Crimps in consumer unit?

[Engineer54]

On this occaision i'm going to have to disagree with you darkwood. You make a good solidly crimped connection to a solid cored cable, sound as if it's a disaster waiting to happen, and i know the truth of the matter, is that it isn't! It'll still be there giving sterling service long after i've left this earth.

I defy anyone to wiggle or pull a solid core conductor out of a well made crimped connection (unless your King Kong..lol!!). If you can say the same for a screwed connection, i'd be very impressed!!

Having said that, i'm not keen at all on the popular coloured PVC crimps, to big and bulky and easily misaligned in the crimping tool jaws. My preference is bare crimps that are then over covered with heat shrink over the actual connection and an over all cover of heat-shrink (talking about Butt crimps here).

I can understand your reasoning if were talking about a moving/vibrating environment, but were not. ... Moving a cable within a DB/CU at a future date isn't going to degrade a crimped connection to a point of failure, this is also a non-starter for an argument against crimped connectors...

 

[Darkwood]

Well on this occasion we will agree to disagree as i have alot of respect for your input on this forum but out of interest il set you a task of finding a picture of butt crimps or even ring lugs on the internet done on solid cable (without taking a pic yourself and cheating)...I found examples of poor crimps and bad practices but all are shown using stranded or fine wire ...out of the whole world wide web you'd have thought if it was so designed for solid there would be at least some examples of crimping it?

 

[KAS1]

and these will be stranded cables no doubt

Only place I would use crimps and lugs when hoose bashing would be on the bonding conductors or at the rod if its a TT

 

[Engineer54]

Well on this occasion we will agree to disagree as i have alot of respect for your input on this forum but out of interest il set you a task of finding a picture of butt crimps or even ring lugs on the internet done on solid cable (without taking a pic yourself and cheating)...I found examples of poor crimps and bad practices but all are shown using stranded or fine wire ...out of the whole world wide web you'd have thought if it was so designed for solid there would be at least some examples of crimping it?

Agreed, and also have a lot of respect for your inputs on the forum too...

I'm not going by what others have stated, or what has been printed etc. I'm basing all i have stated on this issue, on the literary hundreds of thousands of crimped terminations at final DB/CU boards among other areas, over numerous specified project contracts, over too many years to think about!! lol!!

 

[Darkwood]

Just relating back to those who express the crimps feel sound and cant be pulled apart i like to show a few examples... one good and one bad but both pass the strain test and this is why its a poor way to judge a crimp joint. PS i couldnt find a crimp joint on solid as manufacturers dont design butt crimps and lugs for this so examples of them are scarce.

. .

 

[gjcone44]

well darkwood is technically,correct, but who on here does everthing by the book?

 

[KAS1]

sorry, do you mean you use materials for jobs that they are not intended for?

well darkwood is technically,correct, but who on here does everthing by the book?

 

[Engineer54]

sorry, do you mean you use materials for jobs that they are not intended for?

I'd stick with your ''screwed'' connectors they will surely out perform a ''crimped'' connection!! Well in your world anyway!! lol!!

 

[gjcone44]

not materails?, but say live in no.1, then connects nuetral in busbar no,6 them type of things

 

[KAS1]

Perhaps in China they do as they please with crimps lol just accept the fact you have been wrong all these years, please use the right crimp for the right job, the type of crimp that this threat started with as far as I could make out is the straight through insulated blue type, which is fine as long as it is used on stranded / flexible cores and in an enclosure. End of story

I'd stick with your ''screwed'' connectors they will surely out perform a ''crimped'' connection!! Well in your world anyway!! lol!!

 

[Engineer54]

Perhaps in China they do as they please with crimps lol just accept the fact you have been wrong all these years, please use the right crimp for the right job, the type of crimp that this threat started with as far as I could make out is the straight through insulated blue type, which is fine as long as it is used on stranded / flexible cores and in an enclosure. End of story

As i thought , ..you haven't a clue what your talking about!! Stick to your screwed connector strips, and you'll be fine!!

 

[Des 56]

I have read that the standard crimps should not be used with solid cores and will have to accept the statement, although I have never had cause to doubt their effectiveness

I will however state, given the choice between a solid core with a crimp or a push contact such as a Wago
I would use a crimp every time

A push fit Wago type connection would not be found on my own installations.a crimp however, if needed,I would use without hesitation

 

[Darkwood]

Pmsl now now boys!....
Im showing the argument from the technical side now if you work for Aviation, NASA etc this is vital and errors can cost millions or billions but with regards to domestic use the worst case is the crimp would burn out, its made of fire resistant plastic so should at worse just get hot and char, this is the same for any type of connector whether it be screw, clamp or crimp....
The problem with the reg's is it would be almost impossible to cover every aspect of every subject and il show this in that any thing you install you are required to follow manufacturers instructions but no mantion on the tools you use are subject to this... now common sense denotes that this is applicable to follow manufacturers guidelines on using their tools and i have no doubt if you contact the crimp manufacturers they will state its not suitable for solid drawn but because you dont get supplied with a set of how to crimp correctly instruction sheet with your bag of crimps it generates a senerio where users make there own standards whether correct or not.

So because i have in the past sort manufacturers tech advice regarding insulated butt crimps or similar i now have to abide by the regulation regarding following manufacturers guidelines but those who haven't sourced this info are not subject to same reg' although in industry its a given that a proffessional of any trade knows how to correctly use the equipment which he is expected to use to carry out his work.... i see it been a rare thing for such a failed crimp to end someone in court but you cant argue ignorance in court just because instructions were't supplied with product. Like connectors dont sometimes have ratings on them but how often have you seen burnt out incorrectly sized connectors used possibly by a DIYer.. i lost count but something so fundamentally simple to use will still fail if terminated poorly or in some cases if the connector is poor quality - its having the background knowhow of what is a good joint and what isnt that lets you make a good sound judgement call on a simple thing as a crimp.

Example - WAGO have a push fit connector that has 2 ampage values on it now it fits up to and including 4mm solid/strandard cable but has the stamp 24a and 32amps if i recall so here we have a connector with conflicting info on it... What is its rating?

The answer is 32amp but they print 24amp if using 2.5 because the cable CCC limits the ampage as 2.5 could overheat and could burn out the connector if carrying more than 24amps so even though you may consider it to be plug and play style termination a knowledge of the values and applications of the Wago are needed....and of course of cable calcs.

I asked all the lads at work why exactly the differing values were printed on the wago and they all just argued groundlessly the reasons although one guessed he couldn't honestly tell me he was confident he was right... i believe its your responsibility to understand what tols and equipment you use even the basic simple things will can fail if you use with assumptions only.

So question... if its 24amp rated for using 2.5 can you use it as part of a ring main thus the front end 32amp mcb effectively overates a connector in the ring main?

 

[Engineer54]

Perhaps someone here can answer the question of why the manufacturers approved lug connection to solid core HV cable is a crimped lug?? Only been involved with this type of cable on one project, but the termination kits all came with crimped lugs!! In this case all conductors were 120mm...

I'll state for the last time, a correctly terminated crimp connection, using correctly sized crimp terminals for the size of the solid cable being used, in combination with a good crimping tool, equals one very sound termination that isn't going to pull or wiggle free, or cause a high resistance joint, nor deteriorate over time.

 

[john999uk]

So question... if its 24amp rated for using 2.5 can you use it as part of a ring main thus the front end 32amp mcb effectively overates a connector in the ring main?

I will answer with a question. If the connector is rated at 24 amps the 2.5 that it is joining is rated at somewhere between 17.5amps and 24amps, excluding Ref Method E (according to BS7671). So unless the cable is in free air the connector is rated within the cable rating.

If it is in Free Air (Ref Method E) then a better rated connector should be used or have I missed something?

 

[Darkwood]

I did stress this was only refering to the recognised ratchet crimper most sparkies should have in their kit and associated crimps and lugs.... never once said other crimpers and connectors cant be used on solid if so designed as i already mentioned many ratchet and hand action crimps are designed for solid often used in data, telecom systems etc up to HV networks... and also i have stated a few times that with re' to this discussion that said crimps are not designed to be used on solid and even if crimped correctly you cant assume a good crimp has been made, and even a bad crimp can last indefinately if the load running through it is no where near the rating of the crimp, the crimpers designed for solid core cables do not try to shape the cable but usally (not always) indent the core which with the correct crimps sees no stress cracks and give a tight allround contact with no air pockets.

Im just going with the regs here as its manufacturers guidelines you should go with and yes it might be the case a good durable crimp can be made on the solid with standard ratchet but you cant guarantee that joint as you could with a correctly terminated stranded cable..... crimp lugs are subject to extensive testing to be credible for use in the wholesale market and its these test that have shown they can't make a reliable solid core crimp thus its the guidelines they are not used for such cable.

This isn't about yours or my experience with them but industry wide guidelines ..i agree i could make a crimp butt joint in solid core and heat shrink a neat sheath over it and also expect it to last but i choose to follow guidelines as the risk exists that in doing so the crimp may not have 100% structural intergrity or afford enoughh surface contact as is designed to be when correctly used, for this reasoning i will not use them on solid drawn cables even it only takes 1 joint in an 100 to fail and it could be costly and as i go through thousands of crimps a year (on stranded and fine wire) ive had up to press no failures in 20yrs although i have come across many crimp failures in my time on both stranded and solid.

 

[Darkwood]

I will answer with a question. If the connector is rated at 24 amps the 2.5 that it is joining is rated at somewhere between 17.5amps and 24amps, excluding Ref Method E (according to BS7671). So unless the cable is in free air the connector is rated within the cable rating.

If it is in Free Air (Ref Method E) then a better rated connector should be used or have I missed something?

To note the connecter will be in some form of enclosure unless you intend to heatshrink a full cover sheath over the whole connector and Yes you can use them as part of a ring.

 

[Engineer54]

Darkwood, ...I wonder if all the criteria you have put forward against crimping solid core conductors can be put forward against the use of solid core cables, for screwed connections within accessory wall plates and the like?? lol!!

Now that WOULD be something, if we could get away from solid core cables as a whole in favour of the much more efficient and workable stranded conductors!! lol!!

 

[SPARTYKUS]

choccy blocks, don't they get a beating these days.


Every CU installed in this country is .... a glorified choccy block. A box with screw terminals.

 

[KAS1]

I know straight through crimps are legal (after all that was what this was all about at the start, using straight through crimps) having said that, they should not be used in this situation, it is a bodge bad practice. Next you'll be telling me it's fine to crimp in the back of a socket to extend the cables to form part of a new ring.LOL Comon lads we all know it's a short cut instead of a proper job ie terminating into an enclosed JB (which is no different than another termination at a socket) or better still replacing the cable or re-routing the cable so there are no extra joints than required. Now that should be an end to it, we are not DIY ers or cowboys or bodgers and Darkwood is spot on with his posts, take heed, these types of crimps are not for solid 2.5mm copper cores, how many more times do some of you need telling.