Connecting an EHU Cable

[The Old Man]

Is there a correct way to do this?

Connect the van end first.

Or the supply end first?

My simple thoughts were to connect the van end first because if you connect the supply end first you are walking around with a 'live' cable in your hands.

 

[Techno]

You are using outlandish scenarios like tabloid press ,. Get real

 

[Lee27]

we had an oil radiator that we used from an extension lead, on multiple occasions, over a period of several months and it never gave any problems. once i connected it up and turned it on without unraveling the lead, 30 minutes later the supply tripped and i couldn't unravel it, the insulation had melted and stuck together. i knew at the time i should have unraveled it but was lazy, luckily learned the lesson without more serious consequences, but won't make that mistake again.

is it not common sense to connect to the van prior to connecting to a live supply, meaning you're not walking around with a live lead in your hand? it seems like it is to me. at the end of the day; connecting to the van first can only be safer (however likely/unlikely), so why not do it that way. i could understand if it posed some sort of hardship or something, but it seems to me it's just a slight change of practice with no real negative side effect.

the sole purpose of my watering can is to hold water, guess what; walking across the garden the other day and saw a trail of water on the floor from the hole in the bottom of the can.

nothing is infallible, after all an rcd has a test button.

Lee

 

[BravoTwoZero]

On a recent trip to Cornwall it surprised me how many people had most of their cable in a neat coil under their vans.

 

[Gorse Hill]

You are using outlandish scenarios like tabloid press ,. Get real

Still no answer I see
Substitute Bath for Pool of water next to EHU post c/w leaking water tap, now that's outlandish

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[DBK]

This Thread is longer than my cable! For which I accept some blame.

 

[Techno]

I don't see it as relevant

 

[Techno]

Far more urgent is the number of muppets driving around with their status aerial pointing the wrong way

 

[Don Quixote]

The subject is getting to be a real live wire and is shocking, but I'm sure some bright spark will come along and shed some light on/in the end! however I'm not advising only saying

 

[andrewjw]

Does anyone else unplug their EHU cable from both the van and hook up point if there is lightning about?

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[Don Quixote]

Does anyone else unplug their EHU cable from both the van and hook up point if there is lightning about?

No personally I don't, but Yes some do. Sitting on the fence now

 

[JJ]

Don't you just love the Internet?

Four pages of posts on which end of your hook up cable should be connected first.

No one mentions you should wear rubber gloves, thick soled welly boots and safety goggles as you plug in, just in case.

And don't forget your hard hat too... imagine a conker falling on your head at the critical moment.

JJ

 

[gus-lopez]

HOWEVER, I would still appreciate an explanation as to why coiling them up produced this result.?

The coiled wire , although insulated , acts exactly the same as the coiled wire on an electric fire. Instead of being exposed & radiating heat in the case of the fire, the coiled wire is heating & melting the insulation.

Does anyone else unplug their EHU cable from both the van and hook up point if there is lightning about?

No, but I always do it to anything indoors now since I lost a computer even though it was through a ups .

Don't you just love the Internet?

Four pages of posts on which end of your hook up cable should be connected first.

No one mentions you should wear rubber gloves, thick soled welly boots and safety goggles as you plug in, just in case.

And don't forget your hard hat too... imagine a conker falling on your head at the critical moment.

JJ

I would hope it was a coconut as I would be in sunny climes.Anyway Flt's don't have to worry about plugging in. ( Unless it is a market point )

 

[iandsm]

The original question was a simple one and was answered correctly within one reply in my view. A pity that a simple question leads to do much bickering

 

[The Old Man]

Don't you just love the Internet?

Four pages of posts on which end of your hook up cable should be connected first.

No one mentions you should wear rubber gloves, thick soled welly boots and safety goggles as you plug in, just in case.

And don't forget your hard hat too... imagine a conker falling on your head at the critical moment.

JJ

No Hi-Viz Jacket JJ?

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[Rapido925M]

The coiled wire , although insulated , acts exactly the same as the coiled wire on an electric fire. Instead of being exposed & radiating heat in the case of the fire, the coiled wire is heating & melting the insulation.

I prefer to deal with facts rather than assertions and suppositions.

A 2.5kW heater will draw approx 10A from a mains supply. Its resistance is approx 250ohms. It gets hot! Wrapping/coiling the wires helps the resistance to rise [because metals have a positive coefficient of resistivity] and also keeps the device compact [you need a "long, thin" wire to get a high resistance: if it's too thin it melts easily, so length becomes a major factor].

A EHU cable has, if I got my calculations correct, a resistance of 0.02ohms. If it passes 10A, it dissipates 2W. I do not consider that this can be a significant effect in melting a cable, even if "all" of that heat is concentrated in a small volume: please persuade me otherwise.

(I plug into the van first, then the supply and I also disconnect the supply first: it seems sensible. My cable is wound on an open frame and I unwrap as much as I need. ) - Gordon

 

[Gorse Hill]

I prefer to deal with facts rather than assertions and suppositions.

A 2.5kW heater will draw approx 10A from a mains supply. Its resistance is approx 250ohms. It gets hot! Wrapping/coiling the wires helps the resistance to rise [because metals have a positive coefficient of resistivity] and also keeps the device compact [you need a "long, thin" wire to get a high resistance: if it's too thin it melts easily, so length becomes a major factor].

A EHU cable has, if I got my calculations correct, a resistance of 0.02ohms. If it passes 10A, it dissipates 2W: that is equivalent to one of those dim bulbs that we used in torches, many years ago. I do not consider that this can be a significant effect in melting a cable, even if "all" of that heat is concentrated in a small volume: please persuade me otherwise.

(I plug into the van first, then the supply and I also disconnect the supply first: it seems sensible. My cable is wound on an open frame and I unwrap as much as I need. ) - Gordon

You keep going on about this cable, It's your cable Gordon you can do what you want with it, you can even wrap it round the van 3 times before plugging in if it fits

 

[JJ]

No Hi-Viz Jacket JJ?

Whoops...

You are 100% right, I completely forgot the Hi Viz jacket...

Silly me!

JJ

 

[Gizmouk]

Whoops...

You are 100% right, I completely forgot the Hi Viz jacket...

Silly me!

JJ

You should be suitably suited and booted

 

[Bailey58]

Far safer and easier to uncoil the cable completely than sit there working out ohms and resistance and the like, and you're setting a good example to the bloke in the next van who may not have a degree in electronics.

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[scotjimland]

 

[SuperMike]

When away during the winter, with the cable laid straight out and with a 2kw draw showing on the meter, then I would see no frost for a few inches either side of the cable.

 

[chaser]

Been through all this, and I'm afraid common sense, says you get your cable out, you are by your van, shove it in, unwrap your cable as you go to the point, shove it in, job done

 

[Old Soldier]

Is there a correct way to do this?

Connect the van end first.

Or the supply end first?

My simple thoughts were to connect the van end first because if you connect the supply end first you are walking around with a 'live' cable in your hands.

Next time @The Old Man , please ask difficult questions. As you can see, simple questions do not get simple answers where as difficult questions get fewer answers as fewer people think they know what the correct answer is!!......If you know what I mean!!

 

[gus-lopez]

I prefer to deal with facts rather than assertions and suppositions.

A 2.5kW heater will draw approx 10A from a mains supply. Its resistance is approx 250ohms. It gets hot! Wrapping/coiling the wires helps the resistance to rise [because metals have a positive coefficient of resistivity] and also keeps the device compact [you need a "long, thin" wire to get a high resistance: if it's too thin it melts easily, so length becomes a major factor].

A EHU cable has, if I got my calculations correct, a resistance of 0.02ohms. If it passes 10A, it dissipates 2W. I do not consider that this can be a significant effect in melting a cable, even if "all" of that heat is concentrated in a small volume: please persuade me otherwise.

(I plug into the van first, then the supply and I also disconnect the supply first: it seems sensible. My cable is wound on an open frame and I unwrap as much as I need. ) - Gordon

Try doing it yourself then. Get a vacuum cleaner, like a Henry or LG , that requires the cord to be pulled out first but don't bother. Then use it , it will melt & fuse in no time. Wife has done it on both models. As I stated before I've had workers fail to unwind, then melt the reels. These aren't 'assertions or suppositions ' but statements of fact from someone who has done it & had it done by family members & employee's.

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[gus-lopez]

I would always plug in the 'dead' end , van, first & then the supply. It is alright stating that your lead is undamaged but you aren't watching it all the time & when you have laid out undamaged leads & then picked them up live ,only to find someone else has damaged them , & you get a shock it isn't funny.

 

[The Wino]

I have never heard of anyone having a problem with reverse polarity or their cable I do untangle it and leave some slack so if I trip on it its less likely to dammage the socket on the motorhome but other than that is it worth worrying what to do the trip there is probably a lot more dangerous!!

 

[TheCaller]

With regard to the reel wound/unwound question .....

I probably should have paid more attention in my 'A' level Physics lesson that afternoon, but it was the best part of 50 years ago now.

There is the straightforward resistance heating effect that has been referred to already, with the heat being trapped within the reel.

But an alternating current passing through a coil of wire also produces an electromagnetic effect. A coiled mains lead is half of a transformer. And transformers get hot. Does half a transformer get hot, or does it need the other coil to go with it?

I told you I should have paid more attention ....

 

[Old Soldier]

With regard to the reel wound/unwound question .....

I probably should have paid more attention in my 'A' level Physics lesson that afternoon, but it was the best part of 50 years ago now.

There is the straightforward resistance heating effect that has been referred to already, with the heat being trapped within the reel.

But an alternating current passing through a coil of wire also produces an electromagnetic effect. A coiled mains lead is half of a transformer. And transformers get hot. Does half a transformer get hot, or does it need the other coil to go with it?

I told you I should have paid more attention ....

It only gets half-hot....!

 

[Bailey58]

Mum

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[Cleve]

All sounds half baked to me


I hope that is a grey Fergie in your red bit!