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Ferrules or fork-crimps in screw-clamp terminals

Udtwmc
Currently in a dispute with a customer over bootlace ferrules I have used in screw-clamp type terminals - this is an industrial control panel designed to BS EN 60204-1, the wire used is class 5 tri-rated.


The customer says bootlace ferrules are the wrong type and wants them changing to fork-type crimps, arguing that the screw-clamp applies even pressure on fork crimps and a better contact but not so when ferrules are used - if you can picture the bootlace-ferrule on one side of the screw- with its clamp being at an angle as there is nothing on the other side of the screw. However, the termination is tight and makes a good solid contact with the ferrule so I think this is perfectly acceptable.


While I wouldn't generally disagree with a customer, there are hundreds of terminals to change, they didn't specify fork-crimps at design stages and I don't interpret anywhere in BS 60204-1 or BS 60947-1 that ferrules are wrong in screw-clamps.


Any opinions much appreciated.


Parents
  • 0
    Crabtree once had an M.C.B. design that could accept a single outgoing copper wire, say of 2.5mm2 on just one side of a small plate that had a central screw. I never liked the design as a small movement of the cable could loosen the grip on  the solid copper wire. With a stranded wire with say 7 single copper strands a 3 to 4 split could be made to try to even out the pressure on the wires.


    We normally only use ferrules on fine stranded wires.


    I like the idea of a flat forked crimp lug. What likely current will the crimp be required to carry?


    Will vibration or door opening be likely to cause a terminal failure with a ferrule type connection?

    Wire Ferrules Explained: Why are Ferrules Used and How are Ferrules Crimped - YouTube


    Z.
Reply
  • 0
    Crabtree once had an M.C.B. design that could accept a single outgoing copper wire, say of 2.5mm2 on just one side of a small plate that had a central screw. I never liked the design as a small movement of the cable could loosen the grip on  the solid copper wire. With a stranded wire with say 7 single copper strands a 3 to 4 split could be made to try to even out the pressure on the wires.


    We normally only use ferrules on fine stranded wires.


    I like the idea of a flat forked crimp lug. What likely current will the crimp be required to carry?


    Will vibration or door opening be likely to cause a terminal failure with a ferrule type connection?

    Wire Ferrules Explained: Why are Ferrules Used and How are Ferrules Crimped - YouTube


    Z.
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