DC GFCI [RE-wrenches]

Bob-O Schultze, Electron Connection econnect at snowcrest.net
Mon Jan 14 08:42:34 PST 2002


<x-flowed>
Hiya Bill, etal,

>
>If you bolt the positive and negative together (e.g. with a metal staple
>through both--good reason never to use metal staples), the GFP may not
>detect this fault, but the inverter likely will because most inverters
>detect array shorts. If it is a battery-based system, the reverse current
>from the battery will normally trip the main breaker.

In a battery based system, the required charge controller should do 
the job of stopping reverse current flow. While I totally agree with 
you that a GFP is worthwhile for residence roof mounted arrays of any 
voltage, please do not lobby for them being included on ALL 48VDC 
systems. Their value in an off roof system is more limited to shock 
hazard reduction (yes, you COULD have a fire, but the likelyhood is 
VERY low to start with and even lower is the threat to humans. I will 
just add yet ANOTHER expense to our already overpriced RE systems and 
AGAIN hold RE to a higher standard than the grid.
Bob-O

>
>Can you think of a fault that isn't covered? I'm sure there are some high
>impedance line-to-line faults that might go undetected, but they will likely
>deteriorate into one of these other faults and cause a trip. All-in-all, the
>GFP fills a major gap in detection of faults that normal overcurrent
>protection is likely to miss.

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

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

List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm

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

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com

==^================================================================
This email was sent to: michael.welch at homepower.com

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

T O P I C A -- Register now to manage your mail!
http://www.topica.com/partner/tag02/register
==^================================================================


</x-flowed>



More information about the RE-wrenches mailing list