Can anybody help me with this problem?

I have someone living in my apartment while I am away. He has rung me
up to say that in the last ten months THREE computers have "died" on him
due to being connected to a socket in my apartment. (I think he's
trying to make me feel guilty so that I will compensate him somehow.)

He says that on each occasion his computers have been hit by a power
surge. He says that on the first two occasions he wasn't in when the
surges hit, but that on returning home he found the computers dead. He
says that for the third computer he fitted a surge-protector between the
socket and his computer, but that last week he was at home when his
printer started "smoking". He says this last power surge must have been
really bad.

Today I rang my electricity network provider and they assured me that
there have been NO major surges in my area in the last year, and that if
there had been then the whole apartment would have been knocked out, the
fuses would have blown in the fuseboard, and other equipment and lights
would have been damaged too.

In a couple of days' time I am going to visit the apartment with a
socket-tester - it's a small plug which shows if the socket is wired
correctly. The only thing I can think of which might have caused the
death of three computers (if, in fact, they DID really die) is that the
"live" and the "neutral" wires to the socket (from the fuseboard) might
have been attached to the socket the wrong way round.

If this is the case, I know this wouldn't injure a lightbulb, but my
question is: would this injure a computer? A friend tells me that
current is "alternating" and that it therefore shouldn't matter whether
the live and neural wires to the socket are reversed. But does this
situation ring any bells with anyone?

Or is the guy in my apartment either just someone who has bought three
faulty computers in a row or someone who is just trying to take me for a
ride?

Thanks.

Nell.

Thomas wrote:

Can anybody help me with this problem?

Sorry, the subject line of my message should read as above,
"neutral-live electrical wiring".

Nell.

Thomas wrote:
Can anybody help me with this problem?

I have someone living in my apartment while I am away. He has rung me
up to say that in the last ten months THREE computers have "died" on him
due to being connected to a socket in my apartment. (I think he's
trying to make me feel guilty so that I will compensate him somehow.)

He says that on each occasion his computers have been hit by a power
surge. He says that on the first two occasions he wasn't in when the
surges hit, but that on returning home he found the computers dead. He
says that for the third computer he fitted a surge-protector between the
socket and his computer, but that last week he was at home when his
printer started "smoking". He says this last power surge must have been
really bad.

Today I rang my electricity network provider and they assured me that
there have been NO major surges in my area in the last year, and that if
there had been then the whole apartment would have been knocked out, the
fuses would have blown in the fuseboard, and other equipment and lights
would have been damaged too.

In a couple of days' time I am going to visit the apartment with a
socket-tester - it's a small plug which shows if the socket is wired
correctly. The only thing I can think of which might have caused the
death of three computers (if, in fact, they DID really die) is that the
"live" and the "neutral" wires to the socket (from the fuseboard) might
have been attached to the socket the wrong way round.

If this is the case, I know this wouldn't injure a lightbulb, but my
question is: would this injure a computer? A friend tells me that
current is "alternating" and that it therefore shouldn't matter whether
the live and neural wires to the socket are reversed. But does this
situation ring any bells with anyone?

Or is the guy in my apartment either just someone who has bought three
faulty computers in a row or someone who is just trying to take me for a
ride?

Thanks.

Nell.

FWIW, I vote for the "he's gaming you" option.

I'd ask to see the dead computers, and do a post-mortem.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

Thomas writes:

Can anybody help me with this problem?

I have someone living in my apartment while I am away. He has rung me
up to say that in the last ten months THREE computers have "died" on him
due to being connected to a socket in my apartment. (I think he's
trying to make me feel guilty so that I will compensate him somehow.)

He says that on each occasion his computers have been hit by a power
surge. He says that on the first two occasions he wasn't in when the
surges hit, but that on returning home he found the computers dead. He
says that for the third computer he fitted a surge-protector between the
socket and his computer, but that last week he was at home when his
printer started "smoking". He says this last power surge must have been
really bad.

Today I rang my electricity network provider and they assured me that
there have been NO major surges in my area in the last year, and that if
there had been then the whole apartment would have been knocked out, the
fuses would have blown in the fuseboard, and other equipment and lights
would have been damaged too.

In a couple of days' time I am going to visit the apartment with a
socket-tester - it's a small plug which shows if the socket is wired
correctly. The only thing I can think of which might have caused the
death of three computers (if, in fact, they DID really die) is that the
"live" and the "neutral" wires to the socket (from the fuseboard) might
have been attached to the socket the wrong way round.

If this is the case, I know this wouldn't injure a lightbulb, but my
question is: would this injure a computer? A friend tells me that
current is "alternating" and that it therefore shouldn't matter whether
the live and neural wires to the socket are reversed. But does this
situation ring any bells with anyone?

Or is the guy in my apartment either just someone who has bought three
faulty computers in a row or someone who is just trying to take me for a
ride?

Reversed Hot and Neutral should not damage computers or any other modern
electronics or appliances, nor is it an inherently unsafe condition.
Anything that plugs into the wall must be designed to be safe if H and N
are reversed.

I agree with another post - ask to see the damaged equipment.

There could be other wiring issues like a loose Neutral at the service
entrance causing large variations in voltage but you'd most likely see
other symptoms like changes in lamp brightness,

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Important: Anything sent to the email address in the message header above is
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"Thomas" wrote in message
...
| Can anybody help me with this problem?
|
| I have someone living in my apartment while I am away. He has rung me
| up to say that in the last ten months THREE computers have "died" on him
| due to being connected to a socket in my apartment. (I think he's
| trying to make me feel guilty so that I will compensate him somehow.)
|
| He says that on each occasion his computers have been hit by a power
| surge. ...

It's not your problem. There's no way that there can be any surge that will
do that without smoking every light bulb unless it's a lightning strike
close by. He should check with his insurer to see if he is covered.

N

This dude is trying to soak you up for a few computers, or at least one new
one!

This guy may be buying cheap used computers, or whatever else, and who
knows...

If the neutral and hot are reversed, the load should work normally, but
would not comply to the electrical code. The best verification to be legal
is to have a certified electrician come in to the place, and test his wall
outlets to where he connects the computers, and have him give you a written
letter that the power to those outlets comply to the electrical standards of
your area, and comply to all the local bylaws for performance and safety.

This will cost you the cost for the electrician and his time. But, this will
protect you in case the fellow decides to take you to court, and also try to
make a claim from your insurance company to pay him. In the end without
being protected, you leave yourself opened. Also, in the future, you will
have proof that electrical in the place is safe, and is at no risk for the
insurance company.

The very next step I would do, is to find a way to get rid of this tenant as
quickly as possible. He is not worth the aggravation and stress.

As for power surges, this would be from the electric supply company. If you
read their contract, they are not responsible, unless under particular
circumstances.

--

Jerry G.
=====

"Thomas" wrote in message
...
Can anybody help me with this problem?

I have someone living in my apartment while I am away. He has rung me
up to say that in the last ten months THREE computers have "died" on him
due to being connected to a socket in my apartment. (I think he's
trying to make me feel guilty so that I will compensate him somehow.)

He says that on each occasion his computers have been hit by a power
surge. He says that on the first two occasions he wasn't in when the
surges hit, but that on returning home he found the computers dead. He
says that for the third computer he fitted a surge-protector between the
socket and his computer, but that last week he was at home when his
printer started "smoking". He says this last power surge must have been
really bad.

Today I rang my electricity network provider and they assured me that
there have been NO major surges in my area in the last year, and that if
there had been then the whole apartment would have been knocked out, the
fuses would have blown in the fuseboard, and other equipment and lights
would have been damaged too.

In a couple of days' time I am going to visit the apartment with a
socket-tester - it's a small plug which shows if the socket is wired
correctly. The only thing I can think of which might have caused the
death of three computers (if, in fact, they DID really die) is that the
"live" and the "neutral" wires to the socket (from the fuseboard) might
have been attached to the socket the wrong way round.

If this is the case, I know this wouldn't injure a lightbulb, but my
question is: would this injure a computer? A friend tells me that
current is "alternating" and that it therefore shouldn't matter whether
the live and neural wires to the socket are reversed. But does this
situation ring any bells with anyone?

Or is the guy in my apartment either just someone who has bought three
faulty computers in a row or someone who is just trying to take me for a
ride?

Thanks.

Nell.

A few technically more informed posters have provided the
responsible posts. For example, a defective neutral wire
could cause excessive voltages on one appliance when other
heavy current appliances are turned on. A common reason for
this is a loose screw where the heavy neutral wire connects
inside circuit breaker box. Other reasons would be a failing
utility transformer or badly spliced neutral in the utility
drop. But again, this would also be obvious in incandescent
bulbs dimming or getting brighter and also failing noticeable
faster.

Failed neutral is but another reason why the earth ground
rod (water pipe is no longer acceptable). also called ground
electrode connection, is important for human safety reasons.
Earthing is also why the utility transformer ground is
important ( http://www.tvtower.com/fpl.html ). Both must be
verified by visual inspection. They are responsible for
ground on that transformer. You are responsible for earthing
of the building.


A socket tester will report nothing useful. You need
numbers. No 'go-nogo' test exists for this type problem. You
are looking at electricity which means, at minimum, you need a
3.5 digit multimeter. So ubiquitous and inexpensive today as
to even be sold in Radio Shack, Home Depot, Lowes, and Sears.

Power surges are what the naive hype when they have no
idea. Destructive surges occur typically once every 8 years.
He has damaged parts. As another responsible poster noted,
best evidence is the dead body. But one problem. Most
computer repair people have little idea how electricity works
let alone be able to identify the failed part. If repairman
does not have an oscilloscope AND know how to use it, then he
would typically declare it a power surge using same
'knowledge' failure.

The tenant has a surge protector. So what? Voltages that
would typically damage electronics, as described, may be more
than 130 volts on the 120 volt outlet for prolonged periods.
Voltages that are well below a number on power strip
protectors - 330 volts. IOW surge protector would never even
see nor respond to destructive voltages that are less than 300
volts. Let us say he is suffering 150+ volts, but light bulbs
(incandescent only) are not glowing brighter. OK. Where is
that excessive voltage coming from?

Well computer is connected to AC electric and cable. Or AC
electric and phone line. Or Cable and phone line. To avoid
excessive voltage, all three must first connect to the same
earth ground before entering building - as is demanded by
National Electrical Code requirements. A CATV wire connected
to a water faucet is not sufficient. A phone connected to a
water pipe no longer qualifies. All three utilities must
connect either by direct hardwire (AC electric breaker box and
cable) to the same earth ground rod. Phone line makes same
hardwired connection via a surge protector inside the NID box.

It has been observed. Electrical failures inside an
adjacent house caused excessive voltage in this house because
the incoming utilities were not first earthed at a common
point. Just another possibility that is most easily
eliminated by visual inspection.

More things to look for. The socket tester can report a
failure BUT it cannot report a good socket. You need numbers
which means a meter. You are looking for excessive voltages
such as more than 126 volt on wall receptacle - hot to
neutral. Or more than 2 volts between receptacle neutral and
safety ground. These voltages taken under normal conditions
AND when heavy current appliances are turned on or off.

One further note - if printer and computer are not sharing
a same power strip and are therefore on different circuit
breakers. If the devices do not have good equipment grounds
(wall receptacle safety ground), then this too can create
destructive voltages between a computer and its printer. The
tenant must have a power strip, with the all so important 15
amp circuit breaker and without surge protector (adjacent
surge protector can even contribute to damage of a powered off
appliance). Basic power strip with the important 15 amp
circuit breaker costs $3+ in Home Depot or Walmart. If
printer and computer get power from different circuit breakers
(and if other criteria are met which is beyond the scope of
this text), then computer damage can result due to a 240 volt
leakage via data cable.

Hope this helps. Numerous things to inspect. A meter and
visual inspection is required. A large and well insulated
screwdriver may be necessary to tighten screws on incoming
neutral wire inside breaker box which is the best way to
confirm that connection. Best evidence would be from a list
of components - resistors, capacitors, IC - damaged in
computer and printer. Most computer repairmen don't have
sufficient knowledge to provide that information - which is
why they too always blame surges.

Thomas wrote:
Can anybody help me with this problem?

I have someone living in my apartment while I am away. He has rung me
up to say that in the last ten months THREE computers have "died" on him
due to being connected to a socket in my apartment. (I think he's
trying to make me feel guilty so that I will compensate him somehow.)

He says that on each occasion his computers have been hit by a power
surge. He says that on the first two occasions he wasn't in when the
surges hit, but that on returning home he found the computers dead. He
says that for the third computer he fitted a surge-protector between the
socket and his computer, but that last week he was at home when his
printer started "smoking". He says this last power surge must have been
really bad.

Today I rang my electricity network provider and they assured me that
there have been NO major surges in my area in the last year, and that if
there had been then the whole apartment would have been knocked out, the
fuses would have blown in the fuseboard, and other equipment and lights
would have been damaged too.

In a couple of days' time I am going to visit the apartment with a
socket-tester - it's a small plug which shows if the socket is wired
correctly. The only thing I can think of which might have caused the
death of three computers (if, in fact, they DID really die) is that the
"live" and the "neutral" wires to the socket (from the fuseboard) might
have been attached to the socket the wrong way round.

If this is the case, I know this wouldn't injure a lightbulb, but my
question is: would this injure a computer? A friend tells me that
current is "alternating" and that it therefore shouldn't matter whether
the live and neural wires to the socket are reversed. But does this
situation ring any bells with anyone?

Or is the guy in my apartment either just someone who has bought three
faulty computers in a row or someone who is just trying to take me for a
ride?

Thanks.

Nell.

"Sam Goldwasser" bravely wrote to "All" (20 Dec 04 20:52:48)
--- on the heady topic of " neural-live electrical-wiring to computer ?"

SG From: Sam Goldwasser

SG Thomas writes:

Can anybody help me with this problem?

I have someone living in my apartment while I am away. He has rung me
up to say that in the last ten months THREE computers have "died" on him
due to being connected to a socket in my apartment. (I think he's
trying to make me feel guilty so that I will compensate him somehow.)

He says that on each occasion his computers have been hit by a power
surge. He says that on the first two occasions he wasn't in when the
surges hit, but that on returning home he found the computers dead. He
says that for the third computer he fitted a surge-protector between the
socket and his computer, but that last week he was at home when his
printer started "smoking". He says this last power surge must have been
really bad.

Today I rang my electricity network provider and they assured me that
there have been NO major surges in my area in the last year, and that if
there had been then the whole apartment would have been knocked out, the
fuses would have blown in the fuseboard, and other equipment and lights
would have been damaged too.

In a couple of days' time I am going to visit the apartment with a
socket-tester - it's a small plug which shows if the socket is wired
correctly. The only thing I can think of which might have caused the
death of three computers (if, in fact, they DID really die) is that the
"live" and the "neutral" wires to the socket (from the fuseboard) might
have been attached to the socket the wrong way round.

If this is the case, I know this wouldn't injure a lightbulb, but my
question is: would this injure a computer? A friend tells me that
current is "alternating" and that it therefore shouldn't matter whether
the live and neural wires to the socket are reversed. But does this
situation ring any bells with anyone?

Or is the guy in my apartment either just someone who has bought three
faulty computers in a row or someone who is just trying to take me for a
ride?

SG Reversed Hot and Neutral should not damage computers or any other
SG modern electronics or appliances, nor is it an inherently unsafe
SG condition. Anything that plugs into the wall must be designed to be
SG safe if H and N are reversed.

SG I agree with another post - ask to see the damaged equipment.

SG There could be other wiring issues like a loose Neutral at the service
SG entrance causing large variations in voltage but you'd most likely see
SG other symptoms like changes in lamp brightness,

Not necessarily, I recall one place where one line on the electric
meter's socket was partially burned (but we didn't know it yet).
Everything worked except that every once in a while (perhaps once per
month) the microwave would pop the breaker. A number of load
measurements couldn't turn up the problem (perhaps a 1 volt difference
if that). The electrician even diagnosed a few unrelated problems
each time he came. Finally it was decided to pop out the meter as the
last thing left to check (I mean, electricity IS simple). Evidently
the carbonized terminal and molten metal contacts had been that way
for a long time. Clearly something like this would create inductive
spikes into the bad line when something like the electric water heater
or baseboard heaters would cycle.

A*s*i*m*o*v

.... You may be a tech if you're entertained by a 6-pack and sparking HV.

"Thomas" wrote in message
...
Can anybody help me with this problem?

I have someone living in my apartment while I am away. He has rung me
up to say that in the last ten months THREE computers have "died" on him
due to being connected to a socket in my apartment. (I think he's
trying to make me feel guilty so that I will compensate him somehow.)


The only feasible thing that could be wrong with your wiring and cause this
(assuming north america, 120-0-120v service) is if there's a loose neutral
connection in the service panel causing an imballance between the voltages
on each side of the floating neutral. Measure the voltage at the wall
socket, if it's higher than 125v then something is wrong, otherwise the guy
is probably getting cheap junk and trying to blame you.

Thanks to all of you who so generously and kindly responded to my
request for help, concerning whether my tenant is right to blame a
socket in my apartment for three of his computers "dying".

I went in to the apartment this morning and found:
he had extension leads plugged into both left and right sockets in the
the one double-socket that he said was to blame, that one of these
extension leads had a quadruple-socket at the end of it, AND into one of
those four he had ANOTHER extension lead plugged in, and THAT had a
further two sockets at its end. Furthermore, he had double-adaptors
plugged in at various points. So, all in all, he really had the two
sockets at the wall really overloaded. I flicked out the fuses in the
plugs of the two extension cords and found that they were 13amp fuses,
just LIKE the fuses he had, for example, in the plug of his printer and
his computer! He plainly has no idea of overloading, amperage, and
making sure you have the right fuses fitted. Whether this actually
caused his problem I don't know, but it sure as eggs wasn't safe. I
told him I was very concerned.

Secondly, I learnt that he had bought his computers from shops on a
particular street which is notorious for operating like a vicious bazaar
in, dare I say it, downtown Calcutta! I wouldn't buy from any of these
people: they don't know what they are talking about. They just hawk the
latest electronics. I wouldn't be surprised if they had wold him duds.

Anyway, I insisted that all the extension leads were immediately removed
and that he plugged some of his many bits of equipment into other
sockets round the apartment. And I gave him the idea that I will be
keeping an eye on what he has plugged in and where in months to come.
From a safety point of view though, I agree that it might be wise to
give him notice fairly soon. He's got no idea. And the last I want to
hear is that it's not his printer that's "smoking" but the whole
apartment!

Nell.

Overloading would not cause internal computer damage. But
overloading is a serious human safety problem. In a previous
post is repeated references to a 15 amp circuit breaker on
every power strip. Your discovery is EXACTLY why that is
breaker (or fuse) is necessary for every receptacle expander
(ie power strip).

Most appliances draw hardly any power. One could easily put
four electronic appliances onto the same wall receptacle and
still not even consume 1/4 of what that wall receptacle must
supply. Number of appliances connected to a wall receptacle
is irrelevant as is the fuse in each cord. If all fuses are 15
amps or less, then no overloading is possible.

Was the wall receptacle overloaded? What was amperage or
wattage rating on each appliance - labeled where power cord
connects to appliance. Those are the only numbers that
matter. Size of fuses must be less than 15 amps. Fuses tell
us nothing more.

Repeated again because it is the first thing a landlord must
inspect - all plug expanders (ie power strips) must have the
15 amp (or less) circuit breaker. Then overloading is not
possible.

Did all three prong computer appliances to share a common
safety ground? Did three prong computer plugs share a common
receptacle and were they safety grounded to a three prong wall
receptacle? If not, then there is but one possible reason for
electronics damage.

Currently, your post does not define a safety problem - does
not indicate any overloading. If every power extension cord
includes a 13 amp fuse, then he has not created an overload or
safety problem. Those 13 amp fused would make overloading not
possible. They do not say or even suggest how much current
the appliance consumes.

So what caused electronics failure? For example, did
printer and computer share a common wall receptacle? Were
they both safety grounded (third prong on plug)? These facts
report far more useful information. Your worry of how many
extension cords were chained is irrelevant if every power cord
is fused or has a circuit breaker (and has a UL label). I see
nothing that says overloading. But then important numbers
were not provided - including those from the 3.5 digit
multimeter.

Nell wrote:
Thanks to all of you who so generously and kindly responded to my
request for help, concerning whether my tenant is right to blame a
socket in my apartment for three of his computers "dying".

I went in to the apartment this morning and found:
he had extension leads plugged into both left and right sockets in the
the one double-socket that he said was to blame, that one of these
extension leads had a quadruple-socket at the end of it, AND into one of
those four he had ANOTHER extension lead plugged in, and THAT had a
further two sockets at its end. Furthermore, he had double-adaptors
plugged in at various points. So, all in all, he really had the two
sockets at the wall really overloaded. I flicked out the fuses in the
plugs of the two extension cords and found that they were 13amp fuses,
just LIKE the fuses he had, for example, in the plug of his printer and
his computer! He plainly has no idea of overloading, amperage, and
making sure you have the right fuses fitted. Whether this actually
caused his problem I don't know, but it sure as eggs wasn't safe. I
told him I was very concerned.

Secondly, I learnt that he had bought his computers from shops on a
particular street which is notorious for operating like a vicious bazaar
in, dare I say it, downtown Calcutta! I wouldn't buy from any of these
people: they don't know what they are talking about. They just hawk the
latest electronics. I wouldn't be surprised if they had wold him duds.

Anyway, I insisted that all the extension leads were immediately removed
and that he plugged some of his many bits of equipment into other
sockets round the apartment. And I gave him the idea that I will be
keeping an eye on what he has plugged in and where in months to come.
From a safety point of view though, I agree that it might be wise to
give him notice fairly soon. He's got no idea. And the last I want to
hear is that it's not his printer that's "smoking" but the whole
apartment!

Nell.

Overloading is ENTIRELY possible. The TOTAL of the individual fuses should
not be over 15 amps in this example. Also many smaller, thinner extension
cords are rated for less. Additionally, some crappy extension cords have
been recalled lately for safety issues. The original poster is correct to
worry. Lots of people get away with plugging in all kinds of stuff, but we
hear about tragedies all too often.

Mark Z.


Repeated again because it is the first thing a landlord must
inspect - all plug expanders (ie power strips) must have the
15 amp (or less) circuit breaker. Then overloading is not
possible.

"w_tom" wrote in message
...
Overloading would not cause internal computer damage. But
overloading is a serious human safety problem. In a previous
post is repeated references to a 15 amp circuit breaker on
every power strip. Your discovery is EXACTLY why that is
breaker (or fuse) is necessary for every receptacle expander
(ie power strip).

Most appliances draw hardly any power. One could easily put
four electronic appliances onto the same wall receptacle and
still not even consume 1/4 of what that wall receptacle must
supply. Number of appliances connected to a wall receptacle
is irrelevant as is the fuse in each cord. If all fuses are 15
amps or less, then no overloading is possible.

Was the wall receptacle overloaded? What was amperage or
wattage rating on each appliance - labeled where power cord
connects to appliance. Those are the only numbers that
matter. Size of fuses must be less than 15 amps. Fuses tell
us nothing more.

Repeated again because it is the first thing a landlord must
inspect - all plug expanders (ie power strips) must have the
15 amp (or less) circuit breaker. Then overloading is not
possible.

Did all three prong computer appliances to share a common
safety ground? Did three prong computer plugs share a common
receptacle and were they safety grounded to a three prong wall
receptacle? If not, then there is but one possible reason for
electronics damage.

Currently, your post does not define a safety problem - does
not indicate any overloading. If every power extension cord
includes a 13 amp fuse, then he has not created an overload or
safety problem. Those 13 amp fused would make overloading not
possible. They do not say or even suggest how much current
the appliance consumes.

So what caused electronics failure? For example, did
printer and computer share a common wall receptacle? Were
they both safety grounded (third prong on plug)? These facts
report far more useful information. Your worry of how many
extension cords were chained is irrelevant if every power cord
is fused or has a circuit breaker (and has a UL label). I see
nothing that says overloading. But then important numbers
were not provided - including those from the 3.5 digit
multimeter.

Nell wrote:
Thanks to all of you who so generously and kindly responded to my
request for help, concerning whether my tenant is right to blame a
socket in my apartment for three of his computers "dying".

I went in to the apartment this morning and found:
he had extension leads plugged into both left and right sockets in the
the one double-socket that he said was to blame, that one of these
extension leads had a quadruple-socket at the end of it, AND into one of
those four he had ANOTHER extension lead plugged in, and THAT had a
further two sockets at its end. Furthermore, he had double-adaptors
plugged in at various points. So, all in all, he really had the two
sockets at the wall really overloaded. I flicked out the fuses in the
plugs of the two extension cords and found that they were 13amp fuses,
just LIKE the fuses he had, for example, in the plug of his printer and
his computer! He plainly has no idea of overloading, amperage, and
making sure you have the right fuses fitted. Whether this actually
caused his problem I don't know, but it sure as eggs wasn't safe. I
told him I was very concerned.

Secondly, I learnt that he had bought his computers from shops on a
particular street which is notorious for operating like a vicious bazaar
in, dare I say it, downtown Calcutta! I wouldn't buy from any of these
people: they don't know what they are talking about. They just hawk the
latest electronics. I wouldn't be surprised if they had wold him duds.

Anyway, I insisted that all the extension leads were immediately removed
and that he plugged some of his many bits of equipment into other
sockets round the apartment. And I gave him the idea that I will be
keeping an eye on what he has plugged in and where in months to come.
From a safety point of view though, I agree that it might be wise to
give him notice fairly soon. He's got no idea. And the last I want to
hear is that it's not his printer that's "smoking" but the whole
apartment!

Nell.

"w_tom" wrote in message
...
Most appliances draw hardly any power. One could easily put
four electronic appliances onto the same wall receptacle and
still not even consume 1/4 of what that wall receptacle must
supply. Number of appliances connected to a wall receptacle
is irrelevant as is the fuse in each cord. If all fuses are 15
amps or less, then no overloading is possible.

Wrong! Unsafe advise! It is entirely possible to overload a circuit with
multiple appliances. According to what you are saying you could connect an
infinite number of correctly operating devices and not overload the circuit!
You have come up with some bull**** before but this tops it all. Defining
new laws of physics now? Just what typical appliances have fuses greater
than 15 amps?

Number of appliances is irrelevant? Give me a break! It is the total draw
of the connected appliances that is relevant, and the max possible of each
should be considered. Fuses are for protection in the event of failure in
each unit, not to assure that overloading a circuit under normal or max
operating conditions is prevented.

Leonard

"Leonard Caillouet" bravely wrote to "All" (23 Dec 04 08:05:13)
--- on the heady topic of " Thanks to ALL who responded to above
(live-neutral problem)"

LC Reply-To: "Leonard Caillouet"
LC From: "Leonard Caillouet"


LC "w_tom" wrote in message
LC ...
Most appliances draw hardly any power. One could easily put
four electronic appliances onto the same wall receptacle and
still not even consume 1/4 of what that wall receptacle must
supply. Number of appliances connected to a wall receptacle
is irrelevant as is the fuse in each cord. If all fuses are 15
amps or less, then no overloading is possible.

LC Wrong! Unsafe advise! It is entirely possible to overload a circuit
LC with multiple appliances. According to what you are saying you could
LC connect an infinite number of correctly operating devices and not
LC overload the circuit! You have come up with some bull**** before but
LC this tops it all. Defining new laws of physics now? Just what typical
LC appliances have fuses greater than 15 amps?

LC Number of appliances is irrelevant? Give me a break! It is the total
LC draw of the connected appliances that is relevant, and the max possible
LC of each should be considered. Fuses are for protection in the event of
LC failure in each unit, not to assure that overloading a circuit under
LC normal or max operating conditions is prevented.

LC Leonard


Indeed, according to electrical code if the wall receptacle has 2
sockets and into each is plugged a 15 amp breaker extension then this
adds up to 30 amperes and this circuit will require #10 AWG wiring in
the walls.

More likely the circuit uses #14 AWG wiring but this is only rated for
15 Amperes, #12 AWG will handle 20 Amperes, etc. So clearly the
original writer's appartment situation may be quite unsafe even though
each extension has a 15A breaker.

Furthermore, the number of extensions that follow is a problem from
the point of view of contact reliability. Indeed, each point of
contact has more resistance than the wiring and is where most of the
heating will take place in an albeit cheap wire. Recall your series
resistance theory, that the power is divided proportionally to the
resistance. IOW the greatest resistance does the most heating.

A*s*i*m*o*v

.... Which sparks some mnemonic circuitry.

"Leonard Caillouet" wrote in message
news:Pmzyd.9171$jn.1028@lakeread06...
|
| "w_tom" wrote in message
| ...
| Most appliances draw hardly any power. One could easily put
| four electronic appliances onto the same wall receptacle and
| still not even consume 1/4 of what that wall receptacle must
| supply. Number of appliances connected to a wall receptacle
| is irrelevant as is the fuse in each cord. If all fuses are 15
| amps or less, then no overloading is possible.
|
| Wrong! Unsafe advise! It is entirely possible to overload a circuit with
| multiple appliances. According to what you are saying you could connect
an
| infinite number of correctly operating devices and not overload the
circuit!
| You have come up with some bull**** before but this tops it all. Defining
| new laws of physics now? Just what typical appliances have fuses greater
| than 15 amps?
|
| Number of appliances is irrelevant? Give me a break! It is the total
draw
| of the connected appliances that is relevant, and the max possible of each
| should be considered. Fuses are for protection in the event of failure in
| each unit, not to assure that overloading a circuit under normal or max
| operating conditions is prevented.

He's in the UK. Over there, all devices have a max 13 amp fuse in the plug.
This would include the extension leads.

N

Leonard Caillouet wrote:

That still does not make the load irrelevant. Those fuses are only of use
in the case of a short in a unit. The capacity of the circuit is not
unlimited.

I think what was meant was that the number of devices plugged in does
not matter as long as the total load is kept under the rating of the
circuit (and the rating of any extension cords, power bars, etc.)

For example, a normal North American 15A circuit can supply 1 15A
device, 15 1A devices or 100 0.15A devices.

A computer is probably around 600W max, which at 220V (The original post
was from Britain, right?) is a bit under 3A. If the circuit can take
13A you could plug in 4 of those computers without a problem (assuming
nothing else is connected).


-----------== Posted via Newsfeed.Com - Uncensored Usenet News ==----------
http://www.newsfeed.com The #1 Newsgroup Service in the World!
-----= Over 100,000 Newsgroups - Unlimited Fast Downloads - 19 Servers =-----

Obviously, what you say is correct, but that is not what he said, and such
careless communication on a forum such as this could be dangerous to those
who do not understand.

Leonard

"Shawn D'Alimonte" wrote in message
...
Leonard Caillouet wrote:

That still does not make the load irrelevant. Those fuses are only of
use
in the case of a short in a unit. The capacity of the circuit is not
unlimited.

I think what was meant was that the number of devices plugged in does
not matter as long as the total load is kept under the rating of the
circuit (and the rating of any extension cords, power bars, etc.)

For example, a normal North American 15A circuit can supply 1 15A
device, 15 1A devices or 100 0.15A devices.

A computer is probably around 600W max, which at 220V (The original post
was from Britain, right?) is a bit under 3A. If the circuit can take
13A you could plug in 4 of those computers without a problem (assuming
nothing else is connected).


-----------== Posted via Newsfeed.Com - Uncensored Usenet News
==----------
http://www.newsfeed.com The #1 Newsgroup Service in the World!
-----= Over 100,000 Newsgroups - Unlimited Fast Downloads - 19 Servers
=-----

"Shawn D'Alimonte" wrote in message
...
| Leonard Caillouet wrote:
|
| That still does not make the load irrelevant. Those fuses are only of
use
| in the case of a short in a unit. The capacity of the circuit is not
| unlimited.
|
| I think what was meant was that the number of devices plugged in does
| not matter as long as the total load is kept under the rating of the
| circuit (and the rating of any extension cords, power bars, etc.)
|
| For example, a normal North American 15A circuit can supply 1 15A
| device, 15 1A devices or 100 0.15A devices.
|
| A computer is probably around 600W max, which at 220V (The original post
| was from Britain, right?) is a bit under 3A. If the circuit can take
| 13A you could plug in 4 of those computers without a problem (assuming
| nothing else is connected).

In the UK I believe the voltage is 230 VAC nominal, and the max fuse is a
13A. ISTR that's sized for a particular cable, possibly the old 7/.029
copper.

N

"Asimov" wrote in message
...

| Indeed, according to electrical code if the wall receptacle has 2
| sockets and into each is plugged a 15 amp breaker extension then this
| adds up to 30 amperes and this circuit will require #10 AWG wiring in
| the walls.
|
| More likely the circuit uses #14 AWG wiring but this is only rated for
| 15 Amperes, #12 AWG will handle 20 Amperes, etc. So clearly the
| original writer's appartment situation may be quite unsafe even though
| each extension has a 15A breaker.

This is the UK. Cable sizes are quoted in square mm (probably 2.5 mm^2).
Plugs are the UK square pin style with fuses internally.

NM

What was posted was correct. One here should have read
better - or at less told us WHICH wire was at risk for
overload. If he had specifically cited the overloaded wire,
then he would have immediately understood his mistake. But
then he could not misrepresent what was posted.

Two 15 amp device connected to a wall outlet (in US). 30
amps? What is that breaker box (mains panel) circuit breaker
of 15 or 20 amps is doing? Singing the blues? It trips. It
limits current. A 15 amp circuit breaker (or 13 amp fuse in
UK power plugs) makes overload of external power wires not
possible - and informs human of his mistake. 100 devices on a
power strip will create a fire? If too much load for a power
strip, then the power strip 15 amp circuit breaker trips. No
fire. No overload. Those who read before posting learned
repeatedly about a 15 amp circuit breaker so that power cords
could not be overloaded.

What was posted is safe. Not necessarily preferred or
recommended. But one can plug 6 10 amp appliances into a
power strip and not overload wires IF each power strip has
the all so critical 15 amp circuit breaker. What Leonard must
forget to posted insults - the repeatedly stated 15 amp
circuit breaker.

Power strip will not overload because power strip 15 amp
breaker will trip. That is the point. Any extension cord or
power strip that does not have the 15 amp breaker should be
every landlord's concern.

Leonard Caillouet never comprehended what was posted - as
others have noted. Leonard: others had to explain to you
what was posted because again you attack before you
comprehend. Tell us specifically which wire is overloaded.
Explain why the circuit breaker or fuse did not blow. Please
fill us with your wisdom. Yes Leonard, those fuses and
circuit breakers DO limit current through wires. We
specifically put numbers on circuit breakers and fuses so that
current through wires is limited to that number. Why am I
telling you something that even teenagers know?

Leonard Caillouet wrote:
Obviously, what you say is correct, but that is not what he said,
and such careless communication on a forum such as this could be
dangerous to those who do not understand.

Even in the UK, things that could cause electronic failure
as posted still apply. Need for computer and printer to share
same safety ground. Need for the AC mains to be properly
earthed. Fact remains - overloaded wall receptacles still do
not cause electronic damage. Even if the tenant had to many
appliances on a wall receptacle, that still does not explain
electronics damage. No matter what size fuses were in his UK
power plugs, electronic failure would not and should not be
created. Fuses do not stop or permit electronic damage. The
tenant complained of electronics failures. The landlord
provided no information that explains that damage.

NSM wrote:
This is the UK. Cable sizes are quoted in square mm (probably 2.5
mm^2). Plugs are the UK square pin style with fuses internally.

NM

You're not totally wrong, but you're looking at things much differently. All
of us here have seen and heard where house fires were started by overloaded
outlets, especially where the person (or tenant) did not understand about
electrical current. One hundred devices would not overload a circuit UNLESS
a certain number were actually in operation. A constant 12 amp current draw
might start a fire in a given extension cord, especially because these type
items are often manufactured substandard these days.

In the UK, each device may be limited to 13 amps, but that's no assurance
that several devices operating within their limits would not overload a
given outlet strip. One cannot absolutely trust a circuit breaker. Fuses can
be mislabeled or defeated.

Also, where there's current-flow, any contact resistance generates HEAT. A
loose plug or socket can be frying inside a wall outlet or outlet strip,
even with moderate current flow. If for example, no one were home to see or
smell it, or if a person with disabilities could not correct the situation,
one could return home to a charred pile of rubble.

Once again, we're talking about an unknowledgeable tenant. A friend of mine
had major damage to a rental property because his tenants were stupid this
way.


Mark Z.

"w_tom" wrote in message
...
Even in the UK, things that could cause electronic failure
as posted still apply. Need for computer and printer to share
same safety ground. Need for the AC mains to be properly
earthed. Fact remains - overloaded wall receptacles still do
not cause electronic damage. Even if the tenant had to many
appliances on a wall receptacle, that still does not explain
electronics damage. No matter what size fuses were in his UK
power plugs, electronic failure would not and should not be
created. Fuses do not stop or permit electronic damage. The
tenant complained of electronics failures. The landlord
provided no information that explains that damage.

NSM wrote:
This is the UK. Cable sizes are quoted in square mm (probably 2.5
mm^2). Plugs are the UK square pin style with fuses internally.

NM

How much current must be traveling through a standard 13 amp
UK power cord to cause a fire? Put up numbers. And now how
does all that current pass through a 13 amp fuse without
blowing the fuse. Tenant was not (apparently) blowing fuses.

WE have seen fires due to power cords WITHOUT that all so
essential 15 amp circuit breaker on the power strip. Yes
there are power strips (including surge protector types) sold
without that 15 amp breaker. Shame on them. So and again,
what does the landlord want? He wants his tenants to use
power strips only with the 15 amp circuit breaker (or 13 amp
fuses) so that no overloaded wire can exist. Again because it
is not required and is so important - that 15 amp circuit
breaker on power strip (plug moles).

No blowing fuses or tripping circuit breakers. Even with
numerous items on the power cords, still the current was well
under what could be called overloading. The landlord did not
list amperages from various appliances. He just 'assumed'
multiple appliances meant overloading - an invalid conclusion.

What is the major source of fires in power cords? Not
overloading and especially not if the outlet expanders have
circuit breakers. The major source of such fires is
insulation breakdown. This is also why your Christmas tree
should be powered via an arc fault breaker. Fire due to
insulation breakdown can occur no matter how few plugs are
attached to one receptacle.

Although it will not eliminate these types of fires, the
fuse or circuit breaker would also make those fires less
possible. Fires due to overloading a wall receptacle - not
possible if the plug expander has been properly fused or
circuit breaker. Again, to make any claim of overloading,
first one must say - in detail - which wire is overloaded. No
such claim has demonstrated overloading exists. The overload
accusation is simply speculation.

Why does overloading cause fires? We still permit power
strips and other plug expanders to be sold without the
necessary 15 amp circuit breaker. Do you look at the power
strips your friends use? That was the source of a recent
local fire. But again, power strips (plug moles) did not have
that all so necessary 15 amp circuit breaker. *WE* still
don't demand that circuit breaker be on all plug expanders.
If you consider overloading to be dangerous, then you are
always looking for that 'killer'.

All above is totally and completely irrelevant to the OP's
original post. Landlord did not find a problem even though he
posts as if he did. Every power cord (apparently) was
properly fused meaning no wire could be overloaded. And yet
he still provided no information to explain damaged
electronics. He looked at things totally irrelevant -
suspected overloading, possible wrong size fuses, etc - to
explain electronic damage. False reasoning.

First, although chaining power expanders is not responsible,
still, it could not overload any wire - being as all were
fused. Furthermore, those power expanders do not explain why
the tenant suffered so much computer damage. Reasons for
electronics damage still have not been identified.
Overloading is not the reason for damage and apparently did
not exist - as demonstrated by all those 13 amp fuses that did
not blow.

Lets not forget the #1 target of this discussion. What was
damaging multiple computers and printer? Overloading did not
exist. Fuses were not blowing. And overloading would not
explain electronics damage.

"Mark D. Zacharias" wrote:
You're not totally wrong, but you're looking at things much
differently. All of us here have seen and heard where house fires
were started by overloaded outlets, especially where the person (or
tenant) did not understand about electrical current. One hundred
devices would not overload a circuit UNLESS a certain number
were actually in operation. A constant 12 amp current draw might
start a fire in a given extension cord, especially because these
type items are often manufactured substandard these days.

In the UK, each device may be limited to 13 amps, but that's no
assurance that several devices operating within their limits would
not overload a given outlet strip. One cannot absolutely trust a
circuit breaker. Fuses can be mislabeled or defeated.

Also, where there's current-flow, any contact resistance
generates HEAT. A loose plug or socket can be frying inside a wall
outlet or outlet strip, even with moderate current flow. If for
example, no one were home to see or smell it, or if a person with
disabilities could not correct the situation, one could return home
to a charred pile of rubble.

Once again, we're talking about an unknowledgeable tenant. A
friend of mine had major damage to a rental property because his
tenants were stupid this way.

Once again, you miss the point of the response and refuse to accept that the
statements that you make might not get the reception that you intended. You
said:

"w_tom" wrote in message
...
Most appliances draw hardly any power. One could easily put
four electronic appliances onto the same wall receptacle and
still not even consume 1/4 of what that wall receptacle must
supply. Number of appliances connected to a wall receptacle
is irrelevant as is the fuse in each cord. If all fuses are 15
amps or less, then no overloading is possible.


This is simply incorrect in any country and unsafe advice. The number of
devices is completely relevant. You may have meant something different than
what you stated, but inexperienced readers would easily take this for advice
that could cause big problems.

Leonard








"w_tom" wrote in message
...
What was posted was correct. One here should have read
better - or at less told us WHICH wire was at risk for
overload. If he had specifically cited the overloaded wire,
then he would have immediately understood his mistake. But
then he could not misrepresent what was posted.

Two 15 amp device connected to a wall outlet (in US). 30
amps? What is that breaker box (mains panel) circuit breaker
of 15 or 20 amps is doing? Singing the blues? It trips. It
limits current. A 15 amp circuit breaker (or 13 amp fuse in
UK power plugs) makes overload of external power wires not
possible - and informs human of his mistake. 100 devices on a
power strip will create a fire? If too much load for a power
strip, then the power strip 15 amp circuit breaker trips. No
fire. No overload. Those who read before posting learned
repeatedly about a 15 amp circuit breaker so that power cords
could not be overloaded.

What was posted is safe. Not necessarily preferred or
recommended. But one can plug 6 10 amp appliances into a
power strip and not overload wires IF each power strip has
the all so critical 15 amp circuit breaker. What Leonard must
forget to posted insults - the repeatedly stated 15 amp
circuit breaker.

Power strip will not overload because power strip 15 amp
breaker will trip. That is the point. Any extension cord or
power strip that does not have the 15 amp breaker should be
every landlord's concern.

Leonard Caillouet never comprehended what was posted - as
others have noted. Leonard: others had to explain to you
what was posted because again you attack before you
comprehend. Tell us specifically which wire is overloaded.
Explain why the circuit breaker or fuse did not blow. Please
fill us with your wisdom. Yes Leonard, those fuses and
circuit breakers DO limit current through wires. We
specifically put numbers on circuit breakers and fuses so that
current through wires is limited to that number. Why am I
telling you something that even teenagers know?

Leonard Caillouet wrote:
Obviously, what you say is correct, but that is not what he said,
and such careless communication on a forum such as this could be
dangerous to those who do not understand.

Also, where there's current-flow, any contact resistance generates HEAT. A
loose plug or socket can be frying inside a wall outlet or outlet strip,
even with moderate current flow. If for example, no one were home to see
or
smell it, or if a person with disabilities could not correct the
situation,
one could return home to a charred pile of rubble.


My grandmothers house nearly burned down a few years ago from this. The
circuit was not overloaded, but the refrigerator was on the end of a run and
an outlet in the middle devloped a loose connection. The load of the fridge
and the resistance of that outlet caused it to heat up and melt. The
contacts inside the outlet were glowing red when she noticed the coffee
grinder plug fall out of the melting outlet and ran to shut off the breaker.
Replacing the receptacle and trimming back the oxidized wires fixed the
problem.

"w_tom" wrote in message
...
How much current must be traveling through a standard 13 amp
UK power cord to cause a fire? Put up numbers. And now how
does all that current pass through a 13 amp fuse without
blowing the fuse. Tenant was not (apparently) blowing fuses.

WE have seen fires due to power cords WITHOUT that all so
essential 15 amp circuit breaker on the power strip. Yes
there are power strips (including surge protector types) sold
without that 15 amp breaker. Shame on them. So and again,
what does the landlord want? He wants his tenants to use
power strips only with the 15 amp circuit breaker (or 13 amp
fuses) so that no overloaded wire can exist. Again because it
is not required and is so important - that 15 amp circuit
breaker on power strip (plug moles).

What about all the 15A outlets on 20A circuits? It's quite common in the US
anyway, to have a number of 15A outlets on a 20A branch. It's fully possible
to overload the outlet with unfused plug adapters, lots of those out there.
The circuit breakers on power strips aren't of the highest quality either.

Again you post only to argue. Read before posting the
irrelevant. Remember what this discussion is all about? Tell
the OP why overloaded power cords (that could not even blow 13
amp fuses) would cause computer and printer damage. This is
exactly what my previous posts discussed. Somehow you got
totally off on some tangent. Leonard - it really is not so
hard to stay on topic when you want to discuss technically
rather than argue. You posted based only upon what you wanted
to see. Now here is the OP's original problem. How does
overloading not blow 13 amp fuses BUT does cause electronic
damage?

Point one - he had no overloading. Point two - overloading
does not cause electonics damage.

Leonard Caillouet wrote:
Once again, you miss the point of the response and refuse to accept
that the statements that you make might not get the reception that
you intended.

Cited are things totally irrelevant to the OP. Why discuss
"unfused plug adaptors" when there are none? Why even raise
this totally irrelevant issue? Apparently all power cords had
13 amp fuses or equivalent protection. Apparently his loads
were so small as to not even blow those 13 amp fuses.

However what is the expression I keep posting multiple times
in every post? 15 amp circuit breaker on every power strip.
Why are we now discussion a green moon - also known as
"unfused plug adaptors"? Please return to the relevant
topic. Please tell the OP why overloading caused damage to
multiple computers and a printer.

I would not be surprised if someone threw in a discussion of
a refrigerator connected to a defective wall outlet. Why
would speculated and unsubstantiated overloading (that also
could not blow line fuses) cause damage to multiple computers
and a printer?

James Sweet wrote:
What about all the 15A outlets on 20A circuits? It's quite common
in the US anyway, to have a number of 15A outlets on a 20A branch.
It's fully possible to overload the outlet with unfused plug
adapters, lots of those out there. The circuit breakers on power
strips aren't of the highest quality either.

"w_tom" wrote in message
...
Cited are things totally irrelevant to the OP. Why discuss
"unfused plug adaptors" when there are none? Why even raise
this totally irrelevant issue? Apparently all power cords had
13 amp fuses or equivalent protection. Apparently his loads
were so small as to not even blow those 13 amp fuses.


I don't even know what the OP was about at this point, the discussion has
morphed onto other things.

On Thu, 23 Dec 2004 17:12:41 -0500, Shawn D'Alimonte
wrote:

Leonard Caillouet wrote:

That still does not make the load irrelevant. Those fuses are only of use
in the case of a short in a unit. The capacity of the circuit is not
unlimited.

I think what was meant was that the number of devices plugged in does
not matter as long as the total load is kept under the rating of the
circuit (and the rating of any extension cords, power bars, etc.)

Right...people are so busy fighting with this guy all the time that
they don't clearly see what he intends to explain sometimes, but he
doesn't help with his wording either. That being said, the number is
not irrelevant, as, at some point, the limit will be exceeded, even by
a large number of tiny loads, as you explain below..


For example, a normal North American 15A circuit can supply 1 15A
device, 15 1A devices or 100 0.15A devices.

A computer is probably around 600W max, which at 220V (The original post
was from Britain, right?) is a bit under 3A. If the circuit can take
13A you could plug in 4 of those computers without a problem (assuming
nothing else is connected).


600 W sounds high for a PC, to me. I wish I had had more opportunities
to connect PC's to the Sencore (metered) variac where I used to work.
I do recall that some older PC's were typically under 100 W, around
600-700 mA. I know that it is higher today, but if 4 were connected
together, they would be unlikely to be peaking at the same time
either, I'd think.

Tom

On 20 Dec 2004 20:52:48 -0500, Sam Goldwasser
wrote:

Thomas writes:

Can anybody help me with this problem?

snip

In a couple of days' time I am going to visit the apartment with a
socket-tester - it's a small plug which shows if the socket is wired
correctly. The only thing I can think of which might have caused the
death of three computers (if, in fact, they DID really die) is that the
"live" and the "neutral" wires to the socket (from the fuseboard) might
have been attached to the socket the wrong way round.

If this is the case, I know this wouldn't injure a lightbulb, but my
question is: would this injure a computer? A friend tells me that
current is "alternating" and that it therefore shouldn't matter whether
the live and neural wires to the socket are reversed. But does this
situation ring any bells with anyone?

Or is the guy in my apartment either just someone who has bought three
faulty computers in a row or someone who is just trying to take me for a
ride?

Reversed Hot and Neutral should not damage computers or any other modern
electronics or appliances, nor is it an inherently unsafe condition.
Anything that plugs into the wall must be designed to be safe if H and N
are reversed.

In isolation yes, but all bets may be off if they connect to another
device which is connected to a correctly phased plug. Been there, got
the T-shirt, saw the lights dim, and smelled the smoke. :-)

Granted, when isolated devices are involved, there really shouldn't be
a problem, and nowadays that is usually the case.

Tom


I agree with another post - ask to see the damaged equipment.

There could be other wiring issues like a loose Neutral at the service
entrance causing large variations in voltage but you'd most likely see
other symptoms like changes in lamp brightness,

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"w_tom" wrote in message
...
How much current must be traveling through a standard 13 amp
UK power cord to cause a fire? Put up numbers.

Not possible. Depends on the exact current draw, the exact resistance, the
"heat-sinking" or power dissipation of the load, the presence or
non-presence of combustible material nearby, etc.

And now how
does all that current pass through a 13 amp fuse without
blowing the fuse. Tenant was not (apparently) blowing fuses.


The one device with the 13 amp fuse, as I recall is potentially only one of
several devices on the line.

A single device might start a fire with as little as 4 or 5 watts energy
dissipated in a small enough point with flammable material there. In this
admittedly extreme example, as little as 25 milliamps could start a fire at
220 volts.

All we American tech types are really trying to say is that many people
(tenants, for example) are so unknowledeable in the way they hook up AC
power cords, extension cords, heaters, lamps, etc as to be a hazard to
themselves, others, and in the specific example of the OP, his valuable
rental property.

snip

Mark Z.

Tom MacIntyre writes:

On 20 Dec 2004 20:52:48 -0500, Sam Goldwasser
wrote:

Thomas writes:

Can anybody help me with this problem?

snip

In a couple of days' time I am going to visit the apartment with a
socket-tester - it's a small plug which shows if the socket is wired
correctly. The only thing I can think of which might have caused the
death of three computers (if, in fact, they DID really die) is that the
"live" and the "neutral" wires to the socket (from the fuseboard) might
have been attached to the socket the wrong way round.

If this is the case, I know this wouldn't injure a lightbulb, but my
question is: would this injure a computer? A friend tells me that
current is "alternating" and that it therefore shouldn't matter whether
the live and neural wires to the socket are reversed. But does this
situation ring any bells with anyone?

Or is the guy in my apartment either just someone who has bought three
faulty computers in a row or someone who is just trying to take me for a
ride?

Reversed Hot and Neutral should not damage computers or any other modern
electronics or appliances, nor is it an inherently unsafe condition.
Anything that plugs into the wall must be designed to be safe if H and N
are reversed.

In isolation yes, but all bets may be off if they connect to another
device which is connected to a correctly phased plug. Been there, got
the T-shirt, saw the lights dim, and smelled the smoke. :-)

No, not true with anything less than maybe 75 years old.

Granted, when isolated devices are involved, there really shouldn't be
a problem, and nowadays that is usually the case.

Should always be the case unless you have antique radios or something
like that.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

On 25 Dec 2004 13:13:59 -0500, Sam Goldwasser
wrote:

Tom MacIntyre writes:

On 20 Dec 2004 20:52:48 -0500, Sam Goldwasser
wrote:

Thomas writes:

Can anybody help me with this problem?

snip

In a couple of days' time I am going to visit the apartment with a
socket-tester - it's a small plug which shows if the socket is wired
correctly. The only thing I can think of which might have caused the
death of three computers (if, in fact, they DID really die) is that the
"live" and the "neutral" wires to the socket (from the fuseboard) might
have been attached to the socket the wrong way round.

If this is the case, I know this wouldn't injure a lightbulb, but my
question is: would this injure a computer? A friend tells me that
current is "alternating" and that it therefore shouldn't matter whether
the live and neural wires to the socket are reversed. But does this
situation ring any bells with anyone?

Or is the guy in my apartment either just someone who has bought three
faulty computers in a row or someone who is just trying to take me for a
ride?

Reversed Hot and Neutral should not damage computers or any other modern
electronics or appliances, nor is it an inherently unsafe condition.
Anything that plugs into the wall must be designed to be safe if H and N
are reversed.

In isolation yes, but all bets may be off if they connect to another
device which is connected to a correctly phased plug. Been there, got
the T-shirt, saw the lights dim, and smelled the smoke. :-)

No, not true with anything less than maybe 75 years old.

Sorry, Sam, you should've really paid attention to the "been there"
part...I have had a situation like this arise, and within the past 25
years, with fairly new (at the time) equipment. While attaching a
video cable between 2 pieces of Telidon equipment in 1983, the lights
dimmed, a growling noise occured, and smoke emanated from one of the
units. A meter check revealed that one plug was wired in reverse.

Heck, all you have to do is defeat the capacitor in line with the F
connector on a modern TV set and you'll pop the fuse.

A disturbing aside...I once spoke to an electrician and told him this
story...he said that it didn't matter whether the plug was installed
ground over or under on an AC receptacle, the hot and neutral always
had to each go on the same side. And they don't want us wiring our own
houses...

Tom


Granted, when isolated devices are involved, there really shouldn't be
a problem, and nowadays that is usually the case.

Should always be the case unless you have antique radios or something
like that.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

"Tom MacIntyre" wrote in message
...

| Sorry, Sam, you should've really paid attention to the "been there"
| part...I have had a situation like this arise, and within the past 25
| years, with fairly new (at the time) equipment. While attaching a
| video cable between 2 pieces of Telidon equipment in 1983, the lights
| dimmed, a growling noise occured, and smoke emanated from one of the
| units. A meter check revealed that one plug was wired in reverse.

Irrespective, that should never happen. In 1983, no equipment should have
had a hot chassis. The only maker who used to do this (to save the cost of a
power transformer) was Philips who made tube radios and TVs like this and
they went to great lengths to avoid problems. All devices had a well
attached back cover, all pot shafts etc. had sealant applied over the grub
screws and antenna wires were isolated with capacitors.

N

On Sat, 25 Dec 2004 21:45:07 GMT, "NSM" wrote:


"Tom MacIntyre" wrote in message
.. .

| Sorry, Sam, you should've really paid attention to the "been there"
| part...I have had a situation like this arise, and within the past 25
| years, with fairly new (at the time) equipment. While attaching a
| video cable between 2 pieces of Telidon equipment in 1983, the lights
| dimmed, a growling noise occured, and smoke emanated from one of the
| units. A meter check revealed that one plug was wired in reverse.

Irrespective, that should never happen. In 1983, no equipment should have
had a hot chassis. The only maker who used to do this (to save the cost of a
power transformer) was Philips who made tube radios and TVs like this and
they went to great lengths to avoid problems. All devices had a well
attached back cover, all pot shafts etc. had sealant applied over the grub
screws and antenna wires were isolated with capacitors.

N


You are missing the point...once an Abominable Snowman has been
captured and identified, it officially exists. Coelecanth, etc...it
happened, and it happened to me; I witnessed it...therefore, it
exists.

Tom

"Tom MacIntyre" wrote in message
...
| On Sat, 25 Dec 2004 21:45:07 GMT, "NSM" wrote:

| Irrespective, that should never happen. In 1983, no equipment should have
| had a hot chassis. The only maker who used to do this (to save the cost
of a
| power transformer) was Philips who made tube radios and TVs like this and
| they went to great lengths to avoid problems. All devices had a well
| attached back cover, all pot shafts etc. had sealant applied over the
grub
| screws and antenna wires were isolated with capacitors.

| You are missing the point...once an Abominable Snowman has been
| captured and identified, it officially exists. Coelecanth, etc...it
| happened, and it happened to me; I witnessed it...therefore, it
| exists.

No doubt, but I would certainly have investigated as to how anything wound
up with a hot chassis. Even back then double-insulated was a standard
production methodology. This fault indicates serious and dangerous
mis-wiring (ground to hot)? I might well have contacted the local electrical
safety branch.

N

Tom MacIntyre writes:

On 25 Dec 2004 13:13:59 -0500, Sam Goldwasser
wrote:

Tom MacIntyre writes:

On 20 Dec 2004 20:52:48 -0500, Sam Goldwasser
wrote:

Thomas writes:

Can anybody help me with this problem?

snip

In a couple of days' time I am going to visit the apartment with a
socket-tester - it's a small plug which shows if the socket is wired
correctly. The only thing I can think of which might have caused the
death of three computers (if, in fact, they DID really die) is that the
"live" and the "neutral" wires to the socket (from the fuseboard) might
have been attached to the socket the wrong way round.

If this is the case, I know this wouldn't injure a lightbulb, but my
question is: would this injure a computer? A friend tells me that
current is "alternating" and that it therefore shouldn't matter whether
the live and neural wires to the socket are reversed. But does this
situation ring any bells with anyone?

Or is the guy in my apartment either just someone who has bought three
faulty computers in a row or someone who is just trying to take me for a
ride?

Reversed Hot and Neutral should not damage computers or any other modern
electronics or appliances, nor is it an inherently unsafe condition.
Anything that plugs into the wall must be designed to be safe if H and N
are reversed.

In isolation yes, but all bets may be off if they connect to another
device which is connected to a correctly phased plug. Been there, got
the T-shirt, saw the lights dim, and smelled the smoke. :-)

No, not true with anything less than maybe 75 years old.

Sorry, Sam, you should've really paid attention to the "been there"
part...I have had a situation like this arise, and within the past 25
years, with fairly new (at the time) equipment. While attaching a
video cable between 2 pieces of Telidon equipment in 1983, the lights
dimmed, a growling noise occured, and smoke emanated from one of the
units. A meter check revealed that one plug was wired in reverse.

Heck, all you have to do is defeat the capacitor in line with the F
connector on a modern TV set and you'll pop the fuse.

A disturbing aside...I once spoke to an electrician and told him this
story...he said that it didn't matter whether the plug was installed
ground over or under on an AC receptacle, the hot and neutral always
had to each go on the same side. And they don't want us wiring our own
houses...

What I said is that equipment must be designed such that this shouldn't
happen, not that a fault couldn't result in the situation you describe.

So, I should have perhaps been more explicit and said 'designed and
manufactured'.

No user accessible part should be connected to H or N directly or via a
low enough impedance to result in an unsafe fault current.

And, not just a plug with reverse H and N - that should still not cause
this. Yes, capacitors can fail. Wires can break loose and short.

--- sam | Sci.Electronics.Repair FAQ Mirror: http://repairfaq.ece.drexel.edu/
Repair | Main Table of Contents: http://repairfaq.ece.drexel.edu/REPAIR/
+Lasers | Sam's Laser FAQ: http://repairfaq.ece.drexel.edu/sam/lasersam.htm
| Mirror Sites: http://repairfaq.ece.drexel.edu/REPAIR/F_mirror.html

Note: These links are hopefully temporary until we can sort out the excessive
traffic on Repairfaq.org.

Important: Anything sent to the email address in the message header above is
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

Tom


Granted, when isolated devices are involved, there really shouldn't be
a problem, and nowadays that is usually the case.

Should always be the case unless you have antique radios or something
like that.

I missed half the thread, and the intended subject, but the fact is it there is
no way in the world reversing the polarity of an AC plug can ever cause voltage
differential between two pieces of equipment. Nope, unless one or most likely
both are hot chassis and both have been tampered with in some way to compromise
the hot chassis safety features such as jumping caps etc. There's a minimum of
about 1meg resistance between hot chassis and any jacks, catv input ect. 1meg
sure isn't going to cause lights to dim or damage regardless of the polarity of
the cords.

On Sat, 25 Dec 2004 20:43:43 GMT Tom MacIntyre
wrote:

Sorry, Sam, you should've really paid attention to the "been there"
part...I have had a situation like this arise, and within the past 25
years, with fairly new (at the time) equipment. While attaching a
video cable between 2 pieces of Telidon equipment in 1983, the lights
dimmed, a growling noise occured, and smoke emanated from one of the
units. A meter check revealed that one plug was wired in reverse.

I'm not familiar with that brand. Where was it made? Was this consumer
type equipment or specialized video test equipment?

I agree with both you and Sam. You apparently have a counterexample,
but Sam is right that this should never have happened. It's possible
that your experience was the result of two problems: a reversed outlet
AND an internal fault in one of the units.

BTW, I have an early 50s Knight "Space Spanner" that has a chassis
which is hot no matter which way you plug in the power cord, and this
set was even sold without a case. The manual warns against trying to
operate it on your kitchen sink, but it doesn't explain why.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------