[TowerTalk] Coax as powerline - NOT

Jim Lux jimlux at earthlink.net
Tue Apr 15 15:02:08 EDT 2008


Jim Miller wrote:
> I thought it would work fine also but was going to wait for other comments.
> Water, yes but same as other use for coax.  BUT, let's take an extreme
> example, say 200 feet distance, and even 5 amp load.  You will see a voltage
> drop at the work end of the line.  OK, the voltage drop may be fine.  The
> problem is that the difference in voltage measured across the two conductors
> occurs partially on BOTH conductors.  THAT leaves the "ground" side of the
> coax at some potential that is above ground.  Now both wires are HOT.
> DANGER here, if you are going to do it, you MUST be aware of it and take the
> proper precautions and NOT connect the "ground" side of the line to anything
> other that a load that is NOT GROUNDED.  Just not a good situation.  The
> NEXT guy might get electrocuted.



Not that I want to encourage the use of coax for AC line power (I'm not 
too wild about the idea), but something that can also be considered here 
is that there could be isolation transformers in the system, so the two 
sides of the coax could be floating relative to "physical ground", with 
the grounding done, say, at the load end (this would be like the utility 
distribution... the grounding is done at the service entrance)

And, of course, ground fault interrupters would greatly ameliorate the 
personnel safety issues.



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