[TowerTalk] Coax as powerline

[Sadtip]

PLEASE DON'T DO THIS!!

I used to work as an engineer at a radio station and someone before me had
used
2 conductor with grounded shield wire for AC in some places. It was DAMN
annoying
to have to check EVERY (supposedly audio) wire with a meter before messing
with it.
There were literally MILES of wire run over the drop ceiling and any one of
them could
be AC hot. I wanted to shoot the person that did it!
In my opinion, it's better to have AC on AC type wire and RF on RF type wire
just for
sanities sake.

RoD
KD0XX

> -----Original Message-----
> From: towertalk-bounces at contesting.com
> [mailto:towertalk-bounces at contesting.com]On Behalf Of Jim Brown
> Sent: Monday, April 14, 2008 2:41 PM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Coax as powerline
>
>
> On Mon, 14 Apr 2008 09:53:08 -0600, Doug Renwick wrote:
>
> >Has anyone successfully used ca RG-8 or RG-11 center conductor only to
> >carry 120 or 240 volts in place of an underground power cable?
>
> There are several issues with this one. First is the obvious one of
> moisture. Second -- is the coax rated for carrying mains power? If you
> ever had a problem (lightning, a fire), there could be serious legal
> and/or insurance issues if it is not.
>
> Third -- NEUTRAL is NOT GROUND. For a 120V circuit, you MUST run a phase
> (hot), a neutral, and an equipment (safety) ground. The ground may be
> connected to the earth (it MUST be connected to the power system earth).
> The neutral MUST NOT be connected to ground or earth anywhere. It
> can only
> be connected to the neutral bus in the panel, and to the neutral terminal
> on the outlet (or load) at the other end.
>
> Likewise, for a 240V (only) circuit, you must run two hots ande a ground.
> And if you want to run both a 120V load and a 240V load, you must also
> pull a neutral.
>
> Fourth, the most "noise-resistant" way you can run a line like this is as
> a twisted pair for the phase and neutral, with a third wire as the
> equipment ground. If you ran this with coax, it would have to be as two
> parallel runs of coax, with one center conductor being the hot (phase),
> the other center conductor being the neutral, and the shields being the
> equipment ground. The twisted pair is actually FAR better at rejecting
> power-frequency magnetic coupling than the coax.
>
> 73,
>
> Jim Brown K9YC
>
>
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