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.

Main incoming fused isolator

Ok noted, I plan to add a MAXGUARD SPD CLASS 2 as well, should be good enough to protect from lighting strike right? My unit located at top floor of 20years 5 storey old apartment.