SMA Combi-Switch questions about UL rating [RE-wrenches]

Steve Johnson stevejohnson at comcast.net
Tue Dec 11 17:58:38 PST 2007


I think the clue is where you note the SMA combiner is not wired 
according to any figure on this data sheet!

The 10 amp fuses can carry 6.4 amps of current (6.4 x 1.56=10a)
6.4 x 4 strings  = 25.6
Fusible safety switches may carry 80 percent of nameplate current
rating (continuous use). -from SQ D sheet-
32 amps x 0.8 is 25.6

The Combi-switch manual lists "Max Continuous Output Current 32 A DC"

I don't know if that's right but it sounds reasonably good.  Or you 
could say they have two 30 amp knife blades in parallel (60 amps) that 
are rated for 40 amps DC.  (This is the simplistic view!)

http://download.sma.de/smaprosa/dateien/4286/Combi-Switch_User_Manual.pdf



> The SMA combiner is not wired according to any figure on this data 
> sheet. They have landed two legs on the two outer poles and then 
> combined the DC before it feeds the load. I asked the SMA rep and he 
> told me it was approved by UL. So how can this be a UL listed 40 amp 
> disconnect when it conflicts with the OEM's UL approval?
> 
> see Sq D document here: 
> http://ecatalog.squared.com/pubs/Electrical%20Distribution/Safety%20Switches/Heavy%20Duty/3110DB0401.pdf
> 
> 
> 




Steve Johnson
LightWave Solar Electric
Nashville, Tennessee


- - - -
Hosted by Home Power magazine

To send a message: RE-wrenches at topica.com

Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read

List rules & how to change your email address: www.mrsharkey.com/wrenches/etiquette.php

Check out participant bios: www.mrsharkey.com/wrenches/

Moderator: michael.welch at homepower.com
--^----------------------------------------------------------------
This email was sent to: michael.welch at re-wrenches.org

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9.bWljaGFl
Or send an email to: RE-wrenches-unsubscribe at topica.com

For Topica's complete suite of email marketing solutions visit:
http://www.topica.com/?p=TEXFOOTER
--^----------------------------------------------------------------




More information about the RE-wrenches mailing list