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Topic Title: Head scratcher tingling from lightswitches.
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Created On: 05 November 2017 11:41 AM
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 05 November 2017 11:41 AM
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Paradigm

Posts: 872
Joined: 10 September 2010

Morning everybody.

This one has got me flummoxed , more so that its happening in my own house.

We are getting intermittent tingling/vibration sensations from our bedside lightswitches. They are metal faceplates, standard switches (not dimmers or anything electronic) and are controlling bedside lights & main downlights.

All the light fittings are LED's.

Things that have been checked are the obvious:

Earthing is good at all points, this is certainly not a floating earth.

It doesnt happen all the time.

We have both felt it at different times on our respective switches but the last time it happened on Lady Paradigms side, she could feel it but I couldn't (No entendre meant you dirty minded beasts!!)

Any ideas, I am baffled.

rgds


Nick

-------------------------
"be careful of what you write"
 05 November 2017 12:00 PM
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leckie

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Blimey, never heard of that as long as the faceplate is earthed..

I can only imagine something like that, if it was electric tingling, If it were PME and you were simultaneously in contact with something earthy, unlikely in a bedroom.

Or is it actual vibration, not electricity?
 05 November 2017 12:18 PM
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broadgage

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Joined: 07 August 2007

Is there an electric blanket on the bed ?
And are the tingles only received when in or on the bed and not when standing near the bed ?

If so, then I would strongly suspect capacitive coupling from the electric blanket to the person, and then passage of a minute current from the person to the earthed light switch.
Note that the electric blanket does not have to be in use for this to occur, being plugged in and turned on at the mains socket can do it even if turned off at the electric blanket controller.

Is the bed an electrically adjustable version ?If so it might be leakage from this, or even the adjustable mechanism being live at line voltage, with serious shock only being averted by insulating bedding etc.

It is not a water bed is it ? Leakage from the heating element could be the cause, with dangerous shock being averted by the plastic water bladder.


If the tingling is only brief, then static electricity is a possibly especially if any synthetic fibre bedding or clothing is present.

If the tingling occurs when standing, it might be static from synthetic shoes or socks, try going barefoot and see if it still occurs.
 05 November 2017 12:35 PM
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mikejumper

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Originally posted by: broadgage
Note that the electric blanket does not have to be in use for this to occur, being plugged in and turned on at the mains socket can do it even if turned off at the electric blanket controller.

Good idea Broadgage but how does that work?
 05 November 2017 12:48 PM
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broadgage

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Joined: 07 August 2007

If an electric blanket is plugged in, and any switch on the outlet is turned on, then the switch or thermostat in the electric blanket controller may well be in the neutral and thereby leave the whole length of the element live at line voltage when turned off.

That would produce a worse tingle when turned off, than when turned on, since one end would be connected to neutral whilst turned on.

I avoid electric blankets.
 05 November 2017 12:53 PM
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geoffsd

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I would have thought that electric blankets would have a double pole switch as they may be used in Europe.

Is this not so?
 05 November 2017 01:12 PM
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broadgage

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Originally posted by: geoffsd
I would have thought that electric blankets would have a double pole switch as they may be used in Europe.
Is this not so?


Not in my experience, I presume that the argument is that the switch is for functional control, not for isolation.
Isolation is by removing the plug from the socket outlet.
 05 November 2017 01:28 PM
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geoffsd

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Mmm. That doesn't seem ideal.

So, if Paradigm were in Europe (and does have an electric blanket), he could turn the plug around and the problem may well go away.

Here, it presumably has a moulded plug.
 05 November 2017 01:34 PM
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Zoomup

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It'll be static discharge from the nylon sheets.

Z.
 05 November 2017 01:36 PM
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lyledunn

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Might it be that a wee bit of tossing and turning under certain types of bedding or indeed night ware could cause a bit of charge to develop which is discharged on touching the earthed switch. If this is the case, the best remedy is to stop tossing and turning.

-------------------------
Regards,

Lyle Dunn
 05 November 2017 01:43 PM
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Zoomup

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http://ask.metafilter.com/3159...tart-a-fire-in-my-bed

Or change the sheets to cotton ones rather that use nylon sheets. Also the carpet will allow a build up of static on you and the Mrs. which stays on your bodies when you get into the nice dry insulated bed..................then you touch the nice earthed light switches and ZAP you get a tingling. i would change the switches to all plastic. Bedrooms are normally dry and warm, the sort of place that static electricity likes to occupy and build up in. You pick it up just moving about and walking on the carpet.



Z.
 05 November 2017 01:47 PM
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Paradigm

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Thank you Gentlemen for the time taken to write out these replies.

I think broadgage could be onto something. We certainly do have an electric blanket but I had dismissed it because we were still getting the tingling when it was turned off and I had assumed that it was double pole like Geoff.

Admittedly, I could have unplugged it but it was behind a very heavy unit and didn't think to. Next time it happens, I certainly will try the unplugging to see if it solves it. It would also make sense that my wife was getting the tingling and I wasn't as the blankets are fed from different sockets.

It certainly isn't static as it's continuous rather than a quick zap.

Again, thank you for helping me with this, it proves that you never stop learning, I thought I was going mad..

Reds

Nick

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"be careful of what you write"
 05 November 2017 02:29 PM
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mapj1

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If you have a meter that can measure micro-amps AC, you could try holding the probes one in your hand while in bed and using the other to touch the earthed lights. I'd expect touching the radiators to have a similar effect.
There may also be a fault in the blanket - so take care with this one. Despite all sorts of joke potential, being livened up in bed is not actually desirable.

-------------------------
regards Mike
 05 November 2017 02:38 PM
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broadgage

Posts: 2436
Joined: 07 August 2007

If it is capacitive coupling from the electric blanket, as sounds likely, then try a neon screwdriver.
Though not exactly a proper instrument, a neon screwdriver will light from leakage or capacitive current down to the microamp range.
 05 November 2017 02:55 PM
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broadgage

Posts: 2436
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Originally posted by: lyledunn

Might it be that a wee bit of tossing and turning under certain types of bedding or indeed night ware could cause a bit of charge to develop which is discharged on touching the earthed switch. If this is the case, the best remedy is to stop tossing and turning.


Synthetic fibre bedding and nightwear should be avoided IMHO, primarily on comfort grounds. However static discharges can kill portable electronics.
Many laptop PCs come with a warning "do not use in bed" which is I suspect an effort to avoid warranty claims for laptops killed by static from nylon sheets, polyester blankets and related abominations.

I use only cotton sheets and woollen blankets, mainly on comfort grounds, but also to avoid damage to electronics.
 05 November 2017 07:21 PM
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daveparry1

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I have fitted several LED strip lights recently, can't remember the make but all the same type where I have been able to feel that same tingle/vibration effect. They have all been class 2, with 2 core flex and a figure 8 plug, I found just by chance that reversing the figure 8 plug cured the problem! It seems to me that the rocker switch on the lights is single pole and there is some sort of inductive coupling whithin the light which only shows up when the switch is in the neutral line, if i'm correct in thinking this they should have been fitted with non-reversible plugs shouldn't they.
 05 November 2017 07:41 PM
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MHRestorations

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Daveparry1... that effect can be coupling from the class Y capacitor between the mains and LV sides of the LED driver (which is often referenced to the metal case of the lights). It's there mainly to prevent or reduce RF interference but it can build up enough of a charge to be 'feelable'.

I've had that with the 12v Channel (brand) link lights using the official 12v driver. It made me say bad words in front of a customer!
 05 November 2017 10:24 PM
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sparkingchip

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Joined: 18 January 2003

I definitely remember seeing sparks off an indestructible nylon nightie in the dark of night on numerous occasions and, no, I wasn't wearing it.

Andy B.
 06 November 2017 12:06 PM
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AJJewsbury

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when the switch is in the neutral line, if i'm correct in thinking this they should have been fitted with non-reversible plugs shouldn't they.

Depends on the particular equipment standard, but probably not. If no live parts are accessible then it's only functional switching so should be just as safe in either pole. Remember that most equipment has single pole switching, yet gets its CE mark for use in countries where the normal domestic plugs & sockets aren't polarised and possibly the mains supply is 230V between two phases (so no "N" as such anyway).

The don't switch N rule really only makes sense where there are 'user serviceable' live parts - e.g. BC and ES lampholders or the old radiant electric fires with exposed elements/connections.

- Andy.
 06 November 2017 05:28 PM
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Paradigm

Posts: 872
Joined: 10 September 2010

Its the blanket

Noticed that I was getting it last night on my side, blanket turned off as I rarely use it. Unplugged it and it stopped, plugged back in and it returned.

Thanks to broadgage for his accurate diagnosis.

Now, can someone explain like I'm five years old, what capacative coupling is, I think I have an idea but am struggling to put it into words and more importantly, is there anyway to stop this happening. Lady Paradigm finds it a bit disconcerting, whereas I am grateful for any tingling I can get nowadays !!

Nick

-------------------------
"be careful of what you write"
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