Do all stranded cables now have to be crimped ??

[ianphilip007]

hi there

been reading that all stranded cable terminations have to be crimped and that this is a reg, not sure as i cant find it. Is this just for fine stranded flex or does it apply to any cable that is stranded ?

at present when using single stranded cable i twist the strands of the single cable and terminate to switch/socket/light or MCB, should i be fitting bootlace crimps instead ?

 

[Marvo]

You mean these? I don't think they're necessary for domestic electrical terminations but rather wait for further confirmation.

 

[topquark]

That would be a new one to me. Maybe a new reg?

 

[telectrix]

if it's 7 strand cable, no need for ferrules. it's when you've got the multi stranded fine strand cable that you need to think of ferrules/crimps.

 

[IQ Electrical]

It's always a better connection with a crimp termination but there is no regulation other than the usual 'mechanically and electrically sound' proviso.

 

[ianphilip007]

yes there the ones bootlace crimps/feruls. does anyone know if it is actually a regulation? like to hear how others are terminating stranded cable ?

 

[Marvo]

if it's 7 strand cable, no need for ferrules. it's when you've got the multi stranded fine strand cable that you need to think of ferrules/crimps.

This was exactly my thoughts, the finer stranded panel wiring is prone to damage when terminated with the wire directly under a screw but normal house wire is fine without bootlace ferrules.

 

[ianphilip007]

id agree IQ especially on the smaller size stranded cable/flex. ive always had concerns about the strands splaying when terminating. i guess these ( bootlace crimps) are acceptable to terminate to a MCB?

 

[topquark]

I certainly don't do it on light pendants (unless the manuf has already done it). The only other place I use stranded is singles and I've not currently done there either (which may be poor practice and I should possibly change to doing so?).

 

[ianphilip007]

that was my concern reguarding 1.5mm/2.5mm singles in conduit wiring. think ill look into what crimping tool/crimps ill need, as they always splay when tightened.

 

[phazed out]

Please open the Technical data sheets on Marvo's link to RS there is a French colour code and German colour code for bootlace ferrule sizes which are different.

 

[ianphilip007]

doesnt look like it is a regulation, i cant find it in the book, but has made me think that using the crimps is better practice

 

[Deleted member 26818]

526.81 In order to avoid inappropriate separation or spreading of individual wires of multiwire, fine wire or very fine wire conductors, suitable terminals shall be used or the conductor ends shall be suitably treated.
Apart from using suitable terminals, this can be achieved by doubling over the conductor or using a boot lace ferrule/crimp.

 

[sparks_114]

I have to say I don't like using crimps unless I have to. The way I've been taught is to consolidate the ends of cable (twist them to a degree to make it as though solid but not so much to reduce the csa). You have to bear in mind when using a crimp you have placed your trust in two thing (with two things to go wrong: the crimp and the screw). I'd much rather without the use of a crimps but it seems I am swimming against the waves on this one as the crimps does add a sense of tidiness to a connection and more and more sparks have taken them on board of recent. Just thought I'd my view on them thanks.

 

[Knobhead]

In a clamp type connections bootlace ferules reduce the contact area due to the conductor not being allowed splay out. I’ve experienced problems in control panels where multiple bootlaces have been used in one clamp terminal where one has clamped tight the other has vibrated out.

I don’t like them. They have caused me hours of unnecessary fault finding commissioning new plant.

 

[Adam W]

Yes, IMO ferrules should be used where you're otherwise relying on just a screw on the stranded wires; where there's a 'clamp-type' terminal there's no need because it constitutes a 'suitable terminal'.

In the real world not many people use them, maybe down to cost, laziness, (is 'ignorance' too harsh a word?); I've come accross 600x600 fittings where the manufacturers instructions have actually stipulated that terminations should be ferruled but still nobody seems to bother.

 

[truckster]

Seems unneccesary on 1.5 or 2.5 stranded, just give it a twist to tighten the strands and bend over itself, won't splay and fills the hole better.

 

[Marvo]

I’ve experienced problems in control panels where multiple bootlaces have been used in one clamp terminal

That's a good point, I agree that multiple bootlace ferrules in the same termination are a nightmare. The screw or clamp never grips both ferrules equally tight because of their rigid nature. With control wiring where there a few milliamps flowing it can be a problem but it would be a damn site worse with a load of 10 or 20 amps.