# why solid bonding conductor



## te12co2w (Jun 3, 2007)

what's the purpose of requiring solid bonding conductors in 680.26(B), 680.74, as opposed to stranded? I suppose this requirement is in other articles as well. Does the bonding jumper at the water heater in a residence, #4 on a 200a service, need to be solid as well? The house I live in now has a #4 stranded bonding jumper at the water heater, and I've been in other residences where I have seen #4 stranded at the water heater. Never paid it any nevermind.


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## Celtic (Nov 19, 2007)

I'm guessing here:
The solid requirement is due to the fact that chlorine will eat away at metal. 
A solid conductor *should* last longer than a stranded conductor.

Again, that is a guess.

Onto the WH...
The bonding jumper at the WH could be solid or stranded ~ there is no chlorine there.
250.104 / 250.62


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## electricista (Jan 11, 2009)

Celtic said:


> I'm guessing here:
> The solid requirement is due to the fact that chlorine will eat away at metal.
> A solid conductor *should* last longer than a stranded conductor.


That's a good a guess as any. I was thinking along the lines of more durable overall, not just the chlorine.

On second thought isn't the bond wire from the wet light niche stranded?



> 680.23(B)(2)
> (b) Nonmetallic Conduit. Where a nonmetallic conduit is used, *an 8 AWG insulated solid or stranded copper bonding jumper shall be installed in this conduit *unless a listed low-voltage lighting system not requiring grounding is used. The bonding jumper shall be terminated in the forming shell, junction box or transformer enclosure, or ground-fault circuit-interrupter enclosure. The termination of the 8 AWG bonding jumper in the forming shell shall be covered with, or encapsulated in, a listed potting compound to protect the connection from the possible deteriorating effect of pool water.


Maybe because it is insulated makes it safer.


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## Celtic (Nov 19, 2007)

electricista said:


> On second thought isn't the bond wire from the wet light niche stranded?
> 
> Maybe because it is insulated makes it safer.



Last line of your NEC quote:


> The termination of the 8 AWG bonding jumper in the forming shell shall be covered with, or encapsulated in, a listed* potting compound t*o protect the connection from the possible *deteriorating effect of pool water.*



I'm still guessing.

I can count all the pools I've wired on one finger :blink:


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## electricista (Jan 11, 2009)

Celtic said:


> I can count all the pools I've wired on one finger :blink:


Would that be one pool? 

But that deteriorating effects applies to both solid and stranded.

Interesting enough is that normally we are not allowed to run a solid wire larger than #10 in a raceway.


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## Speedy Petey (Jan 10, 2007)

We are talking about three totally different bonding scenarios here.

The equipotential bonding grid wire can be bare or covered. It also is subject to some abusive environments, such as pouring concrete over it, workers walking on it, backfill and rocks, etc.

A bond for PVC conduit coming from a forming shell is in conduit the whole way except for the portion inside the shell. Not mush abuse going on there.

A main bonding jumper or water bond is also not typically subject to much abuse.


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## Celtic (Nov 19, 2007)

electricista said:


> Would that be one pool?


...and a dam fine job too :thumbsup:
I think 

​


electricista said:


> But that deteriorating effects applies to both solid and stranded.


True....but back to my guess....ever see how #12 stranded is in an outdoor box - practically falling apart...not the same with a solid conductor.
I'm guessing, the voids between strands compounds the situation when you add chlorine.....which leads us to...




electricista said:


> Interesting enough is that normally we are not allowed to run a solid wire larger than #10 in a raceway.


...the #8 stranded in the potting compound ~ the compound impedes the chlorine.


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## Celtic (Nov 19, 2007)

Let's not go trying to make sense of this Pete 

What say you on the chlorine and stranded?
Chlorine deteriorates a stranded more rapidly than a solid conductor?


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## Speedy Petey (Jan 10, 2007)

Celtic said:


> What say you on the chlorine and stranded?
> Chlorine deteriorates a stranded more rapidly than a solid conductor?


Sure. Consider the total surface area of each as compared to the conductor size.


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## Celtic (Nov 19, 2007)

Speedy Petey said:


> Sure. Consider the total surface area of each as compared to the conductor size.



That's what I am thinking....but really don't know.
Have you done many pools?


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## Speedy Petey (Jan 10, 2007)

Celtic said:


> Have you done many pools?


Uh..yeah.


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## Celtic (Nov 19, 2007)

Speedy Petey said:


> Uh..yeah.


:laughing:
[mental image of beavis & butthead]


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## Just Electric (Feb 14, 2009)

I was talking to an inspector today, he said to use a bonding grid for a above ground pool. Have you ever done this?


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## tkb (Jan 21, 2009)

Celtic said:


> ...
> 
> ...the #8 stranded in the potting compound ~ the compound impedes the chlorine.


Water will wick through the strands to the connection, even with the potting compound.


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## electricista (Jan 11, 2009)

Just Electric said:


> I was talking to an inspector today, he said to use a bonding grid for a above ground pool. Have you ever done this?


I believe it would depend on whether or not the pool is a storable pool or not. Art. 680 Part III is for storable pools.



> Storable Swimming, Wading, or Immersion Pool. Those that are constructed on or above the ground and are capable of holding water to a maximum depth of 1.0 m (42 in.), or a pool with nonmetallic, molded polymeric walls or inflatable fabric walls regardless of dimension.


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## Speedy Petey (Jan 10, 2007)

Just Electric said:


> I was talking to an inspector today, he said to use a bonding grid for a above ground pool. Have you ever done this?


Done what??? :001_huh:


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## Speedy Petey (Jan 10, 2007)

tkb said:


> Water will wick through the strands to the connection, even with the potting compound.


Stranded is still legal to use for this bond though.


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## Just Electric (Feb 14, 2009)

Speedy Petey said:


> Done what??? :001_huh:


 
Did you use a bonding grid on an above ground pool with steel sides?


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## Speedy Petey (Jan 10, 2007)

Just Electric said:


> Did you use a bonding grid on an above ground pool with steel sides?


It's the exact same job. What else would you use?

It's not "_bonding grid wire_". It's #8 solid copper. I typically use #8TW green.


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## Just Electric (Feb 14, 2009)

Speedy Petey said:


> It's the exact same job. What else would you use?
> 
> It's not "_bonding grid wire_". It's #8 solid copper. I typically use #8TW green.


 
I have never done one before.... Is this grid on a roll out matt that is layed under the pool and dirt? Then the #8 solid is ran from the pump lug to the grid?


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## electricista (Jan 11, 2009)

Just Electric said:


> I have never done one before.... Is this grid on a roll out matt that is layed under the pool and dirt? Then the #8 solid is ran from the pump lug to the grid?


I don't believe you have to do any bonding or equipotential bonding grid for pools that are storable ( less than 42" deep)

BTW-- The equipotential bonding grid is no longer required in the 08 code-- big changes there. Almost the entire section has been redone. I can post it if you are interested-- almost a page and a half long.


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## Speedy Petey (Jan 10, 2007)

electricista said:


> BTW-- The equipotential bonding grid is no longer required in the 08 code-- big changes there.


Whew! I just checked my '08 book and CD. Yup, still there. I thought someone stole 680.26 from it after you saying this.

Can you explain what you mean "no longer required"? In fact it has been broadened. It used to be only parts that were there needed to be bonded. Now you need to create a grid under "Perimeter Surfaces" if there is no steel reinforcing wire underneath, such as with pavers.


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## Speedy Petey (Jan 10, 2007)

Just Electric, it would be best for you to get a hold of an NEC Handbook. That will explain what would take a while to type.

See 680.26 & 680.42


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## electricista (Jan 11, 2009)

Speedy Petey said:


> Whew! I just checked my '08 book and CD. Yup, still there. I thought someone stole 680.26 from it after you saying this.
> 
> Can you explain what you mean "no longer required"? In fact it has been broadened. It used to be only parts that were there needed to be bonded. Now you need to create a grid under "Perimeter Surfaces" if there is no steel reinforcing wire underneath, such as with pavers.


I did say that equipotential bonding disappeared but was referencing the bonding grid. I was under the impression that the grid was removed and a #8 wire could follow the contour of the pool as an alternative means. 680.26(B)(2)(b)


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## Speedy Petey (Jan 10, 2007)

The "grid" was never really a specific tangible thing. It was a series of bonding requirements that made up the grid.

Here is a good Mike Holt graphic. All of the green wires and reinforcing steel in this picture make up the grid.


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## Speedy Petey (Jan 10, 2007)

Oh, and without actually checking my books, nothing was removed. Only the new "mat" requirement was added.


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## Speedy Petey (Jan 10, 2007)

OK, I checked to be sure.

Nothing was really removed, only re-worded and things added. 
The comment about not having to extend the #8 grid wire to a panel or electrode was changed from an fpn to actual text now.

Oh, and let's not forget the completely idiotic "pool water" bonding requirement.  :laughing:


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## Just Electric (Feb 14, 2009)

Speedy Petey said:


> Just Electric, it would be best for you to get a hold of an NEC Handbook. That will explain what would take a while to type.
> 
> See 680.26 & 680.42


I have read through it and talked with the pool guy... Totally understand now!!! Thanks for your time!


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## electricista (Jan 11, 2009)

In the 2005 NEC the grid structure was clearly defined in art. 680.26(C)(3)(b) and was to cover the decking of the pool. My understanding is that grid on the decking around the pool - perimeter area- is no longer required in NEC 2008. Equipotential bonding is but not the grid. Am I wrong here.


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## Speedy Petey (Jan 10, 2007)

680.26(B)(2) Perimeter Surfaces" was added in 2008

You are right about 680.26(C) being removed. Actually the wording from that was just moved into 680.26(B).


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## leland (Dec 28, 2007)

Speedy Petey said:


> OK, I checked to be sure.
> 
> Nothing was really removed, only re-worded and things added.
> The comment about not having to extend the #8 grid wire to a panel or electrode was changed from an fpn to actual text now.
> ...



At least they kept it to only plastic liners.:no:


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## yoockon (Feb 28, 2009)

Hi Guys.
Was just reading your thread and thought I'd join in.
I specialize in pools for the last 10 years and have about 8000 under my belt.
The bond wire can be stranded in the light niche, but has to be solid from the eqpmt to the pool steel. I assume becasue it is always exposed to the elements on the equipment end, it neeeds to be solid because each strand would corrode quickly if it was stranded. Also, the bare copper grounding loop around the pool has to be solid and bare to serve the purpose of bonding the deck. This is an excepted way of bonding the deck in the 2008 code as opposed to the grid that was being required before. Between the grid, the new gfci rules, and all the other new requirements going on with pools, they're gonna put us all out of business. Seem's like they add hundreds of dollars to what it takes to wire a pool every time a new code comes out.


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## yoockon (Feb 28, 2009)

The grid was in fact a grid. I don't remember the dimensions, but for a while, we were buying rolls of copper "fence" at the tune of $500 a roll. ( about 100'). It had to be placed around the perimeter of the pool. The '08 code has replaced that with a single copper conductor. The manufacturers of that grid are still fighting to get it reinstated.
It's all about the money!!


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## Speedy Petey (Jan 10, 2007)

A stucco build-in pool usually had a grid work of reinforcing mesh that was a grid. That could be the grid, as well as the meal structural walls of a liner pool.
The point prior to 2008 was that if there were no metal walls, or no reinforcing steel mesh then you had to create the "grid out of copper. The is what is referenced in 680.26(C)(3) in the 2005 and earlier.

Like in the image below, they are pointing to the mesh grid with the red words. The same could be shown with metal walls.

I guess 680.26(C)(3) was there in the rare instance where no mesh and no metal walls were used.


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## yoockon (Feb 28, 2009)

Yea, i was referring more to the "perimeter" grid. I see we live in different parts of the country, so i wonder how differently things are done up there. we get quite a few vinyl liner pools and fiberglass pools. Those are the ones with no grid in the shell, of course.
I wasn't able to see the picture you referenced. ??


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