Contactor. Proving dead . 3 phase .

[3phase]

Thanks for all your help. Totally makes sense now

 

[R-fur]

If you have N cables then you have (N * (N-1))/2 pairs to check to know all are safe w.r.t. each other. So for:

• Single phase (L + N + E) = 3 it is (3*2)/2 = 3 checks
• 3-phase without N (just L1-3 + E) = 4 it is (4*3)/2 = 6 checks
• 3-phase normal (L1-3 + N + E) = 5 it is (5*4)/2 = 10 checks

Thanks pc1966, never heard it called that before.