Terminations Of Solid Cores...

[Sidewinder]

I'm torn between opinions.

I'm not going to give my opinion as I don't want to cloud the issues.

I have been working with some other sparks recently and have witnessed debates over the termination of solid cores such as 1.0/1.5/2.5 Flat Twin & CPC & FP200 type cable.

One is adamant that they MUST be doubled over before putting into terminations.

One says it is not necessary.

One has suggested it depends on the type of connection, i.e. a single screw as typically found in sockets/light switches, yes as they can cut into the core, causing weakness, cage clamps as found on some MCB's not necessarily as they clamp evenly, but they may not clamp down onto small cores adequately.

Ideas...

Discuss...

Please elaborate on any suggestions, I'm not looking for right & wrong, just to provoke debate & discussion.

 

[kerching]

You have to tighten the screws! FFS what next?

Mmmmm tricky one

Screw connection....doubled over , unless stranded and space is at a premium. El crapo socket last week had only just enough space for one cable!......shucking fight

Cage clamps, solid core, doubled over, tightened to correct torque ( with the proper tool, not grunt- tight )..... Cable fell out when I gave it a tug. I must have got the doubled over core sort of diagonally across the cage, terminal thought it was tight, torque driver thought it was tight. Tug test didn't!

Stranded ie 4,6,10,16 mm in any terminal is an issue. Tri rated I always ferrule it, t' other stuff...whenever you tighten it if you go for a brew, come back you can always tighten it a bit more!

So in summary.....dunno

 

[Steve3948]

Well all my working life I have always doubled over a single conductor into a termination, 2.5 and 1.0mm²  to give it some meat, especially on 1.0mm², however if say a ring then straight in.

 

[Robin Spark]

Anything 2.5mm or below where it is a single conductor into a screw type terminal, then i always double over so as to get more surface area of the conductor for the screw terminal to clamp onto, hence a more reliable connection.

Where there is more than one conductor into a terminal then i wouldnt double the end over and the same for anything above 2.5mm.

 

[ProDave]

And what about twisting them together? :coat

 

[Steve3948]

Never twist, pain in the ars*e  :red card

 

[steptoe]

depends on the terminal shape imo.

round terminals straight in,

flat terminals then doubled over in the smaller sizes especially.

 

[wozz]

Always double over, seen no end of crap connections burnt out with non doubled over, seen far far less with with doubled over.

At college the lectures would go mad if you didn't double over.

Slight twist on stranded cables to stop it fraying everywhere.

 

[Zeespark]

NEVER twist conductors together, if they were to work loose in an accessory, you would still get a continuity reading, but not at the accessory terminals as you would expect.

As for doubling over, I don't due to the stresses that the tightening screw can invert, especially where the conductors start and finish the 90 degree loop.

Andy Guinness

 

[Evans Electric]

Historically , when metrication inflicted solid strand T/E upon us , many terminals changed to suit ,  either cage or fat grubscrews that filled the terminal and didn't allow a core to escape to the side and become loose .  

Now we seem to have returned to the basic screw , but personally I only double up if nessesary , mostly just shove them in , don't get any problems .  1 X  1.00mm in an MCB I usually double up .    Never used a torque driver in my life ...  probably never will...  never had any problems TBH . 

Theres a need to tell apprentices that when connecting , say , meter tails to a board, then pulling them about to connect to the meter , you need to return to the board terminals and pinch them up .      (OOps  When the DNO man comes to connect to the meter is what I meant )

And if its mentioned , twisting solid core cable wasn't recommended  ( Really crap when you untwist them for testing , often breaks) 

As the Kercher says, always give them a pull .   Three solid 2.5s in the previous Crabtree socket range would often leave one loose .

 

[Manator]

Interesting, the only reason for doubling smaller cables over was an age old saying "fill it with copper". The guillotine effect works equally as well on two cores as it does on one. I know some of you are against torque settings but they do work and are recognised, and in fact are the only way that you can actually prove compliance with any manufacturers instructions.

Some smaller cables are difficult to terminate properly due to the type of screw or clamp, in such instances I use ferrules. 

 

[ProDave]

I was actually taught to double over small cables TWICE, and then make sure only the doubled over fold touches the screw, not the incoming cable end.

Try that with a modern light switch and the cable wouldn't go in the hole.

 

[Sidewinder]

Some smaller cables are difficult to terminate properly due to the type of screw or clamp, in such instances I use ferrules. 

Would you put ferrules on solid cores though Manator?

What would be gained, as the ferruled end would be not much larger than the bare end, though it could enhance the resistance to penetration by the clamping screw.

Another discussion...

Ferrules or not and on what types of core, solid, stranded as in 6491 type or fine stranded as in flex, "tri-rated"...

Also what about crimps on solid cores?...

Another discussion?...

Come on please, I think this is a worthwhile debate/discussion.

FWIW, I would NEVER twist solid cores together, I do twist 6491 type wires before terminating to prevent the strands from separating.

Oh what about multiple cpc's in the same sleeving, twisted together, I know my opinion...

Next!...

 

[Manator]

I do use ferrules on smaller solid cores to "beef them up", I also use them on smaller flex cables because outlets like fused spurs have large connector recepticles, not suitable for say 0.75 or lower flex cables.

I never twist, and I never ever sleeve two cores into one sleeve.

 

[steptoe]

two earths in one sleeving is the sheer work of the devil himself

two earths twisted together in one sleeving is the work of the devils boss!!!!!!!!!!

headbang

the only people that put 2 earths in one sleeving are the people that NEVER test anything.

 

[kerching]

He who has twisted has rarely tested!

Who remembers Copperclad? Tighten screw- cut through wire

 

[Blue Duck]

Always double over single cores in terminals that will accept, I have seen too many singles snapped on switches due to over-tightening.

wanted to use ferrules on stranded but have not managed to find decent set for a good price.

 

[Marvo]

We always bootlace ferrules on stranded wiring in panels. We don't use twin and earth very often so I can't really say we have a system but we don't twist solid wires together and we also don't usually fold them over in caged or screw terminations unless they seem insecure when pulled. I've heard it said you shouldn't use crimped ferrules and lugs on solid core wires but on larger solid core cables like aluminium SWA (>16mm csa) we use crimped lugs and ferrules specifically for the purpose similar to the ones used on normal copper SWA. We also use torque screwdrivers and socket wrenches, it's amazing how much terminations are overtightened if you don't.

 

[OnOff]

Always double over single cores in terminals that will accept, I have seen too many singles snapped on switches due to over-tightening.

wanted to use ferrules on stranded but have not managed to find decent set for a good price.

I've been using this type for years on stranded:

http://uk.rs-online.com/web/p/cable-crimpers/3992031/

And for some reason have always used the French rather than German coloured ferrules:

http://uk.rs-online.com/web/p/crimp-terminal-kits/2280321/

 

[Blue Duck]

Thanks onoff now we just need to buy 100 to get them at a good price!