Are ferrules recommended with stranded wire on a fused spur?

[adrian_ros]

Hello. Are ferrules recommended or strongly recommnded when connecting stranded wired to a fused spur like the one in the picture below?
I think ferrules are not mandatory for this type of connections in UK, but would like to know whether one should go the extra length and use them.
I am connecting a 1500W heater to the spur.
Thanks!

 

[ericmark]

If the terminal has a pad of some sort, so the screw does not directly contact the wire, then no need, other than to hold any wire label in place, but if the screw directly contacts the wire, then to stop a filament binding screw, using a feral is a good idea. As to maintenance free, yes really should use a feral, as wires can jam and leave filaments behind so not correct pressure on the wire.

I don't like torque screwdrivers, as you can't feel when a filament has jammed the terminal, or anything else is binding the screw, and with ferals we rely on selecting the connect jaw, in the main the terminal screw will crush the feral so even if wrong jaw used no problem, but with maintenance free terminals wrong size feral or tool/jaw can result in a slack connection, I worked with one firm who calibrated the crimp pliers (GEC) but that is the only one who did, so it is so easy with an over centre crimp tool to select the wrong point in the jaw, or wrong jaw, with GEC we never had multi-size crimp tools, one of orange, one for red, one for blue, and one for yellow, so carrying 4 crimp tools instead of one universal tool, pain in the neck.

 

[ebee]

I dont usuallly use ferrules but when using flex then a good bit of neat twisting and doubling, in an ideal world any conductor should, in theory, be made to fill the (round tunnel type ?) terminal to get maximum contact area and a good mechincal joint, ferrules can go a long way towards achieving this aim, another trick might be to twist and maybe double a time or two hold tightly then a good solder joint.

 

[adrian_ros]

Thank you both for the answers.

I took a picture of the spur - on the left, the SUPPLY side, there are solid wires. That is OK.

On the right though, in the yellow rectangle, would go the stranded wires. There is no pad on which the wires would nicely sit. For now I went without ferrules, but I just got a Preciva crimper + ferrules from Amazon and will add ferrules at the next iteration.

 

[Harry Bloomfield]

another trick might be to twist and maybe double a time or two hold tightly then a good solder joint.

Never, ever solder tin a flex, to be gripped by a screw. The solder can gradually, under pressure from the screw, migrate - the result can then be a lose terminal screw.

 

[EFLImpudence]

I took a picture of the spur - on the left, the SUPPLY side, there are solid wires. That is OK.

You say that and it might be the case but, to me, one of the red wires does not look like it is in the right place.

 

[mattylad]

Bootlace Ferrules/Cord End Grips (whatever name you give them) are always recommended on fine stranded wire, especially when in a terminal that the screw directly hits the wire.
They are thin strands and break too easily in this situation.

 

[morqthana]

Hands up anybody who's seen a CU where the tri-rated cables inside have not had some kind of ferrule on them.

 

[JohnD]

Bootlace Ferrules/Cord End Grips (whatever name you give them) are always recommended on fine stranded wire, especially when in a terminal that the screw directly hits the wire.
They are thin strands and break too easily in this situation.

Like flex in a plug?

 

[ebee]

Never, ever solder tin a flex, to be gripped by a screw. The solder can gradually, under pressure from the screw, migrate - the result can then be a lose terminal screw.

I`ll not argue with that one Harry.

Dont get me wrong - I am not against ferules,in fact I am for them, it`s just for years we did not really bother with them unless we happened to actually have some.
To me, the most important thing is a nice neat correction with plenty surface area of contact in such a way that it invites pretty much the whole csa of the conductor into that transfer and pressured enough to be both eletrically and mechanically sound, We used to do them by hand, no ratchets for torque settings, not much in the way of stripping tools, just a sharp knife and practice practice practice till we know how to use it properly.
It became of second nature.

All Electricians, Mechanical Engineers, and others were brought up on the "Rack of the eye" and the "Feel of the Thumb" and hadto master it before any clever tools were even mentioned or allowed to be used.

I am not decrying the use of those tools either, some of them can be absolutely brilliant (watch out for cheapo tools of any trade though, they can be not good sometimes and therefore a false economy)

 

[mattylad]

Like flex in a plug?

Yes, that's why a lot of time you will see appliances with a rewireable plug fitted, having uninsulated ferrules on the ends.

 

[morqthana]

That's not why. They put ferrules on the end so that a machine can insert the ends of the cables into the terminals.