Rental Electrician



  • Whilst working in a computer shop I had a lot of contact with end users and thus many pretty standard WTFs, however the best ones always came from the boss. A proper little cornershop keeper he liked to do everything on the cheap, get stuff sold and forget about it and he insisted there was no such word as 'refund'.

    I hated some of the unethical, illegal and downright dangerous things that went on in that shop and hated being a part of it.

    One day the boss turns up with a van full of speakers for us to unload, turning up with a van full of stock was far from unusual but these speakers, we usually get delivered. They were the same brand of powered PC speakers we usually got but apparently he'd found them cheaper from somewhere.

    We moved them into the shop, priced them up and began selling. Pretty soon the first set came back, the customer had discovered that the speakers had the wrong mains connection on, a eruo plug instead of the three pin UK type. I found a set with the right plug and swapped them over.

    On checking the others we found that most of the new stock appart from about nine sets (the ones at the front of the pile so that he got a good set when he checked before loading the van) had the wrong plug on. His solution? Change all the plugs.

    He returned with a bag full of plugs and had me start changing them whenever I got a chance, it wasn't moving quickly enough so he had the guy from his other shop (video rentals) join me to help out.

    Between the two of us we got them all changed, towards the end I looked at some of co-worker's work and noticed he had stripped ALL the insulation off of the conductors right back to the cord grip. All that seperated phase and nuetral was a minute air gap. My stomach churned when the though that he may well have done all his half like this hit me.

    The boss didn't care, they had the right plugs on now. Sell sell sell.

    It was going pretty well until the phone calls started coming in, a dead short like that on a 240v mains supply can shift a fair few amps before the fuses in the distribution board give out as many customers discovered when the plugs exploded in their hands.

     



  • Not just WTF, mut be illegal..



  •  Yup but like so many of the WTF I experienced working in that place, somehow, god knows how, he got away with it.



  • Doesn't uk plugs have a fuse that would have blown in this situation? Or were the plugs some knockoff illegal in themselves plugs?



  • @Zemm said:

    Doesn't uk plugs have a fuse that would have blown in this situation? Or were the plugs some knockoff illegal in themselves plugs?

    Yes, but creating a short at the cord grip bypasses the fuse.



  • I don't see how - the live pin on a plug passes through the fuse before encountering the screw terminal for the cable.

    The only way to short out the cables without the fuse blowing is to have the cable twisted around the fuse clip, neglecting the screw post entirely.



  • @Cassidy said:

    I don't see how - the live pin on a plug passes through the fuse before encountering the screw terminal for the cable.


    If it's shorting across from the wire to the bottom of the fuse, it's entirely plausible since the electricity won't be going through the fuse. From the description in the OP, you wouldn't have been able to see any of the plastic wire coating in that diagram since it was all stripped off.



  • @EncoreSpod said:

    Yup but like so many of the WTF I experienced working in that place, somehow, god knows how, he got away with it.

    You got away with it too, buddy. Your hands aren't clean here.

    The correct response to being asked to do something dangerous/illegal isn't to sigh and do it, it's to say no.



  • @PJH said:

    If it's shorting across from the wire to the bottom of the fuse, it's entirely plausible since the electricity won't be going through the fuse. From the description in the OP, you wouldn't have been able to see any of the plastic wire coating in that diagram since it was all stripped off.

    That would mean that the stripped neutral (or stripped earth) is managing to avoid all contact with a stripped live and yet come into contact with the bottom of the fuse housing. Not impossible, but there's a greater probability that the short will cause the fuse to blow.

    (pedantic dickweedery since we were taught on an electrician's course that the plug, by design, was intended to safely blow a fuse in the event of an earth failure or a live chassis).



  • @blakeyrat said:

    The correct response to being asked to do something dangerous/illegal isn't to sigh and do it, it's to say no.

    And to report it, that is an important part of the saying no that blakey left off.



  • @EncoreSpod said:

    It was going pretty well until the phone calls started coming in, a dead short like that on a 240v mains supply can shift a fair few amps before the fuses in the distribution board give out as many customers discovered when the plugs exploded in their hands.

     


    When you say "exploded", are we talking bits of plastic embedded in customers' hands?



  • @Cassidy said:

    @PJH said:

    If it's shorting across from the wire to the bottom of the fuse, it's entirely plausible since the electricity won't be going through the fuse. From the description in the OP, you wouldn't have been able to see any of the plastic wire coating in that diagram since it was all stripped off.

    That would mean that the stripped neutral (or stripped earth) is managing to avoid all contact with a stripped live and yet come into contact with the bottom of the fuse housing. Not impossible, but there's a greater probability that the short will cause the fuse to blow.

    (pedantic dickweedery since we were taught on an electrician's course that the plug, by design, was intended to safely blow a fuse in the event of an earth failure or a live chassis).


    If you cut the plug off and twist live and neutral together, would you expect the fuse in the plug to blow? That's essentially the same situation.



  • @Cassidy said:

    but there's a greater probability that the short will cause the fuse to blow.
    Since the fuse isn't involved in the situation, no. Are you incapable of reading?@Cassidy said:
    pedantic dickweedery
    .. fail...@Cassidy said:
    since we were taught on an electrician's course that the plug, by design, was intended to safely blow a fuse in the event of an earth failure or a live chassis
    That only works if the fuse is in the circuit to begin with. In this case, it's being bypassed. It was stated in the OP that this was the case.



  • @pjt33 said:

    If you cut the plug off and twist live and neutral together, would you expect the fuse in the plug to blow?

    Are you talking about detaching the plug from the appliance and twisting the appliance's unpowered cables together, or twisting the live and neutral cables emerging from a powered plug? In the latter case, I'd expect the fuse to blow. In the former case, without a plug it would receive no power.

    @PJH said:

    Since the fuse isn't involved in the situation, no. Are you incapable of reading?

    Clearly. I've re-read the first post, and I don't see any mention of a fuse not being involved. I did, however, make the assumption that when the shop owner returned with some UK 3-pin plugs, they were fused.

    @PJH said:

    That only works if the fuse is in the circuit to begin with. In this case, it's being bypassed. It was stated in the OP that this was the case.

    Some best quote that sentence to me, because I still can't see it.


  • @Cassidy said:

    @PJH said:

    That only works if the fuse is in the circuit
    to begin with. In this case, it's being bypassed. It was stated in the
    OP that this was the case.

    Some best quote that sentence to me, because I still can't see it.

    You're right - I was making the same mistake as PJH before, but obviously the fuse is still in the short circuit. The appliance isn't. I'm not certain the fuse would react fast enough to help completely, though, under those conditions.



  • @Cassidy said:

    @PJH said:

    That only works if the fuse is in the circuit
    to begin with. In this case, it's being bypassed. It was stated in the
    OP that this was the case.

    Some best quote that sentence to me, because I still can't see it.
    Really? Seriously? Here you go then:@EncoreSpod said:
    ...and noticed he had stripped ALL the insulation off of the conductors right back to the cord grip. All that seperated phase and nuetral was a minute air gap.



  • @PJH said:



    If it's shorting across from the wire to the bottom of the fuse, it's entirely plausible since the electricity won't be going through the fuse. From the description in the OP, you wouldn't have been able to see any of the plastic wire coating in that diagram since it was all stripped off.

    That diagram is terrible. I haven't checked the actual standard, but from what I can see the fuse and live prong should be completely walled in:

    / /

    I've just taken apart an old plug, and when screwed together there's a complete wall from top to bottom that seals in the fuse and live prong and ensures that the live wire will never, ever bypass the fuse. The internal walling within the base and lid of the plug is absent from that first, overly simplified diagram.

    Cassidy is correct: the OP said nothing about the fuse in the plug. It could be ignorance on the part of the OP that he didn't recognise that the plugs were non-regulation, which seems more likely given how they were sourced. Fun with a non-regulation BS 1363 plug



  • @Cassidy said:

    @pjt33 said:

    If you cut the plug off and twist live and neutral together, would you expect the fuse in the plug to blow?

    Are you talking about detaching the plug from the appliance and twisting the appliance's unpowered cables together, or twisting the live and neutral cables emerging from a powered plug? In the latter case, I'd expect the fuse to blow. In the former case, without a plug it would receive no power.

    Ah, my apologies. I've realised that I was thinking about sockets rather than plugs.

    In partial mitigation, I have badly wired sockets in the back of my mind because I recently moved into an office where the previous occupants had wired up a multisocket via terminal block, and the terminal block was wandering around loose inside a rack box. Which wasn't earthed.



  •  after market plugs in the uk usually come with 13amp fuses.  Shorting the output of a plug even with a 13 amp fuse is a pretty decent bang, particularly when you are not expecting it.



  • @Zemm said:

    Doesn't uk plugs have a fuse that would have blown in this situation? Or were the plugs some knockoff illegal in themselves plugs?

    The fuse won't blow up fast enough to prevent formation of the arc. It's not really much better than the circuit breaker in the switch-board, especially if it's generic fuse in replacement plug rather than one limited to maximum expected current for a specific device.



  • @blakeyrat said:

    @EncoreSpod said:
    Yup but like so many of the WTF I experienced working in that place, somehow, god knows how, he got away with it.

    You got away with it too, buddy. Your hands aren't clean here.

    The correct response to being asked to do something dangerous/illegal isn't to sigh and do it, it's to say no.

    +1

     



  • @blakeyrat said:

    @EncoreSpod said:
    Yup but like so many of the WTF I experienced working in that place, somehow, god knows how, he got away with it.
    You got away with it too, buddy. Your hands aren't clean here.

    The correct response to being asked to do something dangerous/illegal isn't to sigh and do it, it's to say no.

    Sadly this would not fly in my country as dangerous/illegal is the norm and bosses tend to be demoted up the chain.



  • @Helix said:

     after market plugs in the uk usually come with 13amp fuses.  Shorting the output of a plug even with a 13 amp fuse is a pretty decent bang, particularly when you are not expecting it.

    No it's not. A dead short would not produce much of anything but a blown fuse.  The fusing current of the cable wires is probably an order of magnitude higher.

    On the other hand, bringing the wires close enough to create a spark gap could be pretty impressive.



  • @serguey123 said:

    @blakeyrat said:

    @EncoreSpod said:
    Yup but like so many of the WTF I experienced working in that place, somehow, god knows how, he got away with it.
    You got away with it too, buddy. Your hands aren't clean here.

    The correct response to being asked to do something dangerous/illegal isn't to sigh and do it, it's to say no.

    Sadly this would not fly in my country as dangerous/illegal is the norm and bosses tend to be demoted up the chain.

    In that case the correct response to being asked to do something dangerous/illegal is to give said boss the first one 'to test'.


  • Things like this make me glad I live in the US where our plugs do not need fuses, now I know one more reason why your plugs are so damn huge.



  • The reason for the fuse is due to our using ring circuits – some suitably boring bedtime reading ;-)



  • @Anketam said:

    Things like this make me glad I live in the US where our plugs do not need fuses, now I know one more reason why your plugs are so damn huge.

    Eh? The fuse is there to protect the user. Bit like saying "I'm glad I don't live in a country where our cars need seat belts".

    Yes, I know a circuit breaker does something similar, but the fuse blowing means a power loss to that one device and not to the entire rail.



  • @serguey123 said:

    @blakeyrat said:

    @EncoreSpod said:
    Yup but like so many of the WTF I experienced working in that place, somehow, god knows how, he got away with it.
    You got away with it too, buddy. Your hands aren't clean here.

    The correct response to being asked to do something dangerous/illegal isn't to sigh and do it, it's to say no.

    Sadly this would not fly in my country as dangerous/illegal is the norm and bosses tend to be demoted up the chain.

    So grow a fucking spine and do the right fucking thing. "But what if I get fired!?" Then you should be proud of yourself.

    Maybe your country is so corrupt and useless because everybody else in it is like you.



  • @Cassidy said:

    @Anketam said:

    Things like this make me glad I live in the US where our plugs do not need fuses, now I know one more reason why your plugs are so damn huge.

    Eh? The fuse is there to protect the user. Bit like saying "I'm glad I don't live in a country where our cars need seat belts".

    Yes, I know a circuit breaker does something similar, but the fuse blowing means a power loss to that one device and not to the entire rail.

    We don't use them for 2 reasons:

    1) 120v doesn't carry as much energy, and can't, generally speaking, permanently harm a person. (ATTENTION PEDANTIC DICKWEEDS: you probably wanna grab a hold of the preceding sentence and pedantic dickweed all over it.)

    2) We don't put entire houses on the same "rail". ("rail?" We say "circuit." You know, because it's a circuit.) Even in my old-as-shit house, if my computer blows its breaker, it only takes out its own outlet and one other outlet in the same room. That's not a big deal; you go into the basement, flick the breaker a couple times, and you're golden. The big pain is when the breaker that controls your basement lights blows...



  • @blakeyrat said:

    So grow a fucking spine and do the right fucking thing. "But what if I get fired!?"

    That. In my books, being fired is far more preferable than someone getting fried. Your (serguey123's) values may vary.



  • @blakeyrat said:

    So grow a fucking spine and do the right fucking thing. "But what if I get fired!?" Then you should be proud of yourself.

    Maybe your country is so corrupt and useless because everybody else in it is like you.

    Getting fired would be the least that would happen to you.  Worst case scenario is that you are either unable to work anymore and are dissapeared or end up in jail because in this country everybody at some point has done something that warrant jail time if anybody digs deep enough.

    Also Corruptsylvanians are many things, some of them very bad but spineless is not one of them.  There are other ways to solve this, only they are not legal, as seldom anything here is.

    @Cassidy said:

    In my books, being fired is far more preferable than someone getting fried. Your (serguey123's) values may vary.

    Life in a third world country is incredibly cheap and due to how stuff works (or don't) here there is no company liability, only personal one. so even if a company does something shitty a scapegoat is produced and nothing fucking changes (we have done a lot of stupid, stupid things and I have never seen some measure of accountability until recently and so far is too little too late ). 

    An anonimized example for you:  Big wig from company sees machines in country A.  Said machines are meant to fix something that doesn't fucking exist here.  He buys several millions worths of the machines.  Machines get chucked when they get here because they are useless.  Does he gets fired? No! Reprimanded? No! He get putted in a position to oversee the economy of the fucking country (this actually happened).


     



  • @serguey123 said:

    Getting fired would be the least that would happen to you.  Worst case scenario is that you are either unable to work anymore and are dissapeared or end up in jail because in this country everybody at some point has done something that warrant jail time if anybody digs deep enough.

    Also Corruptsylvanians are many things, some of them very bad but spineless is not one of them.  There are other ways to solve this, only they are not legal, as seldom anything here is.

    Oh please. You're in fucking Florida, you're just a gigantic drama-queen.

    Sorry, some days I just can't buy your candyland bullshit.



  • @Cassidy said:

    @Anketam said:

    Things like this make me glad I live in the US where our plugs do not need fuses, now I know one more reason why your plugs are so damn huge.

    Eh? The fuse is there to protect the user. Bit like saying "I'm glad I don't live in a country where our cars need seat belts".

    Yes, I know a circuit breaker does something similar, but the fuse blowing means a power loss to that one device and not to the entire rail.

    A more correct car analogy would be "I'm glad I don't live in a country where our car engines blow up over a slight fender bender."


  • @blakeyrat said:

    Oh please. You're in fucking Florida

    WTF are you talking about?

    @blakeyrat said:

    you're just a gigantic drama-queen.

    Never been called that, hmmm...

    @blakeyrat said:

    Sorry, some days I just can't buy your candyland bullshit.

    I would not called this country candyland but if you like it I'll change it, I'm cool with whatever as long as is not the real name



  • @blakeyrat said:

    1) 120v doesn't carry as much energy, and can't, generally speaking, permanently harm a person.

    Mmm.. I forgot about your 120V. Yup, our juice carries a greater wallop and is more dangerous. I don't have stats to hand, but 240V@50-60Hz across the chest is enough to shock or disrupt heart activity with normal skin resistance, and kills in the majority of cases. 120V doesn't pack as much punch, and a greater proportion can survive it rather than find it fatal. I recall some article saying that UK was TRWTF for not bringing our voltages inline with the safer 120v... not certain why that plan was dismissed.

    @blakeyrat said:

    ("rail?" We say "circuit." You know, because it's a circuit.)

    Sorry, electrical term. Rail for open-circuit, plugging something into the socket closes the circuit and current flows, with nothing on you have open-circuit which is envisaged as a series of rails with infinite resistance between them. But.. yah, we're talking the same thing here, terminology notwithstanding.

    @blakeyrat said:

    The big pain is when the breaker that controls your basement lights blows...

    My folks have a maglite-style torch in a holder that breaks the contact between its two AA cells, the luminous sheath charging from ambient light. During a power cut, it glows as something to grab - snatching it out of its holder immediately illuminates the torch. You ought to grab one for your basement.

    @serguey123 said:

    Life in a third world country is incredibly
    cheap and due to how stuff works (or don't) here there is no company
    liability, only personal one.

    Okay, what the trolling fuck does that mean? That you treat life as cheap, and you don't give a shit that your cowardice could endanger someone's life? Forget this cultural pressure toss - if you follow the crowd like a spineless sheep, you're becoming part of the problem rather than contributing to the solution. For sooner or later, you'll reap what you sow, and you can look up from your deathbed thinking "well, it's the way of this country" when some easily-preventable accident claims yet another life. Yours.

    Grrrrr.....



  • @Anketam said:

    @Cassidy said:
    @Anketam said:
    Things like this make me glad I live in the US where our plugs do not need fuses, now I know one more reason why your plugs are so damn huge.

    Eh? The fuse is there to protect the user. Bit like saying "I'm glad I don't live in a country where our cars need seat belts".

    Yes, I know a circuit breaker does something similar, but the fuse blowing means a power loss to that one device and not to the entire rail.

    A more correct car analogy would be "I'm glad I don't live in a country where our car engines blow up over a slight fender bender."

    No no no. "I'm glad I don't live in a country where one of my spark plugs has to be replaced after I hit a pot hole."



  • Aw, arseburgers. I knew as soon as I slipped a car analogy in there, I was asking for trouble.

    .. and you lot didn't disappoint.



  • @Cassidy said:

    @blakeyrat said:

    1) 120v doesn't carry as much energy, and can't, generally speaking, permanently harm a person.

    Mmm.. I forgot about your 120V. Yup, our juice carries a greater wallop and is more dangerous. I don't have stats to hand, but 240V@50-60Hz across the chest is enough to shock or disrupt heart activity with normal skin resistance, and kills in the majority of cases. 120V doesn't pack as much punch, and a greater proportion can survive it rather than find it fatal. I recall some article saying that UK was TRWTF for not bringing our voltages inline with the safer 120v... not certain why that plan was dismissed.

    BTW, you guys have a fuse at every plug, a plug design that ensures the hot is disconnected before any copper is exposed, a shutter in the outlet to make accessing the hot terminal difficult, an internal plug design that makes sure that any loose wire short goes through the fuse, all on 240V. We have a flimsy, bare-copper-exposed plug design with no special safety features and an outlet with open cavities, all on 120V. Yet, we kill fewer people from electrocution per capita than you guys do from stepping on your infernal plugs (an exaggeration, but not really that much).

    Our electricity is so inherently safe that our electrical codes are more about fire prevention than electrocution prevention. Your plan to convert to 120V was dismissed because it was too expensive. Increasing the voltage of a carrier increases its power handling capabilities pretty much for free. Going to 120V would require doubling the amount of copper running across the country and copper is expensive. So, your country has decided to keep making crispy critters out of the population instead of investing in a more sane delivery system.



  • Treading on plugs … not sure that's ever happened to me. Treading on LEGO on the other hand …

    200–240 V at 50 Hz pretty much wins out though:

    We used to be 240 V, but we've dropped down 10 V to conform with Europe at 230 V.

    What definitely kills you: there's a video out there of a nutter in India standing on top of a train and grasping the overhead line. One chargrilled Indian coming up. Don't know whether that was 1500 kV DC, or 25 kV AC, as India use overhead lines for both systems (Britain took the more unusual option of third rail for its DC routes). I don't know whether there's any difference in the spectacle of death between the two.

    Edit: The fuse at every plug is not because of the 240 V, it's because we use ring main circuits. There ain't nuffink in Britain that ain't done on the cheap!



  • @Daniel Beardsmore said:

    We used to be 240 V, but we've dropped down 10 V to conform with Europe at 230 V.
     

    TRWTF with some (most?) 240 to 230 conversions was that it is defined as "230V +10% -6%" so that it is really closer to "236V ±8%" - 240V is still within tolerance so no actual voltages were required to be changed.

    Australia started out as 250V anyway!

    @Jaime said:

    Your plan to convert to 120V was dismissed because it was too expensive.
     

    The closest transformer to my house is about 200m away. On a ~110V system that would be far too far away and it would require many many more transformers and running of HV lines.


  • Discourse touched me in a no-no place

    @Jaime said:

    Our electricity is so inherently safe that our electrical codes are more about fire prevention than electrocution prevention. Your plan to convert to 120V was dismissed because it was too expensive. Increasing the voltage of a carrier increases its power handling capabilities pretty much for free. Going to 120V would require doubling the amount of copper running across the country and copper is expensive. So, your country has decided to keep making crispy critters out of the population instead of investing in a more sane delivery system.
    120V is most certainly not what we use for transmission. We use 480v(and higher) for that. It only gets stepped down to 120 (and 240) for local neighborhood service - a few hundred yards at most. If I wanted full 480V service (and I do), I could have it without having to run ANY extra copper, because the transformer is actually adjacent to my property (and the next one is 50 yards down the line - in rural bumfuckery nowhere).

    In fact, you'd struggle to find a house in the entire US without 240V service - we just only use it for serious things. 

    I'm actually wiring my new garage for 3 phases of 480V, 1 phase of 220V, and 1 phase of 120V. The 3-phase is for the machine equipment and lift, 220V is for the computers and stuff, and the 120v is relegated to coffee making, beer refrigerating and lighting.



  • @Weng said:

    @Jaime said:

    Our electricity is so inherently safe that our electrical codes are more about fire prevention than electrocution prevention. Your plan to convert to 120V was dismissed because it was too expensive. Increasing the voltage of a carrier increases its power handling capabilities pretty much for free. Going to 120V would require doubling the amount of copper running across the country and copper is expensive. So, your country has decided to keep making crispy critters out of the population instead of investing in a more sane delivery system.
    120V is most certainly not what we use for transmission. We use 480v(and higher) for that. It only gets stepped down to 120 (and 240) for local neighborhood service - a few hundred yards at most. If I wanted full 480V service (and I do), I could have it without having to run ANY extra copper, because the transformer is actually adjacent to my property.

    In fact, you'd struggle to find a house in the entire US without 240V service - we just only use it for serious things. 

    I'm actually wiring my new garage for 3 phases of 480V, 1 phase of 220V, and 1 phase of 120V. The 3-phase is for the machine equipment and lift, 220V is for the computers and stuff, and the 120v is relegated to coffee making, beer refrigerating and lighting.

    You would be amazed what percentage of the total wire is used for the last mile at 120V. A single 130kV line going 50 miles to a city brings in enough power for 10,000 houses. That gets distributed to 100 or so neighborhood transformers and then to the 10,000 or so houses. There is more cable used in the 10,000 short runs to individual houses (~1000 miles) than in the high voltage lines (50 miles) or the ~10kV distribution network (probably in the ballpark of 200 miles).



  • @Zemm said:

    @Daniel Beardsmore said:

    We used to be 240 V, but we've dropped down 10 V to conform with Europe at 230 V.
     

    TRWTF with some (most?) 240 to 230 conversions was that it is defined as "230V +10% -6%" so that it is really closer to "236V ±8%" - 240V is still within tolerance so no actual voltages were required to be changed.

    Australia started out as 250V anyway!

    @Jaime said:

    Your plan to convert to 120V was dismissed because it was too expensive.
     

    The closest transformer to my house is about 200m away. On a ~110V system that would be far too far away and it would require many many more transformers and running of HV lines.

    Many? 3/0 gauge cable has a resistance of about 0.04 ohms over 200m. At 100 amps, it would drop about 4 volts. Not great, but not a case for "many many more transformers".



  • In the UK they went for the 'ring main' which is really two wires in parallel to save on copper when houses went electric. I think  it was due to not having any money to buy things after paying the US for ships etc after WW2.

    Rather like Ethernet which began using rings rather than stars when it all went down coax which was expensive (lots of copper) before switching over to phone cables (cheaper) in star topology 

     



  • @Weng said:

    ... 

    I'm actually wiring my new garage for 3 phases of 480V, 1 phase of 220V, and 1 phase of 120V. The 3-phase is for the machine equipment and lift, 220V is for the computers and stuff, and the 120v is relegated to coffee making, beer refrigerating and lighting.

    Beer refrigerating being the most important thing on that list.



  • @Jaime said:

    BTW, you guys have a fuse at every plug, a plug design that ensures the hot is disconnected before any copper is exposed, a shutter in the outlet to make accessing the hot terminal difficult, an internal plug design that makes sure that any loose wire short goes through the fuse, all on 240V. We have a flimsy, bare-copper-exposed plug design with no special safety features and an outlet with open cavities, all on 120V. Yet, we kill fewer people from electrocution per capita than you guys do from stepping on your infernal plugs (an exaggeration, but not really that much).

    Yah - nothing's truly idiot-proof, because idiots are ingenious.


  • Discourse touched me in a no-no place

    @Anketam said:

    @Weng said:

    ... 

    I'm actually wiring my new garage for 3 phases of 480V, 1 phase of 220V, and 1 phase of 120V. The 3-phase is for the machine equipment and lift, 220V is for the computers and stuff, and the 120v is relegated to coffee making, beer refrigerating and lighting.

    Beer refrigerating being the most important thing on that list.

    Believe me, I'm aware of that fact. Little known fact: the beer consumption of any given racecar (indirectly, through the guys building it) is an order of magnitude higher than its fuel consumption and I'll have 2 or 3 of those things kicking around.


  • Very few people seem to understand the reason that UK plugs contain fuses - they are to protect the cables.  The principle is that any cable must be protected by a "protective device" (i.e. a fuse or breaker) that will trip before the cable is damaged by high current. The cable entering a property could be safe for hundreds of amps and is protected upstream, then there is main fuse, usually 100A. This means that anything after this fuse must be able to function safely while passing 100A - this includes the main switch for the property, the meter, consumer unit (fuse box) and cables connecting them. In the consumer unit there will be breakers (usually at 32A) which feed ring mains. This means that the wiring for each ring must be able to safely pass 32A. A ring will contain many sockets, and what happens from that point onwards depends on what the homeowner wants to do. A typical example may be a 2kW electric heater being plugged in - this has a design current of about 8.7A. The question is, how much current must the cable to that heater be able to safely take? You have to assume that a fault could develop in the heater causing it to draw more power (a common fault in a heater). If there is no fuse in the plug, then the cable has to be safe at 32A because that it what it will take to trip the breaker. This would not be a good solution, so in this case the plug will have a 13A fuse, and the cable will be designed to be safe at 13A. Note that even though the design current of the heater is less than 9A, the cable must be rated at over 13A as that is the "fault current" for this device (determined by the fuse in the plug). Where it gets even more interesting is where I want to plug in a radio taking a couple of watts (about 10mA). Here I can have a plug with a 3A fuse, and size my cable for 3A rather than 13A. To understand why this is important, consider the fact that 13A cable is fat, expensive and not that flexible, but 3A cable is thin, cheap and considerably more flexible.

    So, why not use the US system and have a breaker for each circuit and noting in the plug? Firstly a typical UK house might have well over 100 sockets, each able to supply 13A if required (not all at once obviously, but you should never be far from a socket that can supply you with 13A if required). Even if you were to put 10 sockets on each breaker, that would require more than 10 breakers for sockets. Assuming that you use 15A breakers for each of those, it will be difficult to be sure whether any socket can supply you with more than 8 or 9 amps without knowing which other sockets are on the same breaker. For a 13A socket on a 32A ring to not be able to supply 13A, there has to be over 19A used elsewhere on the same ring; for a socket on a 15A circuit to not be able to supply 13A, there only has to be 2A use elsewhere on the circuit. Also, to give the same protection as UK wiring, every cable on every device must be safe at 15A, and my understanding is that this is not true of most devices in the USA.



  • @GettinSadda said:

    Also, to give the same protection as UK wiring, every cable on every device must be safe at 15A, and my understanding is that this is not true of most devices in the USA.

    I'm sure it isn't. And that doesn't even address 20A sockets. But is this really a problem? Sure doesn't seem to be.



  • @GettinSadda said:

    So, why not use the US system and have a breaker for each circuit and noting in the plug? Firstly a typical UK house might have well over 100 sockets, each able to supply 13A if required (not all at once obviously, but you should never be far from a socket that can supply you with 13A if required). Even if you were to put 10 sockets on each breaker, that would require more than 10 breakers for sockets. Assuming that you use 15A breakers for each of those, it will be difficult to be sure whether any socket can supply you with more than 8 or 9 amps without knowing which other sockets are on the same breaker.
     

     I don't see the problem. My parents house (albeit a large one) has 28 breakers all for 16A, usually ~5 sockets on each (about 10 are dedicated to kitchen or CV appliances)

    My current 3-room appartment has 4 16A (including one dedicated to the heater) and I just quickly counted the sockets: 15 (altough I may be off by a few)

    Now expecting a sin gle socket to provide 3000W (as you say, 13A @ 230V = 2990W), THAT would be a WTF in my eyes.


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