EHU Leads

[Vic_5039745]

It concerns me and some others to see many caravanners still leaving their EHU leads coiled up under their caravans once they have connected up.

Although the risk is probaby slight, this practice could lead to the cable overheating and bursting into flames.

It's my belief that the lead should always be completely unwound so that the electricity can flow with little or no resistance.

Any chance this could find its way into the magazine please Moderator?

Thanks a lot,

Vic

 

[ProfJohnL]

Hello Vic,

I'm sorry i don't know what you mean by EHU, but I guess you are referring to the mains connection leads?

If I'm right, then you are correct in that a coiled cable can under load Begin to heat up. this is due to the small amount of natural resistance that all conductors have. as the current flows it generates some heat. In an uncoiled cable the heat is easily dissipated to the surrounding air, but if left coiled, then the heat cannot escape so easily, and may be sufficient to melt the insulation and cause a fire.

The cables resistance remains the same whether it is coiled or not, it is the ability to get rid of the heat that is important.

 

[Icemaker]

There are a few that leave the cable wound up Vic, i think this is more to do with lazyness than a lack of education as all the magazines have touched on this subject on many occassions. We have also noticed recently that with the advent of "cheap tent packages" from some of the big retailers we have seen a lot of home made hook up leads made out of domestic quality black or white cable, now it is my understanding that all 240 volt flexible mains cables specifically designed for outdoor use had to be orange.

We recently took issue with a site that we visit regularely about theire policy of allowing tents to pitch next to vans on the hardstandings, now i am not a snob or against tents in anyway but with these cheap packages we have now got a lot of inexperianced campers who have spent 100 quid on a tent and four sleeping bags to come away get p****d and have a laugh, again i have nothing against this we had cause for concern since the tents had become very close to our awning and as this group cooked most of theire food on disposable barbeques a fire was a very real possibility. when i spoke to the group about my concern they simply said it only cost 140 quid so we are not that concerned, but what about my 20 thousand pound outfit that would be burnt with it ? possibly with my kids asleep ?, they just smiled and carried on drinking untill unconcious almost. we told the site owner who blacklisted them from any future bookings. So Vic in my opinion you will never educate those that still leave the lead wound up as they are set in theire ways and you will never reason with some of the cheap package crew as they only have one agenda, and as they have only spent 100 quid on a tent and sleeping bags no way are they going to spend 25 pounds on a proper hook up lead, a danger to themselves and an even bigger danger to us.

 

[Damian]

The only time I have experienced problems with cables overheating is when they are tightly wound on a drum, then the heating effect will melt the cable and cause problems, maybe only shortin the supply or more seriously, catching fire.

As has been said, as long as the eheatcan dissipate, there is no problem, so loosely coiled cable, on the ground, should not present any problem as there is enough air movement and the ground acts like a heat sink.

 

[parker1158]

Hi All

Just been to the CC site at Chedar. The warden there made people coil up their leads and get them out the way as he said they were dangerous left laying all over the place. Much heated discussion then followed between vanners and warden. His argument was that he could catch it with his tractor/mower or other vanners could drive over it and it caught on underside of cars etc etc. I was always educated that electric flex should be uncoiled so I did and carefully laid it out under my van.

While on the subject I have a white lead (it came with the van) should I have a orange one? I have seen both on sites!

 

[BigRoy]

Icemaker has got a good point, I was on a site recently where a tent opposite me had a EHU made up from a domestic 240 lead wired into a 4 gang domestic extension with no RCD, madness, I had a quick word with the guy but it went in one ear and out of the other.

 

[GrahamW]

Whilst I would agree that unraveling the mains lead completely is best practice, a significant build up of heat is unlikely with the relatively low current draw associated with caravan electric's..

 

[WatsonJohnG]

Whilst I would agree that unraveling the mains lead completely is best practice, a significant build up of heat is unlikely with the relatively low current draw associated with caravan electric's..

Martin when I had my altercation I arranged the cable (blue!) on a grassy slope at the rear of the caravan in the word "fire" (joined up writing of course)

 

[WatsonJohnG]

OOps thought I'd replied to this but it was on UKCS

We were accosted by a warden on one site who told us as we waited for our friends to arrive (cable had been plugged in 5 minutes with only fridge on and was on an H type open reel)that our cable was red hot.

My wife uses a walking stick but we were compelled in a state of anxiety to rush a distance to the van.The cable was stone cold .When I asked the couple on the next pitch if they thought that it was hot they replied that he had been "funny" with the as well.

Not amusing

So now we always uncoil the lead not because we think it needed but to avoid holiday spoiling confrontation.

It would be interesting to hear from anyone who has had a 16 amp load burn out a cable.

They could prove as elusive as rocking horse droppings.

This guy also told me that I was ruining my water system because my mains connector did not have a pressure reducer .I tried to explain that it was not connected to the van system but was just filling the tank which in turn fed the pressurised system and also that the site tap was turned off!!I always use a reducer now to avoid confrontation when on service pitches!

He replied that he was not prepared to argue.

We haven't been back to St***ore Hall again!!

 

[RogerL_5041474]

To answer Martyn's supplementary question, there's no mandatory colour for a hook-up lead. The one provided for my first caravan was black but my present one is orange, which is generally more visible.

 

[Viking1]

This myth help.

At work I got told off for not unrolling a cable has it was unsafe.

It was one of the elutriation that told me off for it.

I ask what it would do. He seed it can crate a cruel which cud baste in to flames..

At work we made curtain side trails for H,G,V.

So now I have started caravan I take all the cable off . plug it in put it loose on the floor to the van and put some of it under the caravan has well . so it is not cursing to much of a hazard. For other caravaner

Mark.

 

[ProfJohnL]

Hello Graham,

In response to you posting of 27 Aug 2005 11:51 AM, whilst ingenral I would agree, but caravans with electric heating or air conditioners can easily pull 10+ amps, and that will be sufficient under tightly coiled conditions to generate enough heat to cause concern. Better to be safe than sorry.

 

[Guest]

It is amazing how many peoples do not or never read instruction which is supply in their caravan

 

[Mark_5040952]

Hi Vic and others,

First of all Vic it is not the resistance of the cable that causes a tightly wound cable to heat up, it is the electromagnetic field.

The best way to avoid this happening with any spare cable is to lay the cable in a figure of eight on the ground, when a cable passes another at right angles and field build up is cancelled and no heat will be present.

My job involves long cables being used in the film and TV industry and we always lay our cables in this way even when working on 400Amp supplies, we never have problems!

Hope this helps,

Mark

 

[WatsonJohnG]

Hi Vic and others,

First of all Vic it is not the resistance of the cable that causes a tightly wound cable to heat up, it is the electromagnetic field.

The best way to avoid this happening with any spare cable is to lay the cable in a figure of eight on the ground, when a cable passes another at right angles and field build up is cancelled and no heat will be present.

My job involves long cables being used in the film and TV industry and we always lay our cables in this way even when working on 400Amp supplies, we never have problems!

Hope this helps,

Mark

Very interesting Vic will do that in future.

I have a long lead and a short lead to avoid too much slack lying around.

Its interesting that this comes up regularly But I have never seen anyone write in who has had a fire.

 

[RogerL_5041474]

I'm baffled by Mark's advice.

I coil the cable over my elbow and hand, to fit into my cable bag. When I take it out, can I simply twist the whole coil into a figure of eight by twisting one half of the coil by 180 degree?

This sounds too simple to be true!

 

[Mark_5040952]

I'm baffled by Mark's advice.

I coil the cable over my elbow and hand, to fit into my cable bag. When I take it out, can I simply twist the whole coil into a figure of eight by twisting one half of the coil by 180 degree?

This sounds too simple to be true!

Roger,

Coiling a cable over your elbow and hand is the worst way possible to coil a cable. You risk damaging the inner cores and you can end up with a very messy, twisted cable.

When feeding it out you will find that you can just roll it out without any twists etc. Feed out what you need then with the slack just wind into a figure 8 on the floor so that your socket lies on the top of the pile.

To pack away, just pick up the pile, turn over and pull the slack in, figure 8ing as you go and then fold the coil in half to allow it to fit in the bag.

By doing this you will find your cable no longer has twists in it.

Hope this helps,

Mark

 

[ProfJohnL]

Hello Mark,

Electromagnetic field, yes thats an interesting thought, It could certainly contribute to the heating effect, so effectively you are considering the coil of wire as an inductor.

But in a single phase caravan supply you have both live and neutral carrying the same current but in opposite directions. The resultant field wave form from each conductor will be exactly out of phase with each other and as a consequence the EM field will be cancelled out.

The problem is different with three phase as you have three waveforms at 120 degrees out of phase. These do not cancel out completely and will give inductive heating effects.

So I still maintain the main danger is from resistive heating effects for caravans.

 

[Vic_5039745]

OOps thought I'd replied to this but it was on UKCS

We were accosted by a warden on one site who told us as we waited for our friends to arrive (cable had been plugged in 5 minutes with only fridge on and was on an H type open reel)that our cable was red hot.

My wife uses a walking stick but we were compelled in a state of anxiety to rush a distance to the van.The cable was stone cold .When I asked the couple on the next pitch if they thought that it was hot they replied that he had been "funny" with the as well.

Not amusing

So now we always uncoil the lead not because we think it needed but to avoid holiday spoiling confrontation.

It would be interesting to hear from anyone who has had a 16 amp load burn out a cable.

They could prove as elusive as rocking horse droppings.

This guy also told me that I was ruining my water system because my mains connector did not have a pressure reducer .I tried to explain that it was not connected to the van system but was just filling the tank which in turn fed the pressurised system and also that the site tap was turned off!!I always use a reducer now to avoid confrontation when on service pitches!

He replied that he was not prepared to argue.

We haven't been back to St***ore Hall again!!

Sounds like this warden is a bit of a "wally". Why not name and shame and at the same time write to the site owner/management informing them of this guy's ignorance and attitude. If it is as bad as you say it is - spoiling people's holidays - then he should be "outed" straightaway.

 

[Vic_5039745]

To John L the answer is EHU = Electric Hook - Up.

The consensus seems to suggest that opening the lead right up may be slightly overcautious but by no means silly.

Personally I always undo mine completely ensuring that it won't be a hazard to anyone. So long as the lead is either bright orange or in my case bright yellow, invisibility is not an issue except to someone who is totally blind. Then it would matter if it was sky blue pink.

I also believe that it is encumbent upon site managements to ensure that people are using the correct equipment ergo the right gauge electric lead. If they are not, do not permit them to use the elctrical supply until they do. Many sites that we have stayed on rent out the correct equipment for a small fee.

Thanks for all your responses.

Vic

 

[Vic_5039745]

Hi Vic and others,

First of all Vic it is not the resistance of the cable that causes a tightly wound cable to heat up, it is the electromagnetic field.

The best way to avoid this happening with any spare cable is to lay the cable in a figure of eight on the ground, when a cable passes another at right angles and field build up is cancelled and no heat will be present.

My job involves long cables being used in the film and TV industry and we always lay our cables in this way even when working on 400Amp supplies, we never have problems!

Hope this helps,

Mark

Now THAT is useful and I will certainly do that in future.

Thanks for the correction. I'm not an electrician but I did know that this "wound cable" issue was something to take notice of.

Vic

 

[ProfJohnL]

To John L the answer is EHU = Electric Hook - Up.

The consensus seems to suggest that opening the lead right up may be slightly overcautious but by no means silly.

Personally I always undo mine completely ensuring that it won't be a hazard to anyone. So long as the lead is either bright orange or in my case bright yellow, invisibility is not an issue except to someone who is totally blind. Then it would matter if it was sky blue pink.

I also believe that it is encumbent upon site managements to ensure that people are using the correct equipment ergo the right gauge electric lead. If they are not, do not permit them to use the elctrical supply until they do. Many sites that we have stayed on rent out the correct equipment for a small fee.

Thanks for all your responses.

Vic

Thanks Vic,

It may seem foolish to ask such a question, but I work with many businesses and in so many cases they have developed thier own acronyms for business functions which are unique. I cannot afford to assume I know what each is, so out of habbit I ask.

I had actually concluded that Electric Hook Up was the most likey definition.

but thanks anyway

 

[milliemop]

Hello Mark,

Electromagnetic field, yes thats an interesting thought, It could certainly contribute to the heating effect, so effectively you are considering the coil of wire as an inductor.

But in a single phase caravan supply you have both live and neutral carrying the same current but in opposite directions. The resultant field wave form from each conductor will be exactly out of phase with each other and as a consequence the EM field will be cancelled out.

The problem is different with three phase as you have three waveforms at 120 degrees out of phase. These do not cancel out completely and will give inductive heating effects.

So I still maintain the main danger is from resistive heating effects for caravans.

yes john, maybe thats why in 20 years of caravaning I have never had my hook up cable get even warm---coiled or uncoiled??