Shocking Shower

[Norminn]

This is an interesting thread, although I don't know more than the very basics of what is being discussed....but.....I can understand consulting other DIYers if the writer was the only person being affected. So, a bunch of campers are getting mild electrical shocks and you are diddling about what to do or not to do? You have to be nuts! If there is any possibility that there is a loose or crossed connection that could vibrate or expand and make full contact, then what? Save $200 and electrocute a kid? I will send $10 to the OP to help cover the cost of a licensed electrician.

[mm]

I'd call him then, and say the same sort of thing. So that he wants to come out at no charge and fix the mess he left. You're not using the furnace now so he's bound to be nearby sometime in the next month, and it will take him 10 minutes.

[Wayne Whitney]

Good question. Note that in order for someone to be shocked as described, there must be a double fault. That is, a live conductor must be energizing some metal parts, which are themselves not properly bonded. If you ensure that all the metal parts (hot and cold water pipe, gas pipe, furnace frame) are properly bonded to the EGC in the building service, then a fault in the furnace should trip the breaker.

If there is a return path that parallels the proper neutral path, some current will always flow on it. So a person will get a mild shock when standing on the shower floor and touching the plumbing because they complete a circuit, one that is fairly high resistance compared to the "usual" return path.

This in and of itself will not help you, and under bizarre circumstances it could make the problem worse. You having a bonding problem, not an earthing problem. Earthing provides protection in the case of overvoltage; bonding provides protection in the case of accidentally energizing metal parts.

Cheers, Wayne

[John Grabowski]

I'm thinking that you need to get an experienced electrician to look over the electrical system. There is obviously a hazard to human life. This is not a situation for a do-it-yourselfer to play around with. You need to make things right and soon! Get a professional electrician now! What ever the cost it is still cheaper than a human life.

[Stormin Mormon]

I'm the OP. The building was wired by a licensed electrician, and the furnace was installed by a business. So, anything I do has to be better than that.

[trader4]

Yes, and of the billions of homes, office, business, etc buildings, this one is the only one where this induced AC electromagnetic effect through the air is occuring. And it's coming through the air from the furnace to the bathroom shower? LOL

This is definitely a grounding problem of some kind. We don't even know what the grounding arrangement is, whether it was done correctly, or whether some grounding path has been interrupted. That's where I'd be looking, not at EMI.

Yes, and of the billions of homes and businesses buildings, this one is the only one where this induced AC electromagnetic effect is occuring.

[trader4]

I hope you're joking here. Norminn has a very valid point. I'm an electrical engineer and I would not self diagnose and fix this. What I would do is close that shower, leave the furnace off, make everyone that should know aware of it and get a licensed electrician out there ASAP. There is the very real possibility that something very bad could occur and if it does, the liability here is extremely high. And if you fool around and try to fix it, that liability could extend for years. Say 3 years from now, something changed or got worse and then someone got electrocuted in that shower. Or even in that building. Don't you think someone is gonna say, "gee, I remember Stormin was working on it...." And then, even if you did nothing wrong, you could be ruined.

If you want to do something, make a donation to the church to pay for the licensed electrician.

[dpb]

Since this is the church camp, I think you have an obligation to do this right and immediately also. Which is why I suggested that _surely_ there's an experienced electrician in the congregation. I certainly disagree with the last sentence and think you're opening yourself and your church to a serious potential liability problem.

imo, etc., ...

[T8EPLO96]

The first thing he should do is completely disconnect the furnace. The switch shuts off the HOT. But open the box and disconnect the neutral too. Then see if you get a shock or voltage reading. If not, there is an electrical leak, bad motor or something else. If there is still voltage in the shower, the problem is not the furnace.

You did not mention what kind of pipe feeds that shower. Is it copper, steel or pvc or some other plastic? If it's copper, or steel ground the pipes to a good ground. If its a type of plastic, some wire has to be touching the shower valve. It could be someone punctured a romex cable with a nail and it's leaking into something metal touching the shower valves.

On the other hand, it could be the drain that is getting the voltage. I dont think anyone uses metalic pipe for drainage these days. Thus, with pvc pipes, the voltage it leaking into the drain, or the tub itself if it's a metal tub.

Here's another test. Shut off the MAINS in thge breaker box. Do you still get a shock? If not, turn on the mains and turn off each breaker one by one till you find the one that kills the shock. Trace that entire circuit. I'd guess it does to that bathroom.

Of course, since this is a church project, it could be that the man upstairs is just having a little fun, or maybe he needs more people in heaven. So, if all else fails, blame God.

T8EPLO96

[T8EPLO96]

Sledge hammering a ground rod above your head is a great way to get hurt. I've done it. After that I learned that they make T-post drivers. Much safer and easier. You only need the hammer for the last 18 inches or so. Yes, you really should use an 8 footer. Shorter ones are for tv antennas, electric fence grounds, and other oddball stuff.

[Bud--]

The neutral bar should be insulated from the box. It is possible there is a bonding jumper from the neutral bar to the box. Sometimes a very visible strap. Sometimes a very non-obvious screw - usually green.

Not obvious if you are saying there is no grounding electrode at the shower building. It is code required. Rods are notoriously poor, but the easiest if an electrode is not now present. Code is 8' (as someone said) and 2 are usually installed.

A slight possibility - if you have no grounding electrode and have a neutral-ground bond in the panel, the shower ground wires would lift from earth potential. Adding a furnace could provide a path from the shower ground wires to the shower valve.

Earth potential is not as fixed as is commonly assumed either, though a remote church camp one wouldn't expect much variation.

Around swimming pools (and buildings for animals on farms) the floor and accessible metal are all bonded. The equivalent would be connecting to the reinforcing mesh in the concrete floor when constructed and bonding to the valve, shower head, ...

Bond everything and make sure you have a connection to the earth at the remote shower (as someone else said).

Also not established - separate shower buildings for girls and boys? Could explain why girls get shocks, not boys. As a temporary fix you could have the girls shower with the boys.

A competent electrician sounds like a real good idea.

-- bud--

[Doug Miller]

And that could do it, too -- leaving that screw in, I mean, when it should have been removed. [...]

Actually, Code is 8' or to the depth of permanent soil moisture, whichever is deeper. [Article 250.53(A)]

True, but not by itself sufficient to cause the observed problem. Apparently the water pipes in the shower building are not properly grounded either. Code requires metal water piping to be bonded to the electrical grounding system, to ensure that there won't be any potential difference between the water pipes and ground.

[...]

Even more shocking.

[Norminn]

But you have no license, and altering the work done by the furnace co. might be bad for warranty issues, etc. I appreciate the loss of confidence in the contractor, but that is where I would go first. Call the owner of the company and tell him your campers are getting electrical shocks. Bet it gets his attention. I'm am all for DIYers trouble-shooting leaky pipes, missing shingles, busted windows, but when there is an issue of potential danger to the public - people with no reason to expect a hazard, and much worse if they are children - then the duty to remove the hazard is much greater. My kids roughed it at camp, at a tender age - bugs, heat, cold, long walks in the dark to the outhouse, poison ivy, etc. - but if they called and told me they got electrical shocks in the shower, I'd be there pronto to take them home.

Since you don't know the problem, you have no way of predicting what might happen. Loose wire that vibrates enough to make more complete contact and electrocute somebody? IMO, that is an urgent matter.

[dpb]

...

All of the above and more...

Not shutting the power off or blocking the use of the shower until this is solved and known to have been solved correctly is foolhardy and irresponsible.

As a Trustee of our church, if we had such a situation and a responsible camp director who didn't take _immediate_ action to protect the safety of the the campers and correct the problem, that person would be strongly admonished for their inaction to the point of dismissal.

This is a situation that is NOT the same as futzing around in one's own house -- one has the obligation and duty to ensure the kids are as safe as can possibly be.

A youngster drowned in a Y day camp near here the first day of the season this spring -- needless to say, that organization is going through hell just now and will be for the foreseeable future. While probably not a high probability of serious injury or death from this as described, it's a risk that simply should not be taken as it would, in retrospect, be VERY hard to explain to both law and insurance investigators why such a situation was allowed to continue when it was known to exist if something were to happen.

[trader4]

Bonding without proper grounding can still get you killed. You could have all the nearby metal parts bonded together, but without a proper earth ground the metal could all be at an entirely different potential.

Take for example a spa. Code says all the metal components must be bonded together. And for good reason. You don't want the possibility of one piece of metal that you could touch to be at a different potential than another that you could contact. However, if there is not a proper earth ground back at the service panel to which the spa is grounded, then you could step out of the spa and complete a path between the bonded parts of the spa and the earth, which could be at different potential.

[tnom]

It depends.

If the exposed shower plumbing is large and not grounded properly.

If a person gets wet and increases their contact surface area and thus their conductivity.

It definitely can be. The OP said that people can feel an electrical charge. He didn't say that the charge knocked them down. Seeing how these wet people standing on the wet ground are great conductors it can easily be a induced voltage on the plumbing caused by a near by transformer or motor.

You'd be surprised what voltage is induced on different conductors. 'Normally you would never notice. This one is different because showering people can conduct much more easily. Grounding such systems properly becomes much more important.

The easy fix is to ground the shower plumbing to the floor/ground/drain.

[mm]

He may be going to zap some nasty camper. The kid is probably dirty too, so he has yet to take a shower, but some day he will.

[Stormin Mormon]

: : The first thing he should do is completely disconnect the furnace. : The switch shuts off the HOT. But open the box and disconnect the : neutral too. Then see if you get a shock or voltage reading. If not, : there is an electrical leak, bad motor or something else. If there is : still voltage in the shower, the problem is not the furnace.

CY: That's good. I remember that we did turn off the furnace, and the 5 volts disappeared.

: : You did not mention what kind of pipe feeds that shower. Is it : copper, steel or pvc or some other plastic? If it's copper, or steel : ground the pipes to a good ground. If its a type of plastic, some : wire has to be touching the shower valve. It could be someone : punctured a romex cable with a nail and it's leaking into something : metal touching the shower valves.

CY: The water pipe is copper.

: : On the other hand, it could be the drain that is getting the voltage. : I dont think anyone uses metalic pipe for drainage these days. Thus, : with pvc pipes, the voltage it leaking into the drain, or the tub : itself if it's a metal tub.

CY: Unlikely that the drain is energized.

: : Here's another test. Shut off the MAINS in thge breaker box. Do you : still get a shock? If not, turn on the mains and turn off each : breaker one by one till you find the one that kills the shock. Trace : that entire circuit. I'd guess it does to that bathroom.

CY: Good diagnostic technique.

: : Of course, since this is a church project, it could be that the man : upstairs is just having a little fun, or maybe he needs more people in : heaven. So, if all else fails, blame God.

CY: I'll do that.

: : T8EPLO96 :

[Stormin Mormon]

Thanks for the good advice. I've seen the tube things with two handles for inserting fence posts. I'll put out the word I'm wanting one for a couple days.

[Bud--]

250.53-A is installation and is not whichever. 250.52-A-5 has requirements for the electrode - min 8'.

-- bud--