Shocked by tub or shower

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GG

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Dont we ground a service to a water line to try and keep the service at the earths potential? A guy I talked with today said its because the NEC doesn't want anyone in a shower or tub getting shocked. That didn't sound right to me. In Mike Holts grounding DVD he stated that in the future he could see a time when we will no longer ground a service to the water line. This would mean to me that we are NOT grounding the water line to protect people from shocks. :confused:
 
Re: Shocked by tub or shower

You are right. Protection from shocks from building power sources is achieved by running the neutrals and grounds back to the Tfrmr. Actually, only gfi's give real shock protection, since breakers are slow.

The water pipe is only one of the electrodes required by NEC. Many buildings are supplied with plastic pipes. If metal water pipes were required for shock safety then pity all of us with plastic!

The grounding electrode is for lightning and high voltage surge protection. The many ground rods in the utility's system keep neutral voltage close to ground voltage, and your local electrode plays a miniscule part in that.

Karl
 
Re: Shocked by tub or shower

We connect to the water main because it's a grounding electrode. We bond the interior water piping system to reduce shock potential.
 
Re: Shocked by tub or shower

To be specific, the water pipe is considered a grounding electrode only if the provisions of ('02) Art. 250.52(A)(1) are met (exceptions aside).

Specifically: That the pipe has 10 feet or more of earth contact, and the connection to the pipe be made within 5 feet of the pipe entering the building.

Nonetheless, even piping that does not meet the above requirements must still be bonded in order to minimize voltage between the wiring and the pipes.

This is one reason why the one rod/two rod debate lives. I had an inspector reject my pipe ground as an electrode, even with the clamp 1 foot in.

The reason: I couldn't show him the 10 feet of pipe in the ground (existing house service upgrade). The solution: a second rod.
 
Re: Shocked by tub or shower

Actually the connection of the water pipe can be used as both, a grounding electrode if it meets the requirements of 250.52(A)(1), or a bond as required in 250.104(A)(1).
So if it is serving as an electrode then it is there for to limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.

If it is serving for a bond then it is for electrical continuity and the capacity to conduct safely any fault current likely to be imposed.

It can be for both purpose's.
 
Re: Shocked by tub or shower

Originally posted by hurk27:
Actually the connection of the water pipe can be used as both, a grounding electrode..., or a bond...
It can be for both purpose's.
Click to expand...
Agreed, and didn't mean to imply otherwise.
 
Re: Shocked by tub or shower

I agree that we BOND waterlines to prevent shocks. I disagree with the statement that GFCI's prevent shocks. GFCI's prevent electrocutions. You will still perceive a shock before a GFCI operates if your body is serving as a ground conductor. Also GFCI does not protect against hot to neutral faults, these will be interpreted by the GFCI as a normal load. GFCI is NOT a substitute for proper grounding and bonding, at best it is an added protection. Remember there are dangers from shock other than electrocution, such as falling off a ladder due to the jerk reflex.
 
Re: Shocked by tub or shower

Originally posted by haskindm:
GFCI's prevent electrocutions.
Click to expand...
No they dont. If I grab the hot and the grounded conductor at the same time the GFI will only see me as a load, it wont trip, and I will be getting electrocuted.
 
Re: Shocked by tub or shower

Originally posted by LarryFine:
To be specific, the water pipe is considered a grounding electrode only if the provisions of ('02) Art. 250.52(A)(1) are met (exceptions aside).

This is one reason why the one rod/two rod debate lives. I had an inspector reject my pipe ground as an electrode, even with the clamp 1 foot in.

The reason: I couldn't show him the 10 feet of pipe in the ground (existing house service upgrade). The solution: a second rod.
Click to expand...
The inspector I guess is technically correct but jeez thats going a little far. What are you supposed to do dig up the yard?
As for the 1 or 2 rod "Debate" there is none. Unless you can show less than 25 ohms on one rod you must have at least two when using the water line as your grounding electrode.
 
Re: Shocked by tub or shower

But if you are grounded while you grab the hot and neutral some of the current will go through ground and not through the neutral and the gfi will trip.
 
Re: Shocked by tub or shower

MichaelF, you've been a member since March of 2003 and just submitted your first post? :D

Wow. Welcome to "talking" in the forum. :D
 
Re: Shocked by tub or shower

Michael, that's an intersting point. You are probably right, though I don't want to try it. You could probably do the math on it instead.

In my post way up above I had said GFIs protect from shocks, which was too general, therefore incorrect. We were talking about grounding, so it was in that context.

What I meant by "protect" was that you won't be electrocuted. I didn't mean that you would not feel something in the fraction of a second before it trips.
Karl
 
Re: Shocked by tub or shower

"Larry Fine" Specifically: That the pipe has 10 feet or more of earth contact, and the connection to the pipe be made within 5 feet of the pipe entering the building.

Not exactly Larry. 250.52 Any Interior conections must be made within 5 feet of the pipe entering the building.
Now you are a member of the Iluminati.
 
Re: Shocked by tub or shower

Mac, I have to disagree:

The 5' rule is for using the pipe as an electrode, not for every connection. If you are using the pipe as a grounding electrode, the rule applies.

However, if you are bonding the pipe, but not using it as a grounding electrode, the connection may be made anywhere on the piping system.

250.104(A) ('02 NEC) refers to bonding of metal water piping systems. Note that this does not specify where on the piping system the connection must be made.
 
Re: Shocked by tub or shower

I agree with Larry.

Look at this another way: how could you bond (electrically non-continuous) pieces of metal piping to the GES, always within 5'?

It's still good practice to do so, just in case.
But not required. :)
 
Re: Shocked by tub or shower

Oh I agree with you Larry about water pipe bonding, I just merly disagree with your statement about when used as a grounding electrode it must be within 5 ft of entering the building. Almost every really damm good at their job electrical inspector and electrician I have talked to about this thinks the same thing. BUT if you read carefully you will see it pertains to when it is used as a grounding electrode AND you are making your connection on the INTERIOR as is done frequently with switchgear in malls and residences with basements, etc, it must be within 5 ft of where the pipe enters the building, bonding of the interior water pipe not withstanding. On the exterior connections which you can also find plenty of the pipe connection may or may not necessarily be within 5 ft of where the pipe enters the building, actually its better if the 10' of direct contact to soil water pipe is connected closer to the service connection point if your water pipe enters the building a long way away. IN that case you would need to also bond the interior water piping, but look at how many other good places you can connect that to that might be convienient for you to do.
 
Re: Shocked by tub or shower

how about the water pipe is all plastic,should you bond the faucet or shower head?
 
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