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<DIV><FONT face=Arial size=2>Thanks Guys,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Michael, your memory and/or your expert use of
the archives clarified what I should have remembered as Windy's comments. Thank
you.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>In related matters, what are the benefits /
disadvantages / preferred applications of a thermal-magnetic breaker over a
thermal-hydraulic breaker.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Bill Loesch<BR>Solar 1 - Saint Louis
Solar<BR></FONT></DIV>
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style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=allan@positiveenergysolar.com
href="mailto:allan@positiveenergysolar.com">Allan Sindelar</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=re-wrenches@lists.re-wrenches.org
href="mailto:re-wrenches@lists.re-wrenches.org">RE-wrenches</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, May 13, 2010 9:22
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [RE-wrenches] AC breakers
used in DC applications</DIV>
<DIV><BR></DIV>Wow, Michael, look at the monster you have created, Dr.
Frankensolarbozo! <BR>Yes, that's the thread. And I was about to post that
Windy left today for Costa Rica...just a trip, not a move.<BR>William, there
are certain perfectly appropriate applications - such as a pressure switch
controlling a DC pump, or an A/C disconnect (Square D CU200) 2-pole array
disconnect for an array-direct pump. Historically there was nothing DC-rated
available, and conservative use of available AC equiipment worked fine and
lasted forever. Sometimes it just don' matter how it's Listed, ya just gotta
use it...ya know?<BR>Allan<BR><BR>
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<DIV class=Section1>
<P class=MsoNormal><SPAN class=il><B>Allan</B></SPAN><B> Sindelar</B><SPAN
style="FONT-SIZE: 10pt"><BR><A href="mailto:Allan@positiveenergysolar.com"
target=_blank><SPAN
class=il>Allan</SPAN>@positiveenergysolar.com</A><BR>NABCEP Certified
Photovoltaic Installer<BR>EE98J Journeyman Electrician<BR><B>Positive Energy,
Inc.</B><BR>3201 Calle Marie<BR>Santa Fe, New Mexico 87507<BR><B>505
424-1112</B><BR><A href="http://www.positiveenergysolar.com/"
target=_blank>www.positiveenergysolar.com</A></SPAN></P></DIV></DIV><BR><BR>Michael
Welch wrote:
<BLOCKQUOTE cite=mid:20100514003038.13D345F598@friskymail-a1.g.dreamhost.com
type="cite">Is this conversation what you were refering to?
7/22/01<BR><BR>Others offered caution to this approach, but clearly the
subject was switches, not breakers.<BR><BR>Allan at Positive Energy
wrote:<BR><BR>
<BLOCKQUOTE class=cite cite="" type="cite"><FONT size=2>2. ...<I>
</I>I am using float switches to control 48V mercury displacement relays
for these DC pumps. Can anyone suggest a source of SPST, SPDT, and DPDT
bat (or any style) switches suitable for 48VDC nominal, low current loads?
These would be for a custom relay control enclosure with override and
remote low tank alarm signal circuits.<BR></FONT> </BLOCKQUOTE><BR>My
frequent observation on DC ratings for mechanical switch contacts is that
it's amp rating at 125VAC equals its amp rating at 28VDC. This is consistent
in the specifications of a great many switches, relays, etc. If there are
higher voltage ratings, then if voltage is doubled, amps is
half.<BR><BR>When 48V is not specifically listed (nor any higher DC
voltage), I feel safe following that rule if I apply a good safety margin,
as long as the switch has a rapid snap action like a toggle switch does. For
the low current control and alarm loads you describe, I would feel forevever
safe using a switch with a 15A rating at 28VDC. If you need to get official
approval, ask the manufacturer of the switch you propose to
use.<BR><BR>Windy<BR><BR><BR>Bill Loesch wrote at 05:10 PM
5/13/2010:<BR> <BR>
<BLOCKQUOTE class=cite cite="" type="cite"><BR>Fellow
Wrenches,<BR> <BR>Some time ago, Windy Dankoff had a rule of thumb to
substitute (conservatively) an AC breaker for use in a DC application.
<BR> <BR>Is anybody's memory, or perhaps even the old dog himself; if
he is listening, better than mine?<BR> <BR>TIA,<BR> <BR>Bill
Loesch<BR>Solar 1 - Saint Louis Solar<BR>314 631
1094<BR> <BR> <BR>_______________________________________________<BR><BR></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>