Hot tub

[shortcircuit2]

For some reason the height requirement of 28 inches with a horizontal distance of 30 inches of perimeter surfaces keeps getting inserted as an exception to exempt the bonding grid.

IMO, CMP 17 has accepted reasoning by the hot-tub industry that at 28 inches horizontal above ground, there will not be a chance that a person can have 1 foot in the tub at the same time the other is on the (possibly stray voltage energized) perimeter surface as they enter the tub, therefore no one will get hurt.

Think about it, if a permanently installed above ground pool is installed, it requires the perimeter bond, so why not apply the same principal to a hot-tub? The hot-tub industry also argued that a hot-tub should be considered as portable. The only time I?ve seen a hot-tub being portable is when it is installed or removed from the property.

Under pressure from the hot-tub industry and no body count directly related to hot-tubs, CMP 17 passed TIA 11-1

IMO, the same documented evidence of stray voltage hazards that implemented the perimeter bond for permanently installed pools can be used as guidance for perimeter bonding to be applied to hot-tubs.

shortcircuit

 

[kwired]

How would stray voltage get to the deck when wood is non conductive. That means any wood deck could get stray voltage with or without a hot tub.

Now saturate that wood with water and throw in what it was treated with and it may be somewhat conductive. But how do you effectively bond it?

 

[Dennis Alwon]

How would stray voltage get to the deck when wood is non conductive. That means any wood deck could get stray voltage with or without a hot tub.

Stray voltage is everywhere but not as big an issue until you add water to the mix. I agree with Kwired about the saturated wood and the chemicals in treated wood. It will be conductive. I have been shocked years ago on a wooden ext. ladder when the ladder was wet after a rain. I was hot wiring a service we had changed.

 

[A/A Fuel GTX]

I have been shocked years ago on a wooden ext. ladder when the ladder was wet after a rain. I was hot wiring a service we had changed.

I often see trees making contact with overhead POCO lines and wonder if one could be shocked by making contact with the tree. In my area, that would be 7200V.

 

[kwired]

I often see trees making contact with overhead POCO lines and wonder if one could be shocked by making contact with the tree. In my area, that would be 7200V.

It does happen sometimes. Live trees are more conductive than dead trees, but dead trees don't grow into power lines either.




As to conductivity of wood, it is a poor conductor, but not always a perfect insulator. Why do you suppose they attach insulators to wood poles supporting overhead bare conductors?

 

[GoldDigger]

It does happen sometimes. Live trees are more conductive than dead trees, but dead trees don't grow into power lines either.
As to conductivity of wood, it is a poor conductor, but not always a perfect insulator. Why do you suppose they attach insulators to wood poles supporting overhead bare conductors?

And FWIW, acid rain is a better conductor than neutral pH rain.