Swimming pool electrical very minor shock

Can anyone help me with this problem? The light bulb burned out in my swimming pool and I discovered this problem when trying to replace
that bulb. I read up on how to replace the bulb. That's pretty easy. It's just like a household lamp socket (same size shape - a normal light bulb will fit). The entire light is inside a water tight "can" with a long cord exiting from the "can". The cord goes through the concrete to a GFCI. I tested the GFCI with the test button, and it works fine. However, when I tried to re-install the fixture, I placed it in the pool and pushed it under the water to be sure not air bubbles rose (this would indicate a leak in the seal). This went fine. I turned on the light and it worked fine. I turned off the light and got in the pool to mount it back in the niche in the side of the pool. That's when I noticed a VERY slight shock. Even with the light switched off, I could feel a slight electrical shock. I first noticed it around my lips (I suppose I have sensitive lips!) and then I noticed it a little in my hand even when holding the fixture above the water (I was swimming in the pool.) I believe I could have gone ahead and put the light in the pool wall and all would have been fine.....however I got scared and I thought I would see what I could learn.
I did some testing and here is what I found. Using a Cen-tech P35017 multimeter, I touched one lead to the center of the light socket, then the other lead to the water. And then repeated the same test touching the outside of the light socket, and the water. etc.... If you cut and past the text below in an editor and set the font to Courier, everything will line up properly.
Reading Reading 1st lead 2nd lead Power ON Power Off
Center Water 122.50 1.24 - 1.26 Outside Water 1.3 1.10 - 1.30 Housing Water 1.50 1.12 - 1.15
Center Concrete 30.0 - 60.0 .44 - .50 Outside Concrete .4 - .5 .40 - 1.20 Housing Concrete .5 .62 - .64
Center Air 17.6 - 17.9 .38 - .42 Outside Air .20 - .37 .36 - .38 Housing Air .30 .32 .38 - .42
Air Air .006 - .011 .006- .001
Center = Center part of lamp socket Water = I touched the water in the pool with the probe Outside = Outside of lamp socket Housing = the outside, stainless steel part of the lamp (this is the part that touches the water) Concrete = I simply touched the concrete ground around the swimming pool
All numbers are in volts.
I figure that if I gave lots of information, maybe someone could help me out. Please let me know if this is normal or if I should contact a professional. Thanks for your help.
Chris
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Without wishing to denigrate your efforts IMO you would be better off with pro advice and service. Also IMO you would be better off changing the supply and light bulb to a low voltage source with an approved isolation type transformer. 24v seems to be common. The mains voltage lights have been banned in many countries (for obvious reasons) since the potential danger of installion failure is high and in an old installation quite likely.
Cheers ................. Rheilly P
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 4 Jun 2007 13:06:26 +0800, "Rheilly Phoull"

12v, not 24. If it is over 15v it is not low voltage in the eyes of the NEC pool code. You need a listed swimming pool light transformer.
I am always skeptical of any readinmg with a digital meter when yoiu have one lead connected to something that is "floating" (not firmly connected to a circuit conductor or solidly grounded conductor) Your readings to air and water are probably useless. Try it to the ladder or some other bonded metal. It should be noted that the light may not be properly bonded via the green wire in the cord. Check that in the deck box or elevated junction box. You also get additional bonding when you screw it into the niche via the 8ga in the pipe and the niche bonding to the pool steel. (assuming a legal installation) BTW most light manufacturers say you should be replacing the gasket when you relamp. They take a set in the bezel and may not seal when reinstalled. Since the GFCI is not tripping this is a fairly high resistance problem. I would start with a reinspection of the lamp to be sure there is no water in it, then seal it with a new gasket and try again. If there is any question, get it checked out by an electrician.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"I turned off the light and got in the pool to mount it back in the niche in the side of the pool. That's when I noticed a VERY slight shock. Even with the light switched off, I could feel a slight electrical shock. I first noticed it around my lips (I suppose I have sensitive lips!) and then I noticed it a little in my hand even when holding the fixture above the water (I was swimming in the pool.)"
Are you studying for a Darwin Award?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
If you enjoy swimming, doing your own work on the house, and uh, breathing, you really want a professional electrician to deal with this.
I've done my own electrical work, including the pool stuff, and as long as you have a complete understanding of, not just the procedure, but of whatever's causing the trouble and the complete solution, it's no less dangerous than driving on the freeway.
However, as soon as something weird appears, it's time to call in the cavalry. Electricity has a lot of funny properties, and the last thing you want is any surprises, such as the one you experienced in the pool. With a house nearly 70 years old, my electrician has found causes of weird problems that never would have crossed my mind. Some of these problems were caused by funky wiring that wasn't even close to where I found them, and in one case a commercially purchased light that was wired wrong at the factory was putting the Hot end of the circuit to the shell of the porch light. Scary stuff.
Spending money on something I can do myself isn't my favorite pastime. But neither is being zapped. Or dead.
CS

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.