So I was settled into the jacuzzi with my wife the other night, and we were topping off the tub with some more hot water. I touched one of the (metal) faucet handles and felt a distinctive tingling in my hand, running down my arm. With the water turned off, I felt no such tingling. My first thought was that the electrician(s) had chosen two different pipes to ground some electrical equipment to, and my hand (and the column of water, and the other pipe) were forming a ground loop – two appliances in the house had different ground voltages, and the difference between those voltages was coming through my hand.
I recalled a practical joke that a friend described to me, where you place a plastic trash can in someone’s shower and fill it with water. Supposedly the charge differential created as the water runs through the air (!) builds up if the water can’t ground out on the drain, and the trashcan/bathtub assembly becomes a large capacitor. The unlucky soul who has to tip over the tub gets a strong ZAP from the trashcan when he tips it over. I figured that a big-ass fiberglass tub was just as good as a trashcan if the drain wasn’t grounded, and thought that perhaps that was the more likely explanation.
So, Dopers, which seems like a better explanation: was my bathtub a capacitor, or do I have a (minor) wiring problem?
If you only felt the sensation with the water running, then the only explanation is that you were feeling vibration induced by the running water. Vibration can feel like an electric shock (those wind-up handshake “joy buzzers” come to mind).
Never heard of the trashcan gag, and I’m rather doubtful. Certainly, water moving through air (or rubbing against an insulation medium, like plastic) can build up static potentials–thunderstorms are ample evidence of this–but I’m dubious that you could get much of a charge from a running shower.
You definitely have a problem! Even a mild shock is indicative of a problem. Q.E.D. has a valid point too min which case it is not an electrical problem. :rolleyes: And forget the static electricity in a wet enviornment. It leaks off about as fast as it can build up.
Get a good voltage testor and check for any stray voltages thay may exist in the entire jacuzzi system. Since you have plastic piping for the water to circulate in, an electric motor to drive the pump, and most likely copper water supply piping there is a definite possiblility of stray voltages. The motor frame, its electriclal supply ground wire and water piping should all be connected to ground.
Incidentally, if you want to prove it out, run the water as before and verify that youf eel the tingling when you touch the handle, then pick up a sturdy drinking glass (glass, not plastic; the thicker, the better) and use that to touch the handle. If you still feel it, it’s vibration.
I’m pretty sure it’s not the jacuzzi motor causing the problem, because I only felt the current when the water was running. Q.E.D., I have felt vibration that felt like electricity, but I’ve also felt current (worked with an old-school electric tunnel-type dishwasher in high school and got zapped more than once). This was current, for sure. My arm wasn’t leaning on anything - straight from the water to the handle - and the faucet is very firmly seated.
My wife’s going to want a bath at some point this weekend, so I’ll conduct further experiments and report back. I’m placing a drinking glass next to the tub now so I don’t forget to (objectively) rule out vibration.
One thing you can do to test it is get a noncontact voltage sensor (Lowes or Home Depot would have them, among other places)–basically a doohickey you hold near a suspected source of voltage with a little LED that lights up if voltage is present, whether or not current is actually flowing. Check various parts of the plumbing and grounding system to see if voltage is present where none ought to be. If it is, DO NOT USE THE TUB until you’ve fixed the problem.
One possibility is that the flowing water may be completing a circuit that is normally open due to a section of PVC pipe or rubber/plastic hose between the house plumbing and the jacuzzi. Since clean water is not really a great conductor (just good enough to be dangerous), you may be able to get a clear voltmeter reading across any nonconducting plumbing (check both AC and DC) with the water running or not.
A positive result would be definitive, but a negative result might not be. There may (for example) be more than one insulating segment.
Note that we often bathe after exercising, and use unfiltered city water. I’m not saying that’s going to add enough salts to change the conductivity of the water significantly, but it should be considered. I’ve got a voltmeter and an ammeter left over from Circuits 301 in college. I’ll whip that bad boy out and see if my wife and I still have “that certain spark”. Er… I’ll check my plumbing to see if it’s charged. Ahem… I’ll measure the voltage between various metal parts of our jacuzzi.
