Swimming pools, boat docks snd ground rods

[tom baker]

I went to Mike Holts 2 hr grounfing and bonding seminar in Seattle. He and his staff have done a lot of testing and videos showing results of 120v to swimming pools, boat docks and ground rods.
the used a floating meter board to illustrate step potential and gradient.
Mike said
*Do not have 120v on a boat dock for outlets, lift, or lights.
* No 120v pool lights, use nonmetallic ladders, be very dilligent in bonding mesh around pool.
* be very cautious if called to ts stray voltage in a pool, best to turn off power and call experts, otherwise you could be liable.
he demonstrated how a energized ground rod, 120 v, at a heat pump or street light, with no egc, extends the voltage gradient and makes the installation less safe.
it was interesting and informatitive, i am not sure how the videos will be available.
He almost set the house on fire...energized the pool bond with 120v, current was returning via screen house, metal soffit, can lights and egc.

 

[kwired]

I went to Mike Holts 2 hr grounfing and bonding seminar in Seattle. He and his staff have done a lot of testing and videos showing results of 120v to swimming pools, boat docks and ground rods.
the used a floating meter board to illustrate step potential and gradient.
Mike said
*Do not have 120v on a boat dock for outlets, lift, or lights.
* No 120v pool lights, use nonmetallic ladders, be very dilligent in bonding mesh around pool.
* be very cautious if called to ts stray voltage in a pool, best to turn off power and call experts, otherwise you could be liable.
he demonstrated how a energized ground rod, 120 v, at a heat pump or street light, with no egc, extends the voltage gradient and makes the installation less safe.
it was interesting and informatitive, i am not sure how the videos will be available.
He almost set the house on fire...energized the pool bond with 120v, current was returning via screen house, metal soffit, can lights and egc.

If there is voltage rise on incoming grounded service conductor turning power off won't help, best to simply not use the pool period until problems are solved. Properly bonded pool shouldn't have an issue with this, but "holes" can happen in the equipotential bonding.

Boat docks are probably worse than pools, good luck convincing owners not to power things, at very least a boat lift.

GFCI won't do anything when there is voltage rise on EGC's and give many a false sense they are protected from any possible shock hazard.

 

[Hv&Lv]

At the risk of adding confusion here...
voltage on a pool can also be caused by POCO connections.
we had a development with old concentric neutral cable. The neutral was so eat up being exposed to direct earth for 40 years. We had complaints about pool shocks every summer until we replaced all the cable with JCN cable.

we had spans of copper between transformers for neutrals every summer. Fix a span, go to next problem...

 

[hillbilly1]

Here in Georgia there is a lake above Atlanta called Lanier. It is a very large lake, and basically has a constant 5-10 volts on it due to failing poco underground lines, and bad dock power installs.

 

[kwired]

Here in Georgia there is a lake above Atlanta called Lanier. It is a very large lake, and basically has a constant 5-10 volts on it due to failing poco underground lines, and bad dock power installs.

The lake is going to be at earth potential, it is your grounded/grounding conductors that are 5-10 volts above earth potential though the reason lies more so in the POCO system than in individual services. Bad dock installs should only create problems in local vicinity of the dock.