"As for stray voltage, that would be a real hot topic around here. I have seen lots of problems with stray voltage around pools. Sometimes it was caused by pin hole leaks in the Power Co. (POCO) primary underground feeders.
We would get readings between 5-30 volts around a pool. Enough voltage so that you feel a tingle when you touch metal, the pool deck and had bare feet."Primary (loop or star) Poco Feeders are those conductors that function on the line side of Poco transformers -- pad mount or pole mount. Hence, they operate at "Medium" voltages -- i.e. beyond 2,000 VAC.
Service Laterals to homes and their common Secondary Tap run should best be termed
Secondaries.
Pocos can deliver juice at both Primary and Secondary voltages to Service customers. -- And, obviously, will only provide Medium Voltages to industrial and major commercial ratepayers.
(Las Vegas casinos famously draw only Medium Voltage/ Primary (Distribution) Circuit power. The casinos own and operate all of the utilization transformers, themselves.)
When overhead, the Primary Distribution is unshielded. Any car parked near High Voltage transmission lines will have an induced ( capacitive coupling ) voltage ranging into the hundreds of volts. The actual charge quanta will be very low. It can be tested by a high impedance meter -- like our common DMM -- with one lead stuck in the ground and one on the bodywork.
This phenomena can't happen with buried Primary conductors -- because they are Shielded with a braided neutral -- looking like a massively oversized co-axial cable wire.
Even pin hole leaks in Secondary insulation would vent so much current that the heat would open up the fault until even a Primary transformer fuse would blow. (Pocos don't fuse their secondaries -- as a rule.)
All of which is to say that you're operating under a false conception of where the mystery current is coming from.
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Speaking from experience:
The impressed voltage witnessed in swimming pools and hot tubs that
are not well grounded can have two sources.
Either the slightly salty pool is experiencing capacitive coupling to some nearby high voltage, high power current -- or it's experiencing the Faraday effect.
http://en.wikipedia.org/wiki/MHD_generatorIn the current age, swimming pools and hot tubs have filtration and agitation circuits built entirely of PVC. The pump impellers are typically plastic, too. It's also very, very common for the field windings to be wrapped in a PLASTIC enclosure, too. The only metals are within the field windings and stator.
Because everyone exudes salt from their skin, and such salt does not evaporate out, swimming pools turn into weak salt baths -- every last one.
Making them conductors of electricity, too.
When such a fluid is forced to pass through the unshielded electric fields of the pool pump, by that pump, both the Faraday effect and the Hall effect kick in: the first being dominant.
If the 'salt bath' is well insulated -- it is possible to lift the voltage of the bath into the tens of volts. I have tested it as high as 45 Volts with a DMM.
Once it's sweetly grounded, this voltage bleeds off.
So, the voltage is being built up by magnetic field effects.
While the voltage can build up to dangerous levels -- the discharge current travels through your groin while stepping into the pool, one leg at a time -- the contained energy is easily bled by a ground wire.
Factory built hot tub assemblies specify that they need a grounded plug. They don't explain, even to their tech reps, the above reason. If you're unlucky enough to plug into an exterior receptacle in a home built to 1960 standards -- (no grounding conductor) you'll get a shock.
I was working with my old boss ( back in 1977?) We were working with an old built in pool and there was problems with voltage I believe. However being a 1-3 year apprentice, I did not know what was going on. Some of the old pools around here were concrete but no rebar. Most didn't have bonding wires around them either and they also use to use brass conduit to go to the wet niche.
