After some advice: Mild tingle from shower when in use

[TheGovernor]

Hi Skenk, no it's with 8 RCBO's with spare slots for growth.

The other two aren't fixed, I just didn't copy and paste his whole email, where he'd quite reasonably said anything else he finds will be chargeable, whereas BG are saying it's a fixed price...

 

[skenk]

Fair enough however I very much doubt that the BG quote will cover remedial works to circuits - I expect it will be a fixed price for the CU replacement and additional costs for remedial works will be hidden in the small print. Certainly with their 'homecare' packages the advertising suggests that cover is extensive but in reality the terms are full of exclusions.

Eg (dependent on the product purchased) taps are covered but not ceramic disc replacement; wiring repairs are covered but not for rubber or lead cable; decorative or specialist parts are not covered; damage caused by changes to the gas, electricity or water services are not covered etc etc (x35 pages of terms!)

Ideally full testing would be done before the CU is changed but this takes longer than doing it while changing the board and it could leave you with a bill for testing and the consumer unit unchanged if faults requiring significant remedial works are found. As such most quote for CU replacement and have different arrangements for dealing with faults found during the course of the works (including leaving faulty circuits unconnected to an RCD and issuing appropriate warning paperwork and exclusion note on the installation certificate, if a quote for repairs is refused).

At least BG tend to have extensive written terms (unlike some others) so at the very least it would be worth checking what they say before proceeding.

 

[flyingsparks]

.....(including leaving faulty circuits unconnected to an RCD and issuing appropriate warning paperwork and exclusion note on the installation certificate, if a quote for repairs is refused)..........

 

[skenk]

I'm putting that forward as a possibility of what could happen. Clearly it's not best-practice, it's quite a significant departure from the regs. I've never done it myself, but then I explain about testing beforehand and not proceeding further until/unless quote for required remedials has been accepted. I rarely do CU changes though and have lost some jobs because I couldn't guarantee a fixed price. In general I do give fixed quotes for almost all work because it gives 'peace of mind' to the client (see OP's comments!), maybe that's why I don't do many CU changes. I wouldn't be happy leaving an installation with CU I just installed without RCD protection where it should be, but replacing the CU (and in doing so making significant improvements to the installation) is I think preferable to making no improvements. I think this was discussed here before.

I suppose if there's nothing in BG's terms about it they could be playing the averages and just suck it up when they get a job that requires significant remedial work, (and they may have lower overheads in terms of cost of fleet, materials etc due to buying power), but I doubt it, because people with known problems would try-it-on.

 

[TheGovernor]

I'm putting that forward as a possibility of what could happen. Clearly it's not best-practice, it's quite a significant departure from the regs. I've never done it myself, but then I explain about testing beforehand and not proceeding further until/unless quote for required remedials has been accepted. I rarely do CU changes though and have lost some jobs because I couldn't guarantee a fixed price. In general I do give fixed quotes for almost all work because it gives 'peace of mind' to the client (see OP's comments!), maybe that's why I don't do many CU changes. I wouldn't be happy leaving an installation with CU I just installed without RCD protection where it should be, but replacing the CU (and in doing so making significant improvements to the installation) is I think preferable to making no improvements. I think this was discussed here before.

I suppose if there's nothing in BG's terms about it they could be playing the averages and just suck it up when they get a job that requires significant remedial work, (and they may have lower overheads in terms of cost of fleet, materials etc due to buying power), but I doubt it, because people with known problems would try-it-on.

Thanks for the thoughts, I'll see what I can see in the BG terms

 

[JohnW2]

I suppose if there's nothing in BG's terms about it they could be playing the averages and just suck it up when they get a job that requires significant remedial work, (and they may have lower overheads in terms of cost of fleet, materials etc due to buying power), but I doubt it, because people with known problems would try-it-on.

I would doubt it to. Although that approach is (implicitly or explicitly) taken in a good few walks of life, not only can it be exploited in the manner you suggest but, even if it isn't exploited, it means that those customers with straightforward jobs are 'subsidising' those with the more complex jobs. We obviously accept that concept (of cost-/risk-sharing) in relation to insurance, people probably aren't so keen on it in relation to the direct provision of a service.

Kind Regards, John

 

[KingDave123]

Sorry to jump on this thread and I appreciate this was years ago but I have a similar problem. Did the OP resolve the issue?
I was called out to tingling on a shower riser rail and handset. It was fed by a shower pump. I cross bonded all 4 pipes going in and out and connected that to the current 4mm bonding in the airing cupboard. That eliminated the stray voltage of 1-2 volts.
Verified the main earth was true.
Water main is polypipe with no bond attached. All pipework disappears into the floor (suspended wooden floor on ground floor). Gas bond connected and continuity verified.
The client said they got a tingle as they got out of the shower. For sanity check I even got in the shower when done and proved to the client I wasn't getting shocked!
Then I had a message last night saying that it was fine to start with and towards the end of the shower got worse.
FYI, it is a fully rcbo loaded board.
I've done a long lead test to the MET and readings are between 0.01 and 0.03 MOhms.
Would a faulty shower pump cause this as there have been no issues since the tenants moved in 7 months ago until now.

Any help advice greatly appreciated

 

[JohnD]

Is there a metal soil or waste pipe?

Might a leak be going through the floor and meeting e.g, a light fitting?

Is the householder standing on a concrete floor?

 

[Harry Bloomfield]

That eliminated the stray voltage of 1-2 volts.

1 or 2 volts would not be even felt, it has to be much more than that. For reference, the only way to see if there is voltage across a 9v transistor battery, is by touching across the terminals with your tongue.

 

[KingDave123]

Hi John. Not sure on the waste. I'd imagine it is plastic due to the age of the property.
No concrete as its on the 1st floor of a standard house. On my next visit I will see if I can ascertain that. Leaks are also another avenue for me to explore. I have advised for them to change the shower pump. Worst case scenario is that it isn't that and they have a spare. They don't last long round here with the hard water!

 

[FrodoOne]

Sorry to jump on this thread and I appreciate this was years ago but I have a similar problem. Did the OP resolve the issue?
I was called out to tingling on a shower riser rail and handset. It was fed by a shower pump. I cross bonded all 4 pipes going in and out and connected that to the current 4mm bonding in the airing cupboard. That eliminated the stray voltage of 1-2 volts.
Verified the main earth was true.
Water main is polypipe with no bond attached. All pipework disappears into the floor (suspended wooden floor on ground floor). Gas bond connected and continuity verified.
The client said they got a tingle as they got out of the shower. For sanity check I even got in the shower when done and proved to the client I wasn't getting shocked!
Then I had a message last night saying that it was fine to start with and towards the end of the shower got worse.
FYI, it is a fully rcbo loaded board.
I've done a long lead test to the MET and readings are between 0.01 and 0.03 MOhms.
Would a faulty shower pump cause this as there have been no issues since the tenants moved in 7 months ago until now.

Any help advice greatly appreciated

The original Post is Long Ago and there are many other Posts on that "Thread" - which I have not read.

Such a problem can be if
there is a TN-C-S connection
and
the "building" is on a Concrete Slab
where
the Reinforcing Bars in the "Slab" have not been bonded to the Earthing Electrode(s), later provided
but
the metal piping has been so "Bonded".

A "Concrete Slab", with re-enforcing bars, is an excellent (Ufer) Earth - better than any "Earthing Electrode", driven into the ground.
(https://en.wikipedia.org/wiki/Ufer_ground )

That could be the problem.

If the above is the case, the solution is to (somehow) connect to the "Slab" re-enforcing bars and "Bond" them to the "Earthing Electrode" connection - to the Neutral, Metal Pipes etc.

 

[flameport]

. I cross bonded all 4 pipes going in and out and connected that to the current 4mm bonding in the airing cupboard

Was that actually required, as in was there a valid reason for doing that? Installing bonding where it's not required can make the situation worse.

Would a faulty shower pump cause this

Unlikely.

. I have advised for them to change the shower pump

Unless you are certain that is the problem, doing that will achieve nothing.

Worst case scenario is that it isn't that and they have a spare.

Worst case scenario is someone is seriously injured or killed by electric shock.

The situation requires professional investigation to establish what the problem actually is, and then repairs as required.
Guessing at possible problems and replacing items randomly is not the way to proceed.

 

[Harry Bloomfield]

Was that actually required, as in was there a valid reason for doing that? Installing bonding where it's not required can make the situation worse.

Cross bonding ensures all items are at exactly the same potential.

 

[KingDave123]

It is a real head scratcher for me this one. I cross bonded the pipes as there was a small stray voltage on there. I wanted to do that as they said it was a very mild tingling.
I have only phoned the NICEIC on two occasions, this being one of them. He actually said the pump could be the problem but he was quite wishy washy about things. All circuits in the airing cupboard are adequately earthed through there own cpcs. I have long lead tested everything back to the main earth terminal with extremely low resistance readings. The only thing I haven't looked for is a potential leak somewhere and whether the waste is metallic in any way. Ripping walls or floors open is the last thing i want to do I, bit I will if needs be. I have come on here originally to see what the outcome on here was from the OP. And also some 'helpful' thoughts on the matter. Not to be talked down to in a condescending way. I appreciate the input given on here regardless.

 

[Harry Bloomfield]

It is a real head scratcher for me this one. I cross bonded the pipes as there was a small stray voltage on there. I wanted to do that as they said it was a very mild tingling.

I think you need to explore, and describe the plumbing and drainage network, which are plastic and which copper. Is the shower feed all copper? Is it a steel bath? Is the plughole metal?

Was that actually required, as in was there a valid reason for doing that? Installing bonding where it's not required can make the situation worse.

As mentioned above, bonding, in some rare circumstances, can make the situation worse.

Personally, I believe the risks are minimised by bonding - the risk is one of something becoming inadvertently live, which had not been effectively bonded, and someone making contact between that, and something which is bonded, as seems to be the OP's issue.