Electrical fault?

[Ret.]

I have a stainless steel standard lamp in my lounge. It's of the 'mother and child' type - similar, although not identical, to this:

*bc.htmlThetwo lights are controlled by independent rotary dimmer switches.The lamp is now several years old - but is not moved around and only everswitched on and off.Yesterday I noticed when touching the metal frame of the lamp that there wasa sort of 'buzzing' sensation through my fingers. This was very pronouncedif I lightly stroked the metal. This buzzing is still there today. I havecertainly never been aware of this before.I've checked the wiring and the plug and can find no problems although Ihaven't attempted to take the switch 'box' apart.Is this something that I should be concerned about?Kev

[Ret.]

*bc.htmlThe> two lights are controlled by independent rotary dimmer switches.The

The word 'The' seems to have become tacked on to the end of the link. You will need to delete it to get to the web-page!

[ARWadsworth]

*bc.htmlThe> two lights are controlled by independent rotary dimmer switches.The

Do you get the "buzzing" when the lights are off?

[Brian Gaff]

Well I would if it was not there before. certainly many appliances with metal areas and no earth connection can display this effect, but these are normally double insulated and you will merely feel electrostatic effects, but if its a metal lamp and there is a small scuff in the wire internally connecting one side to it then its a danger, and needs looking at.

Brian

[Old Codger]

*bc.htmlThe> two lights are controlled by independent rotary dimmer switches.The lamp

I would say you should be concerned, certainly if the 'buzzing' sensation is continuous whilst you are holding the lamp body. It suggests that the live or neutral wire is shorting to the lamp case and there is no earth.

Being old fashioned I would expect the metal on that lamp to be earthed, in which case the wiring to the plug should have three cores, red, blue and yellow/green which is the earth wire. These days however it may be that the lamp is double insulated. The object is to ensure that a single fault will not make the lamp dangerous, i.e two lots of insulation have to break down or one lot of insulation and the earth becoming disconnected.

If you have access to a meter try measuring the resistance between the metal case of the lamp and each pin on the plug. If there is an earth wire and it is connected, case to the large pin should read zero ohms. Case to either of the other pins should read infinity, or at least greater than 20 megohms, you may need a megger to check the infinity measurement because it may need a high voltage to cause the insulation to break down.

Being really pessimistic it might be a fault within the wall socket or within the house wiring. Easy enough to check but DIY check methods tend to be a bit dangerous so I would not suggest them to someone who is not used to working with electricity.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "ARWadsworth" saying something like:

Only if his missus is feeling frisky.

[NT]

is now several years old - but is not moved around and only everswitched on= and off.Yesterday I noticed when touching the metal frame of the lamp that= there wasa sort of 'buzzing' sensation through my fingers. This was very p= ronouncedif I lightly stroked the metal. This buzzing is still there today.= I havecertainly never been aware of this before.I've checked the wiring an= d the plug and can find no problems although Ihaven't attempted to take the= switch 'box' apart.Is this something that I should be concerned about?Kev

If its very feint, barely feelable when stroking the metal very lightly, thats normal. Anything more and I'd earth the metal lamp, and check the wiring.

NT

[John Rumm]

*bc.htmlThe> two lights are controlled by independent rotary dimmer switches.The lamp

A few options here... so we need more info to narrow it down.

Do you get the sensation with both lamps turned off, (but still plugged in?)

Is is a double insulated appliance (two concentric square logo on it somewhere):

is is plugged into? What earthing system does your house have?

you have access to any test equipment like a multimeter?

[Andrew Gabriel]

and off.Yesterday I noticed when touching the metal frame of the lamp that there wasa sort of 'buzzing' sensation through my fingers. This was very pronouncedif I lightly stroked the metal. This buzzing is still there today. I havecertainly never been aware of this before.I've checked the wiring and the plug and can find no problems although Ihaven't attempted to take the switch 'box' apart.Is this something that I should be concerned about?Kev

Trouble is, it may be barely feelable because you don't have a good ground connection to yourself, but is nevertheless a live connection. One day you do it again whilst leaning against a radiator, and it's curtains.

Should be checked out.

[Ret.]

*bc.htmlThe>> two lights are controlled by independent rotary dimmer switches.The

Yes. Just reached out and touched it and it's still there even though both lights are off.

[Ret.]

LOL!

[Ret.]

One of the dimmer switches failed a couple of years ago. I managed to obtain a replacement double dimmer unit from the manufacturers and replaced it myself. SFAIAA I did the wiring perfectly - and certainly this 'buzzing' has only become apparent in the last couple of days.

I'll dismantle the casing around the switch unit again, however, and give it a check over.

[Ret.]

*bc.htmlThe>> two lights are controlled by independent rotary dimmer switches.The

There is a standard 3-pin plug on the lamp - and the cable is 3-core with the earth correctly wired.

Which it does. I should have made clear that although I am not an electrician, I am competent in domestic wiring and have added extra sockets and spurs etc over my years in the house.

These

OK - but the lamp is earthed in this instance.

I have a basic 'Hilka' digital multimeter. What setting do you suggest I put the dial on to measure the resistance? The options are 200, 2k, 20k, 200k,

2M, 20M.

I did try this last night on a couple of those settings and there was no reading on the meter at all.

I did have the old fuse box replaced with a modern CU a couple of years ago. The electrician who did the swap did check out my electrics thoroughly and gave them a clean bill of health.

The lamp is plugged into a multi-connector (along with my laptop charger, sofa recliner, and telephone charging base. I'll give the multi-connector a check over as well.

[Ret.]

It certainly isn't a 'tingling' - just this sort of buzzing as the metal is lightly stroked. You cannot feel it if you just grip the metal.

[ARWadsworth]

Agreed.

And it certainly is not normal. Touching the lamp whilst sat on a leather setee that is stood on a wooden floor is the lifesaver.

I wonder if there is an earth at the socket. And it's not one of those jobs where you can suggest that the OP tries the lamp in another socket to see if he still gets a tingle (not unless the Mother in Law is around to test it for you)

[Ret.]

*bc.htmlThe>> two lights are controlled by independent rotary dimmer switches.The

Yes.

lamp is plugged into a four socket multi-connector which is, in turn, plugged into a normal double wall socket.

Just checked in the garage and the main earth lead comes out of the side of the main incoming fuse unit - and then into the CU.

The old fuse box was replaced with a modern CU a couple of years ago and the earthing was upgraded then.

[Andy Burns]

Have you got a socket tester, similar to this?

[Ret.]

years ago - he went around all my sockets with one of these and they were all ok.

[Ret.]

This becomes very weird...

I moved the lamp across the room and tried it in another socket - no problem, no 'buzzing'.

So I removed the wall socket the lamp is normally plugged into and checked the wiring - all firm and wired correctly (it's a spur that I put in myself). I then checked the ring-main socket that I had spurred off. Again - all wiring firm and correct.

So I plugged the lamp back into the original socket and - no buzzing. But then I sit down on the sofa, put the laptop back on my knee - reach across to the lamp and... the buzzing is back. So I then put the laptop on the floor - reach across to the lamp and - no buzzing!

So the problem is clearly related to when I have the laptop on my knee!

If I unplug the laptop charger from the laptop and touch the lamp - then no buzzing. Plug the charger back in - and the buzzing is back...

[js.b1]

Does your laptop power adapter have a 2 pin figure-figure-of-8 connector or 3 pin cloverleaf?