is it possible that a device or activity, that is NOT physically
connected to the power supply, can cause flickering of main lights and
table lamps within a domestic home.

Yes. Certainly.

This is just an example of electrical interference.

Yes it is just as he said, its electrical interference, thats why you
must shut off all electronics during takeoff on a plane so as to not
cause any electrical interference

Almost anything is possible, but my first thoughts were improbable and
unlikely. Since probono is usually correct I reconsidered. A microwave
pulse transmitter, powered by a car battery or bigger battery with a
high gain antenna aimed at your house: Perhaps 2 to 200 random pulses
pulses per minute, would cause a slight flicker of your lights,
perhaps a moderate flicker at an optimum carrier frequency. Florescent
lights and likely the new spiral floresent lights would be more
inclined to flicker than ordinary bulbs. A defect in your wiring could
enhance the flickering. The electro magnetic feild would need to
exceed the level safe for humans, and the activity would be illegal,
but someone could be doing this.   Neil

Does your neighbor have a Tesla coil.

Is it continuous or intermittent?

If intermittent, can you correlate it to some other component that you are using?

Before assuming some evil force at work, explore the more mundane.

Is your domestic home a stand-alone or are there neighbours sharing
the same electrical circuits? Or in adjoining apartments?

Are any of your domestic appliances playing up?

Evilmrfrank-GA
Thanks for that mate.
steve.

Nielzero-GA
Intrigued by your first thoughts and alarmed by your comment Niel.What
would you recomend be done to establish as to whether or not what you
describe is the case. Incidentaly, the rate of flickering dose
resemble a pulse and is between seventy and eighty per minute.
 Steve.

probonopublico-GA
There is a background flicker that fades in and out but will develop
into a stronger pulse like flicker almost as if switched and this
happens mainly in the early evening into the early hours.I have been
unable to link this to any appliance etc in the house. Our power
supply is via a pole in the road which supplies all my near
neighbours.I have had this investigatd by the supplier who tells me I
am now on my own phase and this should stop the problem, which it did
not. I am fairly happy that the problem is probably not of supply. In
the last year we have replaced a fridge,tumble dryer,computer monitor,
TV and inumerable light bulbs. Steve.

Redhoss-GA
 I have no idea, how would you say such a device could be causing the problem.
Would someone with a desire to use one of these be unaware of any
potential damage or nuisance effects that they may generate.
 Steve.

Early evening to the early hours ...

This suggests a neighbour's tv set.

Or maybe he's a ham radio operator?

Or a computer buff?

probonopublico-GA
I have not concidered these as possible causes,can any of them cause the problem?.

Any electrical device that is nearby can cause interference if it has
not been shielded properly or if its shielding has broken down or if
it's malfunctioning in some way.

If your neighbour(s) is/are friendly, you might ask them to oblige by
closing everything down for a while, to see if that has any effect.

Alternatively, if there are occasions when the problem doesn't
manifest itself, it may be related to a neighbour's absence.

Good luck in your investigations!

Probonopublico-GA.
  It would be a great relief to resolve this mystery within the area
of your first observation.

 
   Thank you for your thoughts, Steve.

Hi, Steve

The issue is known as 'Electromagnetic Compatibility' or EMC.

Here's a site that has some stuff which may or may not be helpful:

http://www.fda.gov/cdrh/emc/

I do hope that solve it ... it must be driving you mad!

All the Best

Bryan

probonopublico-ga.

Thanks bryan, I shall have a good sniff around this site and subject.

Your dead right, it is driving me mad not to say uneasy. 

Again, thanks for your help.

Steve.

is it all of your lights or just some, are they fluorescent or
incandescent, fluorescent will flicker for various resons, does any
thing else "flicker" appliances (tv, radio, or fridge etc) you may
just have some bad wiring, maybe copper wires connected to aluminum
wires (possible fire hazzard). more info is needed so we can eliminate
UFO's, cell phone towers, or the illeagle activites of your
neighbours.