We all know that a 60 watts bulb burns brighter than a 40 watts bulb. So the current drawn by a 60 watts
bulb will be more than that for a 40 watts bulb.
The wiring in our houses is done with insulated copper wires (in rare cases aluminium).
In modern apartments proper wiring is provided to fix air-conditioners. But in some of the older houses,
the wiring requirement needs to be checked.
One of the first questions that I ask a customer is where he/she lives and what kind of wiring is available.
To fix an air-conditioner of 1.5 ton capacity (which most people purchase) wiring with 7/20 copper wire with suitable earth connection is required. 7/20 denotes 7 strands of 20 swg wire. A 3 phase electric supply would be ideal.
If you have a single phase supply, there are some constraints. Contact an engineer or a good wireman and get the details.