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

[shaemus]

2 minutes ago, Crossy said:

To clarify, the term "ELCB" is usually reserved for the old Voltage Operated ELCB (VOELCB) which work in a different way to the RCD (differential) device.

 

However, the term ELCB gets used in the non-technical world to refer to an RCD and any "ELCB" you see in the domestic market will actually be an RCD.

 

Yes quite right. Earth Leakage Circuit Breaker. 

[bankruatsteve]

36 minutes ago, shaemus said:

Confirm the neutrals are in the right terminal before you go any further. 

 

The neutrals would going to the neutral BUS (except for RCBO).  What terminal do you refer?

[shaemus]

1 hour ago, bankruatsteve said:

The neutrals would going to the neutral BUS (except for RCBO).  What terminal do you refer?

Lets get back to basics: i have 3 heaters, 1,2&3 i have separate rcbo's also called 1,2 & 3, if the live conductors for each heater feed cable are installed in the corresponding and correct terminals on the rcbo and the neutral cables are not terminated to the correct corresponding terminals, will the rcbo trip.

 

That is why i suggested checking the cabling teminations are correct 

 

you could also describe them as the load terminals where as the line would be as you highlighted earlier the phase connection to the bus bar and the fly lead to the common neutral, you could also say in and out.

 

the image below although slightly different to the OP's equipment is a good image to describe the conversation

[Grouse]

The images of RCBOs (ELCBs in Thailand) are DIN rail types. In Thailand we usually see bus bar type breakers. Connections are load phase and neutral and pigtail to load panel neutral.

ELCB protection on circuits supplying water heaters is a requirement for compliance with the Thai EIT code 2013.

Borrowed neutrals will defeat ELCBs. That is why the so called electrician left the pigtails disconnected and probably connected the load neutrals direct to the N bus bar.

Borrowed neutrals are a potential fire hazard

They are difficult to rectify for even real electricians particularly with a large load panel.

Also difficult to know if your electrician has fixed all the neutrals not just the circuits defeating the ELCBs

This is a real hazard and you should get professional assistance and sign off by Professional engineer (Thai engineers can show qualification but even that is no guarantee of competence)


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[Grouse]

From the description of the water heaters, I suspect these are multi-point instant water heaters. These may well not have local ELCB protection. What size are they in kW? May as well check cable / breaker sizes while we're at it!


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[maxpower]

9 hours ago, Grouse said:

The images of RCBOs (ELCBs in Thailand) are DIN rail types. In Thailand we usually see bus bar type breakers. Connections are load phase and neutral and pigtail to load panel neutral.

ELCB protection on circuits supplying water heaters is a requirement for compliance with the Thai EIT code 2013.

Borrowed neutrals will defeat ELCBs. That is why the so called electrician left the pigtails disconnected and probably connected the load neutrals direct to the N bus bar.

Borrowed neutrals are a potential fire hazard

They are difficult to rectify for even real electricians particularly with a large load panel.

Also difficult to know if your electrician has fixed all the neutrals not just the circuits defeating the ELCBs

This is a real hazard and you should get professional assistance and sign off by Professional engineer (Thai engineers can show qualification but even that is no guarantee of competence)


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Please can you help with Professional engineer for sign off of my water heater in shower room. I think water heater not Thai EIT code.

I also confuse over ELCB and RCBO rail din and bus bar type in Thailand. Can help please.

[Elkski]

First off no house in USA ever has a professional engineer sign off on the electric work.  Sure a building inspector looks at wiring before the dry wall goes on.  But much trust is given to the electrician.   

Finding an errant connection can be easy or hard but it's not rocket science.   Worse case is you need disconnect all the junctions in the light and outlets.  And then figure out the wiring.  It does take two people and cell phones or radios and some time.  It may mean power will be off for several hours so get ice for the beer.   It can also be a nightmare like a screw piercing a wire just anywhere.   I had to find one of these once.  It will be nice to learn how the wiring access is in the attic and how it is run down the walls.   I agree earth ground is a separate issue.   But may not be so hard to fix.  I assume the outlets usually have a ground connection in Thailand?

The difference in breakers is #1 old style protection vs new style.  I swear by these things as I think one on a 220 v hot tub saved me some pain or my life.   #2 they just have different mounting methods depending on the brand.  You need a din breaker to fit in a din box.   Most times modern ones snap in place.   

I assume the heater power and neutrals can be sorted out and I would download the heater installation guide and wire up per instructions.   Usually there is an isolation  of the supply line going to the heater.    

[shaemus]

10 hours ago, maxpower said:

 

Please can you help with Professional engineer for sign off of my water heater in shower room. I think water heater not Thai EIT code.

I also confuse over ELCB and RCBO rail din and bus bar type in Thailand. Can help please.

Firstly, I am pretty sure you won't have a an ELCB available to you to use to as a disconnection and safety device, There for some reason seems to be a fascination and determination to continue to call RCBO's  and RCD's  ELCB's. They are different things. 

 

 

 

http://www.crossy.co.uk/wiring/Consumer.html 

i found this link, i have had a  quick read and it will answer your questions. Maybe

 

i have put a few picture below, the one on the left is not a good example of cable looming, the next a neat example of a rcd protected CU, the commercial panel shows the chassis mounted RCBo's which is some like the OP's DB at a guess although potentially not so neat, the next example  is a typical example of someone who doesn't now how to terminate a spill load board. the next is a pretty standard CU from Thailand 

 

 

One thing, this thread is about the OP's problem,  If there is in fact a borrowed Neutral. Its not to hard to find out on which circuit it is. Once you have ascertained the cabling and installation is correct i.e. cable size, Circuit breaker size, correct installation of the water heater, if the  earth requirements for the bathroom slab or any metal piping have been installed and the PFC of the incoming supply, then and only then should you move forward to rectify the potential borrowed neutral. But without seeing the installation it is hard to say to how complete the job.

Probably easier and cheaper just to run a new cable Then do your faults loop tests and ensure your RCD/ RCBO's are tripping below the correct time. Then label the switchboard and leave a record of the test results with the owner. As i am sure you all are aware just pushing the button only test the mechanism on the protective device and not its capability to connection within the required time frame. 

[Grouse]

Matters electrical can be a matter of life and death. Fatalities in Thailand are far too frequent. On TV, everyone is entitled to an opinion but I think posts from professionally qualified people should be indentifiable. Crossy, what do you think?

[Grouse]

In Thailand, there are several problems:-

 

1) The Thai EIT code 2013 is becoming closer to the international standard IEC 60364 but is not yet harmonised and there are important differences. Most Thai electricians don't have a copy. (Available from Chula bookshop - Thai only but numbers in English)

 

2) Thai electricians are not coded- they don't have to pass examinations and do not have a card.

 

3) In my experience, many Thai engineers are not competent. Thai level II engineers are usually reliable

 

4) testing of new installations (there are no periodic inspections) is the responsibility of the PEA (MEA in Bangkok. They dont have the time, money, expertise, instrumentation, inclination to do it so it rarely happens.

[Grouse]

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.

 

 

Edited September 3, 2017 by Grouse

[Crossy]

36 minutes ago, Grouse said:

On TV, everyone is entitled to an opinion but I think posts from professionally qualified people should be indentifiable. Crossy, what do you think?

We have thought long and hard about just this subject and we're using the same rationale as in the Health / medical forum. I stole the Local Forum Rules from Health.

 

I don't believe we can ask members for their qualifications to post here. Of course if they wish to include such information in a post they are quite welcome to, but we have no means (or intention) to verify same.

 

I for one don't have any current UK certifications, I have a BSc in Electrical and Electronic Engineering from Bath, a long expired JIB card and a current membership of the IET, I never joined NICEIC or any of the other schemes, never needed to.

 

Another issue is the variation of regulations around the world, install to the NEC or BS7671 and you'll be close, but both have rules that would not be acceptable here (Ufer grounds and ring final circuits spring to mind). If you want English language regs to use then AS3000 is pretty close to the Thai requirements.

 

Opinions are like backsides, everyone has one and everyone is indeed entitled to theirs. As noted in the local rules, any advice deemed immediately dangerous will be removed, but Forkinhades and Myself can't be here all the time, use the Report button to attract our attention if you see something dangerous.

 

 

 

[Grouse]

MCBs (miniature circuit breakers) protect against over current (they protect wiring from risk of fire or insulation damage). They may be plug in / bus bar types, DIN rail types or stand alone types and maybe single phase or 3phase.

 

Plug in / bus bar types have phase/load screw connections. The phase/supply connection plugs onto the phase bus bar(s) in the load panel / consumer unit.

 

Din rail types are installed on a DIN rail and have both load and supply screw connections.

 

Free standing circuit breakers (often erroneously called safety  breakers in Thailand) are usually installed outside of the load panel or consumer unit.

 

MCBs are rated according to maximum continuous current in A, maximum breaking capacity in kA, and instantaneous trip current (A, B,  C or D). In Thailand, MCBs are usually type C and require 10x rated continuous current to trip instantly. This is frequently misunderstood. For example a 20A, 6kA, type C MCB will allow continuous current of 20A, will break a current of up to 6,000A but will only trip instantly if the current reaches 200A. Take great care in selecting breaker and Cable sizes.

[shaemus]

4 minutes ago, Crossy said:

Another issue is the variation of regulations around the world, install to the NEC or BS7671 and you'll be close, but both have rules that would not be acceptable here (Ufer grounds and ring final circuits spring to mind). If you want English language regs to use then AS3000 is pretty close to the Thai requirements.

 Do you have a copy of the Thai Regs in English? AS3000 is quite a hefty document and  quite thorough in some areas. I would like to compare the 2 documents as you have. 

[Grouse]

6 minutes ago, Crossy said:

We have thought long and hard about just this subject and we're using the same rationale as in the Health / medical forum. I stole the Local Forum Rules from Health.

 

I don't believe we can ask members for their qualifications to post here. Of course if they wish to include such information in a post they are quite welcome to, but we have no means (or intention) to verify same.

 

I for one don't have any current UK certifications, I have a BSc in Electrical and Electronic Engineering from Bath, a long expired JIB card and a current membership of the IET, I never joined NICEIC or any of the other schemes, never needed to.

 

Another issue is the variation of regulations around the world, install to the NEC or BS7671 and you'll be close, but both have rules that would not be acceptable here (Ufer grounds and ring final circuits spring to mind). If you want English language regs to use then AS3000 is pretty close to the Thai requirements.

 

Opinions are like backsides, everyone has one and everyone is indeed entitled to theirs. As noted in the local rules, any advice deemed immediately dangerous will be removed, but Forkinhades and Myself can't be here all the time, use the Report button to attract our attention if you see something dangerous.

 

 

 

OK, understood. Thanks!

 

For what it's worth, I have been a consultant engineer for nearly 40 years! Durham university 1975. Member IEE/IET and so on.

 

We provide certification of compliance with both Thai EIT code 2013, and IEC 60364 with which BS7671 2008 as modified 2011 is harmonised as is AS/NZS 3000.

 

NEC is substantially different. The Thai code was originally based on the NEC code but is moving closer to IEC60364 harmonisation.

 

It worries me when I see posts which indicate some knowledge but not complete understanding because the result may be fatal.

 

I, all to frequently, act as expert witness when there has been a fatal accident ?

[Crossy]

2 minutes ago, shaemus said:

 Do you have a copy of the Thai Regs in English? 

Sadly I don't, it too is a hefty document and covers far more than just domestic.

[Crossy]

2 minutes ago, Grouse said:

It worries me when I see posts which indicate some knowledge but not complete understanding because the result may be fatal.

Me too. All we can do is point out (gently) the failings and remove anything that's going to get someone killed.

 

I too have a full time job as a Consultant Engineer, and that's not closely related to electrical installations, you can work out what I do and for whom from my other posts

 

[shaemus]

10 minutes ago, Grouse said:

MCBs are rated according to maximum continuous current in A, maximum breaking capacity in kA, and instantaneous trip current (A, B,  C or D). In Thailand, MCBs are usually type C and require 10x rated continuous current to trip instantly. This is frequently misunderstood. For example a 20A, 6kA, type C MCB will allow continuous current of 20A, will break a current of up to 6,000A but will only trip instantly if the current reaches 200A. Take great care in selecting breaker and Cable sizes.

 

Mate The kA rating on circuit breaker is the maximum short circuit current that the breaker can handle safely. Short circuit currents can be very high in Thailand as the authority, from what i have seen doesn't install HRC fuses on the line side of their equipment.

[shaemus]

9 minutes ago, Crossy said:

Sadly I don't, it too is a hefty document and covers far more than just domestic.

 

If you could point me in the right direction as to where is can get a translated copy that would be very helpful. I quite enjoy reading standards and my current work as a hazardous area electrical inspector requires me to be constantly referring to different standards. AS3000  2017 is just going through its release now. Maybe you can let me know the documents full name so i can download the translated version, although its quite bizarre that a regulatory body or standards committee would choose to translate such a document. But if you would be so kind as to share the name or source of the translated document, that would be very helpful.

 

Thanks

[Grouse]

That's what I mean by maximum breaking capacity. PFC! Prospective fault current.

 

HRC fuses are always installed on the primary side of transformers. MCCBs are normally used on the load side to protect the transformer. We then have a main breaker at the  load panel. 

[Crossy]

Well, we've really deviated well off the original topic (yes, guilty as charged m'lud).

 

The lack of supplier fuses worried me when we first came here. PFC in the UK could be >>10kA if you're near the sub-station, the front end BS88 fuse (80kA breaking capacity) is essential. Here I measured our PFC and, despite only being about 300m from the village transformer, got just over 2kA, that's not going to trouble our 10kA incoming MCB.

 

I always advise those with their own transformers to install HRC fuses, but invariably the Thai sparks says "no need, fuses old style", at least those with 3-phase tend to get MCCBs on the front end.

 

[Grouse]

8 minutes ago, shaemus said:

 

If you could point me in the right direction as to where is can get a translated copy that would be very helpful. I quite enjoy reading standards and my current work as a hazardous area electrical inspector requires me to be constantly referring to different standards. AS3000  2017 is just going through its release now. Maybe you can let me know the documents full name so i can download the translated version, although its quite bizarre that a regulatory body or standards committee would choose to translate such a document. But if you would be so kind as to share the name or source of the translated document, that would be very helpful.

 

Thanks

To the best of my knowledge there is no formal translation. I can give the ISBN number but the Thai EIT code 2013 is available from Chulalongkorn University book shop. 300 THB

[Crossy]

1 minute ago, Grouse said:

EIT code 2013 is available from Chulalongkorn University book shop. 300 THB

Rather cheaper than BS7671 at about 80 Squid.

[shaemus]

On 8/26/2017 at 1:38 PM, AJBangkok said:

Recently I had a problem with a plug in the kitchen which just went dead. I called in an electrician and to cut a long story short the problem turned out that my wife had turned off the breaker for a water heater in the guest bathroom and by doing that it turned off that particular plug.

 

Now the kitchen is supposed to be on its own circuit and every other plug is to my knowledge. The guest bathroom is over 30 meters away ( I have a big condo ) so why a plug in the kitchen would be connected to a guest bathroom 30 meters away is anyone's guess.

 

The real problem is that when the electrician was inspecting the box he found that the 3 RCBO's I have for the bathroom water heaters were not connected. They all have curly wire that stretches coming from them that instead of being connected to the neutral???? ( I'm not sure about this) were left unconnected and just hidden behind other wires in the box. The fuses all still worked but the safety trip didn't .

 

The electrician connected them but within a few minutes they all tripped and continued to trip every time they were reset. The electrician said the company who wired the house had been lazy and had "stolen neutrals " and it would require major work to fix. He ended up unattaching the curly wires so the breakers wouldn't trip but I'm now concerned it's dangerous 

7 minutes ago, Crossy said:

9 minutes ago, Grouse said:

EIT code 2013 is available from Chulalongkorn University book shop. 300 THB

Rather cheaper than BS7671 at about 80 Squid

 

So Basically we don't have a standard to work to, as we can't (speak for myself) read it and then follow its methodology, content and rules. If that is the case then would it better to refer the response's to the questions posed in this Forum back to an agreed standard of reference, you quite rightly mentioned before about ring mains being a bit dangerous due to the lack of ability /knowledge to fuse accessories and appliances down to a suitable size  (different thread possibly) and therefore AS3000 popped up as a point of reference. And with response to an earlier comment about those persons who answer questions being qualified to so i think that would severely limit the amount of questions answered. 

 

It may be worth someones time and effort to to do a maximum demand calculation using AS3000 and produce a cable list/accessories list with some illustrations of the service equipment and the layout and cabling requirements, for a minimum safety requirement for lets say a 3 bed house with 4 AC etc etc and pin that to the notice board.

 

I have also noticed that the use of an MEN seems to be creeping into posts, this is definitely part of AS3000. There is a well documented set of arguments for and against its use. Personally i won't be having one in Thailand as the the Authority don't maintain their network equipment to a high enough standard to me to risk becoming the local reference point to earth for the local transformer should a poor Neutral/Earth connection every transpire on the local network.

 

And Finally to the OP. I just re read you post. As a sparky, I'd say just rewire the water heaters with the correct size and type of cable. PM for help if you want. it will save you a heap of time. Good luck and happy Sparking everyone..

[Crossy]

2 minutes ago, shaemus said:

I have also noticed that the use of an MEN seems to be creeping into posts, this is definitely part of AS3000. There is a well documented set of arguments for and against its use. Personally i won't be having one in Thailand as the the Authority don't maintain their network equipment to a high enough standard to me to risk becoming the local reference point to earth for the local transformer should a poor Neutral/Earth connection every transpire on the local network.

If you don't do MEN in the Thai way you won't (shouldn't) get a permanent supply, nowt to stop you removing it once the man has gone.

 

Any yes, I like it as little as you, but we have a very solid ground and the neutral is indeed earthed at every 3rd pole.

[Grouse]

The tables for Cable sizes and breakers are understandable in Thai EIT code 2013 and allow for higher temperatures. Thai Cable types are specified such as THW, NYY, CV, VAF etc

 

Orherwise use any code that is harmonised with the IEC 60364 standard: Australia, New Zealand, Singapore, Hong Kong or any EU country. Not NEC though.

 

Remember what I said about RCD requirements on water heaters and wet areas.

[Grouse]

1 hour ago, shaemus said:

 

So Basically we don't have a standard to work to, as we can't (speak for myself) read it and then follow its methodology, content and rules. If that is the case then would it better to refer the response's to the questions posed in this Forum back to an agreed standard of reference, you quite rightly mentioned before about ring mains being a bit dangerous due to the lack of ability /knowledge to fuse accessories and appliances down to a suitable size  (different thread possibly) and therefore AS3000 popped up as a point of reference. And with response to an earlier comment about those persons who answer questions being qualified to so i think that would severely limit the amount of questions answered. 

 

It may be worth someones time and effort to to do a maximum demand calculation using AS3000 and produce a cable list/accessories list with some illustrations of the service equipment and the layout and cabling requirements, for a minimum safety requirement for lets say a 3 bed house with 4 AC etc etc and pin that to the notice board.

 

I have also noticed that the use of an MEN seems to be creeping into posts, this is definitely part of AS3000. There is a well documented set of arguments for and against its use. Personally i won't be having one in Thailand as the the Authority don't maintain their network equipment to a high enough standard to me to risk becoming the local reference point to earth for the local transformer should a poor Neutral/Earth connection every transpire on the local network.

 

And Finally to the OP. I just re read you post. As a sparky, I'd say just rewire the water heaters with the correct size and type of cable. PM for help if you want. it will save you a heap of time. Good luck and happy Sparking everyone..

I personally use T-N-CS grounding with a local ground rod array (at least 3 x 3m Cu clad steel delta) with ground conductor not less than 50% neutral. Essential to get <5 ohms resistance to main body of earth though.

[carlyai]

'I personally use T-N-CS grounding with a local ground rod array (at least 3 x 3m Cu clad steel delta) with ground conductor not less than 50% neutral.'

Well, I've waited for others to ask, but must be my turn.

Why did you use 3 earth rods?

I know broadcast stations use a ground array for propagation purposes, and think I know the Australian power system uses only one earth rod, and I can see the reasons.
This is the 2nd time I've heard of this type of ground rod installation, the first was the electrician who initially wired our house.





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[Antioc]

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.

[carlyai]

@Antioc Don't get a false sense of security.

Still keep on his case until ALL done, or it won't be....

My guy spent a many weeks doing our place, earths everywhere, but when I had to go away, SWMBO got him to install metal driveway lights and there ain't no earths attached to the fixtures.

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