Yow!  The National Electric Code sez that only one panel in a building =
may have a bonding jumper from Neutral to ground.  There also can be =
only one connection from ground (ground rods and such) to the main =
panel.  You may have many grounding devices (ground rod, cadweld to =
building steel, or wire to concrete rebar) but this grounding system may =
connect to the electrical system at only one point.  The reason is, just =
like people have mentioned, ground loops.  They affect more than signal =
wiring. =20



-- Lawrence Lile, P.E.
Electrical and Electronic Solutions
Project Solutions Companies
www.projsolco.com
573-443-7100 ext 221

> -----Original Message-----
> From: M. Adam Davis [mailto:adampic@UBASICS.COM]
> Sent: Wednesday, August 25, 2004 10:45 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [OT:] Wiring detached garage (reprise)
>=20
> I would bond them together.  There will be a ground loop, but if you
> don't bond them then neutral will be several or dozens of volts away
> from ground - not good.
>=20
> The problem gets worse with an intermittent or poor ground.  I used an
> extension cord to power a computer across a basement once.  The ground
> was bad somewhere along the line, and the computer case ended up
> floating and giving a nasty shock to anyone who touched it.
>=20
> If you bond the ground wire, the ground loop stays in wiring and not =
in
> equipment (and people) if you don't bond it then you have a potential
> problem since the ground loop may terminate in one of more pieces of
> electrical equipment (or they may push ground and neutral further =
apart).
>=20
> Treat the remote panel like a regular circuit breaker box - ground =
rod,
> bonded neutral.
>=20
> I am not a licensed electrician, though, so follow my advice at your =
own
> peril.
>=20
> -Adam
>=20
> Matt Redmond wrote:
>=20
> >Please no flaming about inspectors, etc... that we got off-topic on =
last
> time (the 'what cable gauge?' discussion)!  I have another question =
about
> wiring my detached garage - this one is about grounding.
> >
> >The way I read things, I have two acceptable choices when it comes to
> grounding in the detached garage.  They are:
> >
> >(a) Run H-H-N-G from main panel to garage.  Do NOT bond N-G in the =
remote
> panel.
> >
> >(b) Run H-H-N from main panel to garage.  DO bond N-G in the remote
> panel.
> >
> >In either case the garage gets its own earth ground.
> >
> >Any opinions on which is the 'betterer' approach.  Any advantages to =
one
> over the other?  I'm already going to be running 3-conductor cable +
> ground - any reason not to use (a)?
> >
> >Thanks!
> >
> >-matt redmond
> >
> >--
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> >
> >
> >
> >
>=20
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>=20

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