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Dull thud, and all the lights dim momentarily.
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Graham.
Sep 7, 2012, 5:12:01 PM9/7/12
to
I am trying to help some friends discover what is wrong with their
electrics.
The last 3 or 4 times I have visited them I have heard a thud, and the
lights blink at the same moment. This happens maybe twice per hour,
but not regularly enough to be able to predict the next event.
My friends had not attached any significance to these events until I
called them catastrophic explosions, now they are worried. They hadn't
noticed the lights flicker at all, they had heard the thuds but put it
down to their neighbours door slamming, which isn't unreasonable
having heard it.
All the circuits are affected, lights and power.
For the record, his consumer unit is an old MK type with rewireable
fuses, one lighting cct has a retrofit 5 or 6 amp MCB, one of the
later lever type.
There is no history of any fuse blowing.
The house is a semi, the meter and CU are in the hall cupboard far
away from the party wall.
The supply incomer, I imagine, enters from the street.
The bangs however seem to emanate under the floor at the back of the
house near to, or maybe even beyond the party wall. The elderly lady
next door says she hasn't noticed anything.
There is a conservatory with a solid floor at the back of the house.
I thought water would be involved, and we have had torrential rain
recently, however not a drop has fallen this week and I witnessed 3 of
these events last night.
I have an idea or two of diagnostic measures to try next time I visit,
but what does the team say?
--
Graham.
%Profound_observation%
electrics.
The last 3 or 4 times I have visited them I have heard a thud, and the
lights blink at the same moment. This happens maybe twice per hour,
but not regularly enough to be able to predict the next event.
My friends had not attached any significance to these events until I
called them catastrophic explosions, now they are worried. They hadn't
noticed the lights flicker at all, they had heard the thuds but put it
down to their neighbours door slamming, which isn't unreasonable
having heard it.
All the circuits are affected, lights and power.
For the record, his consumer unit is an old MK type with rewireable
fuses, one lighting cct has a retrofit 5 or 6 amp MCB, one of the
later lever type.
There is no history of any fuse blowing.
The house is a semi, the meter and CU are in the hall cupboard far
away from the party wall.
The supply incomer, I imagine, enters from the street.
The bangs however seem to emanate under the floor at the back of the
house near to, or maybe even beyond the party wall. The elderly lady
next door says she hasn't noticed anything.
There is a conservatory with a solid floor at the back of the house.
I thought water would be involved, and we have had torrential rain
recently, however not a drop has fallen this week and I witnessed 3 of
these events last night.
I have an idea or two of diagnostic measures to try next time I visit,
but what does the team say?
--
Graham.
%Profound_observation%
The Natural Philosopher
Sep 7, 2012, 5:17:50 PM9/7/12
to
Might be a damaged incoming underground.
--
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.
Nick Odell
Sep 7, 2012, 5:20:04 PM9/7/12
to
On Fri, 07 Sep 2012 22:12:01 +0100, Graham. <m...@privacy.net.invalid>
wrote:
Where's the refrigerator? My late mother had a fridge that used to
create some sort of pulse when the thermostat switched it off. I
imagine a capacitor had died, or something. (Probably the 'or
something.') The lights would flicker and the TV would get confused
for a moment or two and then everything would be normal until the next
time.
Nick
wrote:
create some sort of pulse when the thermostat switched it off. I
imagine a capacitor had died, or something. (Probably the 'or
something.') The lights would flicker and the TV would get confused
for a moment or two and then everything would be normal until the next
time.
Nick
Nick Odell
Sep 7, 2012, 5:23:59 PM9/7/12
to
the vibration as the motor ran down. Hence, noise, lights, EMP etc.
N
Andrew Gabriel
Sep 7, 2012, 5:37:24 PM9/7/12
to
In article <7lok48dqghdn9k1pt...@4ax.com>,
or only during the day? What about weekends?
> My friends had not attached any significance to these events until I
> called them catastrophic explosions, now they are worried. They hadn't
> noticed the lights flicker at all, they had heard the thuds but put it
> down to their neighbours door slamming, which isn't unreasonable
> having heard it.
>
> All the circuits are affected, lights and power.
Well, it could still be something next door, interfering with the
local mains supply.
Could the bang be a breaker tripping off next door?
Is the flicker a momentary brown-out, or a momentary surge
(which can happen if there's a short circuit on another phase
which momentarily yanks the neutral part way to that phase
voltage)?
Brown-outs and surges can show up better with mains filament
lamps, because they amplify the effect.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
Graham. <m...@privacy.net.invalid> writes:
> I am trying to help some friends discover what is wrong with their
> electrics.
>
> The last 3 or 4 times I have visited them I have heard a thud, and the
> lights blink at the same moment. This happens maybe twice per hour,
> but not regularly enough to be able to predict the next event.
Does it happen all the time, e.g. including all through the night,
> I am trying to help some friends discover what is wrong with their
> electrics.
>
> The last 3 or 4 times I have visited them I have heard a thud, and the
> lights blink at the same moment. This happens maybe twice per hour,
> but not regularly enough to be able to predict the next event.
or only during the day? What about weekends?
> My friends had not attached any significance to these events until I
> called them catastrophic explosions, now they are worried. They hadn't
> noticed the lights flicker at all, they had heard the thuds but put it
> down to their neighbours door slamming, which isn't unreasonable
> having heard it.
>
> All the circuits are affected, lights and power.
local mains supply.
Could the bang be a breaker tripping off next door?
Is the flicker a momentary brown-out, or a momentary surge
(which can happen if there's a short circuit on another phase
which momentarily yanks the neutral part way to that phase
voltage)?
Brown-outs and surges can show up better with mains filament
lamps, because they amplify the effect.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
Graham.
Sep 7, 2012, 5:54:33 PM9/7/12
to
The lights dim not brighten so brownout.
Certainly does it past midnight, and at weekends so 24/7 AFAIK
Neighbour sad she hasn't noticed anything amiss, I am sure she would
have mentioned having to intervene at her CU several times an hour.
--
Graham.
%Profound_observation%
Dave Liquorice
Sep 7, 2012, 5:51:06 PM9/7/12
to
On Fri, 07 Sep 2012 22:17:50 +0100, The Natural Philosopher wrote:
> Might be a damaged incoming underground.
Aye, I don't like the description of the sound as a "dull thud" that is
> Might be a damaged incoming underground.
too much like a muffled explosion for my likeing.
Think I'd be getting onto the local REC, even on Saturday. If it is an
underground cable fault it could make considerably more than a dull thud
and a little flicker of the lights.
--
Cheers
Dave.
Andrew Gabriel
Sep 7, 2012, 6:24:56 PM9/7/12
to
In article <nyyfbegfubjuvyypb...@srv1.howhill.co.uk>,
A Kentucky Fried Chicken was wrecked by a supply cable fault,
which was basically a fire/arc before the main cutout which
they couldn't put out.
Usually these things eventually turn into a good enough short
circuit to blow the upline fuse (typically 400A on a residential
street supply), or they end up burning out the cable leaving it
open circuit. Until one or other happens, it can be pretty
difficult to locate. One of my work colleagues used to do this
in the 11/33kV network, but I suspect that doesn't mess around
with just the occational pop for so long!
which was basically a fire/arc before the main cutout which
they couldn't put out.
Usually these things eventually turn into a good enough short
circuit to blow the upline fuse (typically 400A on a residential
street supply), or they end up burning out the cable leaving it
open circuit. Until one or other happens, it can be pretty
difficult to locate. One of my work colleagues used to do this
in the 11/33kV network, but I suspect that doesn't mess around
with just the occational pop for so long!
Graham.
Sep 7, 2012, 6:25:56 PM9/7/12
to
40 years ago I encountered something very similar the lights dimmed
and there was a thud, but only after heavy rain. In that case the thud
came from across the road under the pavement beneath a street light.
My friends house is on an ordinary suburban street with underground
distribution. Is it likely his incomer cable will enter from other
than the front of the house? If it does enter at the front there is no
chance the supply main runs where I can hear the noise, but it's still
a worry.
I am wondering about the power to the conservatory. If the cable(s)
were undersized and the loop impendence high enough could you think of
some momentary short circuit scenario that would cause these symptoms
but not blow a 30A wire fuse?
It could well be that the problem is next doors, I just cannot tell.
--
Graham.
%Profound_observation%
John Williamson
Sep 7, 2012, 6:40:01 PM9/7/12
to
runs along the end of the 4 house terrace, then along the back wall,
branching off to each hosue as it goes.
--
Tciao for Now!
John.
Nick Odell
Sep 7, 2012, 6:52:23 PM9/7/12
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On Fri, 07 Sep 2012 22:54:33 +0100, Graham. <m...@privacy.net.invalid>
wrote:
I still reckon it sounds like my mum's old fridge.
Nick
wrote:
Nick
m...@privacy.net
Sep 7, 2012, 6:51:05 PM9/7/12
to
On 7 Sep,
--
B Thumbs
Change lycos to yahoo to reply
Graham. <m...@privacy.net.invalid> wrote:
> The last 3 or 4 times I have visited them I have heard a thud, and the
> lights blink at the same moment. This happens maybe twice per hour,
> but not regularly enough to be able to predict the next event.
>
The freezer starting up?
> The last 3 or 4 times I have visited them I have heard a thud, and the
> lights blink at the same moment. This happens maybe twice per hour,
> but not regularly enough to be able to predict the next event.
>
--
B Thumbs
Change lycos to yahoo to reply
Graham.
Sep 7, 2012, 7:03:49 PM9/7/12
to
local mice are keeping their cheese fresh in one.
--
Graham.
%Profound_observation%
Graham.
Sep 7, 2012, 7:18:34 PM9/7/12
to
On Fri, 07 Sep 2012 23:51:05 +0100, <m...@privacy.net> wrote:
>On 7 Sep,
> Graham. <m...@privacy.net.invalid> wrote:
>
>> The last 3 or 4 times I have visited them I have heard a thud, and the
>> lights blink at the same moment. This happens maybe twice per hour,
>> but not regularly enough to be able to predict the next event.
>>
>The freezer starting up?
I see what you mean, and maybe Nick had this in mind too. It might
>On 7 Sep,
> Graham. <m...@privacy.net.invalid> wrote:
>
>> The last 3 or 4 times I have visited them I have heard a thud, and the
>> lights blink at the same moment. This happens maybe twice per hour,
>> but not regularly enough to be able to predict the next event.
>>
>The freezer starting up?
account for the timing intervals, the inrush surge of the motor
starting acting as the cartelist to set whatever it is off upstream.
Still odd though because where I hear the noise is not between the
kitchen and the CU, Quite the opposite direction in fact.
--
Graham.
%Profound_observation%
John Rumm
Sep 7, 2012, 7:48:42 PM9/7/12
to
On 08/09/2012 00:18, Graham. wrote:
> On Fri, 07 Sep 2012 23:51:05 +0100, <m...@privacy.net> wrote:
>
>> On 7 Sep,
>> Graham. <m...@privacy.net.invalid> wrote:
>>
>>> The last 3 or 4 times I have visited them I have heard a thud, and the
>>> lights blink at the same moment. This happens maybe twice per hour,
>>> but not regularly enough to be able to predict the next event.
>>>
>> The freezer starting up?
>
> I see what you mean, and maybe Nick had this in mind too. It might
> account for the timing intervals, the inrush surge of the motor
> starting acting as the cartelist to set whatever it is off upstream.
The inrush for an induction motor can be enough to dim the lights for
> On Fri, 07 Sep 2012 23:51:05 +0100, <m...@privacy.net> wrote:
>
>> On 7 Sep,
>> Graham. <m...@privacy.net.invalid> wrote:
>>
>>> The last 3 or 4 times I have visited them I have heard a thud, and the
>>> lights blink at the same moment. This happens maybe twice per hour,
>>> but not regularly enough to be able to predict the next event.
>>>
>> The freezer starting up?
>
> I see what you mean, and maybe Nick had this in mind too. It might
> account for the timing intervals, the inrush surge of the motor
> starting acting as the cartelist to set whatever it is off upstream.
the whole house just on its own...
> Still odd though because where I hear the noise is not between the
> kitchen and the CU, Quite the opposite direction in fact.
--
John.
/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/
Grimly Curmudgeon
Sep 7, 2012, 7:54:34 PM9/7/12
to
On Fri, 07 Sep 2012 22:12:01 +0100, Graham. <m...@privacy.net.invalid>
wrote:
wrote:
>The bangs however seem to emanate under the floor at the back of the
>house near to, or maybe even beyond the party wall. The elderly lady
>next door says she hasn't noticed anything.
She would say that.
>house near to, or maybe even beyond the party wall. The elderly lady
>next door says she hasn't noticed anything.
What she's not telling you is the basement and attic are full of dope
plants and the thud-flicker are when the contactor for the lights cuts
in and out via a timer.
The Natural Philosopher
Sep 7, 2012, 7:56:09 PM9/7/12
to
John Rumm wrote:
> On 08/09/2012 00:18, Graham. wrote:
>> On Fri, 07 Sep 2012 23:51:05 +0100, <m...@privacy.net> wrote:
>>
>>> On 7 Sep,
>>> Graham. <m...@privacy.net.invalid> wrote:
>>>
>>>> The last 3 or 4 times I have visited them I have heard a thud, and the
>>>> lights blink at the same moment. This happens maybe twice per hour,
>>>> but not regularly enough to be able to predict the next event.
>>>>
>>> The freezer starting up?
>>
>> I see what you mean, and maybe Nick had this in mind too. It might
>> account for the timing intervals, the inrush surge of the motor
>> starting acting as the cartelist to set whatever it is off upstream.
>
> The inrush for an induction motor can be enough to dim the lights for
> the whole house just on its own...
>
Depends. When I had a 1947 vintage lump of iron up a pole to supply me
> On 08/09/2012 00:18, Graham. wrote:
>> On Fri, 07 Sep 2012 23:51:05 +0100, <m...@privacy.net> wrote:
>>
>>> On 7 Sep,
>>> Graham. <m...@privacy.net.invalid> wrote:
>>>
>>>> The last 3 or 4 times I have visited them I have heard a thud, and the
>>>> lights blink at the same moment. This happens maybe twice per hour,
>>>> but not regularly enough to be able to predict the next event.
>>>>
>>> The freezer starting up?
>>
>> I see what you mean, and maybe Nick had this in mind too. It might
>> account for the timing intervals, the inrush surge of the motor
>> starting acting as the cartelist to set whatever it is off upstream.
>
> The inrush for an induction motor can be enough to dim the lights for
> the whole house just on its own...
>
the microwave would do that all on its own.
And trip the RCD when I installed a load of computers and other shit on it
NOW I have a freezer sized personal transformer to supply the house,
that doesn't happen :-)
>> Still odd though because where I hear the noise is not between the
>> kitchen and the CU, Quite the opposite direction in fact.
>
>
>
--
Graham.
Sep 7, 2012, 8:06:25 PM9/7/12
to
On Sat, 08 Sep 2012 00:48:42 +0100, John Rumm
<see.my.s...@nowhere.null> wrote:
>On 08/09/2012 00:18, Graham. wrote:
>> On Fri, 07 Sep 2012 23:51:05 +0100, <m...@privacy.net> wrote:
>>
>>> On 7 Sep,
>>> Graham. <m...@privacy.net.invalid> wrote:
>>>
>>>> The last 3 or 4 times I have visited them I have heard a thud, and the
>>>> lights blink at the same moment. This happens maybe twice per hour,
>>>> but not regularly enough to be able to predict the next event.
>>>>
>>> The freezer starting up?
>>
>> I see what you mean, and maybe Nick had this in mind too. It might
>> account for the timing intervals, the inrush surge of the motor
>> starting acting as the cartelist to set whatever it is off upstream.
>
>The inrush for an induction motor can be enough to dim the lights for
>the whole house just on its own...
I'd appreciate your view on what might be causing the thud John.
<see.my.s...@nowhere.null> wrote:
>On 08/09/2012 00:18, Graham. wrote:
>> On Fri, 07 Sep 2012 23:51:05 +0100, <m...@privacy.net> wrote:
>>
>>> On 7 Sep,
>>> Graham. <m...@privacy.net.invalid> wrote:
>>>
>>>> The last 3 or 4 times I have visited them I have heard a thud, and the
>>>> lights blink at the same moment. This happens maybe twice per hour,
>>>> but not regularly enough to be able to predict the next event.
>>>>
>>> The freezer starting up?
>>
>> I see what you mean, and maybe Nick had this in mind too. It might
>> account for the timing intervals, the inrush surge of the motor
>> starting acting as the cartelist to set whatever it is off upstream.
>
>The inrush for an induction motor can be enough to dim the lights for
>the whole house just on its own...
--
Graham.
%Profound_observation%
Graham.
Sep 7, 2012, 8:39:59 PM9/7/12
to
few years are on my road.
--
Graham.
%Profound_observation%
Bill Wright
Sep 7, 2012, 9:50:05 PM9/7/12
to
Graham. wrote:
>cartelist
Are you a southerner?
Bill
>cartelist
Are you a southerner?
Bill
Jules Richardson
Sep 7, 2012, 10:14:34 PM9/7/12
to
On Fri, 07 Sep 2012 22:20:04 +0100, Nick Odell wrote:
> Where's the refrigerator?
Yeah, I was going to ask that, too :-)
Old fridge and worn compressor mounts might produce a thump and
flickering lights when the compressor starts. Our old one certainly did
the flickering lights thing - sadly it kicked the bucket last week, but
35 years wasn't bad...
cheers
Jules
> Where's the refrigerator?
Yeah, I was going to ask that, too :-)
Old fridge and worn compressor mounts might produce a thump and
flickering lights when the compressor starts. Our old one certainly did
the flickering lights thing - sadly it kicked the bucket last week, but
35 years wasn't bad...
cheers
Jules
Graham.
Sep 7, 2012, 11:03:51 PM9/7/12
to
On Sat, 08 Sep 2012 02:50:05 +0100, Bill Wright <bi...@invalid.com>
wrote:
http://www.merriam-webster.com/dictionary/cartelist
cartelist
One that belongs to or favors (sic) a cartel.
This word doesn't usually appear in our free dictionary, but the
definition from our premium Unabridged Dictionary is offered here on a
limited basis. Note that some information is displayed differently in
the Unabridged.
Words a commodity. Whatever next.
--
Graham.
%Profound_observation%
wrote:
cartelist
One that belongs to or favors (sic) a cartel.
This word doesn't usually appear in our free dictionary, but the
definition from our premium Unabridged Dictionary is offered here on a
limited basis. Note that some information is displayed differently in
the Unabridged.
Words a commodity. Whatever next.
--
Graham.
%Profound_observation%
John Rumm
Sep 7, 2012, 11:49:56 PM9/7/12
to
A motor kicking in would be one option. Slightly percussive ignition of
a boiler could also cause a thud (although that would not typically be
associated with any electrical drop out).
Big transformers at switch on can have similar effects.
Automated systems like heating and cooling devices would obviously be
prime candidates.
Graham.
Sep 8, 2012, 12:10:17 AM9/8/12
to
On Sat, 08 Sep 2012 04:49:56 +0100, John Rumm
I've pretty much convinced myself it's something electrical blowing
itself apart in a self resettable way. Maybe water gets into a joint
and is instantly and explosively superheated, Do you think that could
happen on a circuit protected by a 30 amp fuse, again and again
without it blowing? I think the answer is yes if the loop impendence
is high and the events are of short enough duration.
I'm just afraid that it might be a cable protected by a fuse 10 times
that value in a substation!
Can't you sleep?
--
Graham.
%Profound_observation%
itself apart in a self resettable way. Maybe water gets into a joint
and is instantly and explosively superheated, Do you think that could
happen on a circuit protected by a 30 amp fuse, again and again
without it blowing? I think the answer is yes if the loop impendence
is high and the events are of short enough duration.
I'm just afraid that it might be a cable protected by a fuse 10 times
that value in a substation!
Can't you sleep?
--
Graham.
%Profound_observation%
Brian Gaff
Sep 8, 2012, 12:38:33 AM9/8/12
to
Well does it affect other properties or not?
If not then as it could be pre meter, I'd suggest a call to the supplier
who may be able to test for problems where you cannot.
Brian
--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email: bri...@blueyonder.co.uk
______________________________________________________________________________________________________________
"Graham." <m...@privacy.net.invalid> wrote in message
news:7lok48dqghdn9k1pt...@4ax.com...
If not then as it could be pre meter, I'd suggest a call to the supplier
who may be able to test for problems where you cannot.
Brian
--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email: bri...@blueyonder.co.uk
______________________________________________________________________________________________________________
"Graham." <m...@privacy.net.invalid> wrote in message
news:7lok48dqghdn9k1pt...@4ax.com...
Brian Gaff
Sep 8, 2012, 12:44:36 AM9/8/12
to
Isolate the circuit to the conservatory for some hours to see if it stops,
but from the description, I have a nasty feeling its before the fuse boxes.
Near here some houses reported similar issues some time back, then one day
a cable blew a hole six feet wide in the pavement outside. It was due to a
leaking sewer near a cable in the street and the sound of the minor problems
was conducted by the cable to nearby properties, one must assume that
eventually the partial short became a major one. Luckily nobody wa hurt but
the power was off for several houses for a day or so while they fixed it.
Brian
--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email: bri...@blueyonder.co.uk
______________________________________________________________________________________________________________
"Graham." <m...@privacy.net.invalid> wrote in message
news:fork485ls6571goqt...@4ax.com...
but from the description, I have a nasty feeling its before the fuse boxes.
Near here some houses reported similar issues some time back, then one day
a cable blew a hole six feet wide in the pavement outside. It was due to a
leaking sewer near a cable in the street and the sound of the minor problems
was conducted by the cable to nearby properties, one must assume that
eventually the partial short became a major one. Luckily nobody wa hurt but
the power was off for several houses for a day or so while they fixed it.
Brian
--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email: bri...@blueyonder.co.uk
______________________________________________________________________________________________________________
"Graham." <m...@privacy.net.invalid> wrote in message
Brian Gaff
Sep 8, 2012, 12:52:32 AM9/8/12
to
Probably the design of the incoming cable makes bypassing the meter easier.
Brian
--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email: bri...@blueyonder.co.uk
______________________________________________________________________________________________________________
"Graham." <m...@privacy.net.invalid> wrote in message
news:jq4l48p8ilsgcsimf...@4ax.com...
Brian
--
Brian Gaff....Note, this account does not accept Bcc: email.
graphics are great, but the blind can't hear them
Email: bri...@blueyonder.co.uk
______________________________________________________________________________________________________________
"Graham." <m...@privacy.net.invalid> wrote in message
Nthkentman
Sep 8, 2012, 3:02:09 AM9/8/12
to
>>Big transformers at switch on can have similar effects.
>>
>>Automated systems like heating and cooling devices would obviously be
>>prime candidates.
>
> I've pretty much convinced myself it's something electrical blowing
> itself apart in a self resettable way. Maybe water gets into a joint
> and is instantly and explosively superheated, Do you think that could
> happen on a circuit protected by a 30 amp fuse, again and again
> without it blowing? I think the answer is yes if the loop impendence
> is high and the events are of short enough duration.
>
> I'm just afraid that it might be a cable protected by a fuse 10 times
> that value in a substation!
Personally I would isolate *every* non used appliance for a few hours,
>>
>>Automated systems like heating and cooling devices would obviously be
>>prime candidates.
>
> I've pretty much convinced myself it's something electrical blowing
> itself apart in a self resettable way. Maybe water gets into a joint
> and is instantly and explosively superheated, Do you think that could
> happen on a circuit protected by a 30 amp fuse, again and again
> without it blowing? I think the answer is yes if the loop impendence
> is high and the events are of short enough duration.
>
> I'm just afraid that it might be a cable protected by a fuse 10 times
> that value in a substation!
fridge, freezer, any heating etc and then reduce the fuse capacity to 15a
and switch a circuit on one by one individually to see if it's house side of
the CU.
If the incoming main is damaged there is an immediate need to get the board
in to investigate as shared runs for water, leccy and gas often result it a
far larger problem when any two coincide during a failure :-(
A scan with a CAT device might be used to determine where any incoming
supply issues might be.
A local "engineer" for the high power supply bods round here who is one of
my customers used to check for blown cables underground at streetlamp
circuit problems by shoving a 6" nail in the last known live feed at a pole
and watching where the ground erupted nearby so he knew where to dig and
repair .... dodgy but it worked.
Can't imagine where he got the nickname dodgy digger from......
Message has been deleted
clanger...@yahoo.co.uk
Sep 8, 2012, 7:31:01 AM9/8/12
to
OP just turn the whole house off at the CU for an hour or so to
determine whether the thump still occurs (or doesn't) even when the
house is isolated. That would narrow the fault down a bit.
GB
Sep 8, 2012, 7:42:19 AM9/8/12
to
On 07/09/2012 23:40, John Williamson wrote:
> If his house is like mine (1930s ex-council), the incoming mains cable
> runs along the end of the 4 house terrace, then along the back wall,
> branching off to each hosue as it goes.
>
That's typical for LA housing long before the Right To Buy legislation.
> If his house is like mine (1930s ex-council), the incoming mains cable
> runs along the end of the 4 house terrace, then along the back wall,
> branching off to each hosue as it goes.
>
Ofc, it causes all sorts of issues now, but at the time it seemed
perfectly reasonable and economical.
Harry Bloomfield
Sep 8, 2012, 2:30:20 PM9/8/12
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It happens that Graham. formulated :
My guess would be your mains supply cable, underground. Typically the
duration of the event and its timing will vary depending upon the
surrounding moisture in the ground.
We had a similar problem between us and the sub-station. The brown out
would last anywhere between a fraction of a second and several seconds
and took months before it became a real issue. Eventually it blasted a
large hole in the pavement.
--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk
> I'm just afraid that it might be a cable protected by a fuse 10 times
> that value in a substation!
Why not start by logging the events?
> that value in a substation!
My guess would be your mains supply cable, underground. Typically the
duration of the event and its timing will vary depending upon the
surrounding moisture in the ground.
We had a similar problem between us and the sub-station. The brown out
would last anywhere between a fraction of a second and several seconds
and took months before it became a real issue. Eventually it blasted a
large hole in the pavement.
--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk
Nthkentman
Sep 8, 2012, 4:13:46 PM9/8/12
to
"Tim Streater" <timst...@greenbee.net> wrote in message
news:timstreater-6ED9...@news.individual.net...
> In article <85dl489eff3ogfv57...@4ax.com>,
>
> 1) <double clicks word>
>
> 2) MT-Newswatcher -> Services -> Look up in Dictionary
>
> 3) Result: No entries found
You should JFGI
http://dictionary.reference.com/browse/cartelist
js...@ntlworld.com
Sep 8, 2012, 4:18:51 PM9/8/12
to
A dull thud can be water hammer from a neighbour?
However that does not usually make the lights dim... if it IS the supply cable then the eventual bag can be quite destructive. It comes down to how fast a fault disconnects and how much moisture there is around - moisture flashes to steam and this can be particularly brutal under a concrete floor.
400A upstream fuse may need >4500A to blow <0.1sec which is 1 megawatt of energy shovelled into moisture which is going to become steam and expand in that 0.1sec.
It sounds old enough to have a Paper Insulated Lead Covered (PILC) cable, which might have been bilked by a conservatory spade or simply a joint that is going high resistance, failing, moisture ingress etc.
A high impedance supply will cause light dimming with high load, as will a stuffed joint box. Freezers require a fair whack to start which is enough of a load, and can bang if they do not start due to high impedance supply. So the two may be interconnected even if the fridge does not appear to be the fault.
Defrost the fridge, switch the conservatory off, diary time. DNO may want them to do that before they come out. Steep sided crater in garden however will not be an asteroid, it will be a cable, wrong blast profile :-) ... could be a mole after Newcastle Brown Ale of course... but that is another matter.
However that does not usually make the lights dim... if it IS the supply cable then the eventual bag can be quite destructive. It comes down to how fast a fault disconnects and how much moisture there is around - moisture flashes to steam and this can be particularly brutal under a concrete floor.
400A upstream fuse may need >4500A to blow <0.1sec which is 1 megawatt of energy shovelled into moisture which is going to become steam and expand in that 0.1sec.
It sounds old enough to have a Paper Insulated Lead Covered (PILC) cable, which might have been bilked by a conservatory spade or simply a joint that is going high resistance, failing, moisture ingress etc.
A high impedance supply will cause light dimming with high load, as will a stuffed joint box. Freezers require a fair whack to start which is enough of a load, and can bang if they do not start due to high impedance supply. So the two may be interconnected even if the fridge does not appear to be the fault.
Defrost the fridge, switch the conservatory off, diary time. DNO may want them to do that before they come out. Steep sided crater in garden however will not be an asteroid, it will be a cable, wrong blast profile :-) ... could be a mole after Newcastle Brown Ale of course... but that is another matter.
The Natural Philosopher
Sep 8, 2012, 4:48:43 PM9/8/12
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line?
*or whichever bunch of charlatans does the same function these days
Dave Liquorice
Sep 8, 2012, 5:07:36 PM9/8/12
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On Sat, 08 Sep 2012 00:56:09 +0100, The Natural Philosopher wrote:
>> The inrush for an induction motor can be enough to dim the lights for
>> the whole house just on its own...
My bench saw does, 1.2kW induction motor IIRC. No soft start either so it
>> The inrush for an induction motor can be enough to dim the lights for
>> the whole house just on its own...
makes quite a bang in itself as well as dipping the lights.
> Depends. When I had a 1947 vintage lump of iron up a pole to supply me
> the microwave would do that all on its own.
the bench saw though, though the Dyson is close.
The pole transformer is quite small probably only rated at 100A. We do
have some E7 heating but I suspect that when that was put in by one of
the previous owners they didn't bother telling the REC...
--
Cheers
Dave.
js...@ntlworld.com
Sep 8, 2012, 5:14:00 PM9/8/12
to
On Saturday, September 8, 2012 9:48:43 PM UTC+1, The Natural Philosopher wrote:
> Is this one of those cases where the Board* will shove a monitor on the
> line?
> *or whichever bunch of charlatans does the same function these days
There are online and offline monitors, they can "spike" the line to force a soft fault to become a hard fault. It is a yellow pelicase box, indeed there are a few re fault tracing on LV.
> Is this one of those cases where the Board* will shove a monitor on the
> line?
> *or whichever bunch of charlatans does the same function these days
The OP should report it at least rather than wait.
The Natural Philosopher
Sep 8, 2012, 5:39:21 PM9/8/12
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3KVA frankly...
Alan J. Wylie
Sep 9, 2012, 3:04:19 PM9/9/12
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Graham. <m...@privacy.net.invalid> writes:
> The last 3 or 4 times I have visited them I have heard a thud, and the
> lights blink at the same moment. This happens maybe twice per hour,
> but not regularly enough to be able to predict the next event.
...
> The last 3 or 4 times I have visited them I have heard a thud, and the
> lights blink at the same moment. This happens maybe twice per hour,
> but not regularly enough to be able to predict the next event.
> The bangs however seem to emanate under the floor at the back of the
> house near to, or maybe even beyond the party wall. The elderly lady
> next door says she hasn't noticed anything.
> I thought water would be involved, and we have had torrential rain
> recently, however not a drop has fallen this week and I witnessed 3 of
> these events last night.
...
> recently, however not a drop has fallen this week and I witnessed 3 of
> these events last night.
I had exactly this problem 20 years ago soon after I moved in to a house
I had just bought. The bangs seemed to be days/weeks apart, though
Eventually diagnosed to a blocked underground watercourse running
through the front garden, water coming in under the floorboards, and
some plonker having left a dangling unterminated live mains cable
lying on the rubble under the floor. The end of the cable was clearly
split and blown apart. I still haven't worked out the exact mechanism:
mains is A/C so electrolysis producing hydrogen shouldn't be the answer.
--
Alan J. Wylie http://www.wylie.me.uk/
The Natural Philosopher
Sep 9, 2012, 3:11:21 PM9/9/12
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Graham.
Sep 9, 2012, 7:38:23 PM9/9/12
to
On Sun, 09 Sep 2012 20:04:19 +0100, al...@wylie.me.uk (Alan J. Wylie)
wrote:
I suppose AC electrolysis of water gives two parts hydrogen and 1 part
oxygen from *both* electrodes. I wonder if that is the mechanism? It
does sound a bit like percussive gas ignition. Earlier I suggested it
might be due to superheated steam.
--
Graham.
%Profound_observation%
wrote:
oxygen from *both* electrodes. I wonder if that is the mechanism? It
does sound a bit like percussive gas ignition. Earlier I suggested it
might be due to superheated steam.
--
Graham.
%Profound_observation%
Fredxx
Sep 9, 2012, 10:01:10 PM9/9/12
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way of explosive gases.
Graham.
Sep 10, 2012, 4:09:27 AM9/10/12
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displacing salt water from the -ve pole of my Hornby transformer.
--
Graham.
%Profound_observation%
The Natural Philosopher
Sep 10, 2012, 4:39:29 AM9/10/12
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electrolysis by simply switching polarity every half an hour. Or every
ten years. Or 50 times a second...
In fact its even more dangerous as H2 and O2 are formed at both electrodes.
>
> When I was a kid I used to fill lemonade bottles full of H2 by
> displacing salt water from the -ve pole of my Hornby transformer.
>
--
Andrew Gabriel
Sep 10, 2012, 4:53:44 AM9/10/12
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In article <k2k901$d2e$1...@news.albasani.net>,
I would guess the ion recombination time to for the electrolysis
products to form is longer than 100th of a second, so they never do.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
The Natural Philosopher <t...@invalid.invalid> writes:
> I think you will find you are wrong. Otherwise you could reverse
> electrolysis by simply switching polarity every half an hour. Or every
> ten years. Or 50 times a second...
>
>
> In fact its even more dangerous as H2 and O2 are formed at both electrodes.
Given that electrode boilers generate no gas, I'd say you are wrong.
> I think you will find you are wrong. Otherwise you could reverse
> electrolysis by simply switching polarity every half an hour. Or every
> ten years. Or 50 times a second...
>
>
> In fact its even more dangerous as H2 and O2 are formed at both electrodes.
I would guess the ion recombination time to for the electrolysis
products to form is longer than 100th of a second, so they never do.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
The Natural Philosopher
Sep 10, 2012, 4:56:51 AM9/10/12
to
Andrew Gabriel wrote:
> In article <k2k901$d2e$1...@news.albasani.net>,
> The Natural Philosopher <t...@invalid.invalid> writes:
>> I think you will find you are wrong. Otherwise you could reverse
>> electrolysis by simply switching polarity every half an hour. Or every
>> ten years. Or 50 times a second...
>>
>>
>> In fact its even more dangerous as H2 and O2 are formed at both electrodes.
>
> Given that electrode boilers generate no gas, I'd say you are wrong.
>
> I would guess the ion recombination time to for the electrolysis
> products to form is longer than 100th of a second, so they never do.
>
Exactly. They never turn back into water again.
> In article <k2k901$d2e$1...@news.albasani.net>,
> The Natural Philosopher <t...@invalid.invalid> writes:
>> I think you will find you are wrong. Otherwise you could reverse
>> electrolysis by simply switching polarity every half an hour. Or every
>> ten years. Or 50 times a second...
>>
>>
>> In fact its even more dangerous as H2 and O2 are formed at both electrodes.
>
> Given that electrode boilers generate no gas, I'd say you are wrong.
>
> I would guess the ion recombination time to for the electrolysis
> products to form is longer than 100th of a second, so they never do.
>
Google it. Everybody says the same thing. You get H2 and O2 together
and its a bloody explosive mix,
js...@ntlworld.com
Sep 10, 2012, 6:09:14 AM9/10/12
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Is the conservatory new?
Could the thud be emanating from a drain / manhole cover / similar?
Is the water pipe shared?
Water hammer can be a dull thud if pipes run under floors, appear at random?
Could the thud be emanating from a drain / manhole cover / similar?
Is the water pipe shared?
Water hammer can be a dull thud if pipes run under floors, appear at random?
Paul D Smith
Sep 10, 2012, 8:21:26 AM9/10/12
to
> Given that electrode boilers generate no gas, I'd say you are wrong.
>
> I would guess the ion recombination time to for the electrolysis
> products to form is longer than 100th of a second, so they never do.
Got to agree. We have a medical humidifier which works by using carbon
>
> I would guess the ion recombination time to for the electrolysis
> products to form is longer than 100th of a second, so they never do.
electrodes to heat the water. As far as I can see, this really is just a
couple of rods running 240V AC straight into water.
With demin water, nothing happens (not enough conduction). With a small
amount of tap water added, we get the required steam. With neat tap water
we get copious steam because our tap ware if very hard.
Paul DS.
dochol...@gmail.com
Sep 10, 2012, 10:05:08 AM9/10/12
to
Fredxx
Sep 10, 2012, 10:24:24 AM9/10/12
to
On 10/09/2012 09:56, The Natural Philosopher wrote:
> Andrew Gabriel wrote:
>> In article <k2k901$d2e$1...@news.albasani.net>,
>> The Natural Philosopher <t...@invalid.invalid> writes:
>>> I think you will find you are wrong. Otherwise you could reverse
>>> electrolysis by simply switching polarity every half an hour. Or
>>> every ten years. Or 50 times a second...
>>>
>>>
>>> In fact its even more dangerous as H2 and O2 are formed at both
>>> electrodes.
>>
>> Given that electrode boilers generate no gas, I'd say you are wrong.
>>
>> I would guess the ion recombination time to for the electrolysis
>> products to form is longer than 100th of a second, so they never do.
>>
> Exactly. They never turn back into water again.
>
> Google it. Everybody says the same thing. You get H2 and O2 together
> and its a bloody explosive mix,
>
I have and I get examples of electrode boilers and water heaters, with
> Andrew Gabriel wrote:
>> In article <k2k901$d2e$1...@news.albasani.net>,
>> The Natural Philosopher <t...@invalid.invalid> writes:
>>> I think you will find you are wrong. Otherwise you could reverse
>>> electrolysis by simply switching polarity every half an hour. Or
>>> every ten years. Or 50 times a second...
>>>
>>>
>>> In fact its even more dangerous as H2 and O2 are formed at both
>>> electrodes.
>>
>> Given that electrode boilers generate no gas, I'd say you are wrong.
>>
>> I would guess the ion recombination time to for the electrolysis
>> products to form is longer than 100th of a second, so they never do.
>>
> Exactly. They never turn back into water again.
>
> Google it. Everybody says the same thing. You get H2 and O2 together
> and its a bloody explosive mix,
>
no mention to beware of explosive gases.
A website closer to home:
http://www.tlc-direct.co.uk/Book/7.11.2.htm
The Natural Philosopher
Sep 10, 2012, 10:34:30 AM9/10/12
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more likely that steam will outnumber H2 by a million to one or so
Andrew Gabriel
Sep 10, 2012, 11:22:23 AM9/10/12
to
In article <257c9af8-1f9d-4fb4...@googlegroups.com>,
That seems to have been an electrode jet boiler (where you heat
just a jet of water so you get instant steam, without having to
first heat a whole tank full to boiling point). That incident seems
to have halted their use according to one article I read.
More usual electrode boilers are just electrodes dunked in a tank
of water, and they don't generate hydrogen according to everything
I can find on google, and my own experience as a teenager...
just a jet of water so you get instant steam, without having to
first heat a whole tank full to boiling point). That incident seems
to have halted their use according to one article I read.
More usual electrode boilers are just electrodes dunked in a tank
of water, and they don't generate hydrogen according to everything
I can find on google, and my own experience as a teenager...
Fredxx
Sep 10, 2012, 11:28:30 AM9/10/12
to
On 10/09/2012 15:34, The Natural Philosopher wrote:
> Fredxx wrote:
>> On 10/09/2012 09:56, The Natural Philosopher wrote:
>>> Andrew Gabriel wrote:
>>>> In article <k2k901$d2e$1...@news.albasani.net>,
>>>> The Natural Philosopher <t...@invalid.invalid> writes:
>>>>> I think you will find you are wrong. Otherwise you could reverse
>>>>> electrolysis by simply switching polarity every half an hour. Or
>>>>> every ten years. Or 50 times a second...
>>>>>
>>>>>
>>>>> In fact its even more dangerous as H2 and O2 are formed at both
>>>>> electrodes.
>>>>
>>>> Given that electrode boilers generate no gas, I'd say you are wrong.
>>>>
>>>> I would guess the ion recombination time to for the electrolysis
>>>> products to form is longer than 100th of a second, so they never do.
>>>>
>>> Exactly. They never turn back into water again.
>>>
>>> Google it. Everybody says the same thing. You get H2 and O2 together
>>> and its a bloody explosive mix,
>>>
>>
>> I have and I get examples of electrode boilers and water heaters, with
>> no mention to beware of explosive gases.
>
> indeed. That because at the currents and conditions they use, its far
> more likely that steam will outnumber H2 by a million to one or so
>
>
>>
>> A website closer to home:
>> http://www.tlc-direct.co.uk/Book/7.11.2.htm
>
>
Excellent, you accept that under AC fault/water conditions, like a
> Fredxx wrote:
>> On 10/09/2012 09:56, The Natural Philosopher wrote:
>>> Andrew Gabriel wrote:
>>>> In article <k2k901$d2e$1...@news.albasani.net>,
>>>> The Natural Philosopher <t...@invalid.invalid> writes:
>>>>> I think you will find you are wrong. Otherwise you could reverse
>>>>> electrolysis by simply switching polarity every half an hour. Or
>>>>> every ten years. Or 50 times a second...
>>>>>
>>>>>
>>>>> In fact its even more dangerous as H2 and O2 are formed at both
>>>>> electrodes.
>>>>
>>>> Given that electrode boilers generate no gas, I'd say you are wrong.
>>>>
>>>> I would guess the ion recombination time to for the electrolysis
>>>> products to form is longer than 100th of a second, so they never do.
>>>>
>>> Exactly. They never turn back into water again.
>>>
>>> Google it. Everybody says the same thing. You get H2 and O2 together
>>> and its a bloody explosive mix,
>>>
>>
>> I have and I get examples of electrode boilers and water heaters, with
>> no mention to beware of explosive gases.
>
> indeed. That because at the currents and conditions they use, its far
> more likely that steam will outnumber H2 by a million to one or so
>
>
>>
>> A website closer to home:
>> http://www.tlc-direct.co.uk/Book/7.11.2.htm
>
>
potential fault outlined in this thread, that any "explosions" will be a
likely to be a result of rapid steam generation rather than from a
hydrogen/oxygen explosion.
Fredxx
Sep 10, 2012, 11:35:51 AM9/10/12
to
cells function, having a thin film of hydrogen or oxygen at each
electrode with reverse polarity will convert that film back into
hydrogen or oxygen ions respectively. The process is reversible.
Have you got any more details of this explosion. Journalists usually
don't have a clue, and will write the most sensational nonsense!
dochol...@gmail.com
Sep 10, 2012, 12:16:15 PM9/10/12
to
On Monday, September 10, 2012 4:36:09 PM UTC+1, Fredxx wrote:
>
> Whilst most heat is generated resistively, in much the same way fuels
> cells function, having a thin film of hydrogen or oxygen at each
> electrode with reverse polarity will convert that film back into
> hydrogen or oxygen ions respectively. The process is reversible.
> Have you got any more details of this explosion. Journalists usually
> don't have a clue, and will write the most sensational nonsense!
Indeed - in this case though the reason I commented this had 'apparently' happened was that the information came from a competing manufacturer of electrode boilers who were claiming their design was safer...
>
> Whilst most heat is generated resistively, in much the same way fuels
> cells function, having a thin film of hydrogen or oxygen at each
> electrode with reverse polarity will convert that film back into
> hydrogen or oxygen ions respectively. The process is reversible.
> Have you got any more details of this explosion. Journalists usually
> don't have a clue, and will write the most sensational nonsense!
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