thanks bro for your update. anyway yesterday night do testing, open 3 heater and open 3 aircon (total 3.5HP)  on the same time. after 10-15 minutes, cutout fuse (next to Tenage Meter) blow. my whole house no electricity. no choice, ask that electrician to come to do troubleshooting. just found out that my cutout fuse only 30A, no wonder blow. So ask him to change the cutout fuse to 100A. On the same time, requested him to change the 40A RCD (maxguard) to 100A and the 60A DP Isolator (maxguard) to 100A as well. And also ask him to change one of the MCB (20A) to 40A (because one of my room aircon power use water heater point to do looping, worry if open aircon/water heater on the same time, will overload, so as precaution ask him to change to 40A). All together quote me RM400, no choice, need to take it coz already ask him to settle my cutout fuse blow.

so bro, what's your recommendation for my house situation?

Thickness of the wire does not mean much. But thickness and the cores inside the wire are more important.
The incoming TNB wire can only support 60A and for single phase, TNB will only provide 60A fuse.

actually not an expert in electrical, so correct me if i am wrong...actually if i change the cutoff fuse to 100A, RSD to 100A and DP Insulator to 100A, isit it means that i change this for the purpose if on the same times if i use  my electrical appliance, total combines can tahan until 100A. why actually still need to check the wire. each individual wire already protected by MCB (20A) where each individual wire cannot exceed 20A, if exceed will cause trip in MCB. actually i did plan upgrade for 1 MCB to maybe 40A (coz my water heater and aircon sharing wire by looling). only need to check this wire whether can tahan 40A or not rite?
or actually  bro here mean need to check cable from tnb box to DB box only bcoz maybe the wire from tnb meter to DB box last time not support for 100A electricity? not the whole house wiring rite?

and one more things, i check thru internet, actually single phase max can support until 100A based on internatioanl standard. isit because of TNB we only can be max 63A?
sorry if my question look dumb coz i am not expert in electical, so hope all sifu here can enlighten me.

actually already pay deposit to that electrician (told me need it to buy electical part) and he will come to install it on saturday, if really got problem, i think i need to consult another electrician. actually i already call them to issue my worry, he just say no problem one and my wiring can support blah blah....not an expert in electical, so not argue with him a lot coz that electrician a little cocky one.....
thanks....

After consult with all sifu here,decided to change cutout fuse to 63A, RCD change to 63A to match My current DP insulator 63A, MCB decided not to upgrade to bigger amp,decided to rewiring my aircon point to nearest power socket (looping) instead of sharing with current water heater point. Thanks for all the sifu advise here,appreciated.

If rewiring, put a 4mm wire. Anything you want to rewiring.

It is for your future expansion and saving.

Hello, my house have 6 AC (1 x 1.5hp, 3 x 1hp, 2 x 2hp) and 4 water heater with pump. Normally it is max to 4 AC open in sleep time. Am I need to change from single phase to 3 phases?

yup whole stretch n also behind the banks .. all telling me dont have or other excuses

even if you swith on all those 6 ACs and all 4 water heater at the same time, total amp still below 70 Amp. single phase can carry up to max 100A.

Depend on what you want to do. For me I use 2 phase for the house and 1 phase dedicated to my entertainment room

I pay what I use. If they come, I am happy for them to check

Please share some knowledge

For that thread is talking about missing neutral from TNB sub station. Having balance spread for 3 phase within 1 house is a totally different thing.

Typically of course from sub station to house is good to be balance. Within inside the house, is up to us how to use. Separate the phase also give you cleaner power

speaking of which, does RM250+- for a single 1.5HP inverter air-cond and a 10-year old (probably non-inverter) fridge makes any sense...? sounds like leakages somewhere...

100 amps? may not need 3 phase wiring.

try talking to tnb for allowing changing the cut out and cut out fuse too 100amps. if they say ok then it is all good.
but make sure your rcb and mcb are rated properly.

The normal current rating for electronic meter is 10~100A.

That rating was stated in TNB guidelines as I remember