baptistry equi potential bonding

[EEuno]

I have a church, full body, immersion baptistry project that I am concerned with stray current shock hazard. The baptistry is a fiberglass "bathtub" used with about 12" of water in it. The water is drained after use. The baptistry is set into a wooden frame that in turn is supported by a concrete "hole" in the main platform of the church, at front of church. The wooden frame isolates the fiberglass baptistry from the concrete. The wood frame extends horizontally less than 3' from the edge of the baptistry. The concrete/wood around the baptistry is covered with carpeting. There is a structural floor covering that covers the baptistry when not in use.

My concern is people standing on the concrete/wood next to the baptistry after an immersion. Does the code require a bond connection to the concrete deck rebar? Would a wooden deck and or rubber matting (non conductive) be a suitable alternative to insulate the people from the concrete deck ?

What is required if there is no rebar in the deck?

 

[VEBill]

An utter lack of faith... ;-)

 

[dpc]

As long as there are no electrical devices within or nearby, what you have is a big bathtub. I don't see a problem as long as portable devices are kept away from it.

Grounding fiberglass isn't going to do much about anything.

Where is the stray current going to come from and where is it going to go?

 

[EEuno]

Sorry, I should have noted that there is a water heater and circulator, both electric and both metal parts of same are bonded to ground and powered by GFI circuits.

There are some floor receptacles 27' away from the baptistry and one receptacle that is much closer but at the main floor level of the church about 4' down/lower on the front wall of the platform ( not within reach). All these ckts are GFI

The only way that a current could wind up leaking is if one of the conduits feeding these receptacles were to break and the wire within were to be exposed and come in contact with the concrete or rebar in the concrete. If the leakage were small, less than 5 ma, nothing would happen in the GFI devices.

I would ask how different is this with a house bathroom with the house built slab-on-grade? Why is a house shower/bathtub not required to have equi potential bonding if one steps out onto concrete/or cermaic tile?

Thanks for your help!

 

[dpc]

Most bathtubs don't have built-in heaters and circ pumps, and residential requirements have a lot of tradition behind them.

I'd follow the requirements of NEC Articles 680 and 640 (assuming you are in the USA)

I don't see a need for additional bonding and I don't see how it is going to help much anyway. You could put an insulating mat where wet people would be stepping onto, I suppose.

The biggest issue is keeping anything else that is powered AWAY from the water, such as microphones, speakers, etc.

 

[zappedagain]

Just make sure that whatever electronic items people may accidentally drop into the baptistry is plugged into a GFCI, or battery powered.

http://boingboing.net/2008/01/07/photo-of-extension-c.html

John D