things. Our Poco has requirements but they don't tell you till after the fact, I took ours to court after every time they came out they wanted something over and above code even after it was inspected by the city. After the third time I got tired of them wasting my time and filed in court. They then produced their rule book after the fact.....they lost.
 
The interpretation I heard was that if DC conductors are on or in your home at all, shutdown modules are required. If the inverter is outside and it's only AC coming in, you're good with just a manual disconnect.
 
I recently learned that the emergency disconnect at the meter must have a sign announcing the type and location of any other power sources. For a grid tie system this would be typically be the inverter disconnects usually mounted on the panel array structure. Not sure what's required if you have battery based supply.
 
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