Some energy saving bulbs in our house flash with switch off. A hand near the bulb and the effect brightens!?

Question

An outside light we have used to cause a 'trip out' sometimes if it rained. I could find no sign of water ingress, so for safety I put the coach light on a two pole isolator breaker circuit. I also fitted an energy saving bulb. I then began to notice, when isolated, the light would flash on and off, about twice a second, but this decreased in frequency (the event) and eventually stoped.

Then after a gap of some months I noticed the same effect in our hallway, again a neon type bulb. When the switch is in the off position the bulb flashes dimly.

In reaching for the bulb to take it out, and before actually touching it, I was puzzled to find the light continues to flash, but at nearly full brightness. Withdraw the hand and the flashing again becomes very dim.

What is happening? Is this the AC somehow still making a circuit, (with the switch off yet somehow earthing), or is static involved? What is my hand doing to the bulb (or the bulb doing to my hand for that matter)?

'An outside light we have used to cause a 'trip out' sometimes if it rained'. SHOULD READ: An outside light we have, used to cause...(comma ommited) i.e. it wasn't my intention to trip the breaker.

Also please note there is no contact with the bulb from my hand, and no electric shock, hence no circuit or grounding through me.

Answer 1

Sorry but I dont know. Some of my bulbs do the same thing, I think it is quite eerie

Answer 2

A few months ago, my parents said their energy saving light bulb came on during the night for no apparent reason. I did not believe them, and got the electrician to check out all the wiring. After some time, it was found out that static electricity from our carpets was somehow causing an electric charge through the wiring and lighting up the bulb. As I am still studying this phenomena, I can not give a full explanation. However, someone may already have solved it. All I can say for sure is that is does happen.

Answer 3

Well mike, that is a very interesting question. Actually it is a multitude of questions (Too bad I cant vote for your question yet). Let me see if I can help you understand some of these phenomenon...

(You might want to refer to the attached link to know how these lamps work: It is pretty similar to the way a flourescent tube aka incandescent tube works)

This could be caused by a multitude of causes:
1. There is a leakage of earthing
2. your switch is placed on the wrong wire: normally the switch in an AC circuit should be placed on the "Live" wire, so that when it is off, there is no charge flowing to the lamp. If, however, the switch is on the Neutral side, there is a permanent pseudo-circuit with the earthing that could, in fact, contribute to point 1 above.
3. As you will also learn from the link I have given, the lamp works somewhat like a "Halogen Tube", depending on charged gas particles to produce light. the static from the environment like carpets etc. (As suggested by Dr. David here), could be causing the glow. This glow will particularly heighten during the wet season because charge carries longer distances and denser as the moisture in the air increases (Remember lightning?)

Now that we have some answers for the glow wihthout switching on the lamp, let us try to tackle the interaction of your body and the lamp:
What you are witnessing here is something that the electronics industry loses it's sleep about: It is called Electro-Static Discharge. unknown to us, we carry around a huge static charge in our bodies, which could be further heightened by environmental factors like humidity, floor carpets etc. As you approach the lamp, this static produces an "Induction" in the lamp, charging the gas particles in the lamp with a polarity opposite to the one on your finger-tips (Google for: "Induction" and "Point of Charge Principal" for electrostatic discharges). this charge causes atomic turbulence in these gasses, causing the lamp to glow brighter.
Why is this a pain to the electronic industry? Well, these charges, when relesed from the humans handling sensitive circuits, cause the Surface mounted Capacitors, resistors etc. to burn out!! that is the reason, if you go to a professional to get your motherboard repaired, you will see a (normally) green colored rubber mat on their desk. This green mat is metallized to conduct charge and then connected to an effective earth, so that all such ESD is grounded while the sensitive circuits are being handled. Similarly there is a huge range of ESD Products available for hobby and industrial use (refer the second link here for one such manufacturer)
Disclaimer: I do not know/solicit the manufacturer: it is just a site I found while googling around.

Answer 4

It would appear that based on the information that you have supplied, that there is a minor short in the circuit.
This would also explain as to why on nearing the bulb with ones hand there is a slight charging effect. See article on gold leaf.

Hope this helps - Albert

Answer 5

It would appear that you have what is called "crossed polarity" on your wiring. Which means that the switch to this lamp is in the neutral conductor, and the lamp (or all lamps) still has/have a live feed to it/them. Your hand is allowing the circuit to become slightly better, hence the lamp brightens. You don't actually have to touch the bulb.Should be checked out.

Answer 6

Lights must not flash when they are off maybe there is an electrical fault it will be wise to a regerstered good electrician check it i would not play around with electrical apparatus you may never know what will cause a fire. Stay safe and have peace of mind call thge professionals.

Answer 7

interesting, my light on the landing also flashes when switched off, I don't know why.

Answer 8

Your hand is actually a ground

Answer 9

That is an optical delusion. If you make poon tang it may go away.

Answer 10

my mum had this too, we never discovered why.....so l look with interest