[tbwoods]

HI,

I recently purchased a new place. For 1 year no problem. Just this weekend though, 2 people have gotten shocked in the shower when touching either the shower head or on/off handles. I've done a lot of checking and here is what I know:

I have continuity between the plumbing (shower head, valve) and the neutral bar in my electrical panel - where all white wires are attached. (10 feet away)

I put a volt meter between the shower head or valving and the floor drain in the shower stall floor. The piping is plastic but full of water. I get 22 to 50 volts AC.

The electrical panel is 10 feet from the shower. The unit is new 200 amp service and has a heavy copper line going from the panel to a grounding rod driven in the ground about 10 feet away.

I exhaustively went through my panel, disconnecting one circuit at a time. I found that when I remove the electric water heater breaker and grounding wire from the heater to the panel, the voltage drops to 4 or 5 volts between shower plumbing and floor drain. This is with every possible electrical device running. If I shut off big items like oven, and electric base board heaters, it still stays around 4 to 5 volts AC. I get the same voltage readings stated above between shower floor drain and the common bar in the electrical box. I guess this makes sense since I have continuity between shower faucet and electrical box common bar.

If I shut the main breaker, with water heater disconnected from the elextric box, I get 0 volts for all readings when the water heater is disconnected.

I have a well. The pipe from the well to the inside of the house is plastic.

I believe I have a water heater problem with the 22 t0 50 volts showing up and was going to call the manufacturer today.

Here are my questions:

1. Should I also be concerned about the 4 to 5 volts that is always present with the electric water heater disconnected?

2. There seems to be a major problem with the water heater. What can cause the 22-50 volts to be present? If this is a failed element, can i put some safety device in place to prevent this voltage from getting to the shower?

All of these devices are withing 20 feet of each other.

Any advice on grounding, etc.. to fix this problem is appreciated. What is bonding? Should I provide further ground my plumbing?

Thanks
tbwoods

 

[tbwoods]

A quick clarification. My water supply lines are all copper. My drain lines are all plastic including the drain in the shower but it has a metal screen on top of it. I have a septic system.

 

[AndrewF]

Can you confirm that you have a ground coming from the ground bus bar of your panel to you water lines?

If you do not, you are required to have one.

 

[InPhase277]

The 5 volts is likely a phantom due to the very presence of electricity when the main is on. The 50 V when the water heater is on is another problem entirely. It sounds like the metal plumbing of the house is not grounded properly. There should be solid electrical continuity between all metal parts of the plumbing system. The main metal water line should be connected to the neutral bus in the main panel, by code within 5 feet of where the pipe enters the house. The hot and cold pipes at the water heater should be jumped together with a conductor. Since your panel and water heater are so close together, you may be able to solve all the problems at once.

You can jump the hot and cold lines together with a piece of #4 copper and continue that to the panel. Also, you need to troubleshoot the elements of the heater to see which one is leaking current, and replace it.

 

[jbberns]

HI,

I have a well. The pipe from the well to the inside of the house is plastic.

tbwoods

Your water lines should not be grounded. Even if your lines in the house are copper. I'd say that is your problem. Ran into a problem like this a few years back. Only they had replace a small section of pipe outside with plastic. Took a lot of head scratching. They were getting shocked everytime they were in the shower and the phone rang.

 

[Code05]

Your water lines should not be grounded.

What about 250.104? It seems to say otherwise.

 

[jbberns]

Ok, I looked. Didn't see enough to justify. More specific, please.

 

[Code05]

Ok, I looked. Didn't see enough to justify. More specific, please.

" Shall be bonded" Seems pretty clear.

 

[jbberns]

Ok, where does it say water lines that are fed with plastic have to be grounded?

 

[jbberns]

Is your panel grounded? Did the wire to the ground rod get broken?

The water lines can't be considered a ground, because they don't have continuity with the earth.

 

[Code05]

A quick clarification. My water supply lines are all copper.

Ok, where does it say water lines that are fed with plastic have to be grounded?

Who said anything about bonding plastic?:huh: Metal piping is what is being bonded. The feed into the copper lines need only be bonded if metal, and then it would become part of GEC system.

 

[jbberns]

Can you confirm that you have a ground coming from the ground bus bar of your panel to you water lines?

If you do not, you are required to have one.

Here it says that

 

[jbberns]

What about 250.104? It seems to say otherwise.

That is talking about bonding not grounding.

 

[tbwoods]

There is a ground wire from the panel to a rod outside the house. And just to confirm, the feed piping from the well is plastic into the house then goes to copper.

I'll have to remove some panneling to see if the water pipes are grounded to the electrical panel. I see continuity between the shower head and electrical panel ground but can't see a heavy ground wire exiting the box to anywhere but the outside grounding rod.

Also - Here are some more measurements I took. Without the water heater connected (white, black or ground), I measure voltage from the electrical box ground bar to the shower drain and get about 5 Volts. It does not go up even with other items turned on such as the electric stove, base board heaters, etc..

But when I hook up the water heater, now the voltage between the shower water supply plumbing (faucet/head) and shower drain goes up as additional electrical items are turned on. For example, the electric heater may cause a rise of 25 volts, then the stove is turned on and it voltage goes up more, then the well pump kicks on and goes up even more. With everything on, I can see up to 50 volts AC. But totally disconnect the water heater (white, black, and ground) and I only get 5 or 6 volts no matter what else is turned on. I see no rise or fall with other items on or off.

 

[tbwoods]

To answer an earlier question, I checked and the ground wire from the panel to the grounding rod outside and the wire is in tact. I removed both ends and reconnected them.

 

[jbberns]

I would say you shouldn't have a ground going to any part of your copper water lines. The only place it could get energized is at the water heater. Even there I don't think it should, so there is no reason to bond it there.

 

[tbwoods]

I MADE A MISTAKE IN THE POST ABOVE. SEE CORRECTION BELOW.

Also - Here are some more measurements I took. Without the water heater connected (white, black or ground), I measure voltage from the electrical box ground bar to the shower drain and get about 5 Volts. It GOES UP SIGNIFICANTLY TO 30 + VOLTS OR MORE AS OTHER ITEMS ARE TURNED ON such as the electric stove, base board heaters, etc.. BUT WHEN I MEASURE BETWEEN THE SHOWER HEAD AND SHOWER DRAIN, THE VOLTAGE STAYS CONSTANT AT ABOUT 5 VOLTS EVEN THOUGH OTHER ITEMS ARE TURNED ON OR OFF.

But when I hook up the water heater, now the voltage between the shower water supply plumbing (faucet/head) and shower drain goes up as additional electrical items are turned on. For example, the electric heater may cause a rise of 15 volts, then the stove is turned on and it voltage goes up more, then the well pump kicks on and goes up even more, ETC. UNTIL YOU ARE AT 50 VOLTS. With everything on, I can see up to 50 volts AC. WITH WATER HEATER CONNECTED, THESE READINGS ARE THE SAME AS IF I WAS MEASURING BETWEEN THE BOX GROUND AND THE SHOWER DRAIN. BOTH GO UP AS ADDITIONAL ITEMS ARE TURNED ON. But totally disconnect the water heater (white, black, and ground) and I only get 5 or 6 volts no matter what else is turned on. I see no rise or fall with other items on or off when measuring betseen shower head and shower drain.

 

[tbwoods]

Also, in case there is any confusion, I have all copper in the house but is fed by a plastic line from the well.

 

[InPhase277]

I would say you shouldn't have a ground going to any part of your copper water lines.

My friend, you are DEAD wrong here. All electrically conductive materials that form parts or pieces of any mechanical system, be it an appliance or building method, should be bonded. Metal water lines SHALL be bonded to the grounding system, as per 250.4(A)(4) and 250.104(A).

Bonding metal water lines and using them as grounding electrode conductors are two different, but related subjects. IF a water line is in contact with the earth for more than 10 feet, it is required by 250.52(A)(1) to be used as a grounding electrode.

In the OP's case, the incoming water line is plastic, so it is not required to be used as an electrode. However, it transitions to copper, which is required to be be bonded by 250.4(A)(4) and 250.104(A).

A journeyman should know that metal piping, above almost anything else, should be bonded. See post #4.

The only place it could get energized is at the water heater. Even there I don't think it should, so there is no reason to bond it there.

No sir, not true. It could get energized literally anywhere. I think the most likely spot is the water heater, but it is simply not true that it can't be from a fault somewhere else.

 

[Stubbie]

Two things cause you to get shocked in the shower when touching metal...

1.) Fault current.....

2.) NEV.....neutral to earth voltage

Since the pipes serving your home from the well are plastic then neutral to earth issues become less of a possible cause. Your pipes are not bonded to the service grounded conductor so it becomes even less of a possible cause.

Don't forget communiction/data cables but again neutral current cannot get to the pipes in this case if they are not bonded to the GES or to the system grounded conductor. Assuming the grounding of these cables is correctly done.

This pretty much leaves us with number 1. And you have already found your problem it would appear. Turning off or disconnecting the hot water tank is reducing 50 volts to 5 volts if I read you correctly......very high possibilty of a failing heater element as previously mentioned I believe. Not likely a hot to ground in the wiring compartment if the ground wire (egc) is terminated correctly.....if so your voltage would be closer to line voltage if somehow the pipes got energized.

Next culprit is your well pump. When the pressure switch closes and water is pumped (the pump turns on..). When pump is off no shock...not necessarily in this order but lets just say the well pump can be a cause. I didn't go back in read if you get reduced voltage with the well pump circuit opened.

The voltage elevating as the other appliances are turned on with the water heater connected is an expected result of the added load to the system electrical.

INPHASE 277 IS CORRECT

YOU MUST BOND THE METAL WATER PIPES to the GROUNDED conductor at the service equipment!!! So that a breaker will open if they get energized. 250.104 (1) specifically requires this and especially in this case where the pipes are plastic supplying the house (well supplied). If the pipes are metal as in 250.52 (A)(1) and 250.4 (A)(4)&(5) then you must run a water pipe bonding/grounding conductor from the pipe to the grounded conductor at the service equipment neutral bar or in some cases to the metal case (lug) of the service entrance enclosure. then you must supplement that with another grounding electrode.