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

[Ray Walters]

This seems like another well meaning but slightly awkward code 
requirement.  I think it would be sufficient to list the nominal battery 
voltage (very important to know)  and then the actual variation in 
voltage is not going to be too hard to comprehend.
Knowing array Voc is also very important.  If you think you have a 12 v 
based battery system, but the array is actually at 480 Voc, you need to 
know that, before taking any covers off.

Code requirements aside, I think we need to list:
Array Voc
Battery Nominal Voltage
AC voltages

That should be on the outside of every J box with connections inside, so 
you know how to set your meter.  If there's DC, and you're testing for 
AC in a box, you might think power is off.  My handy voltage sniffer 
only senses AC for instance, so modern battery based PV systems can get 
dangerous with high voltage DC arrays, especially if you're trouble 
shooting a DIY system.  I've seen wires fed by three different sources, 
and gotten shocked trying to remove the 2nd source.
On code requirements like this, I move closer to the spirit of the law, 
which is to keep everybody safe.  The inspectors usually agree, but 
you'll always have an AHJ that wants something different.

R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760

On 6/11/2013 9:33 AM, jay peltz wrote:
> HI All,
>
> I mean as its worded, it would also be 240vac?
>
> jay
>
> peltz power
>
>
> On Jun 11, 2013, at 7:30 AM, Eric.Bentsen at schneider-electric.com 
> <mailto:Eric.Bentsen at schneider-electric.com> wrote:
>
>>
>> Hi Bob,
>> I would rather it be worded "maximum normal operating voltage".
>> Maximum operating voltage would be the recommended BULK voltage for 
>> the battery type being utilized.
>> Equalization is a maintenance procedure, which is why it calls for 
>> separate listing.
>> It must also include polarity of grounded conductor.
>>
>> Eric
>> _____________________________________________________________________________________
>> *
>> Eric Bentsen*  | *Schneider Electric **  |  Solar Business*  | 
>> *UNITED STATES*  | *Technical Support Representative* *
>> Phone:* +(650) 351-8237 ext. 001#  | *
>> Email:* _eric.bentsen at schneider-electric.com_ 
>> <mailto:eric.bentsen at schneider-electric.com> | 
>> *Site:*_www.schneider-electric.com/solar_ 
>> <http://www.schneider-electric.com/solar> | *Address:* 250 South 
>> Vasco Rd., Livermore, CA 94551
>> _
>> _<Mail Attachment.jpeg> <x-msg://179/www.schneider-electric.com/solar>
>> *** Please consider the environment before printing this e-mail
>>
>>
>>
>> From: 	"Bob Clark" <bclark at solar-wind.us <mailto:bclark at solar-wind.us>>
>> To: 	"'RE-Wrenches'" <re-wrenches at lists.re-wrenches.org 
>> <mailto:re-wrenches at lists.re-wrenches.org>>
>> Date: 	06/10/2013 08:08 PM
>> Subject: 	[RE-wrenches] NEC 690.55 - "maximum operating voltage"
>> Sent by: 	re-wrenches-bounces at lists.re-wrenches.org 
>> <mailto:re-wrenches-bounces at lists.re-wrenches.org>
>>
>>
>> ------------------------------------------------------------------------
>>
>>
>>
>> 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, . . ." ?
>>
>> 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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