Latest fact finding mission for you gurus to help me learn about Todays problem was a quarry pump not running, guy went out and meggared the cable and pump and found one of the two 10mm cables was down on the black phase. So while cable was ordered up and being delivered he was called elsewhere. So I was asked to sort the cable and connect up and test. Cable connected, insulation resistance test showed no faults everything cleared to earth. So got the quarry manager to do the startup procedure on the generator and control gear and it tripped straight away. So I done a bell test between the phases to make sure I joined the correct cable and found between grey and brown it belled, but nothing on the black phase. This was the same on both cables that on each cable brown and grey had continuity but nothing on the black. I expected to have continuity between all phases as the pump is connected delta, but having nothing on the black phase and its clear to earth is puzzling. Daylight beat me so have to wait til tomorrow when a crane will come and lift the pump out. could it be possible that the lead has blown off the terminal block? I never checked the resistances between phases so not sure if its balanced, I will do tomorrow. It was close to 6pm and pitch black so didn't get the chance to try and start the pump without it being connected, as it would be the biggest indication. Am I missing anything obvious? The pump is a 20kw pump with float. DOL, used to be a star delta starter so two 10mm cables were kept in place incase it was reverted back to this.