Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

Thanks

PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

Thanks

Populated or not should make no difference - check plugs/pins/fuse not
getting hot.
Does your CU have an RCD fitted? if so and it is working (use the test
button to check) possibly not too much to worry about but worth
investigating.
If not and you suspect dampness, then I suspect the moisture is building
up where it should not and then vapourising as steam and making the noise.
Isolate the power to that ring or preferably turn off at the CU and
investigate.

In article ,
PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

Is it on an outside wall? Could damp be getting to it?

--
*I'm reading a book about anti-gravity. I just can't put it down.*

Dave Plowman London SW
To e-mail, change noise into sound.

On 03/01/14 14:51, PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

electrocuted mice?
Or arcing.

Thanks


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

On 03/01/2014 15:01, Bob Minchin wrote:
PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

Thanks

Populated or not should make no difference - check plugs/pins/fuse not
getting hot.

No, no heat detected

Does your CU have an RCD fitted? if so and it is working (use the test
button to check) possibly not too much to worry about but worth
investigating.

Yes, RCD is fitted and testing fine

If not and you suspect dampness, then I suspect the moisture is building
up where it should not and then vapourising as steam and making the noise.
Isolate the power to that ring or preferably turn off at the CU and
investigate.

This is an internal partition wall with no likelihood of dampness.

The fact that nothing trips at the CU is re-assuring but it just seems
like such an odd thing to be happening. Is there any possibility it's
related to lightning strikes?

The Natural Philosopher wrote in news:la6kon$foo$1
@news.albasani.net:

On 03/01/14 14:51, PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

electrocuted mice?
Or arcing.

Thanks



Unplug the heaviest rated appliance and plug it in elsewhere. see what
happens

--

DerbyBorn

The Natural Philosopher wrote in news:la6kon$foo$1
@news.albasani.net:

On 03/01/14 14:51, PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

electrocuted mice?
Or arcing.

Thanks



Unplug the heaviest rated appliance and plug it in elsewhere. see what
happens

--

DerbyBorn

On Friday, 3 January 2014 14:51:05 UTC, PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

Just possibly, temperature changes due to the local climate may make the faceplate, for example, change in size with respect to what it is screwed to. If the screws are just at the right tightness, stress might build up and release (stiction) occasionally. Alter the tightness of everything as a test, preferably without electrocuting anybody.

Also, check the bottom inside for such as electro-cremated ants.

--
SL

PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from
a populated double socket. It's happened at most once or twice a day
and is possibly coincident with the bad weather we've been having. There
is no tripping of breakers at the CU.

Does anyone know what it could possibly be?

Probably a loose cable arcing inside the socket.
Isolate it from the mains, remove faceplate screws and check all
connections - it's highly likely the live will have some signs of burning -
clean all blackened copper before re securing in the terminals

"PeterL" wrote in message
...
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and is
possibly coincident with the bad weather we've been having. There is no
tripping of breakers at the CU.

Does anyone know what it could possibly be?

Thanks

Probably a loose connection (popping is an electric arc.)

Needs immediate attention.

On Fri, 03 Jan 2014 14:51:05 +0000, PeterL wrote:

Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

Some nice alternatives have been presented but I'd go for a loose
termination and vibration causing something to arc. Remember on a
ring the ring current flows through the terminals even if there is
nothing plugged into that particular socket.

Switch off, remove the offending socket and check all the wires are
firm in their terminals and then check all the terminal screws are
tight. In fact think I'd actually remove the wires and check them for
damage (arcing will leave marks) and remove any damaged bits and
reterminate.

--
Cheers
Dave.

PeterL wrote:
On 03/01/2014 15:01, Bob Minchin wrote:
PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

Thanks

Populated or not should make no difference - check plugs/pins/fuse not
getting hot.

No, no heat detected

Does your CU have an RCD fitted? if so and it is working (use the test
button to check) possibly not too much to worry about but worth
investigating.

Yes, RCD is fitted and testing fine

If not and you suspect dampness, then I suspect the moisture is building
up where it should not and then vapourising as steam and making the
noise.
Isolate the power to that ring or preferably turn off at the CU and
investigate.

This is an internal partition wall with no likelihood of dampness.

The fact that nothing trips at the CU is re-assuring but it just seems
like such an odd thing to be happening. Is there any possibility it's
related to lightning strikes?

OK with no heat, no damp and no RCD trips, I don't think you have
anything to worry about from a safety point of view.
It is difficult (for me) to think of a lightning related cause either.

Any rodent activity? Clutching at straws here.....

In article ,
PeterL writes:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

In addition to the other comments, if it's got a surge suppressor in
it, it could be that absorbing energy, which for some types causes
part of the component to explode away as it absorbs the excess energy
to try and clamp the voltage. Any lights flickering at the same time
(most noticable from filament lamps)?

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 03/01/2014 16:00, Phil L wrote:
PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from
a populated double socket. It's happened at most once or twice a day
and is possibly coincident with the bad weather we've been having. There
is no tripping of breakers at the CU.

Does anyone know what it could possibly be?

Probably a loose cable arcing inside the socket.
Isolate it from the mains, remove faceplate screws and check all
connections - it's highly likely the live will have some signs of burning -
clean all blackened copper before re securing in the terminals


Wouldn't that trip the RCD though?


--
Dave - The Medway Handyman www.medwayhandyman.co.uk

On Fri, 03 Jan 2014 18:13:59 +0000, The Medway Handyman wrote:

Probably a loose cable arcing inside the socket. Isolate it from
the

Wouldn't that trip the RCD though?

Why would it? There is no current imbalance between L & N that is
required to trip an RCD and the current flowing is that being taken
by the combined loads on that ring, so the MCB won't object either.

All that will happen is the arcing will produce localised heating,
oxidise the copper, increase the resistance, more losses, gets
hotter, may start a fire ... or just go open circuit meaning the ring
is no longer a ring and depending on the loads on it one half may
become overloaded.

--
Cheers
Dave.

On 03/01/2014 18:37, Dave Liquorice wrote:
On Fri, 03 Jan 2014 18:13:59 +0000, The Medway Handyman wrote:

Probably a loose cable arcing inside the socket. Isolate it from
the

Wouldn't that trip the RCD though?

Why would it?

I don't know, that's why I was asking :-)

There is no current imbalance between L & N that is
required to trip an RCD and the current flowing is that being taken
by the combined loads on that ring, so the MCB won't object either.

All that will happen is the arcing will produce localised heating,
oxidise the copper, increase the resistance, more losses, gets
hotter, may start a fire ... or just go open circuit meaning the ring
is no longer a ring and depending on the loads on it one half may
become overloaded.



--
Dave - The Medway Handyman www.medwayhandyman.co.uk

In message , The Medway Handyman
writes
On 03/01/2014 16:00, Phil L wrote:
PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from
a populated double socket. It's happened at most once or twice a day
and is possibly coincident with the bad weather we've been having. There
is no tripping of breakers at the CU.

Does anyone know what it could possibly be?

Probably a loose cable arcing inside the socket.
Isolate it from the mains, remove faceplate screws and check all
connections - it's highly likely the live will have some signs of burning -
clean all blackened copper before re securing in the terminals


Wouldn't that trip the RCD though?


Not unless it was arcing to earth.
--
bert

Is this with things running or not?
Brian

--
From the Sofa of Brian Gaff Reply address is active
"PeterL" wrote in message
...
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and is
possibly coincident with the bad weather we've been having. There is no
tripping of breakers at the CU.

Does anyone know what it could possibly be?

Thanks

Older sockets which have at one time overheated can leave a bit of
carbonised residue, and getting this damp can give the sounds mentioned. It
used to happen in my shed. However, in a house this surely is not good,
where would the dampness come from?
If it is an old socket though its worth a look for a tell tale burn or
looseness inside and replacing the socket.
Smoking guns are pretty obvious!

Brian

--
From the Sofa of Brian Gaff Reply address is active
"Bob Minchin" wrote in message
...
PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

Thanks

Populated or not should make no difference - check plugs/pins/fuse not
getting hot.
Does your CU have an RCD fitted? if so and it is working (use the test
button to check) possibly not too much to worry about but worth
investigating.
If not and you suspect dampness, then I suspect the moisture is building
up where it should not and then vapourising as steam and making the noise.
Isolate the power to that ring or preferably turn off at the CU and
investigate.

Lightning strikes, well I've heard things like that when there is a high
static build up, but normally things start to trip, and the fact yours is
not is a little worrying. I have also come across those multi way trailing
adaptors that make sounds, but this was normally tracked down to an arcing
buss bar in the block not completely connecting to the actual socket piece,
it had got bent.
This is why i asked if the things plugged in were actually turned on, as
some devices still have a capacitor across the mains when off.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"PeterL" wrote in message
...
On 03/01/2014 15:01, Bob Minchin wrote:
PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

Thanks

Populated or not should make no difference - check plugs/pins/fuse not
getting hot.

No, no heat detected

Does your CU have an RCD fitted? if so and it is working (use the test
button to check) possibly not too much to worry about but worth
investigating.

Yes, RCD is fitted and testing fine

If not and you suspect dampness, then I suspect the moisture is building
up where it should not and then vapourising as steam and making the
noise.
Isolate the power to that ring or preferably turn off at the CU and
investigate.

This is an internal partition wall with no likelihood of dampness.

The fact that nothing trips at the CU is re-assuring but it just seems
like such an odd thing to be happening. Is there any possibility it's
related to lightning strikes?

Frying dead spiders?
grin.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Bob Minchin" wrote in message
...
PeterL wrote:
On 03/01/2014 15:01, Bob Minchin wrote:
PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There
is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

Thanks

Populated or not should make no difference - check plugs/pins/fuse not
getting hot.

No, no heat detected

Does your CU have an RCD fitted? if so and it is working (use the test
button to check) possibly not too much to worry about but worth
investigating.

Yes, RCD is fitted and testing fine

If not and you suspect dampness, then I suspect the moisture is building
up where it should not and then vapourising as steam and making the
noise.
Isolate the power to that ring or preferably turn off at the CU and
investigate.

This is an internal partition wall with no likelihood of dampness.

The fact that nothing trips at the CU is re-assuring but it just seems
like such an odd thing to be happening. Is there any possibility it's
related to lightning strikes?

OK with no heat, no damp and no RCD trips, I don't think you have anything
to worry about from a safety point of view.
It is difficult (for me) to think of a lightning related cause either.

Any rodent activity? Clutching at straws here.....

Yes got a portable radio with medium wave. Put it near the socket in a blank
bit of the band and see if you can induce the popping. If wiggling things
gives any interference, get in there and make sure all the screws are tight
and there is not any sign of heating up.
Erm, turn the ring off before taking the socket off, we don't want to
lose any readers.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"The Natural Philosopher" wrote in message
...
On 03/01/14 14:51, PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.

Does anyone know what it could possibly be?

electrocuted mice?
Or arcing.

Thanks


--
Ineptocracy

(in-ep-toc'-ra-cy) - a system of government where the least capable to
lead are elected by the least capable of producing, and where the members
of society least likely to sustain themselves or succeed, are rewarded
with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

It will only do it on some loads I think. After all its just switching the
load on and off fast.

Brian

--
From the Sofa of Brian Gaff Reply address is active
"The Medway Handyman" wrote in message
...
On 03/01/2014 16:00, Phil L wrote:
PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from
a populated double socket. It's happened at most once or twice a day
and is possibly coincident with the bad weather we've been having. There
is no tripping of breakers at the CU.

Does anyone know what it could possibly be?

Probably a loose cable arcing inside the socket.
Isolate it from the mains, remove faceplate screws and check all
connections - it's highly likely the live will have some signs of
burning -
clean all blackened copper before re securing in the terminals


Wouldn't that trip the RCD though?


--
Dave - The Medway Handyman www.medwayhandyman.co.uk

On Sat, 4 Jan 2014 00:31:48 -0000, Brian Gaff wrote:

Older sockets which have at one time overheated can leave a bit of
carbonised residue, and getting this damp can give the sounds mentioned. It
used to happen in my shed. However, in a house this surely is not good,
where would the dampness come from?
If it is an old socket though its worth a look for a tell tale burn or
looseness inside and replacing the socket.
Smoking guns are pretty obvious!

Brian

Also older sockets can have 'soft' contacts on the pins of the plug. It's a
self-accelersting process - as the contact worsens the heating grows and has
more effect on the metal.
I once went through 6 or 7 2- and 3-way 13A adaptors and found that 3 were
soft and dismatled them and dumped the plastic, 2 were a bit slack but still
springy and were reset, t'other(s)OK.
Then I put in some new 13A sockets to stop me mate's wife from using a 3-way
adaptor for a washing machine, tumble dryer and fridge/freezer.
--
Peter.
The gods will stay away
whilst religions hold sway

PeterC wrote:
On Sat, 4 Jan 2014 00:31:48 -0000, Brian Gaff wrote:

Older sockets which have at one time overheated can leave a bit of
carbonised residue, and getting this damp can give the sounds mentioned. It
used to happen in my shed. However, in a house this surely is not good,
where would the dampness come from?
If it is an old socket though its worth a look for a tell tale burn or
looseness inside and replacing the socket.
Smoking guns are pretty obvious!

Brian

Also older sockets can have 'soft' contacts on the pins of the plug. It's a
self-accelersting process - as the contact worsens the heating grows and has
more effect on the metal.
I once went through 6 or 7 2- and 3-way 13A adaptors and found that 3 were
soft and dismatled them and dumped the plastic, 2 were a bit slack but still
springy and were reset, t'other(s)OK.
Then I put in some new 13A sockets to stop me mate's wife from using a 3-way
adaptor for a washing machine, tumble dryer and fridge/freezer.

This was why I asked the OP if the plugs/pins/fuses were getting warm
but apparently not.

On Friday, January 3, 2014 2:51:05 PM UTC, PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.
Does anyone know what it could possibly be?
Thanks

Arcing. Its probably going to catch fire or blow fuses very soon. Replace it right away.


NT

In message ,
writes
On Friday, January 3, 2014 2:51:05 PM UTC, PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.
Does anyone know what it could possibly be?
Thanks

Arcing. Its probably going to catch fire or blow fuses very soon.
Replace it right away.

Oldish fittings usually pong of fish at that stage.

--
Tim Lamb

On Sat, 4 Jan 2014 21:27:03 +0000, Tim Lamb wrote:

In message ,
writes
On Friday, January 3, 2014 2:51:05 PM UTC, PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.
Does anyone know what it could possibly be?
Thanks

Arcing. Its probably going to catch fire or blow fuses very soon.
Replace it right away.

Oldish fittings usually pong of fish at that stage.

That's melamine getting hot and you smell amines. Useful indicator of a
fault approaching.
--
Peter.
The gods will stay away
whilst religions hold sway

On 03/01/2014 18:37, Dave Liquorice wrote:
On Fri, 03 Jan 2014 18:13:59 +0000, The Medway Handyman wrote:

Wouldn't that trip the RCD though?

Why would it? There is no current imbalance between L & N [...]

(a) remember the Jacob's ladder effect - the tendency of an arc to move
away from the source of energy. An arc in an enclosure, especially at
high current, that starts between Line and Neutral will almost always
find its way to earthed metal, if there's any around. (Also to the
other phases in a 3-ph situation.)

(b) OTOH we are told that an RCD is fitted in the CU. I don't think
it's been confirmed that it protects the circuit in question. Pre 17th
ed. OSG advice was for RCDs to to protect only sockets likely to be used
to supply portable equipment outdoors. Often they protected all
sockets, but not always.

Less speculation, more inspection...

--
Andy

PeterC writes:

On Sat, 4 Jan 2014 21:27:03 +0000, Tim Lamb wrote:

In message ,
writes
On Friday, January 3, 2014 2:51:05 PM UTC, PeterL wrote:
Over the past couple of days I've heard a 'popping' noise coming from a
populated double socket. It's happened at most once or twice a day and
is possibly coincident with the bad weather we've been having. There is
no tripping of breakers at the CU.
Does anyone know what it could possibly be?
Thanks

Arcing. Its probably going to catch fire or blow fuses very soon.
Replace it right away.

Oldish fittings usually pong of fish at that stage.

That's melamine getting hot and you smell amines. Useful indicator of a
fault approaching.

That reminds me of when I was in the kitchen and heard a fizzing
noise. I turned round to see a bright bluish white light shining
through the plastic of one of the above-counter mains sockets. I
killed the power pretty damn quick and went to investigate. It
turned out that one of my housemates cats had €œsprayed€� onto the
wall above the socket and it had run down behind the faceplate.

The smell was €¦ particular, but I wouldnt say it was of fish in
this case :-P

--
Jón Fairbairn
http://www.chaos.org.uk/~jf/Stuff-I-dont-want.html (updated 2012-10-07)

On Sun, 05 Jan 2014 00:24:40 +0000, Andy Wade wrote:

Wouldn't that trip the RCD though?

Why would it? There is no current imbalance between L & N [...]

(a) remember the Jacob's ladder effect - the tendency of an arc to move
away from the source of energy. An arc in an enclosure, especially at
high current, that starts between Line and Neutral will almost always
find its way to earthed metal, if there's any around.

er this arc isn't LN it's LL or NN as a poor connection within a
single terminal, think switch arc. I've not seen a jacobs ladder
effect at mains voltages. I think you need considerably more volts to
sustain an arc an inch or so long, the sort of distance between L and
E bits in yer average socket. After all the required safety isolation
switch gap for 240 V mains is only 3 mm.

--
Cheers
Dave.

On 05/01/2014 14:47, Dave Liquorice wrote:

er this arc isn't LN it's LL or NN as a poor connection within a
single terminal, think switch arc.

Point taken, although I might have called that localised sparking,
rather than arcing. Admittedly the boundary between the two can be a
bit fuzzy. In the end this is still all speculation as the OP hasn't
come back to us again. I have a feeling that the popping sound may turn
out to be non-electrical in origin.

I've not seen a jacobs ladder effect at mains voltages.

Maybe not in the form often demonstrated, my point was that any arc will
seek to stretch itself in a manner similar to the way that two wires
carrying current in opposite directions tend to repel.

I think you need considerably more volts to sustain an arc an inch or
so long, the sort of distance between L and E bits in yer average
socket.

Again we're at crossed purposes a bit. I was thinking about arcs at
fault levels of current (several hundred amps and up) where quite long
'flames' can be sustained at low voltage - hopefully not for long as an
OPD should operate before too much damage is done.

After all the required safety isolation switch gap for 240 V mains is
only 3 mm

Sure, but that only provides isolation or switches the rated load
current. In contrast a much larger gap is required in a fuse or MCB
where a high current arc has to be extinguished.

--
Andy

On Sunday, January 5, 2014 10:10:33 PM UTC, Andy Wade wrote:
On 05/01/2014 14:47, Dave Liquorice wrote:

bit fuzzy. In the end this is still all speculation as the OP hasn't
come back to us again. I have a feeling that the popping sound may turn
out to be non-electrical in origin.

Maybe the OP failed to fix it in time...


NT

On 04/01/2014 00:28, Brian Gaff wrote:
Is this with things running or not?
Brian



Dismantled the socket this weekend. No loose screws or wires and no
sign of blackening. No re-occurrence of the 'popping' either.

Odd

PeterL writes:

On 04/01/2014 00:28, Brian Gaff wrote:
Is this with things running or not?
Brian



Dismantled the socket this weekend. No loose screws or wires and no
sign of blackening. No re-occurrence of the 'popping' either.

I had exactly this sort of thing happen after a mains water pipe burst
in the flat above, causing a Niagara of water to flow into mine.

No electrical problem was apparent the first time, even though it took
several hours to get the water shut off (I now own my own 'Toby key'
to allow me to do that myself, though that horse had already bolted).

But despite my asking the owner of the upper flat to tell the plumber
she was getting *not* to turn the water back on, the bloody fool did so
and caused another Niagara. (He 'needed' to do this to find the leak,
which I think turned out to be from a frozen combi boiler).

After the second flood, I started to hear small explosions at intervals
of maybe 5 minutes, and tracked those down to a junction box someone
had installed long ago at the back of a high shelf.
(Perhaps not compatible with today's regulations, but well out of the
reach of someone standing on the floor.)

The box had become saturated and seems to have been electrolysing the
water then periodically igniting the resulting gases.

If you had at one time some water ingress, you might have had the same
sort of problem, which could well disappear after everything dried out.

--
Windmill, Use t m i l l
J.R.R. Tolkien:- @ S c o t s h o m e . c o m
All that is gold does not glister / Not all who wander are lost