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Dvsa Tightening Up On Breakaway Cable Fitting

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I've recently fitted a swan neck tow bar to my 'new to me' Antara. I chose a Westfalia bar because the breakaway cable eye is in a sensible place and relatively easy to reach compared to the Witter swan neck bar.

 

Phil.

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I've found my cable loop on the fixed part of the towbar and have got a 2 ton link from my engine hoist in case the breakaway clip can't pass though (sure it's a loop around cable clip).

 

I'm positive when we picked the caravan up from the dealers (our first van) they showed us to loop the breakaway cable around the towball so this forum has potentially saved me some grief and made our outfit safer.

 

Thanks all!.

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The eye on the Discovery 3 is directly above the tow ball inside the cover for the electrical connections. It is on the centreline of the car which minimises the risk of it tightening when going round tight corners. The pictures on the Land Rover web site are not very clear but it appears to be the same as the Discovery 4. The eye is so heavily built that I doubt whether a caribena clip would fit.

And also on the pre-2016 Sport - the latest with the deployable towbar has an eye on the side

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The breakaway cables do have to conform to certain standards (as already stated on this thread).

 

 

Basically the regulations are as follows.

 

 

Assuming all Trailers and all Coupling devices fitted to vehicles are by now covered by EU Type approval (for the sake of argument), then in order to achieve that type approval they have to conform to Regulation 55.

 

 

This regulation requires that all trailers have a secondary coupling system. For un-braked trailers (IE <750 kg MTPLM) this takes the form of a wire or chain which prevents separation from the tow vehicle in the event of a failure of the primary coupling device.

 

For trailers with brakes the requirement for a Secondary coupling device is for a device that can bring the trailer to a stop should it separate from the towing vehicle. (The feeling here is that it is safer for the heavier trailer to be brought to a standstill than have it waggling around on a chain, the same logic applies to continuous brakes used on larger trailers, break the air line and the brakes apply)

 

The primary coupling device by definition includes the Towball so looping or attaching a cable around the primary coupler is not allowed by the regulation as failure of the primary coupler would also mean the failure of the secondary.

How this is implemented in local road traffic legislation, seems to be left to each member state, but the Dutch approach seems sensible and logical, and is supported by the regulation.

 

Tow bar manufacturers/designers therefore have to provide an attachment point for this secondary coupling, that is not part of the Primary coupler components.

 

 

The wording used is:

 

 

Manufacturers of towing brackets shall incorporate attachment points to which either secondary couplings or devices necessary to enable the trailer to be stopped automatically in the event of separation of the main coupling, may be attached.

 

 

There are strict rules as to the positioning

 

 

The attachment points for a secondary coupling and/or breakaway cable shall be positioned such that when in use, the secondary coupling or breakaway cable does not restrict the normal articulation of the coupling or interfere with the normal inertia braking system operation.

 

A single attachment point shall be positioned within 100 mm of a vertical plane passing through the centre of articulation of the coupling. If this is not practicable, two attachment points shall be provided, one on each side of the vertical centre line and equidistant from the centre line by a maximum of 250 mm. The attachment point(s) shall be as rearward and as high as practicable.

 

 

The secondary coupler attachment point has to be able to withstand a Horizontal force of 2D up to a Max of 15KN, however where the attachment point is specifically for a breakaway cable it only has to with stand a force equivalent to D. So it stands to reason that the cable must also meet or exceed these requirements.

 

 

D = (The MAM of the Towing vehicle in tonnes * The mass transmitted to the ground via the trailer axles at MTPLM) / (The MAM of the Towing vehicle + The mass transmitted to the ground via the trailer axles at MTPLM) * 9. 81

 

 

As an example for a Car with an MAM of 2000kg and a Trailer with a load through the axles of 1400kg (at 100% MTPLM) the D value would be

 

 

D = (2 * 1. 4) / (2 + 1. 4) * 9. 81

 

D = 8. 1 KN

 

(The maximum D value for a car towing an 02 trailer would be 16. 79 KN, in practice it is generally less.)

 

So if a secondary coupler is expected to achieve at least 15KN, it follows that the force required to apply the brake must be less than 15KN, once the brake has applied the force increases and the cable seperates.

Edited by Towtug

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You seem to be mixing stuff up a little here. The primary coupling device is the hitch rather than the ball. The fact that a chain, on an unbraked trailer is designed to go over the ball to prevent separation in the event of a primary coupling device failure bears this out.

 

Of course, in reality not all towbars have a secondary coupling point and there is no other option available other than looping a breakaway cable back upon itself around the ball. Detachable tow bar owners should follow the instructions or seek the advice of the tow bar manufacturer.

 

The likelihood of a tow ball failing is infinitesimal whereas a primary coupling failure (most likely due to operator error) is somewhat greater.

 

A secondary coupling point should always be used if fitted along with an appropriate breakaway cable.

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You seem to be mixing stuff up a little here. The primary coupling device is the hitch rather than the ball. The fact that a chain, on an unbraked trailer is designed to go over the ball to prevent separation in the event of a primary coupling device failure bears this out.

 

Of course, in reality not all towbars have a secondary coupling point and there is no other option available other than looping a breakaway cable back upon itself around the ball. Detachable tow bar owners should follow the instructions or seek the advice of the tow bar manufacturer.

 

The likelihood of a tow ball failing is infinitesimal whereas a primary coupling failure (most likely due to operator error) is somewhat greater.

 

A secondary coupling point should always be used if fitted along with an appropriate breakaway cable.

I don't really disagree with any of that other than to say, the Primary coupler for the trailer (its just described as the mechanical coupling in the regs) and the Coupler or Towbar & Ball for the towing vehicle, are covered and classified by the same piece of legislation.

Only a trailer requires a secondary coupling, a towing vehicle does not, instead the Towbar must have a position for attaching the secondary coupling of the trailer.

 

Whilst there may still be a few towbars available produced under the older directives that do not have secondary coupling attachment points they have to be few and far between. Type approved towbars have for years now required to have this, the big issue for me is that it is rarely if ever referred to in the fitting or use instructions.

Edited by Towtug

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I don't really disagree with any of that other than to say, the Primary coupler for the trailer (its just described as the mechanical coupling in the regs) and the Coupler or Towbar & Ball for the towing vehicle, are covered and classified by the same piece of legislation.

Only a trailer requires a secondary coupling, a towing vehicle does not, instead the Towbar must have a position for attaching the secondary coupling of the trailer.

 

Whilst there may still be a few towbars available produced under the older directives that do not have secondary coupling attachment points they have to be few and far between. Type approved towbars have for years now required to have this, the big issue for me is that it is rarely if ever referred to in the fitting or use instructions.

 

The problem with dedicated points for attachment is the lack of identification as towbar fitters never point them out and the customer never has a chance to see the instructions . They should be painted in a bright colour blob of paint or stuck on label in the area . As you say many towbars have them as the cable regulation has been in since 82 but I find they are not always obvious.

 

 

Dave

Edited by CommanderDave
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The problem with dedicated points for attachment is the lack of identification as towbar fitters never point them out and the customer never has a chance to see the instructions . They should be painted in a bright colour blob of paint or stuck on label in the area . As you say many towbars have them as the cable regulation has been in since 82 but I find they are not always obvious.

 

 

Dave

Most if not all Towbar suppliers allow you to download the instructions (eg PF Jones) but unless you know what you are looking for its not immediately obvious. I registered an amendment to incorporate just what you've mentioned in with the EU commission in November 2013, I suppose it may still be in the sausage machine but Ive never heard anything more about it.

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The breakaway cables do have to conform to certain standards (as already stated on this thread).

 

 

The secondary coupler attachment point has to be able to withstand a Horizontal force of 2D up to a Max of 15KN, however where the attachment point is specifically for a breakaway cable it only has to with stand a force equivalent to D. So it stands to reason that the cable must also meet or exceed these requirements.

 

As an example for a Car with an MAM of 2000kg and a Trailer with a load through the axles of 1400kg (at 100% MTPLM) the D value would be 8. 1 KN

 

 

 

 

However, it appears there is no legal specification for the cable or its breaking strain nor how much tension is required to apply a trailer handbrake.

 

The cable must fail otherwise it becomes a secondary coupling. Which part of the cable is designed to fail? From years of experience and forum reading the cables seem to fail with the (dog collar) clip opening up whether looped or attached directly. The latest cables with carabiner clips, some locking some not, have not appeared in forums as the fail point so far.

 

A few years back I contacted Al-Ko, BPW and Knott enquiring about breakaway cable fail points and was informed by two it was commercially sensitive information and the third never replied.

 

Breakaway cable of 4mm wire rope has a breaking strain of around 1 tonne depending on construction and is formed into loops at each end relying on swaged fittings. It is exposed to weather and road dirt.

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I received my genuine AlKo carabiner cable today and it is a lot more rubust than out "quick fit" pattern cable.

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However, it appears there is no legal specification for the cable or its breaking strain nor how much tension is required to apply a trailer handbrake.

 

The cable must fail otherwise it becomes a secondary coupling. Which part of the cable is designed to fail? From years of experience and forum reading the cables seem to fail with the (dog collar) clip opening up whether looped or attached directly. The latest cables with carabiner clips, some locking some not, have not appeared in forums as the fail point so far.

 

A few years back I contacted Al-Ko, BPW and Knott enquiring about breakaway cable fail points and was informed by two it was commercially sensitive information and the third never replied.

 

Breakaway cable of 4mm wire rope has a breaking strain of around 1 tonne depending on construction and is formed into loops at each end relying on swaged fittings. It is exposed to weather and road dirt.

 

 

 

I thought I read cable have to meet BS au 267 1998 .

 

 

 

Dave

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Regarding the attaching of the breakaway cable to the towbar, I have a detachable swanneck, the connection point on the towbar frame has a ring for attaching the cable. However, it would appear my cable is not long enough to attache (in a loop) through the ring so I have been looping it around the towbar. Apparently this is wrong, if that is the case is it easy enough to get a longer cable fitted.

 

My second query is this. I had dropped off the 'van at the storage place, disconnected everything and started to pull away when it became apparent I hadn't! The breakaway cable was still attached and I had pulled it tought. Doh! I reversed back to slacken it off so I could release it, I then pushed the 'van back a foot or so back on to its pitch. Will I have caused any damage to the break system on the 'van?

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It's probably wiser to renew the cable as you may have tugged it quite hard.

Get one with a carabiner fitting and yes they are reasonably easy to for using a pair of plumbers grips or mole grips.

Edited by springtime

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You won't have damaged anything but the clip and if in luck the cable itself.

 

New direct attached cabinet clip type to replace old one. No loop then! Al-Ko shop sell them. Better made than many alternative replacements!

 

I have never been able to close loop without using my small portable vice to do so. Mole grips and similar did not work for me!

 

Been there done that twice to date!

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There is nothing wrong with looping the cable round the towbar - by which I assume you mean the swan neck. We have been doing it in the UK for decades.

 

However if you go to Dutchland and get stopped you will be fined as such attachment is illegal in Holland. You must attach there by a connection to a specific breakaway loop or you must put a pigtail on one of the ball mounts.

 

Simple solution is to replace your existing cable with a longer one that will reach the correct fitting.

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Personally I wouldn't loop the cable round a detachable ball - if it falls out (and they do) then there is nothing to operate the caravan handbrake, just when you need it.

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You won't have damaged anything but the clip and if in luck the cable itself.

 

New direct attached cabinet clip type to replace old one. No loop then! Al-Ko shop sell them. Better made than many alternative replacements!

 

I have never been able to close loop without using my small portable vice to do so. Mole grips and similar did not work for me!

 

Been there done that twice to date!

Me too twice and and used mole grips / plumbers grips on both occasions so we agree to differ :D

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There is nothing wrong with looping the cable round the towbar - by which I assume you mean the swan neck. We have been doing it in the UK for decades.

 

However if you go to Dutchland and get stopped you will be fined as such attachment is illegal in Holland. You must attach there by a connection to a specific breakaway loop or you must put a pigtail on one of the ball mounts.

 

 

This Dutch issue has come up before. I would say it is not illegal as long as we are in the EU, but it may be another story after Brexit. A couple of years ago I posted a reply I received from the Caravan Club (as was) concerning this issue.

 

Thank you for your e-mail.

It is illegal to wrap the breakaway cable around the towball in Holland however, this law only applies to residents living in Holland. Foreign registered vehicles are not subject to this requirement. The Club are aware that some dutch police officers may not know that the law does not apply to foreign outfits and may enforce the fine of 130 Euros.

It could be difficult arguing with an Dutch policeman who was ignorant of European law, but I think the CC are covering their backs. I wonder if this illegal €130 fine, and policeman waiting to pounce at ferry ports is just an urban myth. When I spoke to the Caravan Club they said they had never heard of anyone being stopped and fined. It always seems to be second hand 'information'. I've driven many times in Holland without the slightest bother but I must admit I find the law off-putting as I have no other way to secure my breakaway cable.

---------------------------------------------------------------------------

Perhaps there are some genuine, first hand reports of fines that have occurred in the last couple of years. It would be interesting to know.

Since then my new detachable has an attachment point so obviously I use it.

Gordon

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Here's ALKO's take on the subject.

 

 

 

John. :)

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Thanks John - That is what I've done for 10 years.

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Here's ALKO's take on the subject.

 

 

 

John. :)

And what happens when it works it's way slack----decent cable won't stay tight as shown on video.

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And what happens when it works it's way slack----decent cable won't stay tight as shown on video.

My Al-Ko cable stays tight on my deployable swan neck towbar when looped around and pulled so. It is identical to the cable in the video, and I would consider it to be one of the best available.

Other users' mileage may vary, of course.

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