OK I have a question for you guys…

We are currently roughing a house that uses all PEX tubing (plastic water piping.)

But, at every bathroom/sink/fixture, etc, they transition to copper in the walls.
So basically, we have several isolated copper water “systems” in the house supplied by this nonmetallic pipe.

How would you handle the bonding/grounding of this? I want to bond it all together, is that necessary?

Code requires you to bond the metallic piping if it is likely to be energized. I might argue that a stand alone sink is not likely to become energized.

You could bond it to the circuit that it is likely to become energized by. If that makes sense. If it is likely to become energized at all.

This is not a pool area or hospital room. You do not have a metallic piping system, you have seperate pieces of metal.

If you are going to bond isolated sections of pipe simply because they are metal, don't forget to bond the towel and curtain rods. What about the couplings and connectors for the PE tubing?

If you are going to bond the piping because is near a counter top receptacle, then don't forget to bond the drawer pulls also.

Only if there is good probability that the metallic item will come in contact with an electrical conductor is bonding required. I can not think of a situation that would energize these pipe stubs.

I can think of a situation where the metallic pipe at the sink may be energized, point of use electric water heater, and if it were installed then I would verify that there was an EGC at the equipment to essentially bond the piping at the same time as the heater.

I agree 100% with JBD


No bonding required.

Thanks for the replies guys. I will leave it as it is.

Good to ask Matt but for some reason this question kills me everytime I hear it. Alot of people are quick to jump on the bond wagon without actually thinking for a couple minutes about the situation.

Well, each bathroom has about 20 or so feet of copper in the walls, for shower, sink, etc.

Master is all copper so about 50 feet, but grounded by the steam shower unit.

NM can touch the pipe in some places.

How about the boiler? Allot of copper in the basement but PEX to the AH. So all that is grounded by the 14/2 to the boiler?

It all just seems a little unsafe. All because of plastic pipe.

This thread ponders the question:

How is any water pipe likely to become energized?

What is the criteria for likely?


Dnk.....

I don't see the term "likely to become energized" in 250.104(A).

Abrasion of nonmetallic against the pipes (due to pressure from insulation)?

Rodents? Lightning strikes? Improperly grounded appliance?

It doesn’t seem all that impossible to me.

Matt, don't forget to bond picture hanging nails also. They may be engergized when the NM is not in the center of the stud.

Good Point!

: Goes to RadioShack to buy bags of alligator jumpers :

And remember to properly bond the PEX with an unspliced length of 1/4" Nylon rope running from the ground bus in the service panel to a listed clamp on the PEX.

[This message has been edited by SolarPowered (edited 07-23-2005).]

Hi Matt, about your concern, it does bear thinking about since the dangers of energized plumbing are many.

I fixed a problem for a camp owner years ago who was getting shocks while taking a shower. The drain had become live due to a chafed piece of old cloth type NM laying on the metal drain piping under the camp, and this was isolated from the shower walls and hot/cold pipes by the stone shower base. There was 110 volts on the drain grate and he got blasted when his foot was touching this and he touched the faucet handles.

I agree with the others that you have to be realistic in assessing the possibilities, however.

JBD, LOL, but you forgot the metal flush handle...if that is energized and you are grounded and you lean back...well, OUCH!

[This message has been edited by poorboy (edited 07-23-2005).]

[This message has been edited by poorboy (edited 07-23-2005).]

Ryan J,

Section 250.104(A)(1) requires the interior metal water piping system and any other metal piping systems likely to become energized to be bonded to the service equipment or grounding electrode conductor.


From the Code CD rom.


The point of my question, was how could a water pipe become energized? I never figured a wire hanging on it, because they all should be strapped up and away from the water pipes.

But what still boggles me is on a well water system, with plastic incoming, and then a change over to metal, why size the bonding jumper for the size of the service? I always wondered how the service conductors could touch the water pipe, if they were no where near it.

I see the answer from poorboys post, I guess the wires could fall somewhere, somehow onto the water pipes.

And I guess the water heater somehow could fail, energizing the pipes.


Dnk....

dnk,
Ryan's point is that the code rule requires bonding for all metal water piping systems, not just those that are 'likely to become energized". Note that the words "likely to become energized" do not appear in the section that you cited. They do appear in 250.104(B) and (C) for other metal piping sytems and structural steel, but not in (A) for water piping systems.
Don

That was my interpretation of the code, IF each network of copper pipe constitutes a “system”.

I thought it did.

Don,

The section I posted was just "cut and Pasted" from the 2002 code Cd.

I didn't write it or reword it, it came word for word from the CD Rom, in the "explanation area".

Is the CD Rom wrong for stating this then?


Dnk...

(edited for spelling)

[This message has been edited by Dnkldorf (edited 07-23-2005).]

As an inspector I look at the word PIPING system. A valve, faucet, etc. is not in my opinion piping. A four foot long piece of metal at a walk in shower with valves and multiple shower heads is again IMO piping.
Alan --Inspector.
The plumber (?) saves copper the electrician has to make up for it.

[This message has been edited by Alan Nadon (edited 07-23-2005).]

Code also requires that the point of attachment to the pipes be accessible… God help me.

DNK: It appears you are quoting the handbook commentary. Disregard that and read what it really says in the code text, not wat the handbook perhaps wants it to say.

OK, I thought the commentary was to make heads or tails in laymans terms, of what the wording meant in the code book.

Sometimes, I can read the words, but can't interpret what the intent is, that is why I also read the commentary that goes with each section.


Stupid me...


Dnk...........

Theres nothing wrong with reading the commentary...I do it myself sometimes. We all just have to keep it in check with what the code text says, because sometimes they conflict.

Is this plumbing you are referring to the blue/orange(cold/hot) stuff with crimped ends? Wired a huge multi-unit retirement complex where that was used, and would hate to think that if we did another one we would have to bond all the piping at the ends of these runs. Would have taken a few miles of #6 bare.

BTW, that stuff holds water for anywhere from a few minutes to a few months when they forget to crimp it...had "occasional showers" off and on for weeks after that project had the water turned on. The ones on the second floor were particularly interesting!(especially for the tenant below...you know, the lady with all the cherry furniture!)

Ryan- Can you give me an example where the commentary conflicts with the Code?

And poorboy, -How did you come up with a #6 bonding conductor?

How about the section we are discussing?

Ryan - I just read the commentary in the '02 handbook and I can't see any conflict?? Seems clear whether I read the text or the commentary that interior and exterior piping needs to be bonded to the GEC etc,etc. What am I missing? The commentary don't mention the exterior piping but the Text does? I'm quite comfortable with the commentary and tho it's not "Code" I find it very helpful.

Ryan,

Try reading the selection this way: Section 250.104(A)(1) requires the 'interior metal water piping system' and 'any other metal piping systems likely to become energized' to be bonded to the service equipment or grounding electrode conductor.

As opposed to: Section 250.104(A)(1) requires the 'interior metal water piping system and any other metal piping systems' likely to become energized to be bonded to the service equipment or grounding electrode conductor.

The first way is the way these two systems are worded in the NEC, the second is not.

To make it perfectly clear: The NEC requires bonding of "interior metal water piping systems" and of "other metal piping systems likely to be energized". Neither the NEC nor the Commentary refer to "interior metal water piping systems likely to be energized".

250.104(A)(1) has nothing to do with "other metal piping". That requirement is found in 250.104(B).

George, I guess the right size ground would be #12 if the circuit likely to energize the pipes is the bathroom lighting or GFCI, and #10 if it was the dryer in the laundry. Kind of a judgement call, is it?

I think because this house has 200A service supplied by 4/0 aluminum that we need a #4 copper that jumps all the water piping and returns to the service ground.

Matt, I think you need to look up the difference between grounding the water piping against becoming accidentally energized and using a metal water pipe feed AS A PART OF YOUR GROUNDING ELECTRODE SYSTEM.

As you can see from my posts, I am no code whiz, but am enjoying the learning process going on here.

With some of the commercial buildings (malls) I am working on it seems like sometimes I can build my whole service in less time than I can figure out and install the proper grounding---sprinkler, water, bldg steel---which may involve running to the high up steel above, getting out thru the masonry to grd rods, etc.

Poorboy, 250.104(A)(1) refers to table 250.66 for sizing the bonding jumper; because this is water piping, 250.104(A)(1) is the only section that applies.

So in my earlier reference to the multiple occupancy retirement building, according to 250.104(A)(2) I would use #8 copper (as per table 250.122) because the sub panels in the apts. were 100A. Am I getting any smarter at all?