Dear ceo684, ozak, weikee and sifus,

Sorry for the super long post, I need some advise. Apologies again, I have to post some pics separately due to my restriction as newbie on LY. The more I speak to “contractors”, the more I’m picking up mixed messaged on how to proceed. Was hoping I may I get some advice on electrical related matters for my home renovation.

It’s a sub-sale house which is currently non-tenanted, double semi-D about 4000sf built up, 6 bedrooms.
Major reno done 2002. I was thinking of re-wiring my whole house, new DB and adding DB at 1st floor. Reno would also include piping (will post separately on this to get advise if needed to redo), retile whole GF, new built-in carpentry works, redo entire GF plaster ceiling, repainting whole house, roof tiles, windows/doors. No major structural works.
This home is for own family long term stay (>=20 yrs). 3 adults, 3 primary school going children

Some info on the reno/current status:
- It’s currently 3 phase
-Estimated reno to have about :
100 x downlights (mostly 4” indoor and 6” outdoor) – likely to get casing + LED bulb (9-11W)
65 x 13AMP sockets
6 x 15AMP or 20AMP for instant/storage heater for 6 bathrooms (15 or 20AMP?)

I’ve done quite a bit of reading and getting tips from you guys and other sifu’s posts, but a bit info overload especially when the topics becomes overly technical. May I humbly get advise on:
1. How do I determine if my current wiring and DB is fine and don’t need to spend a bomb to rewire + change DB + add DB? Or based on 20 years ago reno, I should just get it done?
Turning on lights and fans so far no issues, fast and immediate. Not sure if pics would help, this is the DB.



2. I spoke to a contractor 2 days back, he mentioned that to do change new DB and install new DB upstairs, I’ll have to call TNB to do it. Another electrician didn’t mention anything about TNB and quoted RM6500 (to replace current GF DB and to add new DB at 1st floor).
Is the TNB part true?
Is the quoted price “Reasonable”?
To be prepared with some knowledge of whether the electrician contractor are doing/recommending the safe/right way, is the below list what is required for 2 units DB (ground floor + 1st floor)?
* I hope I’m not creating a Frankenstein DB below, but no worries guys, I’m not gonna DIY at all, just wanting to make sure I have the right “internal organs” in the DB when I clarify with the electrician. Will be going for branded ones like Hager, ABB, Schneider (not that budget is not of concern, but when it comes to electrical, I believe must be willing to spend for safety)

Main switch x 2 DBs : is this main switch necessary (I see it in the existing DB, above pic)? I don’t see one in my current condo DB or those “full set DB sold on Lazada/shopee”.

RCCB : 63A, 4P, 300mA = RM145 x 2 DB = RM290 (is this known as the main RCCB to protect from fire/equipment protection?)
MCB : 3P, 40Amp, 6kA = RM65 x 2 DB = RM130 (what is the purpose of this thing?)
RCCB 25A /10mA x 6 heaters ; RM170 x 6 = RM1020 (this is for “life saving” shock protection right? Does each heater require additional MCB again on top of this RCCB? Sorry if it’s a silly question)

8 MCB for 8Airconds : Is this right? 1 MCB per AC?
2.5 HP x 2, 1.5HP x 6 What MCB rating should be used 16, 20 or 32A?

20 MCBs (6 or 10A?) for 65 (13amp sockets) = 20 x RM10 = RM200 (am I over/under estimating MCB’s required)
100 downlights = ?20 MCBs x RM10=RM200 (5 downlights to 1 direct DB, is it over or underestimation? Using 9-11W LED bulbs)

DB box x 2 = 30 ways + 45 ways? (Should I go for plastic or metal DB box?)

Should I invest in a T2 SPD?
tinyurl.com/m9kmxyms : Maxguard ok? Half the price of ABB
tinyurl.com/k78kbns7 : ABB

3. For cable thickness, is this recommended? :
Water heater : 2.5mm or 4mm?
AC / kitchen sockets (loose electrical appliance, built-in oven) : 2.5mm
Other sockets/lighting/fan : 1.5mm
4. Kitchen appliance, aside from built-in oven, fridge and electric hob, any other kitchen appliance would require a dedicated cable from DB? Eg. electric kettle, toaster, rice cooker, air fryer, coffee machine, non-built in microwave, LG puricare (hot/cold water purifier/dispenser)
(Assuming that 2-3 appliance likely used at same time, eg. electric kettle + rice cooker + air fryer)

4. For cable quality, I read a recent post by CE0684, to either go for:
caramay, Mega kabel (solid cables) ; Fajar cables ( flexicord). Any other brands I should "accept" if my contractor shows me other brands?
And from other sifu’s I read that, it must have at least SIRIM endorsed labelling and the specs on the cable

5. Last but not least, would you still use this existing storage heater + water pump?

All 6 bathrooms have existing joven 25L storage heater, which is at least 10-15 years old.
Would it be best to change all to new ones considering the wear and tear, heating element life span OR invest in solar heater (based on my calculation, cheaper than 6x25L joven storage heaters. Just concerned if my existing roof wood truss can handle 500kg)


Grundfos pump 7 years old – need to replace? Seem to be working, based on the sound I hear while in the roof and also 1-2 sinks I turned on had high pressure

Many many many thanks in advance for any advise/suggestions provided

A bit out of electrical topic, but since I’m sharing the pics of roof pics with the wood truss, should I be concerned with these rusted bolts and nuts holding the wood truss together? Contractor checked previously and mentioned roof wood truss ok, but advised to change all roof tiles + gutter (existing roof tile not done right and no gutter)

Bro that DB is damn old, like 20 year old house kind..
But that doesn't mean old is not good.. just that maybe I don't think the old dB has enough MCB for your new use.

Don't need to talk to tnb ba as this is internal wiring and nothing to do with TNB meter outside as long as the wire from the tnb meter to the DB do not need to upsize.

But I am not electrician just my 2 cents

TQ putera. Yes, it should be ard 20 years old (previous owner reno in 2002/2003). For DB, I'm 99% sure I would change and add new one on 1st floor. Now thinking whether to change all cables/wires in the house

Read some senior forumers here like Ozak and weikee did new DB/2nd DB, no mention of TNB.....sounds like just need to"extend" the main TNB in the existing cable with ?16mm cable (unsure statement by me, as am saying this based on uncle's memory of what I read) to have a separate DB on 1st floor (ie GF and 1st Flr has their own DB).

I think the electrician mentioned need TNB panel contractors as the main 3 wires need to be pulled up to the 1st floor. maybe he meant any TNB certified electrician? Let's see what the "last" electrician I'm meeting tomorrow says

thanks again!

Lighting & 13A SSO, see below vv




Usually if the cables are in good condition, i.e. not chewed by rats in the ceilings and
voltage test is consistent between L-N, and
insulation resistance pass megger test Uni-T megger
you may not need to replace the cables.

More often than not, for <2000 homes the sockets' backbox may need replacement if they're iron when new, are likely to be titanic rusty iron.
I replaced those rusty backboxes to the China spec 86x86mm ones like these: https://shopee.com.my/Atlectric-Internal-Bo...5267.6809104931
These will need a bag of M10 screws from the bolts and nuts store (the usual ones that come with switches do not fit), but small issue. These plastic boxes are deeper than the normal ones and will require a bit of chiseling to expand them but they're hard plastic, not the (since 1980s till now) local made soft plastic backboxes that deform just from the cement used to mount them in place.



Not required to call TNB if you're not messing with the meter. Things after the meter are homeowner responsibility.


Laz/Spee are usually general parts only, for unlisted parts the electrical supply stores can get, sometimes I even ask them to list and I'll buy it once its up.
This main switch is commonly known as main switch isolator. A fancy name for an "on-off switch" that cuts off power to Live phases + Neutral, if installed at the main incomer, your whole house can be safely ISOLATED (off grid) and safe to work on.


In residential, the 30mA is max tolerance for 13A SSO and 100mA for light circuits.
This is main RCCB/RCD. 300mA is NOT according to code. I uninstalled mine for a 30mA.


30mA, still got chance to survive (life protection).
100mA, 300mA...bye bye


RCD is a highly sensitive Income Tax agent, you cannot cheat them of taxes. If INCOME is this much then the OUTGOING taxes must match the income you earn, up to the tolerance level.

The RCD works on principal of current in = current out + some minor losses due to cable resistance. This is safe.
But when the Total current in on live phase(s) is much higher than Total current out on the neutral, we have a 2MDB situation (current CANNOT be missing that much beyond RCD tolerance), as current NOT returned on outgoing neutral is something very wrong (i.e. can mean leakage through humans), and it will trip because it is a fault condition.
High sensitivity 30mA (0.03A) better than mid sensitivity or low sensitivity RCDs (100mA aka 0.1A or 300ma or 0.3A) respectively.

In smaller places with tiny DB box for 3phase, the usual way is to have a 3 phase (one piece RCD) to protect everything.
--This is like a one-piece dress lah, once coffee spill you need to drop everything immediately (leave the meeting) and wash the whole thing.
--This is up to code but the risk is that if any (current imbalance) fault happen, it will trip of course, but whole house blackout.

For a bit more money it is also OK to do 3 pieces of single phase RCD, one ea for Red/Yellow/Blue phases.
--This is like wearing a business suit. Coffee spill on the blazer, you can just wash the blazer. The top and skirt still can continue to wear. Continue with meeting
--This is recommended by ST for "business continuity" since one phase has fault, the other two still work as normal.


This is a "total load" OCPD (overcurrent protective device) to make sure that all the combined loads in the little MCB's (think the little branches on a tree) do not overload the main tree trunk (the main trunk cable).
If the main tree trunk is overloaded, the last protection will be the TNB fuse next to the meter will blow.


Yes, WH RCD protection is just for current leakage (Income Tax agent specifically targeting your business) and
MCB gives you TreeBranch overload protection for short circuit.
Two separate functions and must go hand in hand.



Running current of the NON inverter Pana 2.5hp (2.5HP Standard Non-Inverter R32 Aircon CS-PN24VKH-1) taken as reference = 9.7A. 20A MCB will be sufficient (C20).
Running current of 1.5hp will be around 6A for modern aircons. C16 also more than enough actually.

Note: MCBs are sized to the cable size NOT the APPLIANCE. Its purpose is to trip before the (overloaded) cable gets too hot to start fires.
C curve MCBs are VERY forgiving stuff. Aircons nowadays have soft start and delay randomiser so not all 8 will come on at the exact same moment.



For ABB 6kA MCBs, is around 7.50-8.00 each. Hager MU (6kA) tend to be more expensive ~12.50 ea for some strange reason.
Lighting - Depending on how the lights are set up it is unlikely you will have 125pcs of 11W on just one circuit (i.e. 6A x 230V = 1380W). I personally prefer to use 6A for lighting circuits' MCBs since nowadays LEDs consume very little power.

13A SSO if heavy usage places like kitchen, living room, then can run dedicated circuit each. Per ST rules on radial circuit, how many final circuits needed at a minimum, and whether you need 2.5mm² / 4.0mm² will be guided by the floor area to be served:


DB box x 2 = 30 ways + 45 ways? (Should I go for plastic or metal DB box?)

Metal DB box are the ones specified US latest code. Plastic is still combustible. I'd use metal if possible.
Eaton 48 ways are also available (16x each row). EPS or GEM local made metal boxes also available.
The configuration of the box (2x16 or 1x27 for example) you buy may be limited by the physical wires length coming out of the wall (if you are not replacing the whole wiring if they're in good condition).



T2 SPD look like the pic in my post (ignore the video using RCD as SPD) https://forum.lowyat.net/index.php?showtopi...ost&p=100886222
IMO if you have frequent lightning storms in the area (some areas are quite prone) then it is good insurance as lightning surges can kill devices.



WH use 4mm² if pulling new wires as this is still the biggest or 2nd biggest power hungry device in the whole house.
AC 2.5mm² minimum
13A SSO 2.5mm² minimum (up to 20m² floor area); 4.0mm² (up to 50m² floor area). Kitchen ones if you wanna save one cable run (to use the double sockets with two heavy appliances on one LNE run) can use 4mm².
Built in oven 4.0mm² or better (can also run 6mm²) depending on the wattage of the oven. If it does NOT come with 13A plug from factory this need fixed installation OR high amp (32A) commando plug.



Many fake cables out in the market.. there are many ways to cut corners or fake certification.
MS 2112-3 + SIRIM QAS + cable size (how many mmsq) + mfg name will be embossed or lasered into the quality cables.
If im a mfg and my cables are subpar.. I'll prefer not to label them.. if anything catch fire don't find me pls..



If existing storage heater is connected via a quality 10mA RCD, as it is a highly sensitive device any fault also will trip (including imbalance due to shared neutral on WH circuit but its not due to faulty appliance) then yes I still dare to use. For preventive maintenance - may want to double check the tank condition for signs of internal corrosion just to be sure.

Pump normally if its working fine then no issue, usually pump motor failure to turn (if it jammed) will create Imax and overheat the motor itself (will be more likely to trigger MCB in this case).

This post has been edited by ceo684: May 11 2021, 02:33 AM

Sizing of the incomer & homeowner's main cables should match the TNB supply (either 10mm for 40A / 16mm for 63A) cables; or 25mm+ if you have 100A supply.
The amperage you can draw safely follows lowest common denominator i.e. the smallest cable.

Your DB components have to give the proper protection, i.e.
1. meet the same amperage rating where applicable (for MCBs/isolator); and
2. meet OR exceed (for RCD).

Moving the meter or incomer cable (parts related to TNB) better get TNB panel electrician for less hassle.

IMO, if you haven't moved in your stuff yet it is easier to replace wiring, once you have settled in you won't bother already

This post has been edited by ceo684: May 11 2021, 02:27 AM

my late grandmother's house used bolt nut to hold wood truss same as you. been almost 40years. 1985 to be exact. still ok. steel will rust overtime

Taikor, very long la.

It looks more like a factory than a house from the massive connection!

Most of your question is already covered by ceo684. I think that is enough for you and not to confuse with too many answers.

Rewiring and DB change after the meter is out of TNB cover. Unless you want to relocate the meter. But I guess the meter is beside the gate?

1st, need to come out with the new electrical plan by the electrician. Without the plan, it is a crazy, unorganized, and cost runaway job. Beware that RM6.5k cost is a bit too low for KL/Selangor area.

2nd, identify which area is using a lot of electrical. Living room, 2nd floor or kitchen area. Is the kitchen has a lot of appliances like oven microwave, induction cooker, WM, fridge etc. For example, if the 2nd floor has a lot of AC, heater, PC etc, so it is better to have another DB separated. Or the kitchen is far behind and with plenty of high current running appliances.

3rd do not neglect the earth and lightning. Plunge more earth rods into the ground and run the earth wire separately to DB. You don't want headache later when RCD keeps on kicking.

The bolts rust is only the surface. If knock on it and it doesn't brittly break, that is fine.

If want to change the tiles + gutter, might as well change the wood trust to metal. Consider termite also.

Actually about time to consider replacing the bolts to SS type. Not very expensive at few bucks a piece.. for peace of mind because structurally alot of weight still supported by the rafters.
Wood rafter still usable if theres no termite history. Metal roof structures should be coated with "cooling aid paint" i.e. intumescent paint so in case of fire, the steel will not "buckle under heat" so easily.
Read more here: https://www.ifsecglobal.com/fire-protection...ire-protection/

SS bolts and nuts just cost around RM5-6 a pop for 1/2" size..as a price refernce. Best to replace like for like.
https://shopee.com.my/4%E5%88%86(1-2'&#...5689.4356684848

ceo684 TQVM for the advise & crash course The analogies you used really helped

Is it the same as this : ABB swtich disconnector ?
The electrician I met today asked if I wanted the new DB to have a main switch isolator OR upgrade (pay more) to have a MCCB instead. Is this necessary?
I thought it's 2 entirely different things, isn't it?

Aiks. I just checked my condo DB and it's using EPS 4P 63/0.3. Should I be concerned?


I don't understand the "up to XXm2 floor area" part. Does it mean if my living hall + work area = 25f x 25f = 625sf (pic below), all cables to my living and work area sockets should be 4mm?


Is there a public list of "SIRIM" approved cables? Can't find it on google
The electrician I'm keen to engage says he uses Eco brand cables, supposedly he claims is the same parent company as Caramay? : Eco cables
I'm planning to insist on Caramay or Mega Kable as per your suggestion. Pay more now, sleep better at night (I hope), but

Sorry boss....that's why offer peace offering of potato at the end
TQVM for your pointers!
Will not be relocating the TNB meter. Yup it's at the gate pillar. But, need to change the casing, it's rotted already. To change the case (pic below), looks like need to remove the main TNB cables right? Can electrician do this or need to call TNB (assuming I call TNB, all TNB will do is unplug it while my contractor change the casing and then TNB re plug it in?)


crazy ex right? To replace (GF + 1st floor) roof tiles + gutter + fascia boards (3920sf) whole house already quoted : RM50k. At least another RM30k-RM40k if for truss structure?
Reading into termites also giving my sleepless nights and decided to strip off the parquet which covers half the GF flooring and tile it up, but whole of 1st floor is parquet, planning to refurbish.
I noticed one particular kitchen cabinet previously had termite attack . Am planning to do 1 round of termite barrier with Agenda (Bayer) before tiling +/- sentricon system

ceo684 As mentioned above, so far I only noticed 1 GF kitchen wall cabinet had been damaged by termites, does that mean I should consider to change the wood truss to SS?
noted on the SS bolt/nut. TQ

This post has been edited by vernee26: May 11 2021, 10:46 PM

ceo684 and ozak, your explanation is quite useful. I happen to rebuild a house and receive the following quote for concealed wiring using Mega wires:

1) To supply & install 100A TPN Main Switch Board (MSB) and earthing system = RM6,500
2) To supply & install Distribution Board = RM4,000 per unit
3) To supply and install Main Switch Control to G,1st and Attic Floor = RM 500.00
4) To supply to liason with TNB to relocate the meter location =RM 3,000.00
5) To supply & install 100amp TPN TNB metering panel = RM 650.00
6) To supply & install 100mm HDPE pipe =RM 250.00 per unit
7) Wiring 3phase 100amp main point using 4cX35nnsq xlpe/swa/pvc cable in 100mm HDPE pipe 2pcs = RM 5,000
8) Wiring 3 phase 40amp submain point using 4 x 16mmsq + IE x10mmsq PVC Cable in trucking (D/B-G),(D/B-G/P) & D/B-A/C1) = RM15,000 for 8 units
9) Lighting points = RM100 per point
10) Ceiling Fan points = RM 100 per point
11) Wiring 13amp power points using 2 x 2.5 sq.mm PVC cables, earth cable c/w waterproof switch socket = RM 288 per point
12) Wiring 13amp power points using 2 x 2.5 sq.mm PVC cables, earth cable and single gang 13A 3pin switch socket = RM 110 per point
13) Wiring A/C power point using 2 x 1.5 sq.mm PVC cables, earth cable c/w switch = RM 207 per point
14) Internet LAN port = RM 403 per point
15) To supply and install CP & 15A Power point in PVC conduit = RM 245.00 per point
16) To supply and install Auto Gate point in PVC/SWA/cable = RM 850.00
17) To supply and install Door Bell and Video intercom point = RM 800.00
18) To supply and install 2core Fiber Optic cable from external to FTE board (about 50') = RM 800.00
19) Testing and commissioning = RM 1,500.00

Do you think the prices are reasonable for a location at KL? My contractor is revising the lighting point from the old price of RM 52 to RM 100 per point. I saw the quote of RM67 from TS.

TSvernee26: sorry, hijack your thread to ask the experts.

This post has been edited by ongss: May 11 2021, 11:46 PM

Most welcome Happy to help!

Yes switch disconnector = isolator.
The basic flow goes like this. Zero components are TNB side:

00. TNB to cutout fuse (Plan Z last resort overload protection for your lot).
0. Main cutout fuse to meter.
1. Meter tails to your DB box ("main incomer"), and starts at Main Switch Isolator (aka the ABB switch disconnector).
For smaller installations isolator is optional and this job is often loosely done by the whole house MCB.
The ABB SHD203/63 shown is 3-pole isolator that does NOT isolate the Neutral. For complete protection I recommend to use a 4-pole isolator (3P+N) i.e. SHD204/63 ABB 4P isolator that completely isolates the whole lot from the grid including the neutral. Since single phase isolator cut both 1P+N. This isolator function is to put a very safe roadblock that nothing can come in -or out- from your lot. It makes it safer for anyone working on the electricals.

2. Whole house 3-phase MCB ("tree trunk protection") so this protects your main incomer wiring from overload overheating. This will be sized according to main incomer cable size, 40A for 10mm cable, 63A for 16mm cable, 100A if 25mm cable (rare but not impossible). It is important to size against the tree trunk (cable size), otherwise it will not trip even if tree trunk on fire already..coz haven't reach the overload threshold of MCB.
--this can also be in the form of a MCCB (gardenia bread small size) but kinda waste space for same functionality, although the MCCB will be stronger withstand in case of short circuit, more for commercial/industrial use case.
--MCB work on the live wires (3P). It need not bother with neutral.
--Price wise ABB SH203-C63 3POLE 63A 6KA MCB about RM75.

3. Whole house RCD. In residential, code mandates:
High sensitivity 30mA for 13A sockets where there is higher risk (mistouch plug pins, or stuffing pens into the 13A live terminal).
Fixed apparatus lighting or big motors (dinosaur aircon) can be placed on Medium sensitivity 100mA tolerance RCD. A High sensitivity 30mA will also satisfy this requirement.

For your condo:
Low tolerance 300mA is "illegal" unless special purpose like you have a production line dodol stirring machine.
Recommended to use whole house 30mA. If certain fixed apparatus devices trip the 30mA they can be seconded to a 100mA.



1. At the minimum: Swap out the 300mA to a 30mA 4P RCD to be safe. 300mA is essentially "useless" in residential whether for code compliance or life protection. From the main MCB you have a 40A 3Phase supply.. which means the RCD can be a 40A 3P 30mA (not expensive for 40A for the condo).
Pricewise ABB RCDs tend to be more correctly priced than Hager, equivalent quality since both also made in EU (Italy/France). 4P 40A 30mA RCD ~115 (ABB) , ~175 (Hager).

2. The big blocks like whole house MCB and whole RCD are not really important to be same physical dimensions (same brand) as they are connected with pigtails (short wires, and in 1-1 independent relationship).
3. The small blocks (individual circuit MCBs) should ideally be all the same brand as they are all connected by a flat metal common busbar.
Why this is important: for the short ones you are risking intermittent contact (the busbar teeth are not that long). Loose connections cause fires.
Since (if) you're swapping the 300mA RCD out to a 30mA, might as well change all individual circuit MCBs one shot to the same brand.

More often than not whilst parking lots are drawn the same size, the length of different cars will never be the same.. kancils are short.. trucks are long.. how will a common bar connect the kancils properly?


Cables

Unfortunately no. Usually "you get what you pay for" as raw copper cannot be that cheap for some to price much lower.. making plastic heavy and copper tiny is the way to get 20-30% cost reduction. "Not my house syndrome"

Many of the elcheapo cables will fail vernier caliper/micrometer test.. if really go deep into it.

As a longtime Caramay cable user.. the first thing is.. Caramay cables emboss (not laser printing) their markings into the insulation.
On the other hand I see Eco cables are using laser printed markings.

From a certification standpoint (can't really see in the pic) if its MS2112-3 certified it should work-lah, but I doubt the statement of same factory.. the output is different.

From experience both Caramay and Mega Kabel have proven reliable

This post has been edited by ceo684: May 12 2021, 12:03 AM

Sharing my ID company quotes, pending their reply on what kind of wires/sockets they are using

1) To supply & install 100A TPN Main Switch Board (MSB) and earthing system = RM6,500
2) To supply & install Distribution Board = RM4,000 per unit
RM6500 (replace new DB at GF) and add one new DB at 1st floor

9) Lighting points = RM100 per point
RM95

10) Ceiling Fan points = RM 100 per point
RM75

12) Wiring 13amp power points using 2 x 2.5 sq.mm PVC cables, earth cable and single gang 13A 3pin switch socket = RM 110 per point
RM130

13) Wiring A/C power point using 2 x 1.5 sq.mm PVC cables, earth cable c/w switch = RM 207 per point
ceo684 mentioned 2.5mm2 as minimum.
To supply and install AC point up to 1-2 HP : RM290
To supply and install AC point up to 2.5-3HP : RM380


14) Internet LAN port = RM 403 per point
Cat5e : RM260
Cat 6: RM360

15) To supply and install CP & 15A Power point in PVC conduit = RM 245.00 per point
what is CP?

16) To supply and install Auto Gate point in PVC/SWA/cable = RM 850.00
pending quote


RM67? I was quoted RM95 per lighting point


What is this? Is this armoured cable from the TNB meter to DB?


May I also know what is this for?
I pray that I don't need this, as looking at the price itself is making me sweat already.

I just realized my rewiring quotation did not itemize these items :

1. Cabling from TNB meter to DB - what are the cables referred to? Do I need to get this replaced as well? or its possible to exclude it and only do rewiring from DB to sockets/lightings/appliances?

2. Earthing rods - do these need changing?

Thank you TS for sharing your quotations. Looks like you have a better quotation.

12) Wiring 13amp power points using 2 x 2.5 sq.mm PVC cables, earth cable and single gang 13A 3pin switch socket = RM 110 per point
RM130
I calculated wrong, my old rate was RM133, for VO, they are charging RM156.

7) Wiring 3phase 100amp main point using 4cX35nnsq xlpe/swa/pvc cable in 100mm HDPE pipe 2pcs = RM 5,000
What is this? Is this armoured cable from the TNB meter to DB?
May I also know what is this for?

Ya, I believe it is from TNB meter to the main switch.

8) Wiring 3 phase 40amp submain point using 4 x 16mmsq + IE x10mmsq PVC Cable in trucking (D/B-G),(D/B-G/P) & D/B-A/C1) = RM15,000 for 8 units
These are cable from Main Switch to DB. I have three DB and they quoted 8 units.

I actually knock down the entire house and it appears to be like installing everything new. The main con get the subcon to quote the price. My original lighting unit price was RM 52 last Nov. Now, they revise the price. I have several quotations. Lowest is RM60 and average is RM80. But, my main con revised from RM52 to RM 100 for each lighting point.

This post has been edited by ongss: May 12 2021, 06:06 PM

They revised because of "raw material" price increase? RM52 to RM100 seems quite a big jump.
Yours is quoting based on Mega Kabel, the most expensive already =)
I'm still waiting for my primary contractor to revert on the brand of cables they are using, if it's some no brand/china cable, it's not a good comparison already.

If you are still actively looking for electrical quotes, you can try these 2 people ( I met them earlier this week for site survey and am waiting for their quote). I'll be insisting on using Caramay / Fajar cables with the new quotes :
Ah Hui : +60 12-228 4543 (my close friend recommended this guy. The friend also did major reno, knocked down except beams/pillars)
Chai (Kejuruteraan Letrik Cahaya Baru) : +012 219 7368 (he did repair works for me previously at my current condo, seemed honest and knows what he's doing)

Both nice young chaps (30s-40 years old), chinese speaking (which is a bit tough for me, as I'm half banana )

I noticed your list does not include (just in case you missed it out):
1. Water heater points?
2. Garden lights, gate pillar lights
3. installing lights, fans, AC
(I'm getting separate AC installers)

Thanks for sharing, yes, I have all those items. The unit prices are the same as the rest.

I signed up an agreement with a main con and paid 10% in Aug last year + 15% in Dec immediately after the DBKL approval. So, the price should be locked. To my perspective, I took a risk that I might loss this amount of money in view of MCO. On the other hand, I would expect the main con to hedge the prices of the raw materials. Just like the tile suppliers, if we place our deposit during HomeDec exhibition, the special promotion price will be locked until we collect the tiles.

I knew the main con makes a mark-up from the price. They are going to do the project management and I understand this requires efforts, expertices and times. But, the new prices for additional works are crazy. The cost of raw materials go up a lot - but, the labour cost and other operating cost not necessarily go up totally.

I will contact your friend to see if he is keen to work with my main con. Thank you.

This post has been edited by ongss: May 12 2021, 07:12 PM

btw, the electricians are not my friends yar. One of them (Ah Hui) was recommended by a close friend of mine =)
good luck with the reno! and feel free to hijack this thread anytime. meant for all to share, compare and learn.

Thank you for sharing all the useful info. Will share once I have more update.

Generally cables increased price by around 25-30% (since March 2021)
for 2.5mm Mega Kabel/Caramay used to be around 85, now its 120-125
for 4.0mm used to be around 136, now around 163 online

Since your work volume is quite a big sum, there are such things called double sockets that will make end user life easier (just pay the variation few bucks in parts pricing). It will not "overload the cables" at all under normal usage (whole circuit MCB protected). Singles are used for small jobs to earn the few bucks "per point"..if all installed double how to earn (since your job is a big job the contractor should be pound smart and not penny foolish)

This post has been edited by ceo684: May 12 2021, 10:39 PM

Thanks for your professional advice. I will ask for this double sockets.

You are exactly right. To me, when I viewed the initial estimation, I already knew the wire, main switch, DB and even TNB panels are over priced. My brother is building his house too and faster than my phase. In my mind, I have the budget which I am willing to pay. But, I am willing to close one eye as long as the jobs are done professionally based on the data centre quality (which was quoted by the subcon).

But, when I saw the price hike from the original contract rate to the new rates, I was quite disappointed. I made the work easier by having additional DB. Even for my LAN cables, I split into "one floor one switch" so that the electrician does not need to pull the wires from main switch or DB to all locations. Now, since he is charging me by point basis and the unit price is RM 403, I rather let him do it from ground floor to all locations.

Lastly, thank you so much for your efforts to explain in the thread. I do pick up a few points to add into my VO.

Hi CEO684, just a few more questions, I noted that my contractor quoted me two pricing for every single 13amp point I requested:

Wiring 13amp power points using 2 x 2.5 sq.mm PVC cables, earth cable and single gang 13A 3pin switch socket - RM 110 per point
Wiring bare channel using 2 x 1.5 sq.mm PVC cables, earth cable c/w switch - RM 46.00 per point

Is this correct? One power plug needs one set of 2 x 2.5 sq.mm PVC and 2 x 1.5 sq.mm PVC cables? I did google myself, I saw some picture of bare channel. It appears to be those fitting for the traditional light



I feel something is not right. What do you think?

Also about the double socket, you refer to this?



Also feature light like the following picture, if there are three light bulbs, it is considered as wiring of three points and the price is RM 100 x 3. But, I saw in Lazada something can do the same job but cheaper:





Thank you so much for your guidance.

This post has been edited by ongss: May 13 2021, 09:43 PM

Ref. above diagram and also to the sections 3.4-3.5  ST_Guidelines_For_Electrical_Wiring_2008_Edition.pdf ( 427.2k ) Number of downloads: 41
:
13A SSO need a full set 2.5mm² LNE (3-wires) from DB into the socket.
"Looping" (connect from next door existing socket into a nearby new socket) is the radial diagram.

For lighting point, they are cheaper since the wire length is shorter and the cables are thinner at 1.5mm².
Earth is optional if not using those old type fluorescent tube with the magnetic brick choke, and is usually not fitted, but its alright to have it fitted.
Typically lights do not come with earth wire, but for the old fluorescent tube with magnetic brick choke, this choke is like a "transformer" that need to be bonded to earth, while the lamp casing is not required to be earthed. Modern LED tube does not use the old magnetic choke so no requirement under section 7.5.

Usually (in standard 1 light point 1 switch, no staircase switching) it is:
single wire L from DB box to the switch, from switch and end at light point.
single wire N starting from light point and return to DB box.



Bare channel usually refer to the "casing kosong" for tube lights. Casing kosong meaning NO starter and NO choke (since these dinosaurs are not required) - LED tubes do not need the dinosaur parts to work. A bare casing will be able to operate LED tubes perfectly, usually these casing kosong is described as for use with LED-only.



Yes. As per the diagram the only extra effort is that the box hole need to be hacked bigger, and you need the double socket with matching box. Itu sahaja.
Identical wiring effort as per single socket as there's only 3 holes to be wired.



Per my diagram.. technically 3 runs from DB box, able to individually control 3 different bulbs on a 3-gang switch (in any possible permutations of ABC on/off) are considered chargeable as 3 points.
If per your picture one light circuit to control 3 bulbs either ALL on/ALL off i.e. just add two wires to the left and right should not be charged as full price since its "looping" that short piece of wire.

Technically this will be branching out 8 lights from one light point. Something like Xmas lights, 100 little bulbs on a single run, but with the RF controller you can turn on each of those 100 little bulbs individually. However, you still need some short wiring from the central controller to the 8 lights (like spider legs).

This post has been edited by ceo684: May 13 2021, 11:14 PM

Thank you so much for your advice.

I think something is going wrong with this subcon electrician. Light points are quoted as a separate item in the contract and I reconcile the number.

For each 13A power plug, the subcon electrician is charging one bare channel to pair with this. Based on your description, I don't need the bare channel. I must be one of the best water fishes in town.

This post has been edited by ongss: May 13 2021, 11:24 PM

Most welcome

For the feature lights.. basically just branch out 2 more wires from where the 1 point is.
If my understanding is correct you just need the wires sticking out where the light should be unless you're going with the tube lights?
(this pic shows a light point, fan point c/w hook, and doorbell point out the wall) but essentially the core idea is a ready-to-hook-up point.



Sometimes.. if the main con not clear about what's going on, then the subcon may add in all the side dish upgrades which are not needed or totally don't make sense.
Bare channel basically means tube light casing, i.e. http://www.degindustrial.com/page/products...l/vegas-1l.aspx and are definitely not required for the 13A sockets..

This post has been edited by ceo684: May 13 2021, 11:36 PM

Ya, I just need the wires sticking out like your picture and they already charge me the Lighting Points.

I think the subcon thought that I would not check details and raise any enquiry. The main con takes the quotation and add their mark-up for the project management fees. When I asked if I could bring in my own electrician, the main con wants to penalize me for any delay caused by my new electrician. But, for the past 5 months, I have never threatened them for delays despite I have paid a large lump sum.

It is good to have forummers like you to help people to read through the items. Otherwise, a lot of home owners will be slaughtered like water fishes.

You should hire a clerk-of-works ("kerani" local speak) to help you sort out all your questions. They'll help you with specifications for everything, how to do things, and check that things are done properly and using the correct materials onsite. Good investment if you are doing major renovations as the additional cost is not that high. If you are in the Klang Valley I have the contact of someone experienced if you are interested.
PM me for the contact . I know him from my kampung. Charges were reasonable for the work

Your thread is so useful that I revised it again and again.

Then, I realize I forgot to answer you the above questions.

1. Wiring water heater power point using 4mm sq PVC cable in PVC cable, earth cable c/w 20amp switch - RM 288 per unit
2. Garden Lighting points (including gate pillar lights) using 1 x 1.5 sq.mm PVC cable, earth cable and 10 A switches. - RM 279 per unit
3. Wall Lighting Point using 2 x 1.5 sq.mm PVC cable, earth cable and 6A switches. - RM 100 per unit

About air-con installation, install the fans, light bulbs, and etc - I will have separate quotations.

I am currently also studying the ABB T2 SPD as the area my new house is also an area with frequent lightning and rain stomp.

The price I received is very expensive because of main con mark-up. My house is also a semi-d with attic. I spoke to a few electricians past few days. Unit prices depends on the quantities. For a small house with 40 power points or 80 lighting points, the unit price are higher. For a big house with 120 power points and 100 lighting points, the unit prices are lower. My brother is building his 8000 sqft bungalow. His unit price is even lower.

This post has been edited by ongss: May 14 2021, 03:50 PM

For T2 SPD this has specific placement i.e. after mains MCB and before mains RCD 30mA. SPD need overcurrent protection of MCB only.
It also has to be connected to all wires (L1,L2,L3 no issue if placed next to mains MCB; importantly is the N and E returns) as short as possible.

Just to heads up why we need a bit of slack in the DB box wiring (ability to reposition and reconfigure layout) coz stuffing in a 4-module SPD (three phase) will need that room to fit. If everything hangman tight this will be tricky.

OMG, 100x Downlights!?
Usually I will isolate the area and just focus on the number of circuits for the lighting.
Eg, Master Bedroom- 1x Cove Lighting, 3 or 4 circuits for Downlight/Track Lights. Any other lighting will be just looping.
Same goes for power socket and I usually use the 2-gang instead of the 1-gang SSO.

It is also best to use different ELCB/RCCB for power and lighting circuit. For my own DB, I used 3 different RCCB, 1 each for Power/A/Cond (100mA), Lighting (30mA) and my Solar Heater (10mA) for practicality and safety.
Storage tank heater uses 3KW heating element while instant shower heater uses 3.6KW heating element.
In terms of efficiency, nothing beats Solar Heater.

Rule of thumb, cable size is equivalent to 10x of current carrying capacity, eg 2.5mm = 25A.
Unless you are talking about 3HP and above AC, there is no need to go for 4mm cable size.

In the market there are 2 types of DB that either:

1. MCB/Isolator as Main Incoming
2. MCCB as Main Incoming

For better protection and easier wiring go for the option 2 though it costs more initially.
Local brands like Safety/MaxGuard/EPS all have these DB with 2 type of incoming as option.

For the RCCB/RCD selection is this correct? You may have swapped them around.
Lighting is something that is generally low risk as user don't touch often and its out of reach of small kids. 100mA for lighting because back then people used a lot of old flourescent with chokes that often trip high sensitivity RCD, so a medium sensitivity 100mA is allowed.

13A sockets and metal forks and curious kids are high risk and therefore it need 30mA.



Selection of either MCB or MCCB also depending on the available mounting type of the DB box itself.
MCB/MCCB usually only cut the 3P live wire. It does not isolate the neutral.
Hence, MCCB does not perform the role of isolator

Isolator (4P) cut all 3P+N so even if some idiota wire the wrong way down the road and sets the neutral as hot wire when you're working on the DB box, you can be assured the whole house is completely isolated off the grid safely.

100mA for power circuits are usually good as one will not need to worry about nuisance trip. As all power circuits are connected to a single 100mA, there is a build up of leakages. Hence putting a 30mA into the power circuit is too sensitive.
Most lighting especially LEDs are very efficient hence the chances of earth leakages is very minor hence a 30mA is best to protect it. Main point here is should a trip occur in the middle of the night on the power circuit, one would not need to wander around in the dark or relying on torch lights. I also forgotten to mention that I specifically told the electrician to wire my fans to the lighting circuit. In the event the trip in the power circuit cannot be resolve at least I still have my fans running.
MCCB does come in TPN configurations as well. At any given time I will always choose a MCCB over an isolator (costs aside).

Wiring bare channel sounds like just "ready" wires to plug into something (like the picture ceo684 showed)? like tube lighting, right? can also be used for others like e27casing + LED bulb, feature lights?
For itemization from contractor, wouldn't it count as a "lighting point"?

Can use 3 gang socket to save another LNE? Couldn't find much, but found this MK brand socket : 3 gang DP double earth socket


One electrician did recommend the same for my new DB and rewiring, but he mentioned 2 different RCCBs only, 1 for lighting, 1 for everything else

Hi sifu's can anyone guide me on this? Is item no1. the same as: (ongss quotation)

If the electrician mentioned 2 different RCCB, then it is 1 each for Lighting and Power Circuit. If you have Heater (instant/storage/solar) it is best to have an additional RCCB of 10mA.

3-Gang SSO is rare, best to use 2x 2-Gang so it is easier to find in the market.

Guys, I am electrical engineering students but now working on something else. But suffice to say copper is very expensive commodity nowadays. The price is doubled.

My suggestion to you is do whole house continuity test for what you can still use. Copper especially the old one is of very good quality. Nowadays although still sirim, the quality level is greatly vary. The cost would start MYR 300 plus.

So after electrician have check your wiring is okay or not, then you change the distribution board. i believe your house 2 2 storey right, so i think it is cheaper and long term to have second DB upstairs. Also one important thing is to understand how much incoming you need (based on your load) and also purchase as big as possible (well based on your setup) distribution board to go with.

My previous bungalow i do, 1 storey the kitchen area require more space then the front one. Also if you want to use strictly code the cost will add up quickly, also the space DIN rail inside your distribution board.

Yes I agree, in fact i do this at my customer house 2 earth leakage circuit breaker/RCCB 1 using 100mA sensitivity and the other 30mA sensitivity. That would be 2 for each DB. 100mA is what difficult to touch like fan and lighting because whereas 30mA like power points etc. Also do adopt new 10mA for each water heater, best to be safe then sorry. With that if you have 3 bathroom, also with minimum 4mm wire the cost is very high.

you need more info please reply, I can reply to what you need. My priciple is always consultation is free for my client. If meter not touch, i dont think we require to called up TNB personnel, only wiremen will do.

Actually its a different market segment. It is not about saving the pennies but it has to be up to code so that it doesn't need further investigations for the near future.
I am also interested in why a 30mA whole house RCD is NOT doable in 2021.

My question is - What kind of domestic device leak so much >30mA, that a high sensitivity 30mA RCD always nuisance trip? Note: device trip as leaky device, not circuit wiring aka wrongly connecting shared neutral in to dedicated RCD (WH circuits).

If the devices are that leaky then the old kettle or old fridge is likely due for replacement anyway.
Nowadays, lighting also noone really install old magnetic choke flourescent lights - all LED drivers / LED tube.
Factory high bay sodium lights? Noone use this at home.
Old kettle element leaky, is time to replace the device.
Old fridge? I have a 1997 Mitsu still running. Never tripped 30mA.
Old water heater? I have 1997 National that needed direct LNE to 10mA. Never tripped. (Previously shared neutral problem that tripped its own 10mA).Never tripped 30mA when no 10mA/WH unit was fitted.
Old rusted toaster from decades ago?
Old Grundfos B&W TV?
Unapproved questionable devices?
Commercial 3 phase dodol mixer? Welding machine? This is not domestic 230V appliance.

My point is - I can retrofit a medium sensitivity 100mA if needed if there is a need to run dodol mixer at home;
But if everything (based on 2021) works fine on a high sensitivity 30mA RCD (single mains RCD) why are we settling for less protection AND wasting DB box space/customer money to buy 2nd RCD 100mA?

The code say for lighting/fan circuit and WH circuit (as secondary protection) maximum tolerance of up to 100mA, NOT exactly 100mA.
Hence, one top tier 30mA RCD already cover all the ST mandatory requirement.
I personally run 30mA as single mains RCD and do not experience nuisance trips.

This post has been edited by ceo684: May 30 2021, 02:15 AM

Hi, a condo that 26years old is that safe to use back the existing wiring for other 10-15years? Will replace wall socket, switches, DB components should replace?

Post a picture of the DB box overall and closeup pic of the largest blocks, for better commentary.

Actually I'm still in buying sub sales process, will share once I have it. Currently calculating how much do I need to spend on it.

Switches, 13A sockets, in standard white good brand like MK [or Hager if u like bigger switch] is about RM5 each, WH switches RM20/ea
These are cheap if you DIY.

For MCB parts wise roughly without seeing the DB (assuming its a usual double storey or condo, not a huge mansion bungalow) you will be looking at RM400-600 parts wise only for complete DB replacement with top tier components (ABB/Hager).

Note: Exclude labour.

Hi, thanks for the reply.

It is a 950sqft old condo.
Switches I think will slowly change to smart switch but before that will try few of it first.
How about the wiring concealed inside the wall? How we know is that still useable?

Generally usable but get the electrician inspect for surprises.
Also shared neutral problems at water heater

Thanks for the advice, btw how to find a qualified electrician? Do they have like a license or certified number?

Magic keyword:
Wireman need to
Possess PW1/2 cert for single phase,
Possess PW3/4 cert for 3ph

https://www.st.gov.my/en/web/general/details/99

Chargeman also can do but wont be cheap and u wont want to pay their fees in a residential setting

Generally there's two types of clients
One that emulates purchasing dept and goes for lowest bid. These usually end up with so many cut corner creative shortcuts I also kepala pusing
More reasonable one that dont really bother on pricing (but reasonable lah), as long as work done properly and right materials.

Ok thanks

Shared neutral problem?

Yes, if originally no 10mA RCD fitted but water heater installed - chances are the neutral can be shared by champion contractor last time and it will require pulling direct new LNE from DB to be sure.

Sifu's, house under reno now. armoured cable has been pulled for autogate, pillar lights.
Is it ok to leave the armoured cable copper wires exposed like this (fully outdoor, no shade)?
Wouldn't it expose the copper wires to rain and seep in along the whole stretch of the cable?

Use empty drink bottles or can to cover it.

This post has been edited by mini orchard: Mar 18 2022, 03:44 PM

Wow! Air Conditioner magnetic switch and ceiling fan regulator inside the DB box?

Imagine want to change speed have to go to the DB Box.

Sorry to hijack thread but for those with experience with very old house (70s), any idea how they earth the ground rod? Only two cables from the tnb pole to the meter so can’t be tn-s system. But house surely got earth and measured 0.5v between N and E at the sockets.

Can’t seem to see any earth cables coming out from the main tnb panel. And can’t find any earth concrete casing for ground Rod anywhere in the house compound.




This post has been edited by diffyhelman2: Mar 20 2022, 01:27 PM

The ground rod is normally locate at the garden. If the front yard is tile up whole place, than the tile already cover over it.

The earth wire lay directly to the DB. Doesn’t go through the meter side.

Thanks for the reply. Reason I’m asking is because I’m planning to install an spd and i think the db is full and will require a wire longer than 50 cm to connect to the earth point. When people talk about laying a secondary earth point to make the connection to the spd shorter, how do they do this? Will i have to lay a new grounding rod?

Will 30mA RCD be more prone to tripping whenever there’s thunderstorm?my 100 mA RCD trips when there’s a really huge nearby lightning strike which is a good thing I guess.

This post has been edited by diffyhelman2: Mar 20 2022, 09:02 PM

What happens if the ballast/choke is not bonded with earth? none of the old fluorescent lights in my house is connected the choke with earth. ( in any case I’m changing out these lights to LEd tubes next week). I also don’t see a connection point on the choke for an earth wire ( although some of the casing do have an earth wire bond which is unconnected)

This post has been edited by diffyhelman2: Mar 20 2022, 09:09 PM

Lay another ground rod help reduce the lightning trip.

The earth wire from the 2nd rod not necessary to be joint to the DB. Can wire up to any wall socket or joint to any existing earth wire.

You can get a new DB (smaller) to house the SPD. Than earth wire to existing. Or new ground rod side.

All electrical items with a metal body must be earthed. This includes the casing of the "fluorescent" tube, even if the tube is LED. Items that are double insulated, like plastic downlights, do not need to be earthed. But the 230Vac wiring to the light must still have the green wire, it is just not connected.

If you do not have an earth for any metal cased item, and should the LIVE touch the case, then the case will be at mains potential which can kill when you touch it. But if there is an earth bonding, then as soon as the LIVE touches the metal case, something in the DB should trip safely. Note that a LIVE wire touching an unearthed chassis, can still work as if nothing is wrong with it. With this in mind, you can run any metal cased item without an earth bonding, but your safety is compromised.

Yes i understand the purpose of earth wire. The Fluorescent light fixtures are normally inaccessible. Ceiling height. I’m only asking about the
Earthing of the magnetic choke.

And I am telling you the requirement. All metal cased items that are not double insulated. This supersedes the choke inside the case.

As you have alluded to in your post, exposure determines risk. Just like you will never be mauled by a shark if you never swim in the ocean (unless you Sharknado!) a light fixture that is high and inaccessible is "safe" with no earth than say, a stand lamp. You make your choice on the level of exposure you are willing to risk.

There is no technical reason that a fluorescent tube will not work if the choke is or isn't earthed. It is done for safety.

The ST wiring guide pdf linked by ceo, they list exceptions for earth wiring requirement on metal bodies. One of them is metallic covers for light fixture.

7.6 item iii



This post has been edited by diffyhelman2: Mar 21 2022, 02:03 PM

Okay. If you are so confident, why did you ask the question on the first place?

By the way, this

is not a light cover

This

is a light cover

Lazy to take real life pictures, move to my pc, edit and annotate them, and try to convince you otherwise. You do you.

My original question in post 59 was about earthing the magnetic choke ballast, not about earthing in general. ceo684 said that magnetic choke is considered a transformer so must be bonded to earth. I suspect the last lightning strike that blew up my outdoor lamp on the choke part may have been due to this.

This post has been edited by diffyhelman2: Mar 21 2022, 05:35 PM

tumpang boss, just now electrical contractor told me to use 15A socket for kitchen, but 15A socket pin is round, how do i want to use for my appliance ?

Its bonded to the metal casing.
Hence there is a need for earthing.
You do not want humans to be the path of least resistance. That's why there is an earth for light points.

Chop the cable and change the plug top?
But be aware 15A is unfused, and your MCB need to be properly sized.

If the appliance itself came with factory fitted 13A plug top then there is no reason to change the plug top type. You can replace with heavy duty bakelike MK 13A plug top.

⚠️ There is a duty of care on the mfg when the appliance is sold with 13A plug top it has to be within 13A load.

⚠️ If it doesn't come with a factory fitted plug top for some high power ovens exceeding 3000W, then it is not meant to be used on 13A sockets. However, appropriate methods of permanent installation such as isolator may be used.

This post has been edited by ceo684: Mar 23 2022, 01:44 AM

just clarified with the contractor, their so called 15A is using 4mm wires and 13A plug socket.

My developer connects one end of steel wire of the incoming TNB SWA service feeder to the earth terminal block in the db. I understand this is for safety of the electrician should there be any puncture/leaks to the SWA cable.

But, I was just thinking let's say if there's leak and since the earthing is all shared, does that mean all the electrical appliances with metal casing are all charged - lethal to touch?

Needs sifu opinions

In traditional florescent lamp with metal casing, the choke is held by screw to the casing. The casing is usually earthed. So, the choke itself is considered grounded.

If the degree of lightning is severe, electrical appliances will still get damaged even if it is grounded.

Hi, I want to ask something. I want to put washer and dryer (these are separated not combo) in a room where the wall do not have plug. What should I ask the wireman to do? Pull 1 plug from db then loop another plug? Or do I need to pull both plug from db. Actually I don't even know what I ask is correct or not

Hi, I would really like some advise - recently I have done whole house renovation with a contractor offering "full package" with cabinet and wet works, but their workmanship seriously have been under sub par so after I kicked them out and moved in, I separately got a qualified electrician to look into potential wiring problems in my house, and they told me that most of the black wires (earth wires) has problem and need to be replaced. The cost is of course a minor problem for me (estimate ~RM10k) plus more importantly they have to hack all around the place where we have already moved in.

The electrician said if I don't mind, can wait until when there is problem then only change the whole thing and continue like currently (I have been staying in my Condo unit for 2 weeks).

I understand there are definitely risks involved with not doing anything, but I am not sure what are the risks that is involved for me to consider the trade off. Will it cause electrocution/fire, or at most short circuit and trip/burn the DB?
Can anyone enlighten me?


This post has been edited by yun2: Apr 27 2022, 03:28 PM

Black wires = neutral, not earth.

As for problems with the black wires, I can guess only that they are being shared. This is not automatically dangerous or problematic. Your "qualified electrician" should have given you more information for example like which sockets can be used together, such that you would not need to be asking here for people to guess a solution.

If the problem is the black wires are undersized, then you can get away with just making some changes to the MCBs in your DB to cater to the undersized wires. Not ideal, but still a valid solution.

Hi guys,I'm renovating my house based on information below should I reduce MCB & RCCB rating for better safety?

1. I'm going to add on RCBO for WH, is that ok I purchase MCB/RCCB/RCBO from online?
2. is EPS/MAXGUARD RCBO can tahan? will it break down often? Schneider RCBO 25A higher than 20A is that safe to use?
3. Should I replace the old 63A MCB?


Schneider Electric Easy9 MCB 2P C 6000A 230V (63A/40A?)
Schneider Electric Easy9 RCCB 2P AC-type 230V 30ma (63A/40A?)
Schneider Electric Easy9 RCBO, 25A, 1P+N, 6kA, C Curve 10mA or MAXGUARD RCBO 20A 2P 10mA 6KA RCBO Type AC








This post has been edited by lawrencehl: May 7 2022, 06:01 PM

The 6 A MCBs are fine, but you could reduce the 20A ones to 16A, because of the "C" curve specifications. Please check the IN and OUT wiring, as from your picture they are incorrect
No issues buying online
EPS/Maxguard no issue based on my experience. You can use 25A RCBO only if you are rewiring the water heaters to 4 mm² wiring, but no issue with either amp rating as your heaters are 3600W only (~16 A maximum)
Yes. Rules state must be 30 mA (maximum) for sockets, and 100 mA (maximum) for lighting circuits. You could fulfill this with one 30 mA RCCB for both sockets and lighting Edit : Oops, sorry, I first read it as RCCB. Changing main incoming dual pole MCB is entirely your choice
All these choices are based on brand preference, and budget. All can be used, but stick with 63A as this is the rating you currently have.

Roughly, this is the number of MCBs I can count.


Take kitchen as example : The oven has its own wiring and MCB, so would the microwave. But the food steamer, rice cooker and water purifier I would run own wiring and MCB, but going to a set of 4 sockets.
Take the study : Fan and lights on one set of wiring, but the sockets may be 4 gang so that can plug in the PC, monitor, printer and speakers, going to 1 MCB. I hope my explanation makes sense.

This post has been edited by stormer.lyn: May 7 2022, 07:42 PM

Thanks for the explanation.

Do u mean MCB in & out wiring?

most of the item will use the existing point and I will add additional new set socket at kitchen and wardrobe for those higher current items.