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Swim Meet #99953
09/27/06 05:12 PM
09/27/06 05:12 PM
G
George Little  Offline OP
Member
Joined: Jan 2004
Posts: 1,489
Michigan USA
I had the occasion to inspect wiring associated with a swim meet where the swimmers were racing against the clock as well as their competitors.
My question is based on the fact that they were using touch pads (millivolt) at the water level in the lanes where the swimmers would be swimming. These touch pads were hooked to the computers that would log the times. Has anyone ever run into this in their travels? I questioned this use and the shock hazzard. I was "assured" that this is standard procedure.


George Little
2017 / 2014 NEC & Related Books and Study Guides
Re: Swim Meet #99954
09/27/06 09:45 PM
09/27/06 09:45 PM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,165
Estero,Fl,usa
Was this battery operated or line voltage operated? I understand it may really be a distinction without a difference but you won't have the possibility of 120v present with a fault. Battery equipment is also less likely to have a voltage referenced to ground (and the pool)
I do understand a capacitive "touch" pad is passive in nature with no voltage present but we deal with the worst possible scenario.


Greg Fretwell
Re: Swim Meet #99955
09/27/06 10:03 PM
09/27/06 10:03 PM
G
George Little  Offline OP
Member
Joined: Jan 2004
Posts: 1,489
Michigan USA
Greg- I don't know. They hit town, had their swim meet and left town before I was able to get the info. Seems it was going into the weekend and I thought I'd follow up on Monday and they were gone. I was hoping someone on this Board had some experience with something similar.


George Little
Re: Swim Meet #99956
09/27/06 10:30 PM
09/27/06 10:30 PM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,165
Estero,Fl,usa
I have heard about these systems on one of the BBs I am on and my impression was this was hanging on a laptop USB port. I am not even sure how the AHJ gets involved if they don't plug it in the wall.
It certainly doesn't sound any more dangerous than one of those LED blinkng light floaters that runs on 3 AA cells.


Greg Fretwell
Re: Swim Meet #99957
09/28/06 08:22 AM
09/28/06 08:22 AM
M
Mike Wescoatt  Offline
Member
Joined: Jun 2001
Posts: 161
Cedar City, Utah
OK guys, this is recollection from 8+ years ago...
If I remember right equipmemt approved for use in a swimming pool by UL (not a fountain) has to have a split wound transformer with the secondary on an insulated bobbin. This is where the primary and secondary windings are either on seperate bobbins on a common core or are wound on an insulating bobbin with secondary insulation between the windings (windings side by side). This is opposed to primary and secondary windings right on top of each other. The core was also to be grounded.
The theory, I guess, is that a fault on the primary would be cleared by overcurrent protection (short winding) or by ground fault (short to bobbin) while the secondary was still insulated from the core and primary.

Again, trying to remember from a while ago...


Mike Wescoatt
Re: Swim Meet #99958
09/28/06 11:06 AM
09/28/06 11:06 AM
G
gfretwell  Offline

Member
Joined: Jul 2004
Posts: 9,165
Estero,Fl,usa
These days it is hard to find a conventional transformer in a piece of electronic gear. They use switch mode power supplies. I would still be nervous if this timing device was plugged into the wall, no matter how it was listed.


Greg Fretwell

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