Flashing bathroom light - whilst switched off!
 

"GB" wrote in message
...
Flashing bathroom light - whilst switched off!

This is 2 yrs after a complete rebuild. Recently, the bathroom light has
started to flash whilst switched off. It flashes very briefly once or
twice a second. It's a fluorescent 2D fitting, two wires, no earth.

I suspect one of three reasons:
a) Problem with the switch that allows a small amount of current through.
Seems unlikely. The switch looks fine, and the light switches on and off
okay.
b) Water ingress into the fitting. But this looks fine. No sign of water
damage. And, in any case, it's switched off, so it should have no live
feed. (Yes, I know that live and neutral sometimes get muddled up, but
even so where's current going to without an earth?)
c) Water ingress into the wiring somewhere where I can't see it. This is
in a flat, so $deity knows what the person in the flat upstairs lets
overflow.

Pull the fuse/turn the mcb off and see what happens.
Strong electric fields can cause a fluorescent tube to light up.
HV cables nearby. Source of micrwave energy.

Flashing bathroom light - whilst switched off!
 

Flashing bathroom light - whilst switched off!

This is 2 yrs after a complete rebuild. Recently, the bathroom light has
started to flash whilst switched off. It flashes very briefly once or
twice a second. It's a fluorescent 2D fitting, two wires, no earth.

I suspect one of three reasons:
a) Problem with the switch that allows a small amount of current
through. Seems unlikely. The switch looks fine, and the light switches
on and off okay.
b) Water ingress into the fitting. But this looks fine. No sign of water
damage. And, in any case, it's switched off, so it should have no live
feed. (Yes, I know that live and neutral sometimes get muddled up, but
even so where's current going to without an earth?)
c) Water ingress into the wiring somewhere where I can't see it. This is
in a flat, so $deity knows what the person in the flat upstairs lets
overflow.

Any help would be appreciated.

Flashing bathroom light - whilst switched off!
 

On 29/05/2015 17:06, GB wrote:
Flashing bathroom light - whilst switched off!

This is 2 yrs after a complete rebuild. Recently, the bathroom light has
started to flash whilst switched off. It flashes very briefly once or
twice a second. It's a fluorescent 2D fitting, two wires, no earth.

I suspect one of three reasons:
a) Problem with the switch that allows a small amount of current
through. Seems unlikely. The switch looks fine, and the light switches
on and off okay.
b) Water ingress into the fitting. But this looks fine. No sign of water
damage. And, in any case, it's switched off, so it should have no live
feed. (Yes, I know that live and neutral sometimes get muddled up, but
even so where's current going to without an earth?)
c) Water ingress into the wiring somewhere where I can't see it. This is
in a flat, so $deity knows what the person in the flat upstairs lets
overflow.

Any help would be appreciated.

Does it flash if removed from the socket but taped next to it? Do you
have a radar rotating nearby? Is your neighbour a radio amateur?

Cheers
--
Syd

Flashing bathroom light - whilst switched off!
 

"GB" wrote in message
...
Flashing bathroom light - whilst switched off!

This is 2 yrs after a complete rebuild. Recently, the bathroom light has
started to flash whilst switched off. It flashes very briefly once or
twice a second. It's a fluorescent 2D fitting, two wires, no earth.

I suspect one of three reasons:
a) Problem with the switch that allows a small amount of current through.
Seems unlikely. The switch looks fine, and the light switches on and off
okay.
b) Water ingress into the fitting. But this looks fine. No sign of water
damage. And, in any case, it's switched off, so it should have no live
feed. (Yes, I know that live and neutral sometimes get muddled up, but
even so where's current going to without an earth?)
c) Water ingress into the wiring somewhere where I can't see it. This is
in a flat, so $deity knows what the person in the flat upstairs lets
overflow.

Any help would be appreciated.


None of the 3 reasons sound likely:-)

Not many 2D light fittings do not require an earth - can you give a make and
model no?

Is there an extractor fan in the bathroom?

--
Adam

Flashing bathroom light - whilst switched off!
 

On Fri, 29 May 2015 17:06:15 +0100, GB
wrote:

Flashing bathroom light - whilst switched off!

This is 2 yrs after a complete rebuild. Recently, the bathroom light has
started to flash whilst switched off. It flashes very briefly once or
twice a second. It's a fluorescent 2D fitting, two wires, no earth.

I suspect one of three reasons:
a) Problem with the switch that allows a small amount of current
through. Seems unlikely. The switch looks fine, and the light switches
on and off okay.
b) Water ingress into the fitting. But this looks fine. No sign of water
damage. And, in any case, it's switched off, so it should have no live
feed. (Yes, I know that live and neutral sometimes get muddled up, but
even so where's current going to without an earth?)
c) Water ingress into the wiring somewhere where I can't see it. This is
in a flat, so $deity knows what the person in the flat upstairs lets
overflow.

Any help would be appreciated.




it's actually a common well understood phenomenon, caused by the
capacitance in the order of a few hundred picofarads of the cable run
to the switch.

What is needed is a high value resistor across the lamp to quench the
voltage induced when the switch is off.

You may well find that changing the 2D lamp for a different brand will
cure it.


--

Graham.

%Profound_observation%

Flashing bathroom light - whilst switched off!
 

On 29/05/2015 18:41, ARW wrote:
"GB" wrote in message
...
Flashing bathroom light - whilst switched off!

This is 2 yrs after a complete rebuild. Recently, the bathroom light
has started to flash whilst switched off. It flashes very briefly once
or twice a second. It's a fluorescent 2D fitting, two wires, no earth.

I suspect one of three reasons:
a) Problem with the switch that allows a small amount of current
through. Seems unlikely. The switch looks fine, and the light switches
on and off okay.
b) Water ingress into the fitting. But this looks fine. No sign of
water damage. And, in any case, it's switched off, so it should have
no live feed. (Yes, I know that live and neutral sometimes get muddled
up, but even so where's current going to without an earth?)
c) Water ingress into the wiring somewhere where I can't see it. This
is in a flat, so $deity knows what the person in the flat upstairs
lets overflow.

Any help would be appreciated.


None of the 3 reasons sound likely:-)

Not many 2D light fittings do not require an earth - can you give a make
and model no?

Sadly, I did not write it down. However, there were three wires coming
into the lamp. Live and neutral were appropriately terminated, and the
earth was just loose inside the fitting. I did not take it down and look
what was behind it. I could not reach. I'll have to get a small steps to
go in the car.


The girl in the upstairs flat keeps rabbits. I can't imagine that she
has a radar set up there!


Is there an extractor fan in the bathroom?


There is an extractor fan - in the basement. It's a centralised system,
and I think it's timed, rather than humidistat. There were two wires to
into each terminal of the light switch, so I assume one set connects to
the extractor system.

Flashing bathroom light - whilst switched off!
 

"Graham." wrote in message
...
On Fri, 29 May 2015 17:06:15 +0100, GB
wrote:

Flashing bathroom light - whilst switched off!

This is 2 yrs after a complete rebuild. Recently, the bathroom light has
started to flash whilst switched off. It flashes very briefly once or
twice a second. It's a fluorescent 2D fitting, two wires, no earth.

I suspect one of three reasons:
a) Problem with the switch that allows a small amount of current
through. Seems unlikely. The switch looks fine, and the light switches
on and off okay.
b) Water ingress into the fitting. But this looks fine. No sign of water
damage. And, in any case, it's switched off, so it should have no live
feed. (Yes, I know that live and neutral sometimes get muddled up, but
even so where's current going to without an earth?)
c) Water ingress into the wiring somewhere where I can't see it. This is
in a flat, so $deity knows what the person in the flat upstairs lets
overflow.

Any help would be appreciated.




it's actually a common well understood phenomenon, caused by the
capacitance in the order of a few hundred picofarads of the cable run
to the switch.

What is needed is a high value resistor across the lamp to quench the
voltage induced when the switch is off.

You may well find that changing the 2D lamp for a different brand will
cure it.


It is not a problem I have never come across on 2D fittings (although that
does not mean it does not exist). It is a well known problem for CFLs and
LEDs with integral circuitry built into the lamp.

You should not use a resistor but a snubber (a resistor in series with a
capacitor) to cure the CFL and LED flashing problem..



--
Adam

Flashing bathroom light - whilst switched off!
 

On Friday, 29 May 2015 18:43:57 UTC+1, Graham. wrote:
On Fri, 29 May 2015 17:06:15 +0100, GB
wrote:

Flashing bathroom light - whilst switched off!

This is 2 yrs after a complete rebuild. Recently, the bathroom light has
started to flash whilst switched off. It flashes very briefly once or
twice a second. It's a fluorescent 2D fitting, two wires, no earth.

I suspect one of three reasons:
a) Problem with the switch that allows a small amount of current
through. Seems unlikely. The switch looks fine, and the light switches
on and off okay.
b) Water ingress into the fitting. But this looks fine. No sign of water
damage. And, in any case, it's switched off, so it should have no live
feed. (Yes, I know that live and neutral sometimes get muddled up, but
even so where's current going to without an earth?)
c) Water ingress into the wiring somewhere where I can't see it. This is
in a flat, so $deity knows what the person in the flat upstairs lets
overflow.

Any help would be appreciated.




it's actually a common well understood phenomenon, caused by the
capacitance in the order of a few hundred picofarads of the cable run
to the switch.

What is needed is a high value resistor across the lamp to quench the
voltage induced when the switch is off.

+1, or a capacitor. Either way make sure its properly mains rated.
http://wiki.diyfaq.org.uk/index.php?title=CFL
http://wiki.diyfaq.org.uk/index.php?title=Snubber


NT

Flashing bathroom light - whilst switched off!
 

On Fri, 29 May 2015 17:06:15 +0100
GB wrote:

Flashing bathroom light - whilst switched off!

This is 2 yrs after a complete rebuild. Recently, the bathroom light
has started to flash whilst switched off. It flashes very briefly
once or twice a second. It's a fluorescent 2D fitting, two wires, no
earth.

I suspect one of three reasons:
a) Problem with the switch that allows a small amount of current
through. Seems unlikely. The switch looks fine, and the light
switches on and off okay.
b) Water ingress into the fitting. But this looks fine. No sign of
water damage. And, in any case, it's switched off, so it should have
no live feed. (Yes, I know that live and neutral sometimes get
muddled up, but even so where's current going to without an earth?)
c) Water ingress into the wiring somewhere where I can't see it. This
is in a flat, so $deity knows what the person in the flat upstairs
lets overflow.

Any help would be appreciated.





It's a poltergeist. My mother-in-law had one, it would randomly turn
her bedroom light on at night. It never harmed her.

--
Davey.

Flashing bathroom light - whilst switched off!
 

I'd still suspect something bridging the switch. It would not need much.
Take the switch off then test it and see if it flashes.

I've seen this with these fangled electronic ballasts before.
Really irritating.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"harryagain" wrote in message
...

"GB" wrote in message
...
Flashing bathroom light - whilst switched off!

This is 2 yrs after a complete rebuild. Recently, the bathroom light has
started to flash whilst switched off. It flashes very briefly once or
twice a second. It's a fluorescent 2D fitting, two wires, no earth.

I suspect one of three reasons:
a) Problem with the switch that allows a small amount of current through.
Seems unlikely. The switch looks fine, and the light switches on and off
okay.
b) Water ingress into the fitting. But this looks fine. No sign of water
damage. And, in any case, it's switched off, so it should have no live
feed. (Yes, I know that live and neutral sometimes get muddled up, but
even so where's current going to without an earth?)
c) Water ingress into the wiring somewhere where I can't see it. This is
in a flat, so $deity knows what the person in the flat upstairs lets
overflow.

Pull the fuse/turn the mcb off and see what happens.
Strong electric fields can cause a fluorescent tube to light up.
HV cables nearby. Source of micrwave energy.

Flashing bathroom light - whilst switched off!
 

If there is enough rf energy to do this then something is very wrong indeed
I'd suggest!

Brian

--
From the Sofa of Brian Gaff Reply address is active
"Syd Rumpo" wrote in message
...
On 29/05/2015 17:06, GB wrote:
Flashing bathroom light - whilst switched off!

This is 2 yrs after a complete rebuild. Recently, the bathroom light has
started to flash whilst switched off. It flashes very briefly once or
twice a second. It's a fluorescent 2D fitting, two wires, no earth.

I suspect one of three reasons:
a) Problem with the switch that allows a small amount of current
through. Seems unlikely. The switch looks fine, and the light switches
on and off okay.
b) Water ingress into the fitting. But this looks fine. No sign of water
damage. And, in any case, it's switched off, so it should have no live
feed. (Yes, I know that live and neutral sometimes get muddled up, but
even so where's current going to without an earth?)
c) Water ingress into the wiring somewhere where I can't see it. This is
in a flat, so $deity knows what the person in the flat upstairs lets
overflow.

Any help would be appreciated.

Does it flash if removed from the socket but taped next to it? Do you
have a radar rotating nearby? Is your neighbour a radio amateur?

Cheers
--
Syd

Flashing bathroom light - whilst switched off!
 

No sorry don't believe that. it is probably that there really is an earth.
Did not say what sort of switch this was. We have ours outside the room and
it has been known for there to be a slight leak from one conductor to the
earth point on the metal box in the wall when the switch was screwed don.
Enough to occasionally pop the breaker and to make the light appear to be
on very dimly with occasional bright flashes. This was some years ago and
some sleaving cured the problem, however I'm still suspicious of a switch
leak.

Got a High impedance metar?
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Davey" wrote in message
...
On Fri, 29 May 2015 17:06:15 +0100
GB wrote:

Flashing bathroom light - whilst switched off!

This is 2 yrs after a complete rebuild. Recently, the bathroom light
has started to flash whilst switched off. It flashes very briefly
once or twice a second. It's a fluorescent 2D fitting, two wires, no
earth.

I suspect one of three reasons:
a) Problem with the switch that allows a small amount of current
through. Seems unlikely. The switch looks fine, and the light
switches on and off okay.
b) Water ingress into the fitting. But this looks fine. No sign of
water damage. And, in any case, it's switched off, so it should have
no live feed. (Yes, I know that live and neutral sometimes get
muddled up, but even so where's current going to without an earth?)
c) Water ingress into the wiring somewhere where I can't see it. This
is in a flat, so $deity knows what the person in the flat upstairs
lets overflow.

Any help would be appreciated.





It's a poltergeist. My mother-in-law had one, it would randomly turn
her bedroom light on at night. It never harmed her.

--
Davey.

Flashing bathroom light - whilst switched off!
 

On 30/05/15 10:03, Brian-Gaff wrote:
I'd still suspect something bridging the switch. It would not need much.
Take the switch off then test it and see if it flashes.

I've seen this with these fangled electronic ballasts before.
Really irritating.
Brian



Its normal on almost all installations. Wiring coupling allows small
amounts of charge to be picked up by 'isolated' wiring and eventually
there is enough charge in the reservoir capacitors to energise the unit
- for a tiny period.

Solution is a large value resistor across the live-neutral near the unit.



--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.

Flashing bathroom light - whilst switched off!
 

On 30/05/2015 10:12, Brian-Gaff wrote:
No sorry don't believe that. it is probably that there really is an earth.
Did not say what sort of switch this was. We have ours outside the room and
it has been known for there to be a slight leak from one conductor to the
earth point on the metal box in the wall when the switch was screwed don.
Enough to occasionally pop the breaker and to make the light appear to be
on very dimly with occasional bright flashes. This was some years ago and
some sleaving cured the problem, however I'm still suspicious of a switch
leak.

Got a High impedance metar?
Brian


No, I have a cheapo electronic meter in my toolbox, and an Avometer,
which is nearly 50 years old. :)

The person whose light this is swears blind that her electricity bill
has gone up dramatically since this started flashing. I don't believe her.

I'll change the switch and see if that helps at all.

Flashing bathroom light - whilst switched off!
 

On Sat, 30 May 2015 11:40:27 +0100
GB wrote:

No, I have a cheapo electronic meter in my toolbox, and an Avometer,
which is nearly 50 years old. :)

One of those was up for auction recently. I remember them from my
schooldays.

--
Davey.

Flashing bathroom light - whilst switched off!
 

On Sat, 30 May 2015 12:40:38 +0100, Davey wrote:

On Sat, 30 May 2015 11:40:27 +0100 GB wrote:

No, I have a cheapo electronic meter in my toolbox, and an Avometer,
which is nearly 50 years old. :)

One of those was up for auction recently. I remember them from my
schooldays.

I have three or four...!

Flashing bathroom light - whilst switched off!
 

On 30 May 2015 13:19:06 GMT
Bob Eager wrote:

On Sat, 30 May 2015 12:40:38 +0100, Davey wrote:

On Sat, 30 May 2015 11:40:27 +0100 GB
wrote:

No, I have a cheapo electronic meter in my toolbox, and an
Avometer, which is nearly 50 years old. :)

One of those was up for auction recently. I remember them from my
schooldays.

I have three or four...!

Hang on to them, they might be worth real money.

--
Davey.

Flashing bathroom light - whilst switched off!
 

On 30/05/2015 14:43, Davey wrote:

Hang on to them, they might be worth real money.


I guess as the generation of engineers that used AVOs die the price of
those still in existence will fall through the floor. Their offspring
will consign them to landfill during the house clearance. The only
models that may be worth money will be those that survive for another 50
to 100 years, and then just because of their rarity value.

--
mailto: news {at} admac {dot] myzen {dot} co {dot} uk

Flashing bathroom light - whilst switched off!
 

"Brian-Gaff" wrote in message
...
If there is enough rf energy to do this then something is very wrong
indeed I'd suggest!

Brian

Fluorescent tubes may light up if held in the vertical position under HV
power lines.
Video of it here. (Not much help to you I know).
https://www.youtube.com/watch?v=tRLNNrHg2QE

Flashing bathroom light - whilst switched off!
 

"alan_m" wrote in message
...
On 30/05/2015 14:43, Davey wrote:

Hang on to them, they might be worth real money.


I guess as the generation of engineers that used AVOs die the price of
those still in existence will fall through the floor.

Doesn’t work like that with cars, sewing machines, ancient machinery.

Their offspring will consign them to landfill during the house clearance.

That happens with that other stuff too.

The only models that may be worth money will be those that survive for
another 50 to 100 years, and then just because of their rarity value.

That is always the case with anything that has any real value.

Flashing bathroom light - whilst switched off!
 

On Sat, 30 May 2015 22:12:13 +0000, Huge wrote:

On 2015-05-30, Bob Eager wrote:
On Sat, 30 May 2015 12:40:38 +0100, Davey wrote:

On Sat, 30 May 2015 11:40:27 +0100 GB
wrote:

No, I have a cheapo electronic meter in my toolbox, and an Avometer,
which is nearly 50 years old. :)

One of those was up for auction recently. I remember them from my
schooldays.

I have three or four...!

I saw one in an antique shop, recently. A Mk8 for £40, IIRC.

I have a mint condition one from 2005.

Flashing bathroom light - whilst switched off!
 

On Sat, 30 May 2015 21:33:01 +0100
"harryagain" wrote:


"Brian-Gaff" wrote in message
...
If there is enough rf energy to do this then something is very
wrong indeed I'd suggest!

Brian

Fluorescent tubes may light up if held in the vertical position under
HV power lines.
Video of it here. (Not much help to you I know).
https://www.youtube.com/watch?v=tRLNNrHg2QE



I can confirm that from personal experience, although I don't know what
the voltage was. All you had to do was stand under the power lines
holding one end of a tube, and it would glow. I let somebody else do it
first, before trying it myself!

--
Davey.