Hi! would like to seek for expert opinion,

If we change residential title 1 phase to 3 phase, how much does it cost usually?

contractor got quote need at least 5k. really that expensive?

I ask TNB they just say caj sambungan RM250 and then deposit for residential is RM700 ( if u have deposit RM500 for one phase, then you just neef to top up RM200)

Please advise accordingly thank you!

Regards.

5k is reasonable price

You need to redo your home DB (distribution box) wiring from one phase to three phase
This includes add in rcd,mcb,busbars and a new box, the new three phase cables from the kwh meter to the board, testing and commissioning. Then liasing for the kwh meter installation

Get a second or third party quotation to make the best decision

these are cost related to connection of wiring to TNB only. not the infrastructure itself

may i know why u wanna convert to 3 phase?
if u dont mind, can share what electrical appliance in your house.

boss usually how much does that cost? for the
add in rcd,mcb,busbars and a new box, the new three phase cables from the kwh meter to the board, testing and commissioning?

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

[quote=trust4you,Sep 18 2018, 08:24 PM]
boss usually how much does that cost? for the
add in rcd,mcb,busbars and a new box, the new three phase cables from the kwh meter to the board, testing and commissioning?

[/quote

For a metalclad board 3 row type the material cost alone is roughly rm1500 inclusive 3x100mA RCD, 3x30mA RCD, and 3x10mA RCD for general lights/fans, 13A sockets and water heater the others general mcb's, submain short length PVC cables being comparatively cheaper.

The main cost is the skilled wireman labour to install the box, the connections, all the continuity/insulation/earthing testing to make sure functionality tripping, correct impedances of the earthing system, polarity for the phases and the insulation for the connection cables for his portion of the works. Note this does not test the house wiring at all only the new cables from kWh meter to DB, and the DB itself. Plus percentage profit usually 20% to 50%of the works.

You can get another compare quote and negotiate to make sure you are not getting taken advantage.

Go calculate la.
1 phase can provide 63 amp.
Go read the max amp draw of the device and add them up la.

How do you know 1 phase cannot support it? have you calculate the power load?

It’s all depends on the equipment wattage. And if you overload, your fuse will blow. you will know you got too much load, and it's time to either 3phase to split load, or up the ampere.

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.

Edit* residential internal wiring is only 40/63Amps with 16mm2 PVC copper conductors. O/H hard drawn aluminium conductors to be sized one level higher.

This post has been edited by Richard: Sep 19 2018, 05:06 PM

What’s your opinion on inverter aircon?
Since inverter aircon uses less power draw when maintaining temperature and have soft start motor, the spikes of current draw will be less...

Correct .. Minimize the start stop of electrical motors using electronic speed control by vary the frequency (actually pulse width modulation,)

It works..

DC to three phase AC using ESC(electronic speed control) same. Expensive right now but getting cheaper as more of the electronic components all built-in. Those are expensive to play with.. Right now only familiar with linear through hole and smds.lol.

This post has been edited by Richard: Sep 19 2018, 06:32 PM

bro thank you for the detailed explaination. so lansi the way "slimey" replied. Lazy for me to layan that kind of person though..

besides i also have 60 plug point which will be used many at one shot, therefore my load will be quite high as well

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

No. Unless the current wires are deteriorated to a very bad state.

The reason is a single phase kwh meter supply is limited to maximum 63Amps as the incoming supply cable size(16mm2) fixed for residential supply.

If your house uses more than TNB recommends you apply a three phase kwh meter which means you 3 times 63Amps.

So keep your existing wiring but any additional will be wired to another phase to prevent overload

any one knows there is any diff on electric tariff bill between single phase and three phase?

Tarif would be the same for 1phase or 3phase.

U need 3phase when ur load exceed 10kW or 50A

https://www.tnb.com.my/residential/my-tnb-account/

No diff for residential.
Besides the TNB connection outside, still need to upgrade DB box all to 3phase stuff inside.

Can check if existing wiring is done on 1phase, if want to change to 3phase, is it possible? And will I need to redo all my existing wiring?

Can, yes, no

Thanks. You are electrician? Haha, just wondering whether it is worth to do.
(read the cost could go to replace could go to 10k)
Currently, have 5 airconds. But usually only 2 airconds will on simultaneously.
Perhaps during CNY, will on like 4 units together, for a week.

When u replace ur single phase meter to 3 phase meter u should balance ur load accordingly & this might involved rewiring internal load.

Or u can let it be but if like that what is the purpose of changing to 3phase? Or possible ur gonna planning for future sub-DB which only u know ur future usage

Not required to go 3phase if total load never trip the whole house MCB.
It should be sufficient as long as you don't operate all your electric cookers + all aircon + all WH on simultaneously.

Last time my place's incomer only 40A so previous owner already upgraded 3phase. But if your incomer is 63A I think its not required to do 3 phase.

This post has been edited by ceo684: Oct 22 2021, 11:14 PM

I see. Thanks, since house currently using smart home setup, and previously electrician did warned about it.
Guess I will monitor and upgrade when the trip become more common.

i wonder if anyone got any latest update on the estimated cost now?
my electrician told me easily more than RM10k...

i wanna apply resume 3 phase electricity also 2.6k d just on contractor side.

TNB and application will be around 4-5k. Not sure if you going to change the fuse box and other wiring. Yeah 10k is really not expensive

ok thank you...wanted to consider install solar panel for home and i was told for 6kW and above I need to have 3 phase wiring system. If added this RM10k+ cost just to convert to 3 phase...i think i'm gonna just drop the plan..upfront conversion cost already so high also...

If your property is within the last 10 years, most of it are 3 phase ready.

My curent place, if I remembered right during VP then, some units converted to 3phase for less than 2k. Maybe now higher.

Hi, I am at subang jaya, i wanted to install solar panel up to 9KW, so I have to change to 3 phases.

Electrician is quoting me Rm5K include helping me to install the 3 phases meter, extend the dbbox, apply tnb which require 2 months waiting max. Rm5k didnt include rm300 connection changes by tnb and didnt include security deposit.

My house is the last house in the section and has 4 tnb cables so electrician said doesn't require tnb to pull new cable from the pole.

Any idea if the price is reasonable?

Solar panel 9kW does not mean you will get 9kW output, the main item is the inverter. How many kW you have in mind?

Yes that is about right price.

7 aircon from phase 1, can’t use for phase 3.
Unless the aircon work with phase 3 like VRV or 8 HP and above , must work with phase 3.
Otherwise phase 1 can support up to 7 aircon.

I have a 12 kWp solar installation running on single phase. No problem. Peak feed is 10 KW +/-, TNB approved. So I would not worry about 9 kWp on a single phase.

actually 3 Phase will save alot electric bill compare to 1 phase?

my house normally only turn on 2 aircond at the night , 1 normal fridge , 1 normal topload washing machine and LED downlight

if changing to 3 phase will make huge electric saving price?

Its not really to save energy but more for a better electrical load management


According to tnb,
https://www.mytnb.com.my/business/get-elect...ade-electricity

WHEN TO CHANGE

You are advised to change from a single-phase supply to a 3-phase supply when your household electricity load exceeds 10kW or 50A. As a rule of thumb, if you have three (3) or more air conditioners in your home, you should upgrade to a 3-phase supply as it will increase stability and reliability of electricity supply.

do u mean have 3 aircond or more open at the same time? Because i have 3 aircond room (1hp x2 + 1.5hp x1 + 2hp Living room)

so basically weekend only will be turn on living room 2hp for about 3-4 hour only , and at the night time mostly 1-2 aircond will be turn on ....


very very rare need to turn on all 4 unit aircond at the same time....

in term of stability , mean if over use the power , fuse box will easy burn and will jump fuse box?

This post has been edited by chongkiatz: Jul 1 2024, 04:52 PM

Yes, over usage will lead to the fuse getting burnt.

Also good to upgrade to 3-phase if you are considering using an EV car with EV charger in the future, coupled with CCTV, alarm system, smart home etc. etc.

1 phase can't use the EV charger?

can but need to be cautious dont charge while having 4 aircons and 2 water heaters running

may blow the fuse