Hi,all.

We have a staff house in town, which is the accomodation on a couple of
floors above the shops on the high street.
This was all fully refurbished for us, including the electrical system, by
(presumably ) reputable proffessionals.

The lightbulb failure rate is astronomical.

We have tried normal lamps, and the energy-saver flourescent jobs.
They are lasting around a week!

All lampshades have been removed, to eliminate any possible overheating
issue. We've just got bare bulbs dangling from pendants.

The electricians havn't found anything wrong with the installation, and I've
eyeballed the electrical installation too. There's nothing obviously wrong.
There are several 6A lighting circuits, for various parts of the building,
just as you'd expect.

I can't really imagine what kind of fault within the building's wiring could
cause this.

I can only think of high-voltage spikes or other noise on the mains, perhaps
induced by some impropperly - suppressed large machinery controlled by triac
switching somewhere close by? But it's a light commercial area, not an
industrial area. The RMS voltage reads 240 to 250 depending on time of
day, with a calibrated fluke meter, so the basic voltage is OK.

I've suggested hiring a Power Quality Analyser from someplace to log the
supply voltages and spikes, harmonics, etc, becuase without some hard
evidence of what's going on, we're just shooting wild guesses.

Any other suggestions ?


--
Ron

"Ron Lowe" writes:

Any other suggestions ?

Before you go hiring expensive equipment or professional exorcists how
about using the min-max feature of many DVMs.

Do things fail at a particular time of week ? If not it ought to be
possible to measure something interesting very quickly.

Why not go chat to some of the nearby shopkeepers and residents in
case they are also suffering.

Are the problems confined to the lighting circuits or one lighting
circuit ? Would a desk lamp on the socket circuit suffer in the same
way ?

Are you by any chance getting all your noname brand light bulbs from
the same source ? If so perhaps they're dodgy.

Jon

"Jonathan Schneider" wrote in message
...
"Ron Lowe" writes:

Any other suggestions ?

Before you go hiring expensive equipment or professional exorcists how
about using the min-max feature of many DVMs.


I'm not sure the max/min feature has a fast enough response time for the
kind of glitch that may be happening. But yes, we could do that. Good
idea.

Do things fail at a particular time of week ? If not it ought to be
possible to measure something interesting very quickly.


Not that we have been able to determine.
We rather get the info second-hand from the people who live there.
And they are a transient bunch of students who come to our training school
for a few weeks at a time.

Why not go chat to some of the nearby shopkeepers and residents in
case they are also suffering.

Have done, and they are not aware of anything.

Are the problems confined to the lighting circuits or one lighting
circuit ? Would a desk lamp on the socket circuit suffer in the same
way ?

Now, that's an interesting question.
I don't have hard data, but I think the answer is that the bedside lamps are
not failing.
Which points to something in the lighting circuit, I think.

It also seems that the worst offenders are lights in hallways and corridors.

possible thought...

Switches?
These hallway circuits typically have several lamps per switch.
So possibly a bit more arcy-sparky in the switch?
I'd bet the developers who refurbished the place almost certainly used the
cheapest no-name bulk-pak switches too.
Perhaps as a cheap test, I could replace some switches...
Hmm again...

end of thought

Are you by any chance getting all your noname brand light bulbs from
the same source ? If so perhaps they're dodgy.

That was our first thought.
We have had batches from our normal bulk vendors, and from local tesco and
asda. And we've had so-called long life bulbs, and the low-power
flourescent thingys.

--
Thanks,
Ron

The lightbulb failure rate is astronomical.

If you contact your electricity company, they may be willing to supply some
logging gear that will measure the supply voltage and spikes over a period
of days. The supplier can then work out if there is a supply problem and fix
it.

Christian.

"Ron Lowe" writes:

We rather get the info second-hand from the people who live there.
And they are a transient bunch of students who come to our training school
for a few weeks at a time.

It's conceivable a nasty switch could upset the lights it controls but
not others on the same circuit.

Foreign long-haired students ? Nothing against these people as such.

Here's a possibility. Rather than have proper mains adaptors somebody
is plugging something into a light fitting which is now easier to get
to what with the shades removed. When the landing light is switched
off by a flatmate your nice low energy lamps get an indictive load
dump.

Now I'd imagine a heating hairdryer wouldn't do this because the
element would be in circuit but a cold hairdryer with low energy lamps
just maybe.

Jon

Foreign long-haired students ? Nothing against these people as such.

Here's a possibility. Rather than have proper mains adaptors somebody
is plugging something into a light fitting which is now easier to get
to what with the shades removed. When the landing light is switched
off by a flatmate your nice low energy lamps get an indictive load
dump.



Foreign, yes.
Long-haired, no.

Na, the ceilings in this old place are so high, we had to buy a special
super-extra-long stepladder to change the bulbs! This lives in a
maintenance cupboard which is locked.

They'd have to ballance 3 chairs on top of a table, and then stand on
someone's shoulders to do this!

The issue has outlasted several changes of students, too.
( and has been present since we moved into the place. )

We also provide a stock of universal plug adapters which we loan out to
anyone who needs them.

It amazes me that people visit a foreign country, and are surprised that
their plugs don't fit! Our American guests are the worst offenders. " Gee,
you guys have different plugs here! " If I'm in a less than charitable
mood with them, I just hand them an adapter and say nothing, and wait to
see if their laptop power brick is multi-voltage or not, because they never
think about that either.

--
Ron

On Wed, 21 Jun 2006 14:39:54 +0100 someone who may be "Ron Lowe"
wrote this:-

It amazes me that people visit a foreign country, and are surprised that
their plugs don't fit! Our American guests are the worst offenders. " Gee,
you guys have different plugs here! " If I'm in a less than charitable
mood with them, I just hand them an adapter and say nothing, and wait to
see if their laptop power brick is multi-voltage or not, because they never
think about that either.

Sadly, most have been multi-voltage, with automatic sensing, for a
considerable time. However, it is still worth a try.

How do they get on with trying their US dollars in the shops?

I can only imagine that there is some sort of external spike. Are
the shops open in the evening?

I wouldn't put too much trust in what they, or the students, say.
The only thing to do is probably to hire a gadget to keep a record
of what is happening.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On Wed, 21 Jun 2006 13:14:19 +0100, Ron Lowe wrote:

The RMS voltage reads 240 to 250 depending on time of day, with a
calibrated fluke meter, so the basic voltage is OK.

OK but 250 is rather high and presumably in the evening when the industry
has gone home but the lights are on... Upper limit is 230+10% = 253v.

The voltage here used to hover around 250v and light bulbs didn't last
well. Complained to the board, they came out measured, and adjusted the
tapping on our pole transformer. We now have voltage around 240 and bulbs
have the expected life, like chnaging one is a rare event compared to one
a week...

As to short transients I wouldn't expect tungsten lamps to be that
bothered due to the thermal inertia of the filament. Surges due to big
loads suddenly switching off is another matter.

--
Cheers
Dave. pam is missing e-mail

On Wed, 21 Jun 2006 13:14:19 +0100, "Ron Lowe"
had this to say:


We have a staff house in town, which is the accomodation on a couple of
floors above the shops on the high street.
This was all fully refurbished for us, including the electrical system, by
(presumably ) reputable proffessionals.

The lightbulb failure rate is astronomical.

Are the bulbs you're buying rated at 230V or 240V? A 230V bulb
operating on 240 will have a much shorter life than it oughta.

--
Frank Erskine

Ron Lowe wrote:

Hi,all.

We have a staff house in town, which is the accomodation on a couple of
floors above the shops on the high street.
This was all fully refurbished for us, including the electrical system, by
(presumably ) reputable proffessionals.

The lightbulb failure rate is astronomical.

We have tried normal lamps, and the energy-saver flourescent jobs.
They are lasting around a week!

All lampshades have been removed, to eliminate any possible overheating
issue.

you can put those back now

We've just got bare bulbs dangling from pendants.

The electricians havn't found anything wrong with the installation, and I've
eyeballed the electrical installation too. There's nothing obviously wrong.
There are several 6A lighting circuits, for various parts of the building,
just as you'd expect.

I can't really imagine what kind of fault within the building's wiring could
cause this.

none

I can only think of high-voltage spikes or other noise on the mains, perhaps
induced by some impropperly - suppressed large machinery controlled by triac
switching somewhere close by? But it's a light commercial area, not an
industrial area. The RMS voltage reads 240 to 250 depending on time of
day, with a calibrated fluke meter, so the basic voltage is OK.

I've suggested hiring a Power Quality Analyser from someplace to log the
supply voltages and spikes, harmonics, etc, becuase without some hard
evidence of what's going on, we're just shooting wild guesses.

Any other suggestions ?


we're just shooting wild guesses.

thats the one thing that strikes me about your whole approach here.
Until you gather the facts reliably, youre blowing in the wind.

Forgive me for stating the obvious, but do you think they might be
swapping their dead room bulbs with working corridor ones to avouid
buying replacements? Its not exactly difficult to give someone a leg up
to reach a high ceiling.

Lets establish a few facts.

It wont be spikes, as electronic equipment would be dying faster than
lightbulbs. A filament bulb can take a hell of a big spike without
dying.

If you've used 2 or more brands of bulb it isnt the bulbs either.

Switches and bad wiring wont reduce the life of filament lamps. If
anything it would increase it.

Harmonics have nothing to do with it, as filaments couldnt care less
about anything but rms voltage.

The fact that your neighbours have no such problem ends any discussion
about bad mains supply.

It all leaves only one conclusion. If it were me I'd fit secure
fittings, ie a special tool is needed to reach the bulb, and only
special bulbs will fit, such as unballasted low energy or even 2'
linear fl.


NT

On Wed, 21 Jun 2006 13:02:31 UTC, "Ron Lowe"
wrote:

"Jonathan Schneider" wrote in message
...
"Ron Lowe" writes:

Any other suggestions ?

Before you go hiring expensive equipment or professional exorcists how
about using the min-max feature of many DVMs.


I'm not sure the max/min feature has a fast enough response time for the
kind of glitch that may be happening. But yes, we could do that. Good
idea.

Or a UPS with a PC monitoring it, set to tight margins.

--
The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
Avenue Supplies, http://avenuesupplies.co.uk

I was thinking back to an episode of Grange Hill where the kid(s) made
a few bob taking the school's lightbulbs to a porn shop.

Though if you've had different tenants including yourselves this seems
very unlikely.

As for 250v I don't believe this is the cause otherwise you'd be
buying bulbs not fit for use.

Jon

wrote:

thats the one thing that strikes me about your whole approach here.
Until you gather the facts reliably, youre blowing in the wind.


So are you.

Forgive me for stating the obvious, but do you think they might be
swapping their dead room bulbs with working corridor ones to avouid
buying replacements? Its not exactly difficult to give someone a leg
up to reach a high ceiling.


He did say the bulbs have been blowing since the place had been rewired.


--
Sir Benjamin Middlethwaite

we're just shooting wild guesses.

thats the one thing that strikes me about your whole approach here.
Until you gather the facts reliably, youre blowing in the wind.

Yes, I'm only just getting started on this myself.
I havn't been down there for quite a while, I really need to go back and
take a closer look.
I only did a cursory check with a fluke last time, shrugged my shoulders,
and we just asked the electrician to go check it out.
That was months ago, and I've just had the handyman whinging at me again, so
that's why I need to re-investigate.
It's not really my day-job, just one of the various hats I have to wear!

Forgive me for stating the obvious, but do you think they might be
swapping their dead room bulbs with working corridor ones to avouid
buying replacements? Its not exactly difficult to give someone a leg up
to reach a high ceiling.

I'm fairly certain they are not swapping bulbs, it really is not leg-up
stuff.
You'd need to be an Eastern European circus troup to get up to that height
onother people's shoulders. Then again....

Lets establish a few facts.

It wont be spikes, as electronic equipment would be dying faster than
lightbulbs. A filament bulb can take a hell of a big spike without
dying.

Inclined to agree.

If you've used 2 or more brands of bulb it isnt the bulbs either.

Yes, I agree too.

Switches and bad wiring wont reduce the life of filament lamps. If
anything it would increase it.

Possibly agree, I wondered if nasty switching transients might be a problem,
if they were repeated often enough.

Harmonics have nothing to do with it, as filaments couldnt care less
about anything but rms voltage.

Well, yes. I was just indicating the kind of parameters these machines
monitor. I'm sure that particular parameter is not significant. I'd be
interested to see what the supply voltage fluctuations were over a week or
so, at the actual ceiling rose.

The fact that your neighbours have no such problem ends any discussion
about bad mains supply.

Hmm, possibly.
I don't know how reliable their evidence is.
Also, they may be on different phases, which is something that set me
thinking again...

It all leaves only one conclusion. If it were me I'd fit secure
fittings, ie a special tool is needed to reach the bulb, and only
special bulbs will fit, such as unballasted low energy or even 2'
linear fl.


Possibly, but like I say, I don't believe they are messing with them.


I've just been driving home, and musing this in my head.
I have been able to dream up an obscure scenario......

The incoming cable to this building is 3-phase +N.
This splits off to the various premises in the building, including us.

If the 3 phases are well ballanced, the N current is zero.
But if the load was not well-ballanced, then there may be significant N
current.
And that in turn may cause voltage drops along the N line.
Which means the N voltage at our distribution board may be slightly
elevated, not a true N.
For a single phase supply, this would be in-phase with the L current, and
would subtract from the voltage available at the load.
But in a 3-phase system, this N voltage would actually be an additive value
on 1 or 2 of the phases, depending on the exact phase of the N current,
which in turn depends on the relative L1, L2 and L3 currents.

Now I think about it, it is possible the lights are on a different phase
from the power rings.
And that may well be significant.
I need to go down there and make some better measurments, and with a closer
eye on what phases things are on.
I might just also clamp a current meter round the incoming tails...


--
Ron

Ron Lowe wrote:


I've just been driving home, and musing this in my head.
I have been able to dream up an obscure scenario......

The incoming cable to this building is 3-phase +N.
This splits off to the various premises in the building, including us.

If the 3 phases are well ballanced, the N current is zero.
But if the load was not well-ballanced, then there may be significant N
current.
And that in turn may cause voltage drops along the N line.
Which means the N voltage at our distribution board may be slightly
elevated, not a true N.
For a single phase supply, this would be in-phase with the L current, and
would subtract from the voltage available at the load.
But in a 3-phase system, this N voltage would actually be an additive value
on 1 or 2 of the phases, depending on the exact phase of the N current,
which in turn depends on the relative L1, L2 and L3 currents.

Now I think about it, it is possible the lights are on a different phase
from the power rings.
And that may well be significant.
I need to go down there and make some better measurments, and with a closer
eye on what phases things are on.
I might just also clamp a current meter round the incoming tails...

I thought it was against Regs to feed different circuits (e.g. power &
lights and/or upstairs power & downstairs power) in the same residence
off different phases - otherwise people can get 415V unexpectedly. I'm
not an electrician, but ISTR that asonishment was expressed when
someone found out that German regs allowed it. Andrew Gabriel may be
along to correct me presently....

Sid

Sid

wrote in message
oups.com...

Ron Lowe wrote:


I've just been driving home, and musing this in my head.
I have been able to dream up an obscure scenario......

The incoming cable to this building is 3-phase +N.
This splits off to the various premises in the building, including us.

If the 3 phases are well ballanced, the N current is zero.
But if the load was not well-ballanced, then there may be significant N
current.
And that in turn may cause voltage drops along the N line.
Which means the N voltage at our distribution board may be slightly
elevated, not a true N.
For a single phase supply, this would be in-phase with the L current, and
would subtract from the voltage available at the load.
But in a 3-phase system, this N voltage would actually be an additive
value
on 1 or 2 of the phases, depending on the exact phase of the N current,
which in turn depends on the relative L1, L2 and L3 currents.

Now I think about it, it is possible the lights are on a different phase
from the power rings.
And that may well be significant.
I need to go down there and make some better measurments, and with a
closer
eye on what phases things are on.
I might just also clamp a current meter round the incoming tails...

I thought it was against Regs to feed different circuits (e.g. power &
lights and/or upstairs power & downstairs power) in the same residence
off different phases - otherwise people can get 415V unexpectedly. I'm
not an electrician, but ISTR that asonishment was expressed when
someone found out that German regs allowed it. Andrew Gabriel may be
along to correct me presently....

Sid

That can't be right, or that would mean a property can't have more then one
phase!

I would think you can have lighting on one phase, sockets on another, but
you are not allowed to have more than one phase's wiring in a single phase
item (for example, a normal 13A socket can't have wiring for another phase
in the same box)

But I stand to be corrected too!

I thought it was against Regs to feed different circuits (e.g. power &
lights and/or upstairs power & downstairs power) in the same residence
off different phases - otherwise people can get 415V unexpectedly. I'm
not an electrician, but ISTR that asonishment was expressed when
someone found out that German regs allowed it. Andrew Gabriel may be
along to correct me presently....

Sid




Well, our office is supplied from a Merlin 3-phase distribution board, with
3-phase loads obviously coming off all 3, but individual rings and lighting
ccts come off different phases.

Indeed, if someone were to put their finger in the L of live socket, whilst
sticking their tounge in the L of another ( they'd need a long tounge... )
then yes, they'd get a 415v tingle instead of a 240 one. Or if they
drilled into the ceiling with a 240 drill powered off one phase, and drilled
through a lighting cable on another, then within the drill, there would be
415 v available...

Perhaps there's a difference in the regs as regards domestic and commercial
premises.
I also don't know if our hostel premises would count as domestic or
commercial.
( I'm in Scotland, so the regs might be different again from English ones,
possibly. )

I can't even remember if the feed to our staff house board is 1 or 3 phase!
And that's a rather fundamental question.
That's why I need to go back and take a closer look.

--
Ron

Ron Lowe was thinking very hard :
I can only think of high-voltage spikes or other noise on the mains, perhaps
induced by some impropperly - suppressed large machinery controlled by triac
switching somewhere close by? But it's a light commercial area, not an
industrial area. The RMS voltage reads 240 to 250 depending on time of
day, with a calibrated fluke meter, so the basic voltage is OK.

240 to 250v would seem a little high, combine that with perhaps cheap
no name lamps and they may not last long. I once bought a batch of 230v
European lamps which lasted no more than a week or two each. Our supply
generally measures 240v or occasionally a volt or two over.

As someone else suggested - as a first step use the min/max logging
facility included in some meters.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On Wed, 21 Jun 2006 15:08:05 GMT, Jonathan Schneider
wrote:

I was thinking back to an episode of Grange Hill where the kid(s) made
a few bob taking the school's lightbulbs to a porn shop.


pawn! Unless Grange Hill went downhill after I stopped watching it.

Though if you've had different tenants including yourselves this seems
very unlikely.

As for 250v I don't believe this is the cause otherwise you'd be
buying bulbs not fit for use.

Jon

--
UK Top 10 freebies
http://www.top10freebies.co.uk

In article ,
Ron Lowe wrote:
Do things fail at a particular time of week ? If not it ought to be
possible to measure something interesting very quickly.


Not that we have been able to determine. We rather get the info
second-hand from the people who live there. And they are a transient
bunch of students who come to our training school for a few weeks at a
time.

Hmm. Students selling the good ones and replacing them with faulty?

--
*It's lonely at the top, but you eat better.

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

Ron Lowe wrote:
Hi,all.

We have a staff house in town, which is the accomodation on a couple of
floors above the shops on the high street.
This was all fully refurbished for us, including the electrical system, by
(presumably ) reputable proffessionals.

The lightbulb failure rate is astronomical.

We have tried normal lamps, and the energy-saver flourescent jobs.
They are lasting around a week!

All lampshades have been removed, to eliminate any possible overheating
issue. We've just got bare bulbs dangling from pendants.

The electricians havn't found anything wrong with the installation, and I've
eyeballed the electrical installation too. There's nothing obviously wrong.
There are several 6A lighting circuits, for various parts of the building,
just as you'd expect.

I can't really imagine what kind of fault within the building's wiring could
cause this.

The inhabitants are selling the bulbs in exchange for 'blown' bulbs.

Mark each one with a lick of red paint before inserting.

Also, be aware that in semi public spaces, its customary to nick the
bulb in the hall when your room light goes..it may simply be that what
appears o be short lived bulbs are simply common areas where people have
nicked the bulbs.

Also bulk buy quality bulbs online from reputable dealers..a LOT of east
europe bulbs are suitable only for road fill.


I can only think of high-voltage spikes or other noise on the mains, perhaps
induced by some impropperly - suppressed large machinery controlled by triac
switching somewhere close by? But it's a light commercial area, not an
industrial area. The RMS voltage reads 240 to 250 depending on time of
day, with a calibrated fluke meter, so the basic voltage is OK.

I've suggested hiring a Power Quality Analyser from someplace to log the
supply voltages and spikes, harmonics, etc, becuase without some hard
evidence of what's going on, we're just shooting wild guesses.

Any other suggestions ?

wrote:
Ron Lowe wrote:

Hi,all.

We have a staff house in town, which is the accomodation on a couple of
floors above the shops on the high street.
This was all fully refurbished for us, including the electrical system, by
(presumably ) reputable proffessionals.

The lightbulb failure rate is astronomical.

We have tried normal lamps, and the energy-saver flourescent jobs.
They are lasting around a week!

All lampshades have been removed, to eliminate any possible overheating
issue.

you can put those back now

We've just got bare bulbs dangling from pendants.

The electricians havn't found anything wrong with the installation, and I've
eyeballed the electrical installation too. There's nothing obviously wrong.
There are several 6A lighting circuits, for various parts of the building,
just as you'd expect.

I can't really imagine what kind of fault within the building's wiring could
cause this.

none

I can only think of high-voltage spikes or other noise on the mains, perhaps
induced by some impropperly - suppressed large machinery controlled by triac
switching somewhere close by? But it's a light commercial area, not an
industrial area. The RMS voltage reads 240 to 250 depending on time of
day, with a calibrated fluke meter, so the basic voltage is OK.

I've suggested hiring a Power Quality Analyser from someplace to log the
supply voltages and spikes, harmonics, etc, becuase without some hard
evidence of what's going on, we're just shooting wild guesses.

Any other suggestions ?


we're just shooting wild guesses.

thats the one thing that strikes me about your whole approach here.
Until you gather the facts reliably, youre blowing in the wind.

Forgive me for stating the obvious, but do you think they might be
swapping their dead room bulbs with working corridor ones to avouid
buying replacements? Its not exactly difficult to give someone a leg up
to reach a high ceiling.

Lets establish a few facts.

It wont be spikes, as electronic equipment would be dying faster than
lightbulbs. A filament bulb can take a hell of a big spike without
dying.

If you've used 2 or more brands of bulb it isnt the bulbs either.

Switches and bad wiring wont reduce the life of filament lamps. If
anything it would increase it.

Harmonics have nothing to do with it, as filaments couldnt care less
about anything but rms voltage.

The fact that your neighbours have no such problem ends any discussion
about bad mains supply.

It all leaves only one conclusion. If it were me I'd fit secure
fittings, ie a special tool is needed to reach the bulb, and only
special bulbs will fit, such as unballasted low energy or even 2'
linear fl.


NT

boy i was in a good mood :/

NT

Ron Lowe wrote:

Forgive me for stating the obvious, but do you think they might be
swapping their dead room bulbs with working corridor ones to avouid
buying replacements? Its not exactly difficult to give someone a leg up
to reach a high ceiling.

I'm fairly certain they are not swapping bulbs, it really is not leg-up
stuff.
You'd need to be an Eastern European circus troup to get up to that height
onother people's shoulders.

I accept its unliekly then, but still possible. If you put a mark on
the base of the communal bulbs, and collected all the dead ones, you
cuold at least confirm whether imitating famous circuses was a popular
pastime in some cultures. You never know.


Then again....

Lets establish a few facts.

It wont be spikes, as electronic equipment would be dying faster than
lightbulbs. A filament bulb can take a hell of a big spike without
dying.

Inclined to agree.

If you've used 2 or more brands of bulb it isnt the bulbs either.

Yes, I agree too.

Switches and bad wiring wont reduce the life of filament lamps. If
anything it would increase it.

Possibly agree, I wondered if nasty switching transients might be a problem,
if they were repeated often enough.

but see above where you agree it cant be those. Electronics is far more
vulnerable than filaments to transients, and theyre not a significant
problem on domestic premises anyway.


Harmonics have nothing to do with it, as filaments couldnt care less
about anything but rms voltage.

Well, yes. I was just indicating the kind of parameters these machines
monitor. I'm sure that particular parameter is not significant. I'd be
interested to see what the supply voltage fluctuations were over a week or
so, at the actual ceiling rose.

thats really the only thing that may be killing them, if it rises to
270v at 4am or something.


The fact that your neighbours have no such problem ends any discussion
about bad mains supply.

Hmm, possibly.
I don't know how reliable their evidence is.
Also, they may be on different phases, which is something that set me
thinking again...

fair point. Still its hard to see how one pahse would get 240 and
another much more. If there were a neutral problem on the supply side
you'd expect it to show up here there and everywhere, and at peak times
not out of hours. 1/3 of the tenants would be complaining about dead
bulbs.


I've just been driving home, and musing this in my head.
I have been able to dream up an obscure scenario......

The incoming cable to this building is 3-phase +N.
This splits off to the various premises in the building, including us.

If the 3 phases are well ballanced, the N current is zero.
But if the load was not well-ballanced, then there may be significant N
current.
And that in turn may cause voltage drops along the N line.
Which means the N voltage at our distribution board may be slightly
elevated, not a true N.
For a single phase supply, this would be in-phase with the L current, and
would subtract from the voltage available at the load.
But in a 3-phase system, this N voltage would actually be an additive value
on 1 or 2 of the phases, depending on the exact phase of the N current,
which in turn depends on the relative L1, L2 and L3 currents.

Now I think about it, it is possible the lights are on a different phase
from the power rings.
And that may well be significant.
I need to go down there and make some better measurments, and with a closer
eye on what phases things are on.
I might just also clamp a current meter round the incoming tails...

But if youve got elevated Vs, so has someone else. It would be a
chaotic wiring system that puts only one persons lights on one of the
phases.


Whatever the deal is, I think we could all agree you need some hard
facts re supply voltage. Hopefully you can log the voltage at the light
fittings.


NT

Whatever the deal is, I think we could all agree you need some hard
facts re supply voltage. Hopefully you can log the voltage at the light
fittings.


NT



Yes, I think that's the only way forward.
I'll log the voltage at the fitting.

I'll also set up a datalogger if I can on all 3 Phase-N and Phase- Phase and
see what I can see.
--
Ron

On 21 Jun 2006 08:46:27 -0700 someone who may be
wrote this:-

I thought it was against Regs to feed different circuits (e.g. power &
lights and/or upstairs power & downstairs power) in the same residence
off different phases - otherwise people can get 415V unexpectedly.

Provided that there are suitable warning notices there is no
problem.

However, when designing an electrical installation it is a lot
neater if lots of electrical bits and pieces are not covered with
warning notices. Depending on the building shape and expected loads
floors will probably be split into three areas, with the same phase
in each area for all circuits.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

"Jonathan Schneider" wrote in message
...
I was thinking back to an episode of Grange Hill where the kid(s) made
a few bob taking the school's lightbulbs to a porn shop.

Do dirty magazines require a lot of illumination?
--
Dave Baker
www.pumaracing.co.uk
Usenet - a collection of people who only open their mouth to change feet.

"Ron Lowe" wrote in message
...
Hi,all.

We have a staff house in town, which is the accomodation on a couple of
floors above the shops on the high street.
This was all fully refurbished for us, including the electrical system, by
(presumably ) reputable proffessionals.

The lightbulb failure rate is astronomical.

We have tried normal lamps, and the energy-saver flourescent jobs.
They are lasting around a week!

Electrickery isn't really my thing but in cars when bulbs start blowing the
first thing you check is the condition of the earth connections. Dunno if
this also applies to AC installations but someone on here will. If so then
that's what I'd be looking at.
--
Dave Baker
www.pumaracing.co.uk
Usenet - a collection of people who only open their mouth to change feet.

one thought - is it heavy-footed people upstairs. Friend of mine had some
fat bird that lived above him and her
stomping shook the fitting below and blew the bulbs fairly regularly. She
moved out - problem solved

DMac wrote:
one thought - is it heavy-footed people upstairs. Friend of mine had some
fat bird that lived above him and her
stomping shook the fitting below and blew the bulbs fairly regularly. She
moved out - problem solved

Rough service bulbs would solve or eliminate that, and are available
from screwfix and the like.

NT

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "DMac" saying
something like:

one thought - is it heavy-footed people upstairs. Friend of mine had some
fat bird that lived above him and her
stomping shook the fitting below and blew the bulbs fairly regularly. She
moved out - problem solved

Dear Madam,

Please find enclosed the bill for replacement light bulbs for the past
year. These replacements were necessary because you are such a fat git.

Yours, etc
--

Dave