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NEC RSS regulations and 12v systems

Blazer3664

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Dec 2, 2019
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I have read pages and pages of NEC regs, and am still unsure if the whole rapid shutdown system requirements even apply to all 12v systems.

I keep seeing "below 30v in under 30 seconds".
On a 12v system you can just connect the panels in parallel and stay under 30v.
Would a system done that way still need a rss control?

Series would be better with a mppt controller, but to avoid the rss extras it could stay under 30v in parallel.
 
Thats a good question , I wold like to know the answer too. Im going to keep an eye on this thread.
 
(2) Controlled conductors shall be limited to no more than 30 volts and 240VA within 30 seconds of rapid shutdown initiation.
 
So, basically the array cannot have over 240watts of production outside the 1foot mark of the array.
 
The update is calling for module level shutdown. Good to know which code cycle is being complied with in your jurisdiction.

The article applies to all pv source circuits installed on or in a building.

12v would work under the array and 1' away. Still needs to be disconnected outside the array footprint.

Mike holt and ec&m magazine have some of the best in depth analysis of the various code.
 
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