What's a stolen neutral and how to fix it.

[shaemus]

1 hour ago, Antioc said:

This has been a great post as it has dealt with the issues and not gone off the track as many seem to do.  I have Sparkies in the house at the moment as all electrical wiring and the RCBO are being replaced  Actually there wasn't an RCBO as such, just a 60 Amp Mains Switch and 3 RCBs.  No Earth at all to the building.  I was watching the Boss man starting to run two wires, an Earth and Active and promptly asked him where the Neutral was.  Oh, he said, I get one from next room, plenty there.  After a careful half hour drawing and explaining that he must run his Neutral in one MCB Circuit and not borrow from another, he finally got the message.  I had to explain that it is what I wanted and that I was paying him to do it.  He grudgingly re-run new wires and next day (3 core flex), obviously after some thought, agreed wholeheartedly with me.  Trying to get these fellows to correctly wire something is like mating elephants.  I had many other patient sessions with him over other complete irregularities, fortunately each time he came around and is now competently completing the job.

 

A good news story in the making. 

 

 

[JohanB]

On 2017-09-03 at 9:17 AM, Grouse said:

RCBO, ELCB, RCD, RCCB are the same but different.

 

In all cases they monitor the current in the phase and neutral (they should be the same). If they differ by more than a fixed amount, they will disconnect the supply quickly. This is the function of an RCD

 

An RCBO combines an RCD with over current protection. A combined MCB with RCD. The RCD element will be rated at 10mA, 30mA, 100mA or 300mA usually.

 

For protection against shock, 10mA or 30mA are suitable. 10mA can result in nuisance tripping ( equipment with switching power supplies can have high leakage currents)

 

ELCB is common expression in Thailand for RCBO, RCD or RCCB

 

RCDs are frequently 2 pole, and may be single phase or 3 phase.

 

RCBOs may be single phase or 3 phase.

 

RCCB just means combined RCD with circuit breaker.

 

 

Again you missinform people about the ELCB's. There are many, many maybe many 100.000's of older water heaters with true ELCB's in Thailand. IT IS NOT THE SAME AS RCD's

They need the ground wire to be connected to a ground rod (normally when a good installation is made)

Thats the working principle for the ELCB protection device.

 

Most installations I've seen is lacking the ground wire and the ELCB is not working and the appliance is very dangerous.

Specially in combination with a stainless steel shower hose it' leathal!

 

A true RCD, RCBO, RCCB etc. anywhere in the line feeding to that old true ELCB-fitted heater will make it safe.

 

A good explanation of the difference ELCB vs a Residual Current Breaker:

https://www.quora.com/What-is-the-difference-between-ELCB-and-RCCB

 

ELCB and RCCB :

• ELCB is the old name and often refers to voltage operated devices that are no longer available and it is advised you replace them if you find one.
• RCCB or RCD is the new name that specifies current operated (hence the new name to distinguish from voltage operated).
• The new RCCB is best because it will detect any earth fault. The voltage type only detects earth faults that flow back through the main earth wire so this is why they stopped being used.
• The easy way to tell an old voltage operated trip is to look for the main earth wire connected through it.
• RCCB will only have the line and neutral connections.
• ELCB is working based on Earth leakage current. But RCCB is not having sensing or connectivity of Earth, because fundamentally Phase current is equal to the neutral current in single phase. That's why RCCB can trip when the both currents are deferent and it withstand up to both the currents are same. Both the neutral and phase currents are different that means current is flowing through the Earth.
• Finally both are working for same, but the thing is connectivity is difference.
• RCD does not necessarily require an earth connection itself (it monitors only the live and neutral).In addition it detects current flows to earth even in equipment without an earth of its own.
• This means that an RCD will continue to give shock protection in equipment that has a faulty earth. It is these properties that have made the RCD more popular than its rivals. For example, earth-leakage circuit breakers (ELCBs) were widely used about ten years ago. These devices measured the voltage on the earth conductor; if this voltage was not zero this indicated a current leakage to earth. The problem is that ELCBs need a sound earth connection, as does the equipment it protects. As a result, the use of ELCBs is no longer recommended.

[shaemus]

 

24 minutes ago, JohanB said:

  On 9/3/2017 at 4:47 PM, Grouse said:

RCBO, ELCB, RCD, RCCB are the same same but different

Right but wrong. obviously Thaid up in the Language here

[maprao]

I am with Johan b same same but different

Sent from my SM-N9005 using Thailand Forum - Thaivisa mobile app

[Crossy]

@JohanB are you saying you have SEEN a water heater with a "real" ELCB fitted (not just labelled ELCB) here in Thailand? How old was it?

 

All the ones I've looked at (OK not every brand) have had RCD or RCBO (despite being labelled as ELCB) or nothing.

 

NOTE To those suddenly worried, any modern unit you buy here will be an RCD or RCBO even if labelled "ELCB".

 

[JohanB]

On 2017-09-08 at 0:09 AM, Crossy said:

@JohanB are you saying you have SEEN a water heater with a "real" ELCB fitted (not just labelled ELCB) here in Thailand? How old was it?

 

All the ones I've looked at (OK not every brand) have had RCD or RCBO (despite being labelled as ELCB) or nothing.

 

NOTE To those suddenly worried, any modern unit you buy here will be an RCD or RCBO even if labelled "ELCB".

 

I have been at probably over 70 different guesthoses and cheap hotels/hostels since the mid 1970's and seen a lot of wall instant water heaters.

Most of them had no test buttons at all and consequently have no built in protection at all.

I have never disassembled anyone with testbuttons to investigate if there was a voltage or current protection device. If there was a green thin eart wire attached, I assumed it to bee a voltage controlled protection type, as the thin earth wire (if it at all was connected to a ground?) could not blow a 20-40 Amp fuse.

Most older heaters was only connected with 2 wires and no groundwire. If there was a non functioning test button on one of these, I also assumed a true ELCB type, but not working because of the missing ground wire.

 

But all these heaters was covered with plastic housing and plastic non conducting knobs. So, as long they were not lose on the wall and threatening to fall down, I didn't conciderate any of them as dangerous, as the plastic shower hose (and the water in it) is not conducting electric current to any extent.

 

What really make me scared is when I see a metal (type stainless steel) hose on a wall heater or in a bungalow.

These metal hoses are the killers if the unprotected/faulty heater has a metal threaded tap on the outlet (most modern heaters have plastic threads, but there can be a metal tube insert)

 

You are not even safe in type twin bungalows, where a couple of bathrooms share an above ceiling electric hot water tank. The built in hot water tubings are often made of galvanized steel and will conduct all the way from the faulty electric H/w tank to a metal shower hose. Even if not carrying high voltage continously, it can kick in when you, or the neightbour, are showering and the thermostat in the tank switches on. This killed a swedish couple, entangeled in a stainless hose, a few years ago.

 

So if you spot a metal shower hose in any suspect installation, never never never hold it in your hand and around your body when showering. Let it sit in the wall- holder and do not touch it when showering.