titch2k6

To know for sure, you should have some knowledge of the IEE Regulations, particularly Tables 4D1A to 4F3B (Current carrying capacities & Voltage drops) in the current Edition, and work it out. A lot depends on the reference (fixing) method, length of run, cable load (using P=VI to work out), thermal allowances (ambient and conductor operating temperatures), cable type (flexible, T&E, Armoured), core type, etc.