48V hardware [RE-wrenches]

Bill Brooks billbrooks7 at earthlink.net
Thu Jul 19 07:27:26 PDT 2001


Travis,

Well done. No ice will form under your feet. Have an equally sunny day.

Bill.


-----Original Message-----
From: Travis Creswell, Ozark Solar [mailto:ozsolar at ipa.net]
Sent: Thursday, July 19, 2001 5:17 AM
To: RE-wrenches at topica.com
Subject: Re: 48V hardware [RE-wrenches]


Ok, you made me get my code book out ....  and I quote from the 1999 NEC
Handbook page 20

"3R - Outdoor use, undamaged by the formation of ice on the enclosure"

"Enclosure marked with a Type may also be marked as follows"   (note the MAY
ALSO)

"type 3R may be marked "Raintight""

"For equipment designated "Raintight" testing to simulate a exposure to a
beating rain will not result in entrance of water"

In summary 3R is not rainproof.  A 3R enclosures with the "Rainproof "
designation is "Rainproof".  And that's all the nits I'm going to pick
today.

Have nice day Bill.

Travis


----- Original Message -----
From: "Bill Brooks" <billbrooks7 at earthlink.net>
To: <RE-wrenches at topica.com>
Sent: Wednesday, July 18, 2001 11:45 PM
Subject: RE: 48V hardware [RE-wrenches]


> 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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