How how to bond existing in ground pool?

[SteB88]

Hello all,

First post for me, a very frustrated DIYer whos leaving in a country (Czech Republic) where its near impossible to find an English speaking electrician who knows what they are talking about.

My issue is that the company who installed our vinyl pool a few years back clearly didn't do something correctly with the electrics and the result is that you can get a little shock when touching the pool water and the surrounding deck at the same time. We have already paid for three different 'professionals' to take a look, but all claim it makes no sense.

I've spent hours researching and believe that this is due to equipotential bonding, or lack there of. I'm 100% sure the rebar around the pool was never bonded to any of the other pool equipment.

Firstly, looking for some professional opinions if that makes sense?

Second, looking for some clarification on how to best go about resolving. Important to note, i do not want to do this myself, but after past experience i want to understand it so as to be sure its done properly.

The setup:
In ground pool with a light fixture.
Service pit with all of the equipment is 70cm from the pool
Heat pump is 4m from the pool and obviously connect to the service pit.

What i know is that the heat pump, water pump, and even the water pipes (some lug in them) all have earth wires leading back to the main fuse board. This fuse board leads to another in the garage which finally leads to the main board in the house and all are certified as up to standard.

My idea, and its just an idea, was to chip away the concrete at the four corners to the pool to expose the rebar. No idea then if that can then just run to the heat pump, which is easily accessible, or if it needs to go back to the service pit (headache).

Appreciate you taking the time to read, and even more so for any advice you may have.

Regards,
Steve

P.S If there is an electrician from Czech Republic who's reading and knows what they are talking about, you can have the job

 

[Vortigern]

There is a thread on here with a video that goes in depth on this subject. Haven't a clue where it is but if you want some clarity on the matter this video explains in exquisite detail all about bonding and pools in depth.

 

[SteB88]

There is a thread on here with a video that goes in depth on this subject. Haven't a clue where it is but if you want some clarity on the matter this video explains in exquisite detail all about bonding and pools in depth.

Thanks for the tip, will try to find it.

 

[pc1966]

Swimming pools have all sorts of extra regulations in the UK for the obvious reason that water, electricity, and humans don't make for a happy mix.

I have no idea how systems are normally done in the Czech republic, though it is likely that @Lucien Nunes will. But there are supply arrangements (TN-C, TN-C-S) that might be functioning normally but still have a noticeable voltage between the supply earth and the real Earth.

The two options that you typically have are either:

• Try to force the ground around the pool and your supply earth to be closer by means of bonding to rebar, buried earth mats, etc
• Create a local TT supply where there is an earth rod just for the earthing the load(s), and a dedicated RCD to allow any fault in the TT side to disconnect quickly (as the earth rod will almost certainly not divert enough current to take out a fuse or circuit breaker)

Bonding the supply earth to buried concrete reinforcement is quite common practice, in the USA I think it is mandatory in buildings (probably @Megawatt will be able to comment). The issue is the trouble to achieve that after the concrete has been poured & set, and even then to reliably bond you need clamps that will keep good contact and resist corrosion.

 

[pc1966]

Here is an example of rebar clamps, no idea where to get price & delivery options for Czech though:

Earth Clamps

Earth Clamps - REQUEST QUOTE | Thorne & Derrick UK & Exports for best prices, customer service and fast delivery worldwide. TEL +44 191 410 4292

www.cablejoints.co.uk

 

[FatAlan]

I find the best way to bond around a pool is with a few beers, good music and a BBQ. Job done ??

 

[SteB88]

Swimming pools have all sorts of extra regulations in the UK for the obvious reason that water, electricity, and humans don't make for a happy mix.

I have no idea how systems are normally done in the Czech republic, though it is likely that @Lucien Nunes will. But there are supply arrangements (TN-C, TN-C-S) that might be functioning normally but still have a noticeable voltage between the supply earth and the real Earth.

The two options that you typically have are either:

• Try to force the ground around the pool and your supply earth to be closer by means of bonding to rebar, buried earth mats, etc
• Create a local TT supply where there is an earth rod just for the earthing the load(s), and a dedicated RCD to allow any fault in the TT side to disconnect quickly (as the earth rod will almost certainly not divert enough current to take out a fuse or circuit breaker)

Bonding the supply earth to buried concrete reinforcement is quite common practice, in the USA I think it is mandatory in buildings (probably @Megawatt will be able to comment). The issue is the trouble to achieve that after the concrete has been poured & set, and even then to reliably bond you need clamps that will keep good contact and resist corrosion.

Thanks allot for the info pc, much appreciated.

We had a technician come out to review and make sure that the equipment is correctly earthed etc, and his 'professional' opinion was that the electricity (DC,) is simply being naturally generated.. seems a bit voodoo to me, but I'm obviously not an expert. Based on this however, he claims that bonding is unlikely to work, which is the part i cant wrap my head around. Honestly, it doesn't bother me as much to feel a little tingle, and only ever seem to feel it on broken skin, but I've two kids that its puts off.. moreover, its the uncertainty in my head that something just isn't right and could get dangerous.

If i try to bond the rebar (thanks for the link on clips btw), can i simply run an 8mm copper wire around the edges of the deck connecting at the corners and just one line to the heat pump? Would this accomplish to bond everything together assuming everything in the pit are earthed through the same fuse board.. prepared an expert drawing to illustrate, see attached .

Again, appreciate all of the feedback.

Regards,
Steve

 

[Megawatt]

Hello all,

First post for me, a very frustrated DIYer whos leaving in a country (Czech Republic) where its near impossible to find an English speaking electrician who knows what they are talking about.

My issue is that the company who installed our vinyl pool a few years back clearly didn't do something correctly with the electrics and the result is that you can get a little shock when touching the pool water and the surrounding deck at the same time. We have already paid for three different 'professionals' to take a look, but all claim it makes no sense.

I've spent hours researching and believe that this is due to equipotential bonding, or lack there of. I'm 100% sure the rebar around the pool was never bonded to any of the other pool equipment.

Firstly, looking for some professional opinions if that makes sense?

Second, looking for some clarification on how to best go about resolving. Important to note, i do not want to do this myself, but after past experience i want to understand it so as to be sure its done properly.

The setup:
In ground pool with a light fixture.
Service pit with all of the equipment is 70cm from the pool
Heat pump is 4m from the pool and obviously connect to the service pit.

What i know is that the heat pump, water pump, and even the water pipes (some lug in them) all have earth wires leading back to the main fuse board. This fuse board leads to another in the garage which finally leads to the main board in the house and all are certified as up to standard.

My idea, and its just an idea, was to chip away the concrete at the four corners to the pool to expose the rebar. No idea then if that can then just run to the heat pump, which is easily accessible, or if it needs to go back to the service pit (headache).

Appreciate you taking the time to read, and even more so for any advice you may have.

Regards,
Steve

P.S If there is an electrician from Czech Republic who's reading and knows what they are talking about, you can have the job

There is no sense cutting up concrete to get to the rebar. Swimming pools are required to have a # 8 bare wire in a ring around your pool. Having said that I’m going to assume the light fixture is 120vac which should be GFCI PROTECTED or RCD as our friends in the UK call it. Get you a hammer drill with a ground rod driver and drill a 1 inch hole through the concrete and then drive a ground rod at each corner. ALL metal parts are required to be bonded and talking about the pump it is required to be GFCI protected also. Good luck my friend

 

[nicebutdim]

There is a thread on here with a video that goes in depth on this subject. Haven't a clue where it is but if you want some clarity on the matter this video explains in exquisite detail all about bonding and pools in depth.

Not sure how to find the thread, but the guy who made that video is Mike Holt. His Youtube channel is a mine of information on this subject, albeit from a US perspective.

I couldn't find the video you were referring to, so tried searching Google. It seems that video has been made private - probably to stop people repeating his experiment.

 

[Mike Johnson]

I don't understand why bonding at all four corners is required, all the reinforcing bars in the concrete are connected to each other with tying wire, I would have thought one connection would be sufficient, conveniently in the pit, but then your are reliant on the pool being constructed correctly, if not then even four rods may not do it, but I would try connecting in the pit before going to the expense and work of putting in four rods.

 

[Vortigern]

I don't understand the reference to DC from your person who inspected the situation.

 

[Wilko]

My take on this is that you are experiencing results from voltage difference between the pool and its surroundings. This should not exist if all was well. The fact that it exists indicates all is not well. Without knowing exactly what it is I can’t really advise how to fix it, but I do know there is always the possibility that things degenerate and become worse, so I wouldn’t use the pool until you are happy the cause is found and fixed.

Perhaps confirm the light is 12V and is supplied by an isolation transformer?

 

[pc1966]

My suspicion is this is a TN-C(S) supply and that the supply earth is seeing several volts of neutral drop, especially if it is rural. However, it might be worse, a TT system without an (functioning) earth rod and the pool is becoming the route for all leakage!

Can the original poster put up some photos of the power supply arrangement and main panel/fuse box so we can guess?

The other thing not mentioned by the OP by raised by @Megawatt is the supply to the pool electrics has to be on a RCD/GFCI. Might as well confirm this while other things are being discussed.

In terms of earth bonding to the concrete then it might well be simpler to just drill and insert some rods at each corner in the USA-style. But as @Mike Johnson says if it has rebar in there, that would be a very good earthing system if attached at any point that can be accessed (assuming without too much difficulty).

 

[SteB88]

Not sure how to find the thread, but the guy who made that video is Mike Holt. His Youtube channel is a mine of information on this subject, albeit from a US perspective.

I couldn't find the video you were referring to, so tried searching Google. It seems that video has been made private - probably to stop people repeating his experiment.

watched allot of his vids already, thanks for the tip.

 

[SteB88]

My take on this is that you are experiencing results from voltage difference between the pool and its surroundings. This should not exist if all was well. The fact that it exists indicates all is not well. Without knowing exactly what it is I can’t really advise how to fix it, but I do know there is always the possibility that things degenerate and become worse, so I wouldn’t use the pool until you are happy the cause is found and fixed.

Perhaps confirm the light is 12V and is supplied by an isolation transformer?

We actually disconnected the light as the first thing to check and be sure it was not the cause. Issue still there though

 

[SteB88]

My suspicion is this is a TN-C(S) supply and that the supply earth is seeing several volts of neutral drop, especially if it is rural. However, it might be worse, a TT system without an (functioning) earth rod and the pool is becoming the route for all leakage!

Can the original poster put up some photos of the power supply arrangement and main panel/fuse box so we can guess?

The other thing not mentioned by the OP by raised by @Megawatt is the supply to the pool electrics has to be on a RCD/GFCI. Might as well confirm this while other things are being discussed.

In terms of earth bonding to the concrete then it might well be simpler to just drill and insert some rods at each corner in the USA-style. But as @Mike Johnson says if it has rebar in there, that would be a very good earthing system if attached at any point that can be accessed (assuming without too much difficulty).

Attached some pics of the fuse boards we have. the run is House > Garage > Pool.
How do i check RCD/GFCI? keeping in mind I'm not an electrician

About earthing the Rebar.. can this actually do any harm or make things worse? wondering if to just get someone to give it a go and see, but then i'm worried it might make a different issue.

 

[SteB88]

I don't understand why bonding at all four corners is required, all the reinforcing bars in the concrete are connected to each other with tying wire, I would have thought one connection would be sufficient, conveniently in the pit, but then your are reliant on the pool being constructed correctly, if not then even four rods may not do it, but I would try connecting in the pit before going to the expense and work of putting in four rods.

Makes sense, thanks for the feedback Mike.

 

[SteB88]

I don't understand the reference to DC from your person who inspected the situation.

Nor me, but i checked once again and its clear written in his very short report that he gave back to the pool company. Would share but its not in English.

 

[pc1966]

Attached some pics of the fuse boards we have. the run is House > Garage > Pool.
How do i check RCD/GFCI? keeping in mind I'm not an electrician

More detailed photos might help!

It looks as if there are RCD at each of the boards, but it is not really possible to say from that level of detail. However, it all looks reasonable quality equipment so I would imagine so.

About earthing the Rebar.. can this actually do any harm or make things worse? wondering if to just get someone to give it a go and see, but then i'm worried it might make a different issue.

Electrically, no.

However, I have no idea of the risk of causing physical damage to the pool arising from trying to access it!

If you are sure there are no buried service pipes or cables around the pool it might be safer to put in rods at the corners beyond the concrete area. Typically rods have to be deep to be effective, say 2-3m, and often they are in 1.2m segments that can be screwed together as they are driven in.

If you are unsure about buried stuff and are willing to dig down manually (and with care in case you do meet something) then by time you have dug a post-sized hole to around 1m down you are probably clear of any buried service cables & pipes.

Here are a couple of UK suppliers of earthing stuff, more from a lightning protection point of view:

Earthing Archives - Kingsmill Industries

kingsmillindustries.com

Home

A.N. Wallis is the number one supplier for all your earthing, lightning protection and surge protection equipment.

www.an-wallis.co.uk

 

[pc1966]

Incidentally if putting in a ring of conductor around the pool you generally can and should bury is a bit under the surface, less likely to get noticed/stolen and contributes better to the earth conductance. At the corner rods you can have inspection pits to access the wire and rod fixing bolt, etc.