[AT] grounds

[Dudley Rupert]

Warren,

I am not suggesting at all that you doubt your' friend but I am curious as
to what his reasoning would be for advising you not to connect the sub panel
in your' shop to its' own ground rod ... or at least this is what I think I
hear you saying.


I wired the house I am living in with 400 amp service (this is more like
commercial than the typical residential service) and then ran 3-wire 240
from the house down to the barn and put a 100 amp sub panel there with the
ground lug connected to a ground rod (and, of course, to the neutral wire
from the house panel).  This was permitted/inspected but it was thirty years
ago so maybe something has changed since then.


I did redo the main entry service to my daughter and SIL's place this past
summer.  The main house has the 325 amp service coming in from the road.  I
don't know if the 325 amp service is available all across the country or not
but for little more $$ than it costs for a 200 amp service (particularly if
you've got dad providing the labor for coffee/sandwich/cookies) you've got
closer to a 400 amp service than 200.  Their guesthouse, shop and barn each
has its' own sub panel and grounding rod and is serviced by 3-wire 240 from
the main house.  This was permitted/inspected as well but as I wasn't there
when the inspector came I can't say for sure that he would have even looked
at the service to/at the "out buildings" as I applied only to change the
main entry service.


I can think of three or four other inspected services I've done where I've
installed a sub panel/grounding rod (in addition to the main service) but
none within the past ten years so that bit of history/memory is of no help.
My copy/edition of the NEC is thirty or more years old so it's of no help
either.  In conclusion I guess I've just been trying to give a bit of my
thinking as to why I am wondering at what your' friend told you regarding
not installing the ground rod at your' shop but I am most likely the one
that's got some new learning to do.

Dudley
Snohomish, Washington

-----Original Message-----
From: at-bounces at lists.antique-tractor.com
[mailto:at-bounces at lists.antique-tractor.com]On Behalf Of Mogrits
Sent: Sunday, December 16, 2007 10:24 PM
To: Antique tractor email discussion group
Subject: [AT] grounds

This is all anecdotal but nevertheless:

I have a 10kw briggs powered generator with a grounding lug on the generator
housing. When I use the genset to power the house I connect the houseground
to the generator by a copper wire I leave connected and coiled up just below
the house service.

When I built my shop a few hundred feet from the house and wanted to power
it from the house service instead of a separate meter I asked my electrical
engineer friend about installing a ground rod and he advised me to NOT
separately ground the building. He says the ground should come from the same
source as the power, so I ran four-wire mobilehome service cable up to the
shop.

Warren
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