[TowerTalk] Challenging Grounding/Bonding Situation ?

[Gary Schafer]

> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of
> Jim Brown
> Sent: Friday, September 12, 2014 7:07 PM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Challenging Grounding/Bonding Situation ?
> 
> On Fri,9/12/2014 4:39 PM, Bill Turner wrote:
> > I'm not an electrician but I'm pretty sure that is not according to
> > code. You should have four wires, not three, going from the house to
> > the shack:  Two hots, a neutral and ground. Having no ground in the
> > shack is asking for trouble. And I do NOT mean a ground rod in the
> > shack - I mean a green ground wire from the service entrance to the
> > shack.
> 
> The system I described is legal per the latest NEC I have from my
> working days designing sound systems (about 2003, I think). I looked it
> up before I did it.
> 
> There is nothing "magic" (or even desirable) about carrying ground from
> one building to another, or even from the utility. The utility brings us
> center-tapped 240. The center tap goes to earth along the power system
> at multiple points, but it's rarely much of a ground. AND there's a lot
> of inductance between that ground and ours.
> 
> 73, Jim K9YC

The whole purpose of the 4 wire system is to keep neutral current off of the
ground wire.

With a 3 wire system, if the neutral/ground should open there could be 120
volts on cabinets that are connected to the green wire ground.

There will also be a voltage difference between grounds due to voltage drop
on the common neutral/ground.

73
Gary  K4FMX