[RE-wrenches] Rapid Shutdown Battery Systems

jay jay.peltz at gmail.com
Thu Aug 27 08:07:31 PDT 2015


HI Bill,

Thanks for your thoughts and clarifications on this super simple ( HA) topic.

But can you elaborate on the batteries are a potential massive bomb thing?

thanks

jay

peltz power



> On Aug 26, 2015, at 9:19 PM, <billbrooks7 at sbcglobal.net> <billbrooks7 at sbcglobal.net> wrote:
> 
> Ray,
> 
> Do you have a massive battery bank and 3, 8kW inverters inside the house? Is
> this in a garage or power shed. If it is a power shed, then 690.12 is not
> intended to relate to the power shed. That will be clarified in the 2017
> NEC.
> 
> The area for discussion is what constitutes the length of battery cables.
> 690.71 has restrictions on where overcurrent protection needs to be for
> circuits longer than 5'. Do people really follow that religiously? This
> would be a discussion that really needs to happen with the AHJ. My basic
> view is that if I have a 4' run from a battery box to my inverters (even
> though one lead may be 10' long), many would call that a 4' run. That is
> what is exposed from a fire fighter point of view. Remember the battery is
> potentially a massive bomb in a fire, so 48V conductors are the least of a
> fire fighter's concern.
> 
> Bottom line is how to make it easy for a firefighter to kill the vast
> majority of wires in a building. A backup system simply reenergizes
> everything. Cutting off the dc from the array and the ac out of the
> inverters solves the problem--keep the battery as close as possible and
> don't worry about trying to turn off the battery circuit to the inverter.
> 
> Bill.
> 
> 




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