boss convert 3 phase because i have 7 air cond, possible on 5 at the same time, one of it is 2 horsepower.
if 1 phase can support ah boss

For five one HP aircon running at the same time, the possibilities of all inductive loads being on simultaneously very high due to the auto temp sensors of the aircon.
The standard running amps roughly 4.5Amps and starting amps 6x minimum thus adding other auxiliary loads will overload the standard 63amps rated protection devices and cabling connection.

For such a situation it is recommended to split the loads to 50%of the rated protection device and cabling connection. Thus adding a three phase incomer supply for safety and peace of mind.For minimizing risk hazard of an electrical fire

Thefor are situations where a very high quality material and installation where the 63Amp rated fuse and oversized cabling will not blow fuse but such situations are discounted from the average situation.

Conclusion for single phase to three phase per standard TNB supply 63amp HRC fuse c/w 16mm2 PVC cable is correct recommended.

guys do we have top change whole house internal cabling if changing from single phase to 3 phase  ?