So, I have some 1mm2 (cataloged in the USA as 17AWG) fine strand (259 * 0.07mm) test lead wire that I am trying to adapt to Eurostyle terminal blocks (which I can then adapt to other things, such as header pins or barrel plugs). Since this is normally done with ferrules, I got some uninsulated ferrules for 1mm2 wire (said to be for 18AWG in North American catalogs) and tried fitting them to the wire.
However, they simply will not go on cleanly — if I force them to go on all the way, several strands (at least a dozen) do not make it into the ferrule barrel, flying out instead. Is this an issue with technique, or a sign I need to go up to a ferrule made for 1.5mm2 (16AWG) wire? Should I just clip the loose strands, even? Or are ferrules simply not made for wire this size with this fine of a stranding?
The ferrules I am using have a nominal barrel ID of 1.4mm and a flare diameter of 2.5mm — these seem to be standard dimensions for 1mm2 uninsulated ferrules. I cannot use insulated ones, either, for the insulation barrel on them (at 3mm ID) is too small for the 3.7mm diameter insulation on my test lead wires.
Best Answer
High-strand-count wire such as the test lead wire you are using has a larger conductor diameter than wire with a lower strand count and the same cross-sectional area. Go up to the next ferrule size.