Use ferrule to increase solid wire size

Hi,

I need to fit a 3-phase distribution block, and the closest candidate has two types of inputs—input (two) and output (six). The input is 7.6mm2, and the output is 5.6mm2, and one of the inputs can be used as an output. I only use rigid conductors of 1.5-6mm2 in the house - the lights are 1.5, the majority is 2.5, power-hungry is 4mm2, and one fat transit is 6mm2. Depending on the breaker's possible load, I use 4 or 6mm2 inside the wiring closet to pass between the power-hungry groups. I don't use

Within this paradigm, I would like to use 6mm2 as an input and possibly 4mm2 as an output for the distribution block. But, following Legrand's user manual, the 7.6mm2 should accommodate 10 to 25 mm, and I am falling one step short of matching 6mm2. IMHO, I can use aluminum pressed ferrule to increase the solid wire size - the connection surface must be enough to avoid any dangerous situations. What is your take on it?

Regards

Parents
  • Ah and all is revealed.

    you mean hole diameters when you talk about the 7.6mm and the output is 5.6mm- thats' the circle and line symbol.




    so the large holes take 10- to 25 square mm, and the small holes take 1.5sqmm to 10sqmm


    So in your shoes, looking at the picture, I'd either just use the small holes for everything, or if I had to then double over the end of the 6mm into the larger hole, so that the screw has something to bite down onto. The risk to avoid is that the wire goes beside, and not under, the screw, and is damaged by the threads but not well gripped.
    What I  mean by 'double back'

    Personally, for those terminals I'd only ferrule for stranded (hairy) wires. However to an extent it is a personal house style thing, and I'd give it about 10 mins before someone else says the opposite.

    note that in the UK 6mm2 would normally be 7 strands, not solid core. I'd still fold if the  hole was too big,  so the terminal was better filled.
    Mike


  • note that in the UK 6mm2 would normally be 7 strands, not solid core. I'd still fold if the  hole was too big, 

    German ferrules (DIN 46228-1 and DIN 46228-4) at least, are intended for use with Class 2 (7 strand + rigid), Class 5 (flexible) and Class 6 (extra flexible) stranding ... but NOT Class 1 (solid) conductors.

    However, I'd be careful with csa > 6 sq mm Class 2 stranded conductors, to not flex the cable too much after crimping the ferrule, until the terminal is tightened. Whilst some screwless terminals are suitable for use with ferrules, I would not use ferrules and screwless terminals for class 2 stranded conductors with csa > 6 sq mm.

    If you took a Class 2 conductor, and "doubled it back" in a twin ferrule for the suitable CSA, would that be OK I wonder?

  • looking at the actual terminals he has, which have more in common with a UK MET than a UK junction box of any kind let alone screwless terminals I'm not convinced that it needs a ferrule at all, it just needs to be in one of the smaller holes, or folded.  Had it been some sort of cage-clamp, maybe  a ferrule would be needed, Solid core 6mm will  be quite willful however and probably wont go easily into a ferule anyway,

    We commonly stuff extra strands along side into crimp bodies to ensure a good fill for the crimper when the chosen wire is too thin for the crimp terminals on things like the mil spect 38999 connectors - but it is always fine stranded in that case.

    Mike

  • Solid core 6mm

    I thought OP said it was 'rigid' - i.e. Class 2 or Class 1 ?

    • s - solid, Class 1 only,
    • r - rigid, Class 1 or Class 2,
    • f - flexible, usually Class 5 but may be Class 6

    It would be unusual to find Solid 6 sq mm wiring in domestic ... but I agree not necessarily 4 sq mm could be either Class 1 or Class 2 dependent on cable type ?

  • given the confusion of diameter and area in mm2, and a few other odd choices of words, I'm not too sure if the OPs use  of the phrase "IMHO, I can use aluminum pressed ferrule to increase the solid wire size" should be taken as what we would normally mean either - I think we should allow the possibility for things "lost in translation".

    But I'm not that sure of current Netherlands practice either - maybe their 6mm is solid cored. And I missed the 'aluminium' on the first pass, or I'd have said that unless the wire is aluminium, tinned copper would be better, if we need it at all,  mixed metals things usually end badly.

    M

  • Good moring Mike,

    Don't kick me too much - I am not a professional installer and didn't think of folding these ;-) I have followed your advice with the double backing - it worked like a charm. The one on the left is six sqm, and the one on the right is four sqm. Thank you!

    Regards Matvey

    Block

  • Please don't think I'm 'kicking' you - it can be hard to judge the level of someones knowledge right just by their typing -  especially when things are posted by folk in other countries and may be  not in the Mother tongue. (In reverse, I can do some German but the result can be pretty lumpy.)

    Something obvious to you may not be so obvious to me or the other way about


    That photo looks pretty solid, & as I imagined it is now impossible for the wire to  slide up the side of the screw.- I presume it survives the ' wiggle & pull' unofficial test as well. I also assume you won't be mixing earth and neutral colours in the real thing.;-)

    Mike.

    Ps As general note, it is far better to ask the 'silly' questions early on, it  is how we learn, and it is a lot sillier not to ask and to assume the wrong thing and have to do the job twice.

Reply
  • Please don't think I'm 'kicking' you - it can be hard to judge the level of someones knowledge right just by their typing -  especially when things are posted by folk in other countries and may be  not in the Mother tongue. (In reverse, I can do some German but the result can be pretty lumpy.)

    Something obvious to you may not be so obvious to me or the other way about


    That photo looks pretty solid, & as I imagined it is now impossible for the wire to  slide up the side of the screw.- I presume it survives the ' wiggle & pull' unofficial test as well. I also assume you won't be mixing earth and neutral colours in the real thing.;-)

    Mike.

    Ps As general note, it is far better to ask the 'silly' questions early on, it  is how we learn, and it is a lot sillier not to ask and to assume the wrong thing and have to do the job twice.

Children
  • Mike,

    These were just two short wires around that I took for the purpose of demonstration. Thank you for your answers and verification!

    Cheers