For a professionally made junction it is recommended to use the “Kit GC”, it has excellent requirements in terms of electric, mechanical and water resistance. This kit is composed of: crimp wire connectors in tinplated copper, thin wall heat-shrinkable tubing to cover the conductor of the cable, a strip of Scotch 2547, one of Scotchfil and medium wall heat-shrinkable tubing to cover the junction. It is recommended to seal the two end points of the sheath with PVC textured insulating tape.
 
FORAS-PENTAX CABLE JOINT KIT for Borehole Motors is made in Italy and is not a cheap copy from Far East countries.