Thanks ceo684

Yeah I appreciate the need for some extra length of wire in there as well as not too much; else cannot close the box LOL Still, i think a longer section with narrow insulation between the barrier/finger guard & the tip will speed up work

Btw, I was learning about RCDs and I think I found a use case for current measurement. Since they work on residual current, one might want to find out how much that residual current is.

My friend had a RCCB that just wouldn't reset after a thunderstorm. The electrician said RCCB damaged by surge & recommended to instal a new one. So my friend did that himself; turned off the Main circuit breaker after the meter & took out the old RCCB & put in a new one, ensuring the Line & Neutral were inserted correctly and tightly

Before he turned the main circuit breaker back on, he pushed the RCCB's switch back on; but it wouldn't engage     He also had a good look at the old one (not connected at all) and tried to push the switch back on AND he could! So he took out the new one and connected the old one back in the DB.  LOL the switch wouldn't engage in the ON position hahaha

He then reconfirmed that the main CB was OFF & removed one of the Neutral wire from the RCCB; tried to push the switch up again - it engaged & stayed up!

We think there's current in the Neutral but none in the Line - that's why the RCCB wouldn't allow the switch to stay up. I'm waiting for my new Kyoritsu to arrive & I plan to go over to measure the amps across the In & Out Neutral poles on the RCCB (mains off) to test our suspicion. What do you think?

The touch at in and out N will not work for current because you're measuring in parallel. 
Running current through the meter directly produce a lot of heat. 

Before he turned the main circuit breaker back on, he pushed the RCCB's switch back on; but it wouldn't engage    He also had a good look at the old one (not connected at all) and tried to push the switch back on AND he could! So he took out the new one and connected the old one back in the DB.  LOL the switch wouldn't engage in the ON position hahaha

He then reconfirmed that the main CB was OFF & removed one of the Neutral wire from the RCCB; tried to push the switch up again - it engaged & stayed up!

ummmmmm the thing is that the RCCB refuse to engage in ON position... ie there's a break in the circuit because the RCCB refuse to close the circuit ....so if "touch at in and out N" it is in series.... Isn't it?

Only IF the RCCB is in ON position will "touch at in and out N" be in parallel IMHO haha I wasn't sleeping in form five physics class    Am I mistaken? hehe double check
thanks for that practical tip about stressing the meter 

…..wires incorrectly wired are touching earth (lately this miswiring issues are very common - not sure intentional sabotage or just pure noob workers wiring power strips and plugs incorrectly) etc.

Cant agree with you more. Recently while installing a simple water filter next to my washing machine, I received a mild electric shock* when my elbow accidentally touched the side panel of the washing machine. When tested with a Philip test pen on the metal drum n metal door hinges of the washer, to my horror, the pen lit up! I suspected during house renovation more than 15 years ago an inexperienced electrical contractor worker must have wired the wires wrongly. My suspicion was proven right when I checked it with a power outlet/socket tester (see pic below). It showed that there was no Earth! 😅 After dismantling the wall socket, I found out that the PVC insulation of Earth cable was not peeled off enough and the tightening screw was actually screwing onto the PVC insulation only instead of on the copper wire! Imagine if there had been a short circuit during the 15+ odd years, you guys wouldn’t be hearing this from me already unless…. 😂😂😂

*Talking about mild electric shock, I had also experienced the same with my MacBook but I had already check the power outlet it’s connected to and the L, N and E were in order. Wonder what could be the reason…🤔

IKR. Look at this idiota's work!
Nowadays buy new home really need to tear down every switch and every socket just to ensure that they are all wired correctly.

Some customer place the wires are not even screwed in at the terminal. They just popped out once I open the socket up

OMG!!! 🤦‍♂️

In fact, I had gone to the length of checking all my house power outlets with the outlet tester to make sure that they were wired properly. I don’t know how I could have missed the power outlet of the washer despite being so meticulous! 😂 I had also labeled all the outlets to avoid overloading any particular circuit but in spite of that, recently a 3-pin plug and the wall socket melted! It must have happened over years. Good thing the ELCB had tripped eventually else… The mistake was in connecting a 2400W kettle and a fridge in parallel in the same circuit AND most probably the use of a 3-core flexible cable which was lower than the required rating. Notice that the PVC insulation of the Live wire inside the plug and parts of the plug melted.

This plug seems like it didn't even get a Sirim sticker

I recommend MK. Good stuff and technically not super expensive.

Normally I do not pay much attention to whether a product has SIRIM sticker or not. Now I know better! 😅

Yeah, usually if I were buying 3-pin plug, socket or switches, i would go for MK or Schneider-Clipsal. This burnt plug was happened to be on hand when I needed one and I didn’t think much of it. Most likely it came with another product I bought earlier but which had went kaput.

You are making the association that the plug burnt because of the SIRIM status. While this may be somewhat true due to the quality of the plug that can pass SIRIM, it is not always true.

A fuse inserted into a circuit is a weak point for high resistance, as the connection depends on the spring tension and the fuse contacting its socket on both ends. That is why you see burning failure at the fuse - for sockets, for house incoming fuses, for equipment fuses, etc - the contacts go high resistance due to oxidisation over time or losing spring tension. And when something is high resistance, it begins to heat up, maybe to the point of failure.

All my high current extension sockets have the plug fuse bypassed, and overcurrent protection is provided by a MCB. I also wirebrush the socket pins from oxidisation to ensure a good contact within the socket.


On a side note, SIRIM will certify a product for any specifications; for example "this roll of cable is 100 m long ± 1 mm" and SIRIM will pass it if all your cable meets this length. So technically, this roll of cable has a SIRIM certificate. But of course you actually want a roll of cable with a SIRIM certificate to MS2112-3 for electrical specifications to be sure of the electrical characteristics.

All your high current extension sockets have the plug fuse bypassed? Wow, very brave of you! What happens if your MCB fails to trip cos MCBs do fail sometimes.

Actually not really brave. I make my own high current extensions, so I include a 16A MCB at the metal clad socket extension itself. So 2 MCBs (one at the DB, another at my socket) need to fail at the same time for a failure to trip. Don't forget the item plugged into the extension still has their fuse in the plug.

I also have a 10 mA RCCB mounted with a short lead and a socket, just in case I need to use power tools and work in damp areas.

See, actually NOT brave, and take a lot of extra precautions. Actually, now that I'm talking about it, I think I should change all of them to 10 mA RCBOs. After all, I can only die once, and I don't want to use that card too soon.

MCB or RCCB at the wall socket? I’m curious to learn how you do it. Mind share a picture of it? TIA

Sure. Just do something like this. Since the fuse in my 3-pin plug for my extension is bypassed, then the board is installed with a MCB for protection. This picture is from Sh*pee, mine is in the car, lazy to go and take. But I hope you get the idea.

RM125 SANWA DIGITAL MULTIMETER CD800A - 600V/0.4 A/Ω/100 μF capacitance
RM130 FLUKE 101 - 600V/NO A/Ω/100 μF capacitance
RM120 Kyoritsu KEW1018H  - 600V/NO A/Ω/200 μF capacitance
RM150 Kyoritsu 1009 - 600V/10 A/Ω/100 μF capacitance 
RM170 Kyoritsu KEW1021R  - 600V/10 A/Ω/1000 μF capacitance 

Sure. Just do something like this. Since the fuse in my 3-pin plug for my extension is bypassed, then the board is installed with a MCB for protection. This picture is from Sh*pee, mine is in the car, lazy to go and take. But I hope you get the idea.

These are actually what I want  but the prices... 

Those prices are one thing to consider. But I prefer making my own units as I have control over the parts I use and can replace in case there is a fault. Imagine something drops on the switch and it breaks. I for sure don't want to spend money another time. But in my self-built unit, I can change the metal clad socket by itself. If you can do the replacing/servicing yourself, then it may be something to consider when you buy items.