I would like to know if it is actual code or if only certain areas require grounding plumbing and gas lines within the house.

And if so , why?

My cousin is building a house where there are no inspectors nor permits required.

His water and gas line feeds are plastic/PVC. Once they inter the house the water line is copper and (not sure about gas line). Is he required to bond to these metallic lines? It seems kinda dangerous to me, being that if the main neutral ever gave up. It's load has to go somewhere doesn't it? What if your taking a shower and it decides to use you as its path? Singing in the shower is one thing, but dancing is not preferred. Comments please.

Thanks

glenn35

The copper waterline would still have to be bonded. (and 2 Gr rods - check local requirements) You have to think of it as putting all your metal stuff at the same potential which means that there would be no voltage there. If a live wire touched a pipe and it was not bonded it could remain live and breaker would not trip that would be bad for you standing outside in a puddle touching the water spigot.

The gas line may have different requirements, you better check on that. Maybe someone else can add more info here?

Bill

See 250-104(b)regarding bonding gas lines.
Then see 250-104(c).

Redsy,

Thanks for pointing that out. Any idea whty there is a little x next to (b)?

I thought that gas was to be bonded, but I came across something in our Local Utility rules just today that said the following:

What do you think they mean?
I should ask them about this.

Bill

Bill,
The superscript "x" means that this rule is taken from another NFPA code. In this case it is from NFPA 50, The Fuel Gas Code.
Don(resqcapt19)

I do not have a code manual. I am a lineman not an electrician.

As far as I know only one grnd rod is required here in Houston. At least that is all I have ever seen. Even within the City limits of Hou. where permits and inspectors are required.

I will check into the gas line further but will advise him that the cu. water line must be bonded.

thanks

Glenn35,

Normal fare here is Connect to underground (metallic) waterpipe and 1 Ground Rod. If waterpipe cannot be used because it it plastic outside then 2 rods 6 feet apart and a bond to the interior metal waterpipe.

I'm still confused about the Gas pipe

Bill

Bill,
The gas line bonding is part of an overall bonding philosophy as you described above. The FPN even suggests bonding ductwork. I actually called PECO one day to inquire about this and was told that they actually look for it to be done. Also, article 250-52(a) prohibits metal underground gas lines from being used as the grounding electrode. My brain is too tired to imagine the difference, as far as ramifications, between bonding to it and using it as an electrode. Maybe because complete isolation can't be assured, bonding is in order to minimize potential.

>My brain is too tired to imagine the difference
Simply put, it is bonded, but it cannot be counted as a required electrode.

I feel the same way about waterlines.

Rationale: May be replaced with plastic or disconnected in the future. The plumber shouldn't have to call an electrician to come install electrodes, and I bet he won't. So in go the dedicated ground rods today.

>I would like to know if it is actual code or if only certain areas require grounding plumbing and gas lines within the house.
I say it is code. Bonding is a safety issue.

>Is he required to bond to these metallic lines?
I say yes.

>It seems kinda dangerous to me, being that if the main neutral ever gave up.
No, there is decreased danger when bonded compared to the alternative.

>It's load has to go somewhere doesn't it? What if your taking a shower and it decides to use you as its path?
That is not possible if everything metallic is properly bonded.

You are worried about something that can't happen. And you are trying to avoid something that can't happen by creating the potential for real dangers.

I think now that my quote from the utility was probably just badly written and did not mean what it seems to say. They probably meant "..used for grounding" or something to mean that it was being made part of the grounding electrode system.


Bill

[QUOTE]Originally posted by Dspark:
>[b]My brain is too tired to imagine the difference
Simply put, it is bonded, but it cannot be counted as a required electrode.

Dspark,
What I'm wondering is the ramifications of possible current flowing on the gas line that is bonded as opposed to if it is used as an grounding electrode. Bonding it makes it part of the grounding electrode system. So, if the reason it is not allowed to be an electrode is to minimize the likelihood of current flowing on it, so gas workers don't get zapped, doesn't bonding it defeat this.


[This message has been edited by Redsy (edited 07-26-2001).]

Redsy,

If there are insulating bushings then it's a non-issue, right?

Bill

Bill is right that is the gas company, water company, or whoever is worried about this, they can place a dielectric coupling in the line.

>Bonding it makes it part of the grounding electrode system.
Depends on whether the insulating bushing is there. I'm just saying that it can't count as 10' of buried metallic pipe for an electrode.

>doesn't bonding it defeat this.
The gas man can and should use effective means of electrical jumpering before he breaks continuity. The unsuspecting house dweller can't test the gas lines for voltage before touching them.

I think the risk to the gas man is greater if the gas line is not bonded. If it is bonded, it won't have a full 120 V on it. If it isn't bonded, it just might be energized at a full 120 V.

If a child walks up to a gas meter and touches it, she shouldn't get electrocuted. My job is to try to prevent that no matter what the gas company thinks.

I beg to differ with you Dspark. I have been on many trouble calls where someone is getting shocked from the kitchen sink even to the shower. In all cases the culprit was a bad neutral connection. Alot of folks notice the lights dim/bright(bad neutral) but fail to call the utility to check it out. Most times on these calls I will ask the customer how long has it been doing this? 85% of the time they will tell me that it has been like that for a couple of weeks. Yea weeks!! That tells me that it started way before 2 weeks ago in order for the ground rod to bake out and be of no more use. Then that is when the shocks come into play. I have found voltage line to neutral at full line to line voltage!! 240 big ones . Mind you that is extreme cases. But just think for a moment,
N-L1=0 v
N-L2=240 v
L1-L2=240 v

That neutral is looking for a path back to its source(transformer). If you just so happen to provide that path then you are in for a big surprise. The pipes in the house will be energized, but more than that they will be carrying the full neutral load of the service!! Voltage does not kill but amperage does. Getting into "series" with a neutral that has a load on it will kill you quicker than if you stick your hand into a hot buss.

If it were a perfect world there would be no need for grounds at all but it is less than perfect. So I do agree that the plumbing should be bonded so that they are at or near earth potential. But to say that something cannot happen, well it does and will continue. Probably not to the point of death but.......

Just remember that a neutral is "THE" most dangerous conductor there is in the electrical field.

I said, "That is not possible if everything metallic is properly bonded.".

Glenn replied, "I have been on many trouble calls where someone is getting shocked from the kitchen sink even to the shower."

Could you please suggest for me a path that the current may have followed and why proper bonding did not prevent this (even when the neutral was disconnected); or more to the point, how bonding created a shock hazard that wouldn't have existed had the water pipes and gas lines not been bonded?

I would think that if any current is flowing on the piping system and it encounters a poorly conductive joint, as might be the case across some pipe dope or plumbers putty, a potential difference will exist and present a shock hazard of some degree. I guess it all depends where the bonding occurs in relation to the fault. If the person touches the higher potential side of a poor pipe joint and the other (low potential) side where the bonding to a gas line occurs you will have a possible safety problem.
Anyone?

I don't believe that pipe dope prevents metal to metal contact.


In any event, the described fault was a broken neutral between the point of service and the transformer.

>If the person touches the higher potential side of a poor pipe joint and the other (low potential) side where the bonding to a gas line occurs you will have a possible safety problem.

The could be said if the person touched a water line, drain, vent, or structural steel. Shall we also not bond any of those?

I specified that everything had to be properly bonded, and that including the gas line in the bonding would not create a new hazard even if the neutral broke.

I would never try to suggest that any installation is safe unless everything is either bonded or insulated.

So of course as soon as you start with the premise that something isn't properly bonded, I will immediately concede that a hazard exists.

If everything else is properly bonded, then bonding the gas line also cannot create a new hazard that wouldn't exist if the gas line were not bonded...
even if the neutral is disconnected.


By the way, I saw an installation where the a panel of a duplex residence was grounded just to the bath tub in the adjoining unit. At one time there was a copper line between the units and one unit was grounded to that line. By and by, a water softener was installed and most of the water pipes were replaced with plastic. The only remaining copper ran to the upstairs bath room. No one ever complained of a problem with that and I would guess that it was that way for at least 10 years judging by the age of the softener.

Current has to be able to follow a path. There was nowhere to go from the bath tub.

This has been another true story backing up my belief that waterlines shouldn't count as required grounding electrodes.


[This message has been edited by Dspark (edited 07-27-2001).]

Dspark qoutes"Could you please suggest for me a path that the current may have followed and why proper bonding did not prevent this (even when the neutral was disconnected); or more to the point, how bonding created a shock hazard that wouldn't have existed had the water pipes and gas lines not been bonded?"

As we all know, electric current will follow any given path to ground.

Differences in potential is the key word here I beleive.
If the water line is metal on the inside of the house, PVC going into the ground then it is "isolated" from ground. Bond the water line to the electrical system and now it is bonded. With a baked out or non existent ground rod and a broken/disconnected neutral you have isolated your water line once again from grnd. Although it is isolated from grnd it is also isolated from the source. The path would be someone that touches the water line or its connected fixtures and is touching a ground. Dspark you used the example of an upstairs bath. I'll give you that one because the person himself would more or less be as a bird on a wire. But what if that person was downstairs on a concrete floor, barefooted, and touches that line? Or if that person is standing outside barefooted and reaches for the spicket(which is bonded)? There are many instances that a person can be grounded. The scenario I am using has made the waterline just as energized as any ungrounded conductor!

As I said before I do agree that it should be bonded. But bonded or unbonded a hazard could exist either way. Which would be the most likely to occur? I haven't a clue. It is one of those things that you are damned if you do and damned if you don't.

One last question for all you sparkys out there.
When you arrive on a job and you open the breaker box how do you go about it?

Do you just reach and grab and open it up?
Or do you sweep the back of your hand across it?

My dic* has been knocked in the dirt a couple times when I just reached and grabbed.
What made that box hot? Ahhh, a bad neutral conn. and a non existent grd rod or a baked out grd rod!

[QUOTE]Originally posted by Dspark:
[B]I don't believe that pipe dope prevents metal to metal contact.


I am not suggesting it prevents metal to metal contact. Only that it will introduce a certain amount of impedance. And possibly a voltage drop.

>As we all know, electric current will follow any given path to ground.
Correct - follow each path in inverse proportion to the resistance of that path.

>Differences in potential is the key word here I believe.
Absolutely! And proper bonding is supposed to minimize those differences to a harmless point.


>With a baked out or non existent ground rod and a broken/disconnected neutral you have isolated your water line once again from grnd. Although it is isolated from grnd it is also isolated from the source.
I don't follow.

>The path would be someone that touches the water line or its connected fixtures and is touching a ground.
Can you be specific? What ground?
Why is this ground not bonded to the water pipe via a copper conductor?

>But what if that person was downstairs on a concrete floor, barefooted, and touches that line?
This is why I like having the concrete or dirt floor bonded as well.

>Or if that person is standing outside barefooted and reaches for the spigot (which is bonded)?
No harm done. The earth is baked so basically no current flows.

>There are many instances that a person can be grounded.
Yes, but if proper bonding is done, the person is never more grounded than anything else he touches.

However, the outside spigot is a problem.
Code should require a GE within 18" of an outdoor metallic spigot. That way if the earth becomes damp at the spigot, it will become damp around the GE. And the GEC should be bonded to the spigot preferably from indoors.


>The scenario I am using has made the waterline just as energized as any ungrounded conductor!
But the UGCs are not as energized since they don't have a metallic return path.

If the earth is baked out as you say, then electricity trying to return through a human also has to go through that baked out earth too. If current can't return via a metal rod 8' in the ground, then why will it return via a human? The human just adds a few thousand more ohms to the path.

>bonded or unbonded a hazard could exist either way. Which would be the most likely to occur?
Unbonded. The only time that there is a hazard with them bonded is when the neutral has broken and the person is standing on wet ground holding an outdoor metallic spigot far from the GEs, and that is relatively rare by comparison. If the pipes weren't bonded, many more faults would go undetected - the bird on the wire effect, where metallic objects are like the bird.

The obvious solution is to use more plastic for the water pipes and drains.

And you also make the case for why I like to see panels and meter bases bonded to whatever I am standing on when I have to touch them.

Indoor ground rods or plates make sense to me.

Dspark, what is it that you are not understanding?

Think of it this way. Place one end of your voltmeter probe in the ground(not ground rod), place the other probe on the neutral buss of an electrical system that has a broken neutral. What is the reading on the voltmeter? 120V? 100V? Now consider yourself in place of the voltmeter. How much current is going thru you?

Say for instance the ground rod is in tact and working perfectly. Take a load reading on the ground wire. Lets say its 10A. Now remove the ground wire from the ground rod. This would simulate a non existent ground rod or a rod that has baked out earth surrounding it. By my saying baked out , what I mean is that the earth in contact with the rod has crystalized(probably from a lightning strike or from carrying load for a period of time). When current is introduced into the ground for periods of time the earth at the point of contact becomes insulated(turns into glass). Now if that rod is not making contact then it is useless. Everthng that is bonded to the neutral buss becomes an extension to that buss. And if that buss is isolated from its source anything that tries to create a path to ground will become energized.

I wish my scanner was working because a picture is worth a thousand words.

>What is the reading on the voltmeter? 120V?
Let's just say it is.

>How much current is going thru you?
Next to nothing if I have on sneakers. Take a reading between neutral and me. What is it? 10 V? 5 V?

>Now if that rod is not making contact then it is useless.
I agree with all that.

>Everthng that is bonded to the neutral buss becomes an extension to that buss. And if that buss is isolated from its source anything that tries to create a path to ground will become energized.
I agree with that too.

The only thing that I didn't get was that you meant to isolate the baked out earth to the ground rod only.

My point was that if everything is bonded, then it is all equally energized and there is no potential difference to electrougly anyone.

In this case, I will maintain that the earth is not properly bonded as I mentioned before when you brought up the outdoor spigot.

However, bonding the gas line does not create a new hazard if everything including the floor is properly bonded. Every time you come up with a supposed exception, I find something that is not properly bonded in your example.

Fair enough?