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harold endean #208443 01/19/13 04:24 PM
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Harold:
My take is the bond can be made to any accessable GEC; metalic water piping, ufer conductor, bldg steel, GEC to rods...
The sketch is a little vague IMHO.



John
harold endean #208447 01/20/13 01:25 PM
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John,

Look up CSST bonding and see what the wiring diagram looks like. Most show pictures of #6 cu wire and water clamp on to the gas pipe. OK, great that is one side. How about the other side? Some pictures show another water clamp on the black pipe next to the CSST, and some show the clamp on the CSST connector. So which is it? Quite frankly, I would have thought that the bonding should parallel the CSST, since it can't handle a lightning strike.

harold endean #208471 01/21/13 01:25 PM
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As I read it ...

The CSST is 'bonded' at one end through theusual GEC at the appliance. If there is none - say, the appliance has a pilot light - then we need a jumper between the gas piping at that end and any part of the electrical system. I don't see this wire as being required to be #6.

On the 'supply' side, I see the bond wire being required to be between any point in the grounding electrode system and any point in the gas piping after the meter and before the first CSST. This is the #6 wire.

Bonds are made to the gas pipe - not directly to the CSST - using the usual clamps we use on ground rods.

As I understand the idea, the surge comes from outside the house, and the problem is from the surge using the equipment bond as a path to the grounding electrode system. We're using the #6 to divert the lion's share of that current directly to the grounding electrodes.

I see the local home center is quite enthusiastic in marketing CSST. The CSST makers are also quite confident of their product. I expect CSST to becoem the 'norm' for both new installations and repairs or extensions to existing lines.

That's why, IMO, the only options we have is to either make a bond between the GEC and the gas piping as it exits the gas meter - or discard the concept completely.

That's a concern, because I encounter a tremendous amount of resistance from AHJ's, plumbers, and mechanical contractors to 'grounding' the gas line. As the NEC plainly states, we wil NOT use the gas pipe as a grounding electrode. It's kind of hard to tell the electricity it can flow only in one direction ...

Another AHJ issue I have encountered is a lack of understanding as to our purpose. They want to see the bond go to the panel - not directly to one of the ground rods. Or, they want it to the 'first' rod. Or, they want the GEC to be continuous, unspliced, from panel to both rods and on to the gas piping.

Harold, I can understand your confusion. At first glance, it does seem logical to pull the #6 along with the CSST and 'bridge' the gap. IMO, that's not the purpose.

If it were, the CSST folks would have the wire as part of their assembly.

No, we're not trying to bridge the gap. Nor are we trying to get this current back to the PoCo transformer. Lightning is the one form of electricity that really does want to go to 'gound,' so it's really trying to get to the grounding electrode.

The NEC needs to clarify this topic considerably.

harold endean #208474 01/21/13 03:50 PM
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Harold:
Ny take is from a 'sketch' or 'drawing' that IMHO is on the vague side. I don't know where it originated as I am not in the office today. I'll find it & scan it tommorrow time permitting.

My take is that the bond has to be at the point of entry, on the hard pipe. (Period) Using a suitable pipe clamp.

As I said earlier...this is a real PITA.


John
harold endean #208499 01/23/13 08:05 AM
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The matter certainly IS confusing.

If the attorneys are correct, then the CSST is breaking down BECAUSE it's functioning as a lightning conductor -- obviously just for a split second.

At the extreme surges possible with lightning, mere bends in the conductor create enough impedance to create heating.

It's the contention, at trial, that such heating was enough to burn through the thin CSST -- just enough -- to emit combustable gas.

They further contended that this emission filled the space until a second spark -- could have been another lightning bolt -- and, yes, they do strike repetitively -- detonated the mixure -- flattening the entire house.

To get the Court to go along it's a pretty good bet that the attorney had expert testimony and even a trial mock-up.

It's the contention that the physical mass of the CSST at such pinches is so much reduced that induction effects are able to overwhelm it at pinches, nineties, on a systematic basis.

Homes don't get hit by lightning all that often. Time will tell.

If this legal theory is correct, then a bonding run really does need to parallel the CSST -- end to end.

I regard the matter as thoroughly up in the air. I can easily imagine the industry trying to engineer out as much steel as possible -- pricing was getting crazy. I can also imagine that lightning effects would never come up during product testing.



Tesla
harold endean #208500 01/23/13 10:56 AM
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Here is a link and source of the drawing I mentioned. Note the date of the publication (Spring 2011).

Article is on page 10, drawing on page 11.

http://www.state.nj.us/dca/divisions/codes/publications/pdf_ccc/ccc_2011_spring.pdf


John
harold endean #208502 01/23/13 11:29 AM
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Maybe CSST is not suitable for gas pipe.

Every idea can't be a good one.

If you have to add the cost of an electrician running a parallel #6 to the CSST, the cost savings is somewhat blunted.


Greg Fretwell
harold endean #208547 01/27/13 01:43 PM
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John,

I remember that picture very well and I also remember talking to Suzanne about that picture. She did not draw it, I believe it was Rob A. who drew it up. There were problems with that drawing and Suzanne wanted to re-draw the picture, but it never did get re-drawn.

I too will almost allow bonding from gas pipe to any GEC that is accessible. Right now since the state will allow ANYONE do the bonding, I can see plumbers who are "Certified" to install CSST, but as I stated, I have seen it two different ways. The bonding wire is on the black pipe, and I have seen it on the CSST flex fitting. Now having the bonding connection on the CSST flex is the way that some manufactures show it to be bonded. I guess I have to accept that way also even if it doesn't match the state drawing.

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