Pool

[maswhi00]

Getting a mild shock from a pool. It is a newer pool all bonding is correct. Turned off power still getting shocked. Had the power company come out turn off transformer still getting shocked. Any possible solutions?

 

[suffolkspark]

Tncs supply? Will say on the electrical certification from electrics relating to the pool..

 

[UNG]

Tncs supply? Will say on the electrical certification from electrics relating to the pool..

Do they have TNCS as we know it in the US

 

[telectrix]

Do they have TNCS as we know it in the US

was just wondering that meself

 

[pc1966]

Do they have TNCS as we know it in the US

I think it is mostly TN-C-S but with the N-E link in the DB, not the cut-out (which I think they use removable meters in place of our style fuse link), and each property has a couple of earth rods (like the ROI "neutralising" arrangement) providing a bit more earths on the system.

So I would imagine they are prone to the same issue of the pool's earth/ground connection being several volts above the "true Earth" where the pool is located.

 

[pc1966]

For the OP the solutions, if the pool is OK, are probably one of the following:

• An earth mat buried below the pool area to reduce the potential felt when stepping out
• Putting the pool on a low-conductivity surface like raised wooden or plastic decking so you don't feel it as much
• Changing the supply to 'TT' where there is a dedicated RCD (GCFI) for the pool and the earth/ground is taken from a local rod, and not the main house supply earth/ground.

Probably one for @Megawatt advice as one of our USA members?

 

[suffolkspark]

Do they have TNCS as we know it in the US

Didnt realise it was USA

 

[maswhi00]

It’s an inground pool and within a couple years old so house grounding and utility bonding correct

 

[pc1966]

It’s an inground pool and within a couple years old so house grounding and utility bonding correct

Is this a large concrete base for the pool? Usually they would have bonding to the reinforcing rebar rods, etc., and that largely serves to keep any potential gradient around the pool down.

In the UK if I were looking to install an outdoor pool I wouild probably put it on a TT supply (local earth, not supply) but I don't know if the USA wiring code allows that approach.

 

[Dartlec]

It should be possible for an electrician to check to see whether any stay voltages are present...

If it's a mild shock as in a gentle tingle, then it's likely to be some issue with the bonding somewhere, either that has deteriorated since install, or was not quite as thoroughly done as necessary...

Has it developed suddenly, or over time?

US have different codes so can't comment much on that, though in at least some places they seem to actually bond the water over there - The code does seem to recognise an issue with voltage gradients and how to avoid them...

This seems like something for an electrician experienced in pool installs to take a look at and work out what's going on, and to determine the best way to resolve it...

Looks like the NEC code on bonding swimming pools is quite thorough (2014 at least, I believe different places use different variations too...)