[TowerTalk] Grounding & Generator Questions

[Jim Lux]

At 11:22 AM 8/4/2005, Doug Rehman wrote:
>Gene:
>
>I may not have been clear enough in my description. I plan to use one
>generator, with an auto transfer switch which prevents back-feeding the
>utility, for the house which has its own meter and panel. I plan to use the
>second generator, with an auto transfer switch which prevents back-feeding
>the utility, for the office/shack which has its own meter and panel. There
>are no issues with paralleling the generators, because they will be feeding
>entirely separate panels/circuits.
>
>As to using the conduit as ground, I wasn't referring to the electrical
>safety ground. I am trying to follow best practices and use a single point
>ground and thus need to tie the shack's ground to the power meter ground. My
>question pertains strictly to the issue of using the conduit as the
>connection for the spg.
>
>D

As AD3F points out, grounding of generators and transfer switches is a 
fairly esoteric area.  There's a whole raft of issues. For instance, does 
your transfer switch also switch the grounding conductor (the greenwire 
ground) and/or the grounded conductor (i.e. the Neutral).

As you know, the Neutral is grounded at the panel in a normal installation, 
and that should be the ONLY place that Neutral and ground are 
interconnected.  If you put a transfer switch in, and the Neutral doesn't 
switch, you have to make sure the generator neutral isn't connected to the 
frame (sometimes very hard to insure on lower power generators).  And then, 
there's all sorts of issues with whether the frame of the generator is 
grounded.

Then, there's overcurrent protection (and making sure that when something 
trips, it doesn't screw up your careful grounding and grounded conductor 
arrangement.)

Time to consult a *local* pro.

Jim Lux, W6RMK, P.E.