Ground fault [RE-wrenches]

[Bill Brooks]

Jeff,

It is very difficult to tell what happened with this mess. Not seeing the
size of the array and all would make me very hesitant to blame this on a
ground fault.

My experience tells me that manufacturers rate their equipment the way they
expect it to be used and usually give optimistic numbers on the capabilities
of their equipment. Installers, not fully understanding the designs they are
working with feel like they can operate the equipment at, near, or slightly
above the published rating think that "there must be a safety margin in
here."

All these bad assumptions result in smoke. My guess is that the unit was
overpowered in the fall of the year when the sun was hitting the modules
straight on, voltage was higher because of the cooler weather, and the
controller ran out of current/temperature headroom and something gave up.

The ground fault is likely the result of the board insulation disappearing.
All speculation, but don't fault the wiring until you find the bad wire.
Equipment fails more often unless the installer is careless.

By the way, intermittent insulation faults are extremely common with damaged
wiring. The initial voltage check certainly is an absolute must, but an
insulation test taking all your wiring to 500V is a much better test. This
is commonly done in large commercial industrial projects but is rarely done
on small commercial and residential electrical projects (doesn't make it any
less important however). Even this test does not solve all problems. That is
why GFPs are so valuable. They will catch that intermittent fault when these
other methods fail.

Bill.





-----Original Message-----
From: Jeffery Wolfe, Global Resource Options
[mailto:jeff at globalresourceoptions.com]
Sent: Friday, November 15, 2002 3:33 PM
To: RE-wrenches at topica.com
Subject: RE: Ground fault [RE-wrenches]


>From what I've heard, most of these problems, including the one we've been
discussing, happen at install. I think a voltage check would have caught
this one.

Jeff

-----Original Message-----
From: Bill Brooks [mailto:billb at endecon.com]
Sent: Friday, November 15, 2002 2:10 PM
To: RE-wrenches at topica.com
Subject: RE: Ground fault [RE-wrenches]



Jeff,

A Voc test on your wiring is only going to find gross wiring mistakes. A GFP
works 24-7 to find those faults that don't show up until later.

Bill.

-----Original Message-----
From: Jeffery Wolfe, Global Resource Options
[mailto:jeff at globalresourceoptions.com]
Sent: Thursday, November 14, 2002 5:38 PM
To: RE-wrenches at topica.com
Subject: RE: Ground fault [RE-wrenches]


I'm not ready to add PVGFP's to all my installs. I think that's overkill,
and not addressing the problem of adequate installation (by whoever installs
the panels).
***snip***

- - - -
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

- - - -
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

- - - -
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.bWljaGFl
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
==^================================================================