A
ferrule is a tin or other coated copper tube you fit around the
wire and is sized to the
wire gauge. It's purpose is to band those wires together much similar in a way that a
crimp on
terminal will band those wires together to terminate them in what ever
fitting is desired be it quick
disconnect, fork, ring or what ever
terminal end. In fact there is a type of
crimp on
terminal called a pin
terminal that is designed to go into set screw terminals which would work here given there were enough space within the body of the
plug. Basically this would take all your wires,
crimp them into the body of the
terminal and allow you to install the solid rod off that
crimp into the set screw clamp.
Otherwise, ferrules are just as stated a tube of conductive material that's going to band those wires together in providing equal pressure on all strands, and it's going to provide a
bit harder of a shell when sized to the
wire which the set screw won't dig and cut into in clamping the strands of
wire. It's very common on our
Stage pin plugs a set of 12ga ferrules will be provided with them. This on normal 12ga cable is all you need. On lesser sized
wire however since that
ferrule is now larger than the
wire it's banding together, it's still possible for the screw to dig into and break the conductors after it cuts
thru the
ferrule. Also dispersed pressure on the conductors is not in
effect any longer short of bending the conductors in half thus doubling up the
wire inside of it. Ferrules need to be sized to the
wire, or the
wire needs to fill itself up to the size of the
ferrule or it's not doing it's job in protecting and providing a good termination to the
wire.
Here is a web
page http://www.mcmaster.com/ that you probably won't be able to order from given you are in Europe, but punch in part number 7850k24 than go to the catalog
page for a list of about every type of
ferrule on the market. Your local domestic electronics supplier would be the source for such things just as McMaster is not the only source for ferrules in the US.
Cee Form connectors while they don't normally come with ferrules work in a similar way to
stage pin connectors. Cee Form is just more of a pain in the rear to
wire. In any case, since it's often screws bearing directly onto the
wire's conductors, use of a
ferrule would allow for a much better connection. Where you don't need a
ferrule is when it's a plate and not screw clamping down on the wires. Barrior strips and
Edison type plugs have plates that bear down on the conductors thus there is no screw twisting and turning it's way in digging into the strands of
wire. Should your Speakon
plug have a plate clamping on the
wire, a
ferrule often won't hurt but most likely is not necessary.
