Swimming Pool Bonding and Ground Connections

[jaybjeepn78]

My family is in the process of contracting out in-ground swimming pool. Although we are using subcontractors and everything is inspected, I personally want to make sure all electrical bonding and grounding is completed correctly. With that being said, I understand that all electrical equipment must be connected to the grounding connection back to the home’s service panel as any circuit would do. I also understand the diagrams that show the use to 8awg bare copper to connect all metal and/conductive components in and around the pool, including the housings of filtration equipment for bonding.

What I am uncertain about is whether or not the bonding grid must be tied directly to the ground connection back to the service panel or any other element of the actual electrical wiring. I see examples online that show this and do not show this interconnection of the ground system and the bond grid.

My question is whether or not the bonding grid is a self-sufficient grid that only ties directly to each metal/conductive component?

in other words, does the bonding grid components get connected to the ground? Or is the bonding simply connect among itself?

thanks in advance!
Jason

 

[Dennis Alwon]

If your pool people don't know this you are in trouble. I am sure they know how to do it. The bonding is all connected together and indirectly is connected to the grounding system of the house through the motor housing. The motor housing is connected to the equipment grounding conductor unless it is a double insulated pump in which case the grid needs to be connected to the equipment grounding conductor of the pump.

 

[jaybjeepn78]

The pool people do all of the bonding to the metal surrounding the pool, including decking, ladders, pool structure itself etc. with the bare #8 wire, leaving the end of the bond wire for the electrician to complete at the equipment pad. I wasn’t sure if the electricians completion included tying it directly into the grounding wires or not.

I want the peace of mind that the job is done correctly, but as it sounds, the indirect connection via ground wire inside pump and the bond connection point via outside pump housing is the way I thought. I just wanted to make sure a direct copper wire connection wasn’t supposed to be established from the bond to the ground/service panel grounding strip.

 

[Dennis Alwon]

Hopefully your inspector will verify that the job is done correctly

 

[Dennis Alwon]

 

[Little Bill]

The bonding grid does not need to go back to the system ground. Just all metal parts on/in the pool, equipment serving the pool, and the pool water is all that is required to be connected to the grid.

 

[charlesaf3]

I was actually just thinking of this. There is a pretty strong debate around here whether the bonding wire has to be tied directly to the ground bar in the panel.

Can anyone cite a code section that says it should, or should not be tied? I recognize the are functionally tied, because I, at least, run my #10 in the concrete and in bare dirt, plus the bonding lugs,but in general the take around here is that they are left out of the panel. The worry seems to be the possibility that a bonding wire will become a ground under certain failure circumstances.

 

[infinity]

It is not required and explicitly spelled out right in the equipotential bonding requirements in Article 680.

680.26(B) Bonded Parts. The parts specified in 680.26(B)(1) through (B)(7) shall be bonded together using solid copper
conductors, insulated covered, or bare, not smaller than 8 AWG or with rigid metal conduit of brass or other identified
corrosion-resistant metal. Connections to bonded parts shall be made in accordance with 250.8. An 8 AWG or larger solid
copper bonding conductor provided to reduce voltage gradients in the pool area shall not be required to be extended or
attached to remote panelboards, service equipment, or electrodes.

 

[kwired]

One must understand the reason for bonding all the non electric equipment. It has very little to do with fault clearing or grounding and is called "equipotential bonding" for a reason, it brings all those components to the same voltage potential.

The electrical grounded conductor and equipment grounding conductor are tied to one another back at the service. The grounded conductor may have a rise in voltage as referenced from earth because of voltage drop on that conductor, that is normal but that voltage rise is also imposed on anything that is bonded intentionally or not at the pool. This can leave voltage gradients in the pool area and just a few volts is much more of a danger when you are immersed in the pool than if you are standing on relatively dry ground and subject to the same few volts. So we protect pool users from these possible voltage gradients by bringing every conductive object in the pool vicinity to the same potential via this bonding system.

We don't care if the entire pool is running at 1000 volts above earth potential, just that there is no potential between objects in the pool area. This is reason why a bird on an overhead high voltage line doesn't get electrocuted, it is at same potential as the line but is not touching anything of different potential so no current flows through it.

Any item that is required to be bonded that also is required to have an EGC run to it, will inherently yield an interconnection between the electrical grounding system and the equipotential bonding system of the pool. This most often occurs at least at a pump motor

 

[charlesaf3]

It is not required and explicitly spelled out right in the equipotential bonding requirements in Article 680.

Thank you. I do understand the purpose of equipotential grounding, though I won't lie, it took me a bit of reading as it's generally not so well explained as above.

So next question is, is it good practice to to attach bonding wires to the ground bus? Pool is running off a subpanel, and we ran the bonding wires (bare, buried in dirt) back to the panel and left them long. We have a ground rod driven off the panel, so I imagined ground was effectively connected by their proximity, but was wondering what best practice would be.

My guess is leaving them disconnected, just in case stray voltage gets on the grounds somehow.

 

[infinity]

You're not required to connect the equipotential bonding conductors to the panel or to the ground rod because it will most likely have zero benefit. If there were a need for this connection then the NEC would require it. The EGC in the pump circuit is all that's required to be connected to the panel so that's all that I would use.

 

[charlesaf3]

You're not required to connect the equipotential bonding conductors to the panel or to the ground rod because it will most likely have zero benefit. If there were a need for this connection then the NEC would require it. The EGC in the pump circuit is all that's required to be connected to the panel so that's all that I would use.

ok thank you, makes sense as a way to proceed