[RE-wrenches] Disconnets

[R Ray Walters]

The problem with this stuff is not passing inspection, it's actually turning the system off under load!  I think if you watched the arcing on the contacts, you would agree that the system you saw has only a very limited number of switch cycles before it fails...... possibly in the ON position.  600 VDC rated fuse holders for instance will completely arc across the open contacts at 900 vdc.
This is one area where you don't have much safety factor, IMHO.  

Ray Walters

On Aug 25, 2012, at 9:17 PM, Jesse Dahl wrote:

> I've been using similar "solar" disconnects. Its nice to see UL.  I looked at a local solar project today that the installer used GE 600VAC/250VDC disconnects on the DC side.  Three strings with each being broken by one pole.  It had passed inspection.
> 
> Jesse
> 
> On Sat, Aug 25, 2012 at 7:38 PM, Glenn Burt <glenn.burt at glbcc.com> wrote:
> We switched (ha!) to Siemens disconnects after the hoopla about Square D..
> 
> http://www.sea.siemens.com/us/internet-dms/btlv/CircuitProtection/HeavyDutySafetySwitches/docs_HeavyDutySafetySwitches/HD%20Photovoltaic%20Final%20050110.pdf
> 
>  
> 
> I really don’t think there is a problem using the SQD if you can series up a couple of poles.
> 
>  
> 
> -Glenn
> 
>  
> 
> From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Jesse Dahl
> Sent: Friday, August 24, 2012 9:43 PM
> To: RE-wrenches
> Subject: [RE-wrenches] Disconnets
> 
>  
> 
> Hello,
> 
>  
> 
> I've been having a long conversation with a local guy about disconnects that are usable in DC PV circuits.  From what I have seen, GE, Eaton... they are usable up to the 250VDC it has listed on the labels, or more if poles are wired in series. The squared D 600Vac/dc is self tested to 600VDC/pole.  The disconnects in question are not the "solar disconnects" on the market now. 
> 
>  
> 
> What are people using for the GDI systems?  I seem to think that if if says 250VDC on the label, that is its rating unless you wire pole in series and the manufacturer has literature saying that that is acceptable.  
> 
>  
> 
> Thoughts on the square D self listing?
> 
>  
> 
>  
> 
> Jesse
> 
> 
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