Tuesday, Jul 18, 2023 at 16:20
Blimey Leigh, you've had 6 bites at this Reply!!…….( EDIT: 8 attempts!!!! )
However, I do agree with what you say regarding pre-soldering of the cable end before placing it into the lug.
I left this procedure out of my earlier comments as I feared some people would think this to be too much trouble and not necessary but I do think it to be important, especially so with larger gauge cables.
My early observations of joints made by plunging a cold cable into a pool of molten solder was that the solder appeared to chill and set almost immediately with no time for the cable to 'absorb' solder into the strands. This was borne out when I then applied the gas torch to the assembled lug and the solder 'shrank' as it was absorbed.
I then changed my method by firstly 'tinning' the cable end with solder then going on to melting solder and resin into the lug, followed by inserting the still warm cable. There was no longer the 'chilling' effect and the joint took longer to 'set'. In the case of very large industrial cable I followed-up the cable insertion by re-applying the torch to the lug after cable insertion for a very short time to be sure that the whole assembly was at the same temperature. adding more solder if necessary.
In the case of small cables <16mm2 I will usually place the cable end into the cold lug then heat the assembly whilst feeding resin-cored solder in as it melts until the lug is full. This method achieves the concept above and at the same time ensures that the exact correct amount of solder is provided to the joint.
Any heat damage to the cable insulate is concealed by the applied heatshrink. In the 'olden days' we used to wrap the cable/lug sleeve with insulation tape….. fabric type!
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