[RE-wrenches] NEC 690.55 - "maximum operating voltage"

boB at midnitesolar.com boB at midnitesolar.com
Mon Jun 10 23:12:11 PDT 2013


On 6/10/2013 8:08 PM, Bob Clark wrote:
>
> RE_Wrenches:
>
> Can someone tell me what is being referred to in NEC 690.55 when it says
>

> "Photovoltaic power systems employing energy storage shall also be 
> marked with the "maximum operating voltage, . . ." ?
>


.....including any equalization voltage and the polarity of the grounded 
circuit conductor...

To me, this says  maximum battery voltage and if it is positive or 
negative grounded.

For instance, if your typical off grid house 48V systems' maximum 
battery temperature compensated voltage
is 62.5 volts, then that sign might say 62.5V DC maximum operating 
voltage, negative ground system.

That's my interpretation anyway.

In addition, above 690.55 I see...
690.53 Direct-Current Photovoltaic Power Source.

which to me would indicate MPPT voltage, current, etc.  (not Voc)

boB


> We have an off-grid system which employs energy storage [i.e.; 
> batteries]; so I need to know what exactly is referred to when this 
> section mentions "maximum operating voltage" so I can put it on a sign.
>
> *Bob Clark*
>
> */SolarWind Energy Systems, LLC/*
>
>

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