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Why bond a gas pool heater?


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I'm having trouble understanding why, in most situations I see, the need to bond a gas pool heater. The unit sits on a concrete slab. The pool piping to and from the heater are plastic. The gas piping is plastic underground.

G2411.1 (310.1) Gas pipe bonding.

Each above-ground portion of a gas piping system that is likely to become energized shall be electrically continuous and bonded to an effective ground-fault current path. Gas piping shall be considered to be bonded where it is connected to gas utilization equipment that is connected to the equipment grounding conductor of the circuit supplying that equipment.

The above code reference (emphasis mine) seems to say that it is bonded by being connected to equipment that is grounded.

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I think that this additional safety bonding is required because its part of the water circulating system as water can be a conductor (E4101). Even though the piping is plastic, the water may encounter metal via the motor impeller, pump, filter and water heater. etc.

I could be wrong.

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Originally posted by chrisprickett

I'm having trouble understanding why, in most situations I see, the need to bond a gas pool heater. The unit sits on a concrete slab. The pool piping to and from the heater are plastic. The gas piping is plastic underground.

G2411.1 (310.1) Gas pipe bonding.

Each above-ground portion of a gas piping system that is likely to become energized shall be electrically continuous and bonded to an effective ground-fault current path. Gas piping shall be considered to be bonded where it is connected to gas utilization equipment that is connected to the equipment grounding conductor of the circuit supplying that equipment.

The above code reference (emphasis mine) seems to say that it is bonded by being connected to equipment that is grounded.

I agree with your interpretation. If the gas piping is connected to a grounded appliance, you shouldn't need further bonding.

For perspective on this look to the source. You'll find it in NEC 250.104(B). It's a little more windy than the IRC version, but it makes the same point. Interestingly, it's followed by a fine print note (fpn) that reads thus: Bonding all piping and metal ducts within the premises will provide additional safety.

Perhaps this is where the compulsion to add redundant bonding originates?

- Jim Katen, Oregon

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Before addressing the question it's important to clearly understand the difference between grounding and bonding. Grounding provides a path for errant current to earth. Bonding, at least when it comes to swimming pools, effectively ties together all potentially conductive components of the system utilizing a #8 solid copper conductor. This creates an "equipotential grid" which prevents electrical potential gradients within the same system. Kind of like the little birds which walk along the hot rail of a transit system without being injured. Should a portion of the birds body simultaniously touch another conductive part of the system with a different voltage potential you have roasted bird.

NEC Article 680.26 (B)(4) states "Metal parts of electrical equipment associated with the pool water circulating wystem.....shall be bonded. If the gas heater has a high voltage, low voltage, or photovoltage ighition system it is by definition "electrical equipment" and is required to be bonded. Now to muddy the waters a bit go to NEC Article 680(E) which states "For pool water heaters rated at more than 50 amperes and having specific instructions regarding bonding and grounding, only those parts designated to be bonded shall be bonded......". I think this section is intended for electric heat pump pool and spa heaters since I don't know of a gas heater ignition system of 50 amperes or greater. Further, it seems as though the manufacturers recommendations will determine exactly which components of the heater must be bonded.

Now that I've read and re-read my comments I'm convinced the true definitive answer will come from the chief electrical code officer of the authority having jurisdiction. Ask five code compliance officials the same question and you'll likely get five different answers so why shouldn't I be vague and ambiguous?

NORM SAGE

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Originally posted by Norm

Before addressing the question it's important to clearly understand the difference between grounding and bonding. Grounding provides a path for errant current to earth.

No it doesn't. Equipment grounding provides a path for fault current to return to the transformer via the service neutral, enabling enough current to flow to trip a breaker.

Bonding of interior metal piping (such as gas piping does exactly the same thing.

Bonding a swimming pools does what you describe below, almost, but it's my understanding that you creating potential equal to the earth at the pool, so that stray current flowing through the earth doesn't shock you when you are standing on the earth touching something metal with your bare wet feet, or when sitting on the concrete deck with your feet dangling in the pool.

Bonding, at least when it comes to swimming pools, effectively ties together all potentially conductive components of the system utilizing a #8 solid copper conductor. This creates an "equipotential grid" which prevents electrical potential gradients within the same system.

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Originally posted by mcramer

Originally posted by Norm

Before addressing the question it's important to clearly understand the difference between grounding and bonding. Grounding provides a path for errant current to earth.

No it doesn't. Equipment grounding provides a path for fault current to return to the transformer via the service neutral, enabling enough current to flow to trip a breaker.

Bonding of interior metal piping (such as gas piping does exactly the same thing.

Bonding a swimming pools does what you describe below, almost, but it's my understanding that you creating potential equal to the earth at the pool, so that stray current flowing through the earth doesn't shock you when you are standing on the earth touching something metal with your bare wet feet, or when sitting on the concrete deck with your feet dangling in the pool.

Bonding, at least when it comes to swimming pools, effectively ties together all potentially conductive components of the system utilizing a #8 solid copper conductor. This creates an "equipotential grid" which prevents electrical potential gradients within the same system.

So... do you or don't you need to bond a gas pool heater?????

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Originally posted by chrisprickett

So... do you or don't you need to bond a gas pool heater?????

It's pretty clear to me that it isn't necessary under G2411.1 [NEC 250.104(b)].

It may be necessary to comply with 680.26 (Equipotential Bonding), but it seems unlikely. If the gas pipe is connected to the pool heater and the heater is bonded, I don't see how a voltage potential can ever be established.

- Jim Katen

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This discussion on Bonding is the same type of question that I review when sitting on our Nye County Building & Safety Appeals Board. Listening to our Code Inspectors and the Electrical Contractor discuss the NEC Code is adventure in it self.

The most asked questions on any Inspection Forum are on the Electrical Code. Go to any Electrical Forum and you will find out that the Electrical Inspectors and Electricians have just as much problem with the NEC Code as Home Inspectors. I believe asking that the Building Official for his interpretation is the best way to go on issues relating to NEC Code.

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So what I have gleaned from this is;

If pool items are not bonded the possible results could be Death!

If pool items are bonded it might cost the person some extra $$ to prevent Death!

Kind of a no brainier. I don't think you will ever get in trouble for recommending all pool items need to be properly bonded.

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Originally posted by Scottpat

So what I have gleaned from this is;

If pool items are not bonded the possible results could be Death!

If pool items are bonded it might cost the person some extra $$ to prevent Death!

Kind of a no brainier. I don't think you will ever get in trouble for recommending all pool items need to be properly bonded.

Aha! That is my point! You have some inspectors going around saying that not bonding a gas pool heater can result in DEATH! While others, including myself don't see the big deal, and can't seem to find definitive documentation that not bonding will result in a horrific and imminent demise.

I guess I have a bit of a bug up my butt, because, in my neck of the woods, we have had an epidemic of "puppy-mill" inspectors that are calling out minor (if not irrelevant) stuff as clear and present danger. The gas bond thing was one of them.

I am, in no way, a minimalist inspector. I just think it's irresponsible to your client to make mountains out of molehills. Noting an issue is one thing, making it out to be on the same level as a meth lab, is another.

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I went to some Pool Heater Manufacture websites, and downloaded the instruction - install Manuals. Each and every one said something to the effect:

Bonding

Caution

This heater must be connected to a bonding grid with a solid copper wire not smaller in diameter than 8 ga.

The National Electrical Code and most other codes require that all metallic components of a pool structure, including reinforcing steel, metal fittings and above ground equipment be bonded together with a solid copper conductor not smaller than a number 8 wire. The heater, along with pumps and other such equipment must be connected to this bonding grid. A special labeled bonding lug is provided on the right side of the heater to accommodate this requirement.

_____________________________________________________________________

The heater must be electrically grounded and bonded in accordance with local codes or, in the absence of local codes, with the latest national electrical codes ANSI/NFPA No. 70.

Guess the Manufactures have some saftey concerns.

signed

puppy

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So... do you or don't you need to bond a gas pool heater?????

Yes, assuming it's metal. Not to comply with requirements to bond gas piping, but with requirements in 680.26 to bond everthing metal in and around the pool.

In order to understand this, you need to understand that there's stray current flowing through the earth from the utility distribution system. Usually this is minimal, but in some cases the levels can be high enough to cause death, especially in the wet environment around the pool. It only takes about 20 milliamps to prevent you from letting go of something that's energized, and perhaps half of that when your resistance is much lower because your skin is wet and your feet are bare. It's not implausible that you could have that much current flowing through your body to a metal component.

There are many cases of people who can't use their pool because they get shocked and cases of people getting shocked while standing on a metal shower drain and touching the metal valve.

If you want to delve into this subject, read this: http://www.mikeholt.com/documents/power ... _Stray.pdf and read the articles here: http://mikeholt.com/technical.php?id=st ... ltagelinks

And if you think that the equipment ground will protect you and serve the same purpose, remember that the equipment ground puts the heater at the same potential as the earth AT THE SERVICE, which is distant from the pool heater. The voltage gradients across that distance can be quite large.

This is a well known problem for dairy farmers. The very low stray current affects mild production dramatically.

The short answer is, yes, not bonding the metal pool heater can kill someone. Not every day and not in every case, but it is a hazard.

Maybe those newbie inspectors can teach us old dogs some new tricks.

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Originally posted by chrisprickett

Thanks Mark, that makes sense. Is there any distance from the pool, where this becomes irrelevant? Not to beat a dead horse, but in the case that I was looking at, the heater was a good 50 ft (and around a corner) from the pool.

I don't know. My head hurts from thinking about this. . . .

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quote:

--------------------------------------------------------------------------------

Originally posted by chrisprickett

Thanks Mark, that makes sense. Is there any distance from the pool, where this becomes irrelevant? Not to beat a dead horse, but in the case that I was looking at, the heater was a good 50 ft (and around a corner) from the pool.

Yes, [:D]when the heater is more than 10 feet from the pool and is not connected to any part of the pool or it's plumbing then it would not have to be bonded, however if pool water can or does flow through it, bond it. [:-banghea

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  • 4 years later...

Hello Jim,

This thread seems to be about grounding and bonding as it relates to gas powered pool heaters. Your post is somewhat of a drift from that. Also, this thread has been dormant for almost 5 years. I don't see it as a problem. It's just that most members on this forum, including myself, tend to ignore old threads. You'll get more participation, more learning and more reward if you start a new one.

Just my opinion is all.

Marc

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is it electrically controlled then im guessing? and if thats the case wouldnt it already be grounded through the electrical system?

Yes, it certainly would be. But, if it's a piece of equipment that's covered under 680.26, then it should also be bonded.

Mark Cramer explained this in post #13 above.

- Jim Katen, Oregon

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  • 5 months later...

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