Conspiracy?
Comments
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I understand how coils of wire with current flowing through generate a magnetic field, the basis of a solenoid for example, but how does a magnetic field generate heat? I thought that electrical resistance did that, if so how does a coil provide the right
level of resistance to set fires?you generate a magnetic field if you had a coil of single core cable.
but if you have a flex with the live and neutral coiled the the current flow in the neutral should be the same as the live and the two magnetic fields should oppose each other and cancel each other out.
Not under earth fault conditions - the most common kind of fault. The current doesn't flow back through the neutral. I am reporting actual safety issues not just making it up! However, this was before rcd's were in common use. They only need a few milliamperes
and will work whatever the earth fault impedance.0 -
I understand how coils of wire with current flowing through generate a magnetic field, the basis of a solenoid for example, but how does a magnetic field generate heat? I thought that electrical resistance did that, if so how does a coil provide the right
level of resistance to set fires?you generate a magnetic field if you had a coil of single core cable.
but if you have a flex with the live and neutral coiled the the current flow in the neutral should be the same as the live and the two magnetic fields should oppose each other and cancel each other out.
Not under earth fault conditions - the most common kind of fault. The current doesn't flow back through the neutral. I am reporting actual safety issues not just making it up! However, this was before rcd's were in common use. They only need a few milliamperes
and will work whatever the earth fault impedance.You are not reading what I have written .
a single wire coiled will create a magnetic field, in a 2 or 3 core flex as the currents are balanced the magnetic fields will cancel each other out.
There was no mention of earth fault currents in the post above.
even so if the fault current goes back down the earth conductor in the same flex rather than the neutral it will still generate an opposing magnetic field to the live conductor in the same flex.
if the fault current takes a different path i.e. through you to earth then there will be and imbalance , but it isn't going to be there for hours is it , and in how much of a magnetic field do you think it will make in the flex? the Rcd should operate like
you say.it's obvious to me you know your stuff , but we were taking about magnetic fields not fault currents.
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I understand how coils of wire with current flowing through generate a magnetic field, the basis of a solenoid for example, but how does a magnetic field generate heat? I thought that electrical resistance did that, if so how does a coil provide the right
level of resistance to set fires?you generate a magnetic field if you had a coil of single core cable.
but if you have a flex with the live and neutral coiled the the current flow in the neutral should be the same as the live and the two magnetic fields should oppose each other and cancel each other out.
It creates eddy currents which causes the heating, useful for things like an induction hob but not good in your mains cable.
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What are you people on
So now if I turn my fully wound cable drum over whilst connected to the EHU, I can now sit outside with a saucepan and boil my eggs in the morning, just like an induction hob.
Or use it's magnetic properties to hold fast all my metal tools, screws and whotnots.
I'm sure someone will be along in a minute to sing the praises of a connected wound cable reel that will receive Sky, WiFi and heat the awning at the same time
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Agreed, we carry a 10 m and a 25 m, so there is never that much to zig zag anyway.
same here, steve....use the most appropriate one.....or even join together should it be necessary....
same again with hoses.....one long one and one a bit shorter....again use short when all thats needed (less cumbersome) or longer if required.....also join if tap a long way away....
no large coils of cable or hosepipe.....
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This thread now contains so much duff advice and 'theories' about eddy currents, magnetism, induction heating et al, that it should really now be closed! Please oh please
CnC, I take Trees down, I know nothing whatsoever about Electricity or the Alchemy of its properties-am I ok to give my theory now?
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This thread now contains so much duff advice and 'theories' about eddy currents, magnetism, induction heating et al, that it should really now be closed! Please oh please
CnC, I take Trees down, I know nothing whatsoever about Electricity or the Alchemy of its properties-am I ok to give my theory now?
Why not? Knowledge isn't everything when it comes to giving free advice on here
If someone starts a thread asking how best to perform a frontal lobotomy, you, as a tree surgeon, will be half-way qualified ( by CT standards) to provide advice
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This thread now contains so much duff advice and 'theories' about eddy currents, magnetism, induction heating et al, that it should really now be closed! Please oh please
CnC, I take Trees down, I know nothing whatsoever about Electricity or the Alchemy of its properties-am I ok to give my theory now?
Why not? Knowledge isn't everything when it comes to giving free advice on here
If someone starts a thread asking how best to perform a frontal lobotomy, you, as a tree surgeon, will be half-way qualified ( by CT standards) to provide advice
Eewwwww, respect the Chainsaws, mess, I think not
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This thread now contains so much duff advice and 'theories' about eddy currents, magnetism, induction heating et al, that it should really now be closed! Please oh please
which are the duff advice and theories?
from what I have read on this thread Hitchglitch is highly qualified and experienced I might not have come across as agreeing with every thing he has said but compared to some of the down right dangerous and misinformed electrical advice that is given on
this forum , at least he is trying to pass on some knowledge for free.no ones forcing any one to read it.
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There is a lot of uninformed opinion on here. What is clear from all who understand electrics is that coiled cables generate heat when current passes through them. A fire is theoretically possible but in reality you are more likely to shorten the life of
the cable. Either way it is not a good idea.0 -
As an electrician who worked on the tools all my working life i will give my take on this issue.Its true that a coiled up cable will generate heat but that has to depend on certain things.First it has too be carrying quite a few amps for a very long period.Hookup leads are 2.5mm 3core cables and will carry a hell of a lot more than the 16 amps which we are provided with.The amount of heat will also depend on the copper content of the cable being used.The cheaper the cable the less copper is actually used and the higher the resistance too carrying current freely and therefore heat is produced so a good quality cable should be ok.The standard of hookup leads and connectors used in the UK is second too none and better than most i can assure you.My honest opinion on this is that the chances of a coiled up hookup lead becomeing hot enough too catch fire are miniscule.The fact that its in the open air and would need such sustained high current flowing through it for a very long period make it a very,very rare occurance and then only in extreme circumstances.Yes as said a coiled cable will produce heat but getting hot enough too melt and catch fire is entirely another.This is just my opinion based on my working experience.
peter.
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As an electrician who worked on the tools all my working life i will give my take on this issue.Its true that a coiled up cable will generate heat but that has to depend on certain things.First it has too be carrying quite a few amps for a very long period.Hookup
leads are 2.5mm 3core cables and will carry a hell of a lot more than the 16 amps which we are provided with.The amount of heat will also depend on the copper content of the cable being used.The cheaper the cable the less copper is actually used and the higher
the resistance too carrying current freely and therefore heat is produced so a good quality cable should be ok.The standard of hookup leads and connectors used in the UK is second too none and better than most i can assure you.My honest opinion on this is
that the chances of a coiled up hookup lead becomeing hot enough too catch fire are miniscule.The fact that its in the open air and would need such sustained high current flowing through it for a very long period make it a very,very rare occurance and then
only in extreme circumstances.Yes as said a coiled cable will produce heat but getting hot enough too melt and catch fire is entirely another.This is just my opinion based on my working experience.peter.
Absolutely! Common sense reality instead of scare mongering and posturing.
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As an electrician who worked on the tools all my working life i will give my take on this issue.Its true that a coiled up cable will generate heat but that has to depend on certain things.First it has too be carrying quite a few amps for a very long period.Hookup leads are 2.5mm 3core cables and will carry a hell of a lot more than the 16 amps which we are provided with.The amount of heat will also depend on the copper content of the cable being used.The cheaper the cable the less copper is actually used and the higher the resistance too carrying current freely and therefore heat is produced so a good quality cable should be ok.The standard of hookup leads and connectors used in the UK is second too none and better than most i can assure you.My honest opinion on this is that the chances of a coiled up hookup lead becomeing hot enough too catch fire are miniscule.The fact that its in the open air and would need such sustained high current flowing through it for a very long period make it a very,very rare occurance and then only in extreme circumstances.Yes as said a coiled cable will produce heat but getting hot enough too melt and catch fire is entirely another.This is just my opinion based on my working experience.
peter.
Fully agree too HG, this is essentially what I put earlier in the thread. Having said that, I do always uncoil the cable because:
I have seen 2 melted coils (never on fire, which I see as a very remote risk)risk.
Its the manufacturer's advice.
It extends the life of the cable by minimising the temperature.
But most importantly..... it only takes around 3 seconds at the start of my holiday and 15 at the end for me to feel a little bit safer about this negligible risk.
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As an electrician who worked on the tools all my working life i will give my take on this issue.Its true that a coiled up cable will generate heat but that has to depend on certain things.First it has too be carrying quite a few amps for a very long period.Hookup
leads are 2.5mm 3core cables and will carry a hell of a lot more than the 16 amps which we are provided with.The amount of heat will also depend on the copper content of the cable being used.The cheaper the cable the less copper is actually used and the higher
the resistance too carrying current freely and therefore heat is produced so a good quality cable should be ok.The standard of hookup leads and connectors used in the UK is second too none and better than most i can assure you.My honest opinion on this is
that the chances of a coiled up hookup lead becomeing hot enough too catch fire are miniscule.The fact that its in the open air and would need such sustained high current flowing through it for a very long period make it a very,very rare occurance and then
only in extreme circumstances.Yes as said a coiled cable will produce heat but getting hot enough too melt and catch fire is entirely another.This is just my opinion based on my working experience.peter.
Fully agree too HG, this is essentially what I put earlier in the thread. Having said that, I do always uncoil the cable because:
I have seen 2 melted coils (never on fire, which I see as a very remote risk)risk.
Its the manufacturer's advice.
It extends the life of the cable by minimising the temperature.
But most importantly..... it only takes around 3 seconds at the start of my holiday and 15 at the end for me to feel a little bit safer about this negligible risk.
just as importantly, those on the next pitch may feel safer too. You never know, they may just hold the opposing view or have, as rare as they are, experienced that event of a melted cable or the likes! I suppose any way of reducing risk is good, each tiny
act makes us all a little safer!0 -
Another aspect of this situation is that the cable would have too be very tightly wound in small coils with little or no airgap between the coils for any heat too really manifest itself.Most of us including myself probably coil up our leads with loops of
about a meter in length as doing it in small loops takes a lot longer not just too coil up but also too unroll next time its used.The larger the loop the better the cable will react too being used.The best way too coil up a lead is the same way a cowboy would
coil up a lasso.The best way too unroll is as if you were rolling it along in front of you like a wheel.The worst thing you can get in a lead is a twist and this shows itself when the lead wont sit flat on the floor and looks like a spring that has been over
extended.Never coil the lead up by wrapping it round your shoulder and elbow i remember geting a right roasting as an apprentice for doing this
its a recipe for twists.Current is a bit like water running along a pipe it does.nt mind straight lines or nice round curves but when the
cable is twisted or in tight turns the current starts too bounce off the sides as its path is not as smooth and that is when the heat is generated.But again this heat is very limited unless in a sustained high amperage situation.I hope this helps those of
us who are not sure about electricty or handleing it.If you use it properly you have more chance of being struck by lightning than haveing any mishaps.peter.
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I would say that most, me included, coil our cable onto one of those orange reels where it is quite tightly coiled. Having read the advice on this thread I may have to revise this practice, although I do always fully uncoil.
edit my analysis of numbers is based on how many you see lying around, often with cable still on them.
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Buried in these 10 or so pages of comments there is a lot of misinformation. Please be aware that the bollard will not trip out if your cable overheats, only if you take too much current (overload or short circuit fault).
You would think that the standard UK hook-up cable of 2.5 mm would be more than adequate for the power taken by a caravan, however, when you look at cable ratings the capacity varies enoumously depending on how the cable is installed. A 2.5 mm cable enclosed
in a conduit in a wall is rated at 20 amps and the temperature will rise to 70 deg. C. in a 30 deg. C ambient. If the EHU cable is tightly wound on a drum and you use the maximum Club supply of 16 amps it will get very hot. The cables are bunched together
and the heat is captured. This is a known safety issue which has caused fires.For most of us that trail the lead under the van and don't use much power it is largely irrelevant.
It is interesting to see continental vans which often have black 1.5mm cable leads which to me look totally inadequate just from a mechanical strength point of view. Add to this the habit of joining them together with any old plug/socket it does make you
wonder how many accidents there are.0 -
If you see a wok balanced on the cable drum, perhaps it's time to worry.
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Just reading MMM and there is an article in there, it show a photo of a coiled lead and a warning about possible dangers! Sorry if this has been mention before but the man who is their expert is very highly regarded in such matters. I think his name is Clive
Mott-Gotobed.0 -
Only a miniscule chance of a coiled lead overheating, even less chance of it catching fire and if units are properly spaced an even smaller chance of it spreading to another unit.
Why risk your own or anybody elses property/life just to save your self a thirty second task?
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