Conspiracy?
Comments
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Sorry, sorry, sorry - I didn't mean to start a great debate on this, but this topic keeps comin up. 'Disgusted, Tunbridge Wells' just feels that he or she simply must point out the errors of our way.
It's over 40 years since I did my degree in Electrical & electronic engineering and I can't remember all the maths, but I do know that while a lightweight tightly wound cable is potentially dangerous, a loosely coiled proper EHU cable is very unlikely
to cause problems - unless you trip over it!0 -
It’s reasonable to pay some respect to electricity, especially if you don’t understand it. It can be a killer but, in spite of the chances, I’m not aware of that happening very often. I think there may be more danger of shock from handling damp cable than
it overheating but maybe I’m not aware of the high current being drawn by some.0 -
Engineers used to refer to the 'light bulb in a biscuit tin' effect to describe overheating caused by containment. And so it is with coiled cables, with the added effect that cable resistance increases with temperature. It's got nothing to do with the imaginary components of the cable's impedance.
Promise this is our last contribution to this thread
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I leave my excess cable wound up on the real and leave it under the caravan , that way i get underfloor heating,
I bring mine into the caravan itself and put the reel inside my sleeping bag.
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Leave a coiled cable out in the snow and you will soon see a difference to one laid out 'correctly'. Yes, I have witnessed the heat generated particularly with a heavy load. There have been reports of individual coils welding themselves together but I've
never seen that extreme outcome.0 -
My cable came with a Hymer Caravan, it is black and apears to be a type of rubber coating rather than orange PVC of the UK
supplied type. It came on a wind up reel. Although the van is long gone I still use it in preference to the usual type. I unwind it if staying a while but if its only for the night rarely bother.The reason for an orange cable is safety. It is far more visible to pedestrians but also wardens racing mowers.
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My cable came with a Hymer Caravan, it is black and apears to be a type of rubber coating rather than orange PVC of the UK
supplied type. It came on a wind up reel. Although the van is long gone I still use it in preference to the usual type. I unwind it if staying a while but if its only for the night rarely bother.The reason for an orange cable is safety. It is far more visible to pedestrians but also
wardens racing mowers.shocking
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Sorry, sorry, sorry - I didn't mean to start a great debate on this, but this topic keeps comin up. 'Disgusted, Tunbridge Wells' just feels that he or she simply must point out the errors of our way.
It's over 40 years since I did my degree in Electrical & electronic engineering and I can't remember all the maths, but I do know that while a lightweight tightly wound cable is potentially dangerous, a loosely coiled proper EHU cable is very unlikely
to cause problems - unless you trip over it!This is surely correct and is exactly the advice I was given when I asked a client of mine who is an electrician with years of experence and who also caravans. He did agree that experts argue that it was good practice to unwind the cable but that this was
just an extreme precaution; the reality is that with a good quality typical hook up lead the chances of any problems by not doing so were remote in the most extreme of senses.I started to unreel my cable only recently - a couple of years ago - after nearly 30 years of trouble free wound EHU leads. But I did so only to avoid the wrath of the rather pathetic cable police, who seemed suddenly to become more vociferous. I am rather
inclined to go back to what I have always done and blow the cable police.0 -
Never seen a lead suddenly catch fire ? Has anybody else ?
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Can all of you really guarantee 100% that your cable has not been damaged in some way? A cycle - an aquaroll or a sharp stone? I will carry on unravelling my cable thank you. Heck I got a puncture in a brand new caravan tyre caused by a sharp stone -
and I still have the stone if anyone wants to see it. My EHU cable isn't ANYTHING like as tough.0 -
Surely by enravelling the whole cable you are increasing the risk of that aquaroll,cycle or heavy leaf damaging the cable !!
I jest but you have to manage the risk based on occurancies and based on that there is no need ,IMO, to unravel the whole cable.
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I have seen a cable coil that had stuck together because it had overheated when not unrolled
Me too, twice.
I suspect in the summer there is little issue as the loads are sporadic and low.
However in the winter, with the heating on full and on load for most of the time, heat will build up in the cable.
We have a 3kW oil filled radiator at home - if that is on full blast for a couple of hours, the cable is warm to the touch.
Its not about cable damage, its about the electrical resistance of the cable and losses in electrical transmission resulting in the generation of heat (conservation of energy laws) - A nice long cable has a proportionately higher resistance than a short
flex, if tightly spooled, this heat can build up to a point where the insulation melts (I have seen it myself) - if the insulation breaks down to the extent that the wires can touch, then you will trip the circuit (...or possibly even a fire, though I would
of thought this less likely - but given other writers accounts, clearly possible).0 -
It seems such a silly argument. Why not uncoil it, even if the risk is very small. The risk of me hitting anything in my car is statistically small, but I would still put a seat belt on, even if not required by law. As I think would most others.
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I used to be in the motor trade and lost count of the number of extension cables that had to thrown away because they had short-circuited where they had not been fully unwound.
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Never seen a lead suddenly catch fire ? Has anybody else ?
To meet regs a compliant cable and drum will be made of non-combustible material so unless it's a cheapy eBay 'bargain' it will not 'burst into flames'. If it's laying on dry grass or paper I suppose that could ignite IF the cable got that hot.
However..........
The trip at the bollard should drop out long before the cable gets so hot that it melts. I don't use EHU much and only for a couple minutes at a time for a low wattage electric kettle but from what I've read the current available at bollards is limited to
either 6 or 10 amps which I'd guess is below that which would cause any cable damage before the bollard trip cut out.0 -
Has anyone actually seen one of these coiled up extension leads burst into flames ?
.Yes. It was on a site in Spain in winter. It also tripped the whole site.
In which case the site is non-compliant and potentially very dangerous as a fault in a secondary ring circuit should NEVER trip the main supply. Mind you, several sites I've used in Spain and France had dodgy installations: broken fittings on lighting above
showers, light switches within the washbasin cubicles, cracked shaver sockets, broken or missing doors on bollards.......0 -
Never seen a lead suddenly catch fire ? Has anybody else ?
To meet regs a compliant cable and drum will be made of non-combustible material so unless it's a cheapy eBay 'bargain' it will not 'burst into flames'. If it's laying on dry grass or paper I suppose that could ignite IF the cable got that hot.
However..........
The trip at the bollard should drop out long before the cable gets so hot that it melts. I don't use EHU much and only for a couple minutes at a time for a low wattage electric kettle but from what I've read the current available at bollards is limited to
either 6 or 10 amps which I'd guess is below that which would cause any cable damage before the bollard trip cut out.What regs are these please? Most drums are made of polypropylene or similar!
Why would the trip at the bollard go if the cable got hot? The trip will only activate if you draw too much current (I think cc sites are 16 amps?) Or there is a short - the only way it would short in this situation is if the heat melted the insulation,
and the wires touched.....but it would have to melt the cable first before it would trip!
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This is mainly a Club site issue due to the very generous 16 amp supply and people's desire to use as much of it as they possibly can as we know from other threads! Take the same 2.5mm lead to Europe and use it on a 6 amp supply and you can coil it as much
as you like! Nevertheless the advice is sound.For anybody who likes the technical stuff, if you wind it really closely you create an inductive coil which creates an ac resistance (impedance) which can cause the fuse not to blow under fault conditions. There have apparently been recorded instances of
this but it would be an extremely unusual occurrence. According to calculations I once did, it would have to be one heck of a coil!0 -
Never seen a lead suddenly catch fire ? Has anybody else ?
Write your comments here...No, but I have seen one that had melted and fused together on the tightly wound reel.Half of the reel,about 10-12 metres was a solid mass of orange plastic. I have an open cored cable storage holder, not a drum,this allows the
core to stay cool, even when only partially unwound.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.
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Interesting debate, but let t s be logical about it.
I always unwind mine fully and run it across the back of the caravan a few times.
In this time of health and safety its prudent to do so, but let's not forget that should the worst happen and the insurance company were to become aware they could refuse the claim due to negligence.
Before I get slated for saying this, I used to work in the insurance industry.
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What regs are these please? Most drums are made of polypropylene or similar!
Standard: BSI - BS EN 61242
ELECTRICAL ACCESSORIES - CABLE REELS FOR HOUSEHOLD AND SIMILAR PURPOSES
My point is that neither a compliant cable nor reel would 'burst into flames'.
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