Just went outside to check here in Houston. Same thing, except my
transformer has three drops to 200A house, 200A shack and 100A barn. I also
have two other transformers, each with single drop to two other houses
(daughter, mother-in-law), 200A each. In all cases, the transformer center
tap connects to top wire on pole and to ground. All entrance panels have
neutral connected to box and to ground rod just below. Phone and cable both
enter near service panel with separate ground wires to same rod.
73, Keith NM5G
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Tom Rauch
Sent: Saturday, October 08, 2005 8:12 AM
To: Ian White GM3SEK; towertalk@contesting.com
Subject: [TowerTalk] Pole Pig Transformer wiring
> Jim Lux wrote:
> >> The power company also grounds the
> >>neutral connection at the transformer to earth ground.
> >
> >Not necessarily.. for the same reason as you have a
single interconnect
> >between neutral and ground. You don't want neutral
return currents
> >flowing back to the transformer via the ground path.
Ian Replied:
> Interesting... the power companies in the UK take a
different view. In
> the event of a neutral break in their local distribution
system (230V
> single-phase, neutral close to earth potential) they'd
rather have the
> return current flowing back through earth than create a
shock hazard due
> to the neutral becoming hot.
>
> Therefore they almost always earth the neutral at the
transformer,
> and/or anyplace else they conveniently can.
I had a look at the transformer here.
I have two drops. One to a distribution pole with a meter and a pair of dual
200 amp mains that feeds my radio room and all the outbuildings, the other
drop feeds a single 200A dual mains for the normal house wiring.
At the transformer the heavy neutrals bond directly with very heavy wire to
the bare distribution ground wire passing the pole. The center tap of the
pole pig has what looks like a number 6 solid copper wire to the metal can
and to the ground wire running down the pole. That ground wire bonds to the
neutral wire running down the street.
The ground path at the pole is from the 240V winding CT to earth and to the
HV neutral at the road through a small gauge wire, perhaps number 6 AWG. The
heavy bonding is from the bare triplex drop wire directly to the street
neutral, which is the return for the 7,200 volt distribution line.
Very clearly the utility wants the major bond to be with the 7200 volt
return, a much smaller conductor goes from the pig CT to the pole ground
wire...which eventually after a few splices connects to the area
distribution neutral.
What do others see outside their houses in the USA?
73 Tom
_______________________________________________
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Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
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_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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