neural-live electrical-wiring to computer ?

[Thomas]

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.

 

[Nell]

Can anybody help me with this problem?

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

Nell.

 

[CJT]

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.

 

[Sam Goldwasser]

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
ignored unless my full name is included in the subject line. Or, you can
contact me via the Feedback Form in the FAQs.

 

[NSM]

| 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

 

[Jerry G.]

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.
=====

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.

 

[w_tom]

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.

 

[Asimov]

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

SG> From: Sam Goldwasser <[email protected]>

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.

 

[James Sweet]

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.

 

[Nell]

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]

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.

 

[Mark D. Zacharias]

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.

 

[Leonard Caillouet]

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 bullshit 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

 

[Asimov]

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

LC> Reply-To: "Leonard Caillouet" <[email protected]>
LC> From: "Leonard Caillouet" <[email protected]>

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 bullshit 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.

 

[NSM]

|
| | > 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 bullshit 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]

|
| | > 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 bullshit 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

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.

Leonard

 

[Shawn D'Alimonte]

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).


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[Leonard Caillouet]

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

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).


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[NSM]

| 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

 

[NSM]

| 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