Ground Loop Prevention [RE-wrenches]

[Drake Chamberlin]

<x-flowed>

Hello Wrenches,

Article 690.47 (C) of the NEC requires that the DC grounding 
electrode conductor connect to the grounding electrode of the AC 
system, where DC and AC systems are present.  Or, a separate DC 
grounding electrode may be installed, which is then bonded to the AC 
system grounding electrode.

If an inverter is feeding the grid (such as an Outback with backup 
system) it will have an equipment grounding conductor that connects 
to the neutral bar of the service.  It will also have a grounding 
electrode conductor that makes a loop to the ground rods, separate 
from the equipment grounding conductor, and also connects to the 
neutral bar.  The equipment grounds and the grounding electrode 
conductor connect to the equipment grounding bar in the DC disconnect.

Doesn't this create an induction loop that could bring lightning 
surges into the RE equipment and the building electrical system?

A similar case, that would seem especially problematic, is a ground 
wire run to a ground rod from an array.  It is often required to bond 
this rod to the existing system ground rods.

The array is required to have an equipment grounding conductor run 
back to the DC equipment ground?   This will ultimately connect to 
the utility service neutral bar. This creates a loop.

Is this really the best way, technically, to ground systems?  With 
this requirement, how do we both meet code and avoid creating a 
grounding loop that will attract lightning surges?

Thanks,

Drake 


- - - -
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 sbcglobal.net

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
--^----------------------------------------------------------------



</x-flowed>