600 VDC switches [RE-wrenches]

[matthew tritt]

E.H.Roy,

If this is the same switch I opened this thread with, (is it?), this
information is going to start the sparks flying! Ho Ho Ho.

This subject has gotten quite a bit of mileage on the list, but this is the
first time SQ D has weighed-in. That's good!

Matt
----- Original Message -----
From: "EH Roy" <ehroy at solar-works.com>
To: <RE-wrenches at topica.com>
Sent: Thursday, October 10, 2002 3:28 PM
Subject: RE: 600 VDC switches [RE-wrenches]


> Brad,
>
> I remember that arcing problem, but don't remember the brand of disconnect
> it occurred in.
>
> Square D technical support tells me I don't have to wire two outside poles
> in series to get a 600VDC rating on their HU361 - switching of one
positive
> through one pole is appropriate and covered by the UL listing. They are
> still scratching their heads about how many positives can be switched in
one
> disconnect.
>
> E. H. Roy
> Solar Works, Inc.
> 64 Main Street
> Montpelier, VT 05602
> 1-800-339-7804 ext. 306
> ehroy at solar-works.com
>
> -----Original Message-----
> From: Brad Bassett [mailto:bsbassett at earthlink.net]
> Sent: Wednesday, September 18, 2002 4:32 PM
> To: RE-wrenches at topica.com
> Subject: RE: 600 VDC switches [RE-wrenches]
>
> Matt,
>
> I believe that Sq D does not put the necessary jumper in at the factory
> between the two poles to get the 600vDC rating. The lebelling on various
> disconnects has sometimes been lacking also. Although GE has supplied
> the jumper for many years, their labeling was confusing. It now appears
> that they got the message and the labelling is clear and they call out
> the difference between the single pole 250v DC rating and the two pole
> break 600vDC rating. I don't know what the other mfg's do.
>
> Back almost a decade ago, we had someone in the field installing our
> first 600vDC array and used a single pole, which when opened sustained
> an arc until they literally blew it out. In our subsequent conversations
> with various disconnect engineers we learned that a single pole will
> come close to breaking 600v and sometimes will depending on current etc.
> But to be reliable and meet UL testing, breaking two poles is needed at
> these voltages.
>
> Brad
>
>
> matthew tritt wrote:
> > William,
> >
> > Your questions bring up some very interesting points. I did an install
> > yesterday using a Sq D 3 pole breaker which has no jumper and no mention
> > anywhere of a decreased rating. > > manufacturers achieve the 600 volt
> > rating:  They use a 3 pole disconnectI'm going to check with the
> > distributor and
> > see if I can get an answer on the need to add a 3rd breaker to the
> > system,
> > or if these switches are actually rated @ 600 volts per contact.
> > Also, I regularly used to switch both DC inputs until I was admonished
> > by an
> > electrician who insisted it was illegal to break the negative lead. I
> > believe that he said this because of his assumption that the neutral in
> > AC
> > is grounded and it would be somehow interrupting the ground to break the
> > neutral on the DC circuit as well. Why not switch both?
> >
> > Matt
>
>
>
> Brad Bassett
> Schott Applied Power
> Tumwater, WA office
> bsbassett at earthlink.net
>
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