I have an auxiliary cable which has red , white and black wire . which one these in the ground wire ??

[hardikkothari]

Wire colours in auxiliary cable

 

[Alabalcho]

It his is a bare cable (only wires, no connector) - then it is hard to say. Power cables colors (it seems you're in UK - ask local electrician about that) wary in different parts of the world.

If the cable has connectors, then see what kind of connector you have, and use ohm-meter to "ring" the wires.