48V hardware [RE-wrenches]

[Bill Brooks]

Travis,

NEMA 3R is rainproof. Usually defined by being about to handle water spray
at up to a 45 degree angle without getting water in the box. Drainage is
provided in the bottom of the box.

Bill.


-----Original Message-----
From: Travis Creswell, Ozark Solar [mailto:ozsolar at ipa.net]
Sent: Friday, July 13, 2001 7:44 PM
To: RE-wrenches at topica.com
Subject: Re: 48V hardware [RE-wrenches]


Hey Allan,

1. I'm assuming that you don't need overcurrent protection as that is being
provided by the feed.  I've often use 250v 3 phase unfused disconnects.
They are relatively inexpensive and from what I can tell rated up to 250v
DC.  Let me know if you find a 2 pole rated for 250 vdc.  I haven't seen a
modern one.  Seimens recently has come out with a trade name they call
"rhino" that is really nice and beefy for under a $100 for a 70 3ph unfused.
You would two (one for each pump if you wanted to be able to shut them off
individually) and they are pretty big but the price is right.

It might not need to be raintight though.  If I'm not mistaken 3R really
means that it is able to function with ice on it.  My code book is at the
shop and it does a good job of defining that.  Not much chance of ice
forming on a box inside that pit.

2. Can't help you there.

Travis


----- Original Message -----
From: "Allan Sindelar, Positive Energy, Inc."
<allan at positiveenergysolar.com>
To: "New wrenches posting" <RE-wrenches at topica.com>
Sent: Friday, July 13, 2001 3:39 PM
Subject: 48V hardware [RE-wrenches]


Wrenches,
1. What has proven to be the best approach you have found for small load
centers or disconnects for 48VDC nominal systems? For example, I need two
single pole low-amperage disconnects for a 48VDC (nominal) subpanel, for two
pump loads in a 6' by 6' well pit (so needs raintight, I believe). If I use
1P breakers I can disconnect each load independently, which is desireable;
but a 2P fused or unfused disconnect may be cheaper and simpler to obtain.
Best proven methods, please?
I have saved and reread earlier postings on QO breeaker DC ratings. Nothing
seems appropriate here except Square D FHL16015 breakers in a FA100RB
enclosure. But my supply house quote for two breakers in one box is $480.
Ouch.
Has anyone successfully adapted Heinemann CF/Philips Airpax/Carling 125VDC
breakers to a standard NEMA 3R enclosure for use as a DC load center?

2. For the same application, 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.

Thank you.
Allan at Pos Energy

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