Shower Electric shocks but not everyone

[Roger]

Got a call today to go to a old flat as the lady was getting shocks when she was having a shower.
She explained that when she touches the tap and then the shower unit she gets a tingle and now here daughter is getting them as well.
Considering the property is a rental I was amazed to see a old rewireable fuse with some retrofit Wylex MCB put in there.No RCD ,bit of old twisted uninsulated earth wire coming up from the supply cable buried in the wall.The fuse box was not a stand alone type unit it was integral in a metal type service cabinet about 2 foot tall.
The property has an earth 0.6 (TN-S) however it only goes to power circuits,the lights have no earth and the circuit feeding the shower pump.Pulling of a cover in the cabinet revealed about 3 cables out of 8 actually had a cpc in them.
Incoming water is bonded ,but not gas to this flat and next door.Wondering around my R2 Long lead could get no continuity on any taps ,shower.
There is no supplementary bonding anywhere,lots of plastic unions so continuity if it was there is now broken.
The shower has a pump and the boiler is a conventional type with a hot cylinder upstairs.No bonding in the airing cupboard.
Now I assume she is experiencing a difference in potential which is why she is getting shocks.I could not get any shocks with the shower running and checked for any voltage present just with my volt stick and direct measurement,non existed.

But why does she get it and the previous tenant did not ?

Apart from saying the flat should really be rewired and it is not really suitable for renting i need to provide a detailed explanation as to what is going on and why it has not happened previously.

If i upgraded and put in main bonding to services and run upstairs to bathroom from MET,also supplementary bonding in bathroom under bath and sink and airing cupboard would that fix it.

She has just signed for 6 months so not really practical to rewire now,if he actually wants to go ahead.
Any help greatly received

 

[Antman]

Good Luck^ Can't believe a rented property is in this state

 

[topquark]

Re reading this quickly you say that the pump only feeds the shower so there is a pssibility that the differential is between the tap feeds and the shower pipes so I would bond across the pump. As there is no main bond to the gas there is a possibility of an earth leakage on the boiler which is finding its way to the water pipes and the shower pipes being buried in the wall could be getting an earth potential frm a damp wall.

Or am I talking crap?

You could do that, but it's kinda "papering over the cracks a bit", better to find the source of the problem and fix that before it gets any worse (which it may never do of course).

 

[topquark]

Good Luck^ Can't believe a rented property is in this state

Yep, shouda been checked at change over.

My money's on Pushrod's suggestion of earth/neutral fault elsewhere.

 

[ferg]

Hopefully the landlord will get the remedial works done.

A while back I went to a rental property to find mostly lead sheathed wiring and just about every john wayne job you can think of.
Recommended an immediate rewire.

Landlords response........... Cant afford it I'll tell them to be careful and put in a couple of battery powered smoke alarms!!!

I warned the new tennant they didnt care much either.
I get a shiver down my spine every time I drive past that place.

 

[Antman]

Hopefully the landlord will get the remedial works done.

A while back I went to a rental property to find mostly lead sheathed wiring and just about every john wayne job you can think of.
Recommended an immediate rewire.

Landlords response........... Cant afford it I'll tell them to be careful and put in a couple of battery powered smoke alarms!!!

I warned the new tennant they didnt care much either.
I get a shiver down my spine every time I drive past that place.

That is just mad, there are KIDS in that flat!! It could easily get worse

 

[truckster]

I has been slagged off man Ok here's another left fielder, is the wall live? The shower pipes appear to be electrically isolated from the water pipes by the pump so a potential on the wall could appear on the shower pipes.

Before anybody screams, the mans a fool, I've had a job where the owner was getting tingles on his dining room wall. It was an old solid wall construction with rubber cabling, whenever it rained he got the tingles. When I dug the cables out the rubber had disintegrated to such an extent that the only insulation was the wall plaster. A bit of moisture and tingles!

For pities sake find the answer, it's driving me nuts!

 

[Roger]

Well,I was told a builder friend had fitted a extractor fan just before the new tenant moved in.So I thought I would start there,timer control removed and powered direct to motor from light switch and bless him to save the coppers reused the ceramic thimbles,loose neutral.The fan vent just goes into loft ,not to any soffet or roof vent.Lots of old bakelite JB everywhere in loft but they all looked very good inside and the cables looked in very good condition but any 1/1.5 conductors size cable has no earth,so all lighting.
Thought I would get on with my earthing so a fresh roll of 10mm was grabbed,lots of bonding all over the bathroom,both sides of pump and then ran a length of 10 straight from MET to the bathroom,easy route most of which is lost behind a pipe so not that visable.
When finished ,still got gas to do,i thought i would take the cover of the pump to make sure the connections were all sound. Touched pump body to my nice new bonded pipework and got 24VOLTS !!!!! put voltage probe on earth post in pump and got the same.Pulled a couple of floorboards to find join and a fused spur was found fitted with a 13amp fuse.Removed cover and the earth was not connected at all,goes back to airing cupboard and a fused spur in there so god knows what else it feeds.
Rejoined earth and voltage goes,continuity from pump earth post and to all new bonding perfect.
Now the reason why ?
I assume some voltage leakage from the pump and it had nowhere to go as we had no supplementary bonding or anything so it would discharge itself when a unfortunate person touched the tap and then the shower head at the same time.
Had a look around the area today and the main power cable goes up through a cavity in the middle of the shop below.Interestingley the other flats further down all have a lovely new service head with PME supply all going to a 6 off 80amp switched fuse per flat.Very neat and tidy, professional job by EDF.

 

[truckster]

Hooray!!!

 

[pushrod]

Thanks for the update - very interesting but still wondering what was actually happening?

I assume some voltage leakage from the pump and it had nowhere to go

So do you think it was an induced voltage/ build up of electrical charge due to the running of the motor which had no where to go because of the disconnected cpc, which then discharged when someone touched it? Was anybody ever able to get a tingle and then touch it immediately and get another tingle - if they were that would knock the static build up idea on the head and seem to indicate some permanent fault. But if the tingle was not constantly there and took a little time to build up then may be it was static
I would still deffo recommend a PIR as the fault could still be there just not showing itself as it can take the route through the cpc. A full set of IR tests would check out the other circuits and go along way to help sorting out what was happening here (and get you some more cash!)

 

[Roger]

Hooray!!!

Fixed the fire alarm as well,a good day.

Did ask me to upgrade the board as I highlighted the circuit protection/safety benefits ,but as soon as I said its a rewire the conversation changed.Asked whether he had a periodic electrical inspection ever done and he sad what ! I said the bloke that did the kitchen should have mentioned about the fuseboard upgrade otherwise he can not do the work and connect up the circuits new to old ,Oh no another kitchen fitter !

Anyway back there tomorrow to change the rewireable fuses to those retrofit wylex MCB's,a bit better than a rewireable and I will pull a few sockets off and have a nose to keep my mind at rest.

 

[Roger]

Its still bugging me whats going on,ok have left a bit happier but still not convinced.
To recap:-
If the CPC is disconnected I immediately get the 24 volts again between pump earth post and bonding.Reconnect CPC and voltage goes away,pump does not have to run to get voltage it is there all the time.There must be something internally in the pump which is failing.Its works fine.
If i can identify what else is on the circuit i will carry out a IR test tomorrow on it,I will do between live conductors and earth first just in case.
I'm on a day rate,so lets do it all !

 

[pushrod]

Definitely sounds like there is a fault there still waiting to be found and the reconnection of the cpc/bonding is just masking it - better storyline than coronation street this

 

[Big n Daft]

Pushrods got the best solution, no doubt.Otherwise.........This may sound completly daft but what clothes does she wear. No No No take that thought rite out your disturbed one track mind!! It could just be static build up when removing her clothes prior to showering.
Highly unlikely, I know.
If I turned up at that place the nike's would be going pretty sharpish.

 

[coomers]

be careful what you do on this job you are now working in a bathroom part p applies the pump should be on a rcd its in the bathroom,if it was lekage would knock rcd out new pump required! (obviously if cpc connected and now youve connected it you now need to install rcd)

 

[Roger]

be careful what you do on this job you are now working in a bathroom part p applies the pump should be on a rcd its in the bathroom,if it was lekage would knock rcd out new pump required! (obviously if cpc connected and now youve connected it you now need to install rcd)

Very valid point for the sake of £25.00 its worth putting one on it and compliance.Lets find where the circuit ends and what else is on it.

~Thank you~