[RE-wrenches] AC breakers used in DC applications

[Kurt Albershardt]

Square-D tells me they have tested the breakers to a higher voltage (can't recall now whether it was 80V or 125 VDC) but the listing is indeed for 48 Volts.  24V battery systems are useful for a lot of applications, but the unfortunate lack of a 5A breaker means we can not use them to derive a Class 2 supply, which would make them about 10x as useful to me.



On May 15, 2010, at 9:22 , jay peltz wrote:

> Hi Rebekah,
> 
> The 48v is a max rating not a nominal rating.
> So yes only good for 12 and 24v systems.
> 
> However with CBI breakers I don't understand why the need for QO for DC anymore?
> 
> jay
> 
> peltz power
> On May 15, 2010, at 6:28 AM, Rebekah Hren wrote:
> 
>> Hi,
>> One thing to be clear about is whether these are listed for "48 volt systems," or for max 48 volts?
>> I was under the impression that they were max 48 volts, meaning you really shouldn't use them on a system >24volts nominal.
>> 
>> Rebekah Hren
>> North Carolina
>>  
>> 
>> 
>> http://thecarbonfreehome.com/
>> 
>> --- On Sat, 5/15/10, Kurt Albershardt <info at es-ee.com> wrote:
>> 
>> From: Kurt Albershardt <info at es-ee.com>
>> Subject: Re: [RE-wrenches] AC breakers used in DC applications
>> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
>> Date: Saturday, May 15, 2010, 12:59 AM
>> 
>> The Square-D catalogs are marginally clear on which breakers are listed for DC and for what voltages, but when I tried to select an appropriate load center for a DC application earlier this year I quickly ran into a number of conflicts in their catalogs.  Here is the response from Schneider tech support (Case# 4845778 on 1/19/10 in case anyone runs into problems with an inspector):
>> 
>> 
>> 
>> The load center catalog numbers listed below are UL LISTED, File E6294, for use on 48 V dc systems. The load centers listed ARE NOT MARKED for use on this voltage system, however are suitable for the application. QO branch breakers, 10-70 ampere (1 and 2 pole) are also UL LISTED for use on 48V dc systems. Short circuit current rating is limited to 5,000 amperes when used on 48V dc.
>> QO24L70F, S or RB QO612L100F, S, DF, DS, DFCU, DSCU, RB, TRB or RBCU QO816L100F, S, DF, DS, DFCU, DSCU, RB or RBCU
>> QO112L125G or QO11224L125G QO116L125G QO11624L125G QO120L125G QO12024L125G QO124L125G or QO12030L150G QO124L150G QO130L150G or QO112L200G or QO130L200G or QO13040L200G QO142L225G or
>> GRB or GRB
>> or GRB
>> GRB
>> GRB GRB GRB or GRB QO142L225GRB
>> 
>> 
>> I can email the PDF to anyone who needs a copy.
>> 
>>  
> 
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