One thing good about 3 phase wiring is that each phase draws power from different line. Most of the times when my neighbour hood has a blackout, my house will still have electricity.

single phase could cope your setup at no sweat ler... unless all your aircon is 12000btu & above, after all u dun on the water heaters all the time right? for me, 3-phase is just overkilled...

My old house has 4 air conds in bedrooms and 1 in living room. During night time, all 4 air conds in bedrooms will on together (all 1HP) and for the 10+ years we have not hit any problem.

How do we know if we should upgrade single phase to 3-phase? By counting the no. of airconds & water heater? don't think so right? is it troublesome to upgrade single phase to 3-phase later?

For those interested in finding out about 3 phase wiring, here is some info on the RenoKu.com website.

* Deciding on 3 phase or single phase wiring

* Photos of 3 Phase Wiring

In my opinion, it's troublesome to upgrade to 3 phase wiring later. This is because one needs to carry out internal rewiring for the house.

I think the most accurate way to determine if 3 phase wiring is needed is to count the max load at any one time of all the electrical appliances in the house. If say, 4 air-cons are turned on at the same time, then calculate the combined load. Not sure of the way to calculate this but your electrician will be able to give you a better answer.

i got a client also told me that his house stay normal with 4 air cons on together...
i think maybe have to depend the area's electricity support?

it depend on your total ampere draw....

it is okie when u open aircond one by one....it wont trip....go try open 4 together...at the same time.

How do we go about getting 3-phase wiring for a house still under renovation?

that is if only 1 phase are down (which are quite rare from my experience). If it's cause by substation breaker trip, then all phase down. The reason why TNB encourage domestic heavy user to switch to 3 phase is because of load imbalance (they wanna protect their main breaker from frequent trip and get screwed by domestic user)

Don't see any necessity to change to 3 phase unless they (TNB) pay or subsidies for it. They should pay for this since this is for their own good.

In a residential area, each house electricity are distributed with different phase eg. Yours Red-Neutral, your neighbour may be Yellow-Neutral and the next neighbor Blue-Neutral and so on. When a group of houses eg Red phase are heavy user, this cause the 3 phase load distribution become unbalance. eg Red phase = 200A, Yellow phase = 50A, Blue phase 60A. This may resulting in frequent trip (especially at nite when most ppl are at home).

This post has been edited by Singh_Kalan: Jan 12 2009, 11:07 PM

unless the developer offer an upgrade package to do for u, otherwise, u will have to wait till VP

Actually upgrading to 3 phase from single phase would require the following changes as well:

a) Your metering panel. If your original panel is the single phase one, you need to buy a new one. Fibre panel with metal base RM40-60.

b) New cut out fuse + holder 3 sets and 1 neutral link. RM50-80 can settle all.

c) A bigger DB box with 3phase ELCB and MCB/MCCB modules. Depending whether yours is 32A or 40A or 60A or 100A, the total cost would be around RM150-200-250-400 depends on brand.

d) No need to rewire your whole house. Just reassign your circuit wiring to each phase according as to balance the load will do. While you are at it, go buy some extra spare SP MCB module. Local less prominent brand woudl cost less than RM10 ea for 16A and below. Recommended brand is Hager, Clipsal, Moeller but more expensive about 40-60%.

e) Runner fees can save up. Go to kedai TNB take the upgrade form and pay the extra meter deposit. Jot down your NC number and ask for the estimator and meter installer's hp number. Normally TNB will give them to you if you ask them. If not call back again and quote ur NC number and ask the hp number again.

2-7 weeks later the TNB guy will come to your house and install the meter. Time frame can be varying wildly depending on how busy is the technician assigned to you.

If your incoming is not originally 3phase, be prepared to pay some RM1-2K for the contribution charges to TNB after the estimator submit their report back to TNB.

This post has been edited by TerTop: Aug 25 2008, 08:46 PM

I just want to relate my experience with 3-phase installation in my new house. Instead of applying for 1-phase and later found that I need to upgrade to 3-phase, I want to install 3-phase from the start since I'll probably install 7 airconds and 4 water heaters.

Call up developer and they said my house is 3-phase ready i.e., just need to apply 3-phase from TNB. No other changes required. I called up TNB last week and they said I need to get an electrical contractor to apply for me, can't do it myself. The deposit is rm800 for 3-phase vs rm600 for single phase. Contacted the original electrical contractor for the housing project and paid rm200 fee for the application. End of story, so I thought.

Yesterday the contractor called me up and said my application has been successfully submitted and I need to change the DB to 3-phase since they provided only 1-phase DB for the project. I told them the developer said it is 3-phase ready and I don't need to change anything else but the contractor confirmed that it is just 1-phase DB as they are the one who install it for the project. Apparently only the meter panel/cutout is 3-phase ready and not the DB. Called up the developer again about it and now they said the same as what the contractor have just told me, outside from TNB is 3-phase ready but inside the house is 1-phase only.

For the same contractor to replace it for me, they would charge rm850. DB brand is Doebke from Germany. My total cost in installing 3-phase is now rm200 (application fee) + rm850 (DB change) + rm200 (TNB deposit differences) = rm1250. I'll plan pay in next couple of days. Do you guys think rm850 is fair price or I can get it cheaper from other electrical contractor?

DB box is quite expensive.
My friend is changing the DB box for his single fare and it cost around RM600 IIRC.

Hi All,

My house is currently in a blackout now. I have asked the TNB to come and check and they told me that there's power going into the meter but non going into the house. So I have asked a electrician to come over to check but was told that my wiring from the meter to the DB having some problem and needed rewiring again.

The quoted me RM1800 for 3 phase wiring only, without the application with TNB and new 3 phase DB.

So can someone please advice me whether this is reasonable? I'm in desperate need now as my house is in a blackout now.. Some how I feel that the electrician is trying to con me cause I'm in urgent need to install the wiring..

Can some advice me please?

What does it involved to wire from meter to your DB? Any underground work required ie. digging and hacking required? The cost depends on the amount of work.

Well, the TNB electrician said that the power to the meter is ok. So their job is done and it's their problem. So I hire an electrician and they told me that there's no power coming in from the meter to the fuse box. So it's either the wire was broken or burned. This happened before a 5-6 years back but that time the house was still under warranty, so we could get the developer to changed the wiring which they did. So my electrician told me that they might used a low quality cable or they didn't use one single cable/ use cable that was joint together. So, it's possible that the water went inside the cable and that's why it was burned.

And yes, it involves digging and hacking to conceal the cable...

So it that worth it? RM1800 for this? Btw, mind to share where you staying and your electrician contact number? I'm staying in Kota Kemuning, Shah Alam.

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Added on December 23, 2008, 11:00 amJust got a called from another electrician. They told me that even though that TNB side is 3 phase ready, meaning to the power meter. If we plan to use 3 phase, the TNB will still charge us the cabling for the 3 phase meter once we start using it. Is that true?

This post has been edited by Sitting Duck: Dec 23 2008, 11:00 AM

That is quite a lot of work. Not sure it is worth rm1800 or not. Did the 2nd electrician gave you a quote as well?

When it is 3-phase ready, all wiring from TNB to the meter panel and cutout fuse would be 3-phase. If your meter panel is not for 3-phase, you have to change that as well. There should be no further charges except to increase your deposit. The additional cabling charge is for house that not 3-phase ready.

While the above is correct, the DB box are only able to take around 60A, so in order to benefit, you may need to upgrade your DB Box and add in additional capacitors for optimum performance.

FYI I got 8 Air-Conds in my house and tons of other shit and still on single phase. As overall 100A is still way adequate while certain 3 phase only gives you 30A per phase, making a total of 90A only

1st electrician quote me RM1800, including hacking and patching back after hacking, including some tiles. 2nd electrician quoted me RM1500 for the wiring + hacking but do not include patching as it will be done by third party which would cost up to RM500. Well, 2nd electrician quote seems to be better, since patching is done by third party which is suppose to be expert in patching up things. But I hate the 2nd electrician's boss attitude cause he was acting very "sombong" in front while talking to me. So I have made appointment with the 1st electrician and ask them to lay the wiring as soon as possible for RM1800.

I talked to both the electrician again and once again they confirm that TNB will still charge the 3 phase cabling from the TNB distribution point to your house power meter even though it's ready. Reason being that TNB has laid the cable and now since that you want to utilize it, so you need to pay for it. So they quote me this:

1) Cable from TNB distribution point to your house meter: Electrician #1: RM1250 Electrician #2: RM2250
2) 3 Phase DB box: Electrician #1: RM350 Electrician#2: RM500
3) Panel Electirician: Electrician #1: RM1000(rough estimation) Electrician #3: RM800
4) Deposit to TNB: Electrician #1: top up to RM1000 Electrician #2: top up to RM800


What I really wanted to know is #1, whether is true. Since most post here say that it's not necesary to pay for #1 since it's ready to your house.

Hi kimyee73, would you be kind enough to pass me your electrician contact so that I could apply through him once my wiring is ready?

Forgot to answer the above question. Unfortunately I'm in Penang.

I asked my contractor and TnB before, no further charges...unless they want to spring me another surprise

Aisks..that's too bad...a friend mine told me that there's still a promotion for 3 phase wiring.. need to check TNB directly.. I'll go there after work today..