[TowerTalk] Challenging Grounding/Bonding Situation ?

[Bill Turner]

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On Fri, 12 Sep 2014 17:06:46 -0700, k9yc wrote:

>
>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.

REPLY:

Here's the "magic".  If someone uses the neutral for ground and the
neutral develops an open somewhere down the line, all of a sudden
whatever was "grounded" by the neutral now becomes hot because there
is a current path from hot through the equipment to whatever the
neutral was supposedly grounding. This is a potential killer. 

Imagine something like a washing machine where the neutral is
connected to the frame and down the line the neutral opens up. Now the
frame has the full "hot" voltage on it. The next person to do a load
will be lucky if they live. 

A lot of people use neutral for ground, but it's illegal, as it should
be. The code requires that the ground wire be separate from any
current-carrying wire. Using neutral for ground violates that
requirement. 

BTW, this is only for safety, has nothing to do with lightning. 

73, Bill W6WRT