Please do not mis-guide ppl here. 1-phase doesn't mean it is 63A. depends on what the developer's design, 1-phase could be 30A, 40A, 60A, 100A or other depending on the design and what you apply from TNB.
Open up your Distribution Board cover and take note of the ELCB or Incomming Breaker size to determine how many amps you are supplied with. If possible, do take note of the incoming cable size as well.
If your ELCB rated at 60A but using a 30A cable size, there's possibility of the cable burning up before the breaker/ELCB detect the overloading.

It could happen if all your family members turn them on simultaneously. Btw, In-rush current of air-cond could last longer than 1 sec.

if you opt for extension socket for AC, normal extension plug from supermarket is not advisable. Initially, everything is ok, but in the long run, u will find the socket melted.