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J

Jimmy_Trick

Hi Folks,

Bit of an introduction thread - I'm a total newbie on this forum and looking for a bit of advice.

Just moved in with my gf for the first time as tenants in a nice new build flat. We're the first people to live in there since it was built.

We're moving in yesterday and she and I keep getting odd little electric shocks from stuff. First we noticed our dyson (handheld, battery power) kept giving us little electric shocks.

Then, more worryingly we noticed that the 'edge' of the electric towel rail was giving us weird static shocks. This electric towel rail is a chrome, liquid filled jobbie that's electrically connected to the wall, but is isolated in the 'plumbing' sense from the rest of the water supply => i.e. it's a self contained unit.

At first we thought it was just static - it's a brand new property, we were getting a bit mucky moving lots of boxes and we thought we were probably just picking up charge as we were wearing knackered old primark clothes to move things about.

Noticed that every time we touched the 'edge' of the electric towel rail we got a little shock on the backs of our hands. We didn't get it from our palms (I presume we've got thicker skin => higher resistance than the shin skin on our backs). We also only noticed it on the 'edge' of the electric towel rail, which kinda made sense, as when we touched the main 'body' of the steel rails there was enough conductor that the path of least resistance was still 'within' the metal.

Despite now being a boring old accountant these days, my first degree was in Physics so I went into detective mode and dug an old multi-meter out of the back of our car we used when we were trying to work out why our car wouldn't start (alternator failed!) and started poking things.

The only metal thing nearby was the main mixer tap. I opened up the cupboard under the sink and pawed around till I felt the little metal grounding strip thing so I figured it made a pretty good ground and started poking things.

I detected no DC current and no appreciable DC voltage. HOWEVER, on V AC mode, I detected a bias of 50 volts AC., even when it was switched off on the plug. It only dropped to zero (actually like 1-2v AC, but figured that was probably just noise on my crappy old multimeter) when I flipped the 'radiator' circuit off the main fusebox.

Three questions:

*Firstly, can someone who isn't the muppet lettings agency worker tell me that I'm not imagining that this definitely isn't normal /a bit dangerous? I would assume anything electrical should either be a) earthed, or b) double insulated? I spent a lot of time when I was younger dicking around with breadboards and 741 Op amps so 99.9999% certain an electric towel rail shouldn't have a 50volts AC charge on it, but I'd really appreciate someone just confirming this as I'm happy to admit I know zilch about 230mains and the person I spoke to at the agency was about as helpful as an asbestos confetti...

*Any idea what is causing this? My gut feeling is that if there's an insulative liner between the fluid inside the tube and the metal, it's probably failed, or, alternatively, the person wiring it up as put the live / neutral in the earth. I figure an educated guess might be helpful to try and convince the agency there is actually a problem!

*How serious is this? I mean, the shocks we got were very much in the 'oh I just got an electric shock, how odd' category than 'jesus wept that was painful' - but presumably these sort of things should have been checked when the thing was built / installed?! We were lucky we were only touching it with dry hands, using v=IR, I figure at 50 volts, with say 5-10kohs resistance of human skin (I googled it), we probably got just around the 1mA mark of current which I remember from my own education isn't all that much - but I worry very much what would have happened if we grabbed it reaching for a towel out the shower!!
 
If you're getting tingling sensations from appliances or things that are plugged in then there's actually 2 separate faults that need to be found. Firstly there's a breakdown in the insulation somewhere that's allowing current to 'leak' from the circuit and secondly there's an inadequate earth that's allowing the voltage of the chassis of the item to rise. Both faults must be found and repaired before the installation is safe. Unfortunately your cheap tester isn't going to find them, you're going to have to get in an experienced electrician.

**edit** I think that in the UK rental properties are supposed to be tested periodically. I'd suggest you should approach the landlord about this.
 
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Thanks - appreciate the response! Glad to know this doesn't sit in the 'god you're being paranoid' box of worries

I've got a cheapy multi-meter from maplin that I've had kicking around since god knows when, figured it wasn't going to do much other than highlight 'there might be a problem'... that's useful to know!

Based on my dealings with this agency my gut feeling is that the people they're going to send around to fix it might do it on the cheap, so helpful to know they might need to fix 2 things, not 1.

James



Electric shock from electrically heated towel rail IMG-20160424-WA0000 - EletriciansForums.net
 
It does sound like sn insulation breakdown on the towel rail element, but that does lead to futher questions about your cpc and rcd covering this circuit.. Have you opened up the towel rail isolator and outlet.? And where are the isolator and outlet in relation to bathroom.?
 
The tester you're using isn't going to give you meaningful touch-voltage readings due to its enormously high input impedance. Whilst it will give you an indication of a voltage present it's not the right tester for the job to give an accurate reading of this type of voltage.

If it'sa rntal property I'd suggest you don't go dismantling stuff any further, you might get held responsible for problems even if you didn't cause them.

If electrical contractors attend the problem and you're worried they're cutting corners then ask them for a copy of the test results before and after.
 
Thanks for the reply.

Like I said, I'm not a leccy so I might not 100% perfect on the jargon.

That said, I saw there's an RCD on / near the fusebox, and they're in a little cupboard in room opposite. I did wonder about the RCD - at the time I didn't give it too much thought as I figured there was probably so little current in the shock it didn't trip it.

I think when I call the agency again tomorrow I'll be a bit better tooled up if they try and fob me off. As this is a brand-new, new build I figure this probably is a bit of a one off but a bit scary none the less!

Thanks

Jim
 
Yeh - point taken re:safety. Like I said - at first we were convinced it was just static so it was more of a 'what the hell is going on, lets try and poke things', rather than trying to do a diagnostic device. I've got no ambition to be a superhero, and am not currently in the property (staying at my old place tonight) so will sort it out tomorrow.

Thanks for the tip re: testing certificate.

James
 
......I did wonder about the RCD - at the time I didn't give it too much thought as I figured there was probably so little current in the shock it didn't trip it.....
RCD's are pretty sensitive and if the voltage on your towel rail was actually 50v or more then it should be tripping if you touch it and feel a tingle or shock. Ramp testing the RCD is another test than needs doing when the sparkies come.
 
It could be a fault with the element in the radiator, but needs testing properly to determine this.

Usually these types of electrically heated radiators have an immersion element that is inserted in where one of the valves sits. Sometimes these rads come unfilled and if it was connected and then turned on without any fluid inside, the element could have been damaged. Alternatively if the radiator supply circuit was IR tested at 500v between just L&N whilst switched on this can also damage the element. I've experienced both these scenarios in the past which have caused failure or leakage faults.

But you should get the supply circuit checked out also, as Marv mentioned the worrying part is making sure you are adequately protected against electric shock, i.e make sure its installed correctly and using the correct equipment.

I'd insist on having a qualified electrician in to check it out!
 
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I recently investigated a client getting tingling from touching an extractor fan. It turns out that somewhere along the line the earth had been lost. The tingling was from either induced current, or earth leakage current, which had nowhere to go making the extractor fan framework live with about 55Volts AC. Restoring the earth in the cable corrected the problem.
 
Hi Jimmy
Bit late in the proceedings, but I'm retired and just logged on, you say it's a new build, as per Marvo's advice about certificates post and present, it may be advisable to ask your landlord for a copy of the initial installation certificate as well, this will be the certificate given for the testing of the installation after completion.
 
I guess that's something else worth mentioning. Bathrooms are considered special zones in the electrical regs because of the higher likelihood any electric shock received will result in serious injury or death. Any fault of this nature in a bathroom should be considered as dangerous and should be remedied as soon as possible.
 

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