Are there compulsory rules for grounding electrical devices?

[peteralex]

According to general knowledge electrical appliances in shower rooms must be properly grounded, furthermore that the grounding conductor of green/yellow colour code must be connected to a earthing(grounding) rod inserted in the ground. It is presumable that this provision has validity also in Thailand to protect against fatal accidents . Grounding terminals of all (as well imported) nationally approved electric devices in this mode of use (and others) are therefore designated by a green/yellow colour code and, according to the wiring plan are to be connected with the external grounding rod.
When replacing my hot water heater in the shower in question, it was found that the green/yellow conductor deviant applied a 220 volt potential, another two incoming conductors ( white and black color) were, however, on a "neutral " potential.
The electrical installation is an installation of a new building. According to earlier testimony from the installation company, a central grounding rod was inserted into the ground , all sockets entirely grounded.
This can be disputed by the current fact when on the green / yellow grounding conductor dedicated as " protective conductor " a 220V potential is applied , thus can be impossibly connected to said grounding rod.
A summoned Thai electrician from outside who finally made ​​the water heater functional despite applicable regulations connection, also aware of the (standardized) green/yellow convention as a grounding conductor, shrugged his shoulders and said that this would be done arbitrary in Thailand. Since such a faulty installation poses a fatal danger, it is inconceivable that there shouldn't be existing national requirements for a professional and proper electrical installation.
If any, what are the national relevant regulations and, stating the respective number(s) of, for professional electrical installations in compliance with the law, to which I can refer to and require to eliminate this life-threatening condition?

[Crossy]

The closest we get to a domestic installation code is this PEA document http://www.crossy.co.uk/Handy%20Files/groundwire.pdf which probably doesn't really answer your question directly.

There is an industrial standard which I'll try to find the link for, watch this space.

[Crossy]

Peter, what did you use as your ground reference to check the potential on the green/yellow and other wires?

What equipment did you make these measurements with?

[peteralex]

Peter, what did you use as your ground reference to check the potential on the green/yellow and other wires?

What equipment did you make these measurements with?

Hi Crossy, I appreciate your response.

As common practise I originally connected the white and black coloured conductors coming out from the wall to the water heater's terminals N and L, the yellow/green one to the dedicated Earth terminal. To my surprise the heater did NOT function. Since I have another water heater installed at a second shower room I checked the connection there and it revealed that the yellow/green conductor was connected to either the N or L terminal, I don't remember accurately, however, not to the dedicated earth terminal of the device. I couldn't believe that and I returned to the water heater to be connected, using a multimeter and taking measures between the yellow/green and the white resp. black conductors, both cases indicated a 220V potential, while taking measures between the WHITE and BLACK conductor indicated a Zero potential. Thus the ground reference was as well the white as the black conductor.

Upon this experience I contacted an external Thai electrician to brighten me up about the strange situation who confirmed the yellow/green conductor as the "live" conductor and he continued rendering the water heater operational by connecting the yellow/green conductor to the L terminal and the white resp. black wire to Earth resp. N terminal. (I described his comment about this previously).

The multimeter used is a commercial type with an int. resistance of 9kOhm/V in the AC range.

[Crossy]

That's clear (and scary) now Peter.

Is it your own place or a rental? (do you fix it properly or leave alone as it's working)

Do you have any form of earth leakage protection (Safe-T-Cut)?

[peteralex]

That's clear (and scary) now Peter.

Is it your own place or a rental? (do you fix it properly or leave alone as it's working)

Do you have any form of earth leakage protection (Safe-T-Cut)?

It's my/our own place, we took it over in April 2013 from a village developer. I'm not going to fix it myself nor leave it alone as it is but committing the developer to scrutinize the entire electric installation and to remidiate problems, requiring an installation according to state-of-art. I'm determined to file a lawsuit if necessary, therefore it's necessary to know and to refer to relevant statutory basis.When this country is producing and exporting electric devices and appliances then they must certainly follow international safety standards and have their products produced accordingly.

No Crossy, there is no Safety-Cut installed.

Edit: Sorry, I had to revise the Date "April 07" to now "April 2013"

Edited January 2, 2014 by peteralex

[Crossy]

Peter you may find this book useful in your quest http://www.eit.or.th/book_detail.php?id=17&gid=2 probably 300 Baht well spent.

There used to be an earlier version on the PEA website for free but it seems to have moved, searching now.

[Keesters]

Peter you may find this book useful in your quest http://www.eit.or.th/book_detail.php?id=17&gid=2 probably 300 Baht well spent.

There used to be an earlier version on the PEA website for free but it seems to have moved, searching now.

Thai Electrical Code 2013

Hard to believe there is such a thing.

The code in practice seems to be:

1: use the smallest sized wire possible

2: never ever earth (ground) it.

3: keep it visible so we can see where it has a problem.

4: join it with a twist and sticky tape.

And as far as my local electricity supplier goes:

1: minimum one blackout per day

[CIHUAHUA]

If there is a code it goes on the same page as driving rules. Who is going to enforce them? Driving and electric are really new concepts in Thailand and they will always be new concepts. Just grin and bare it.

[Crossy]

Peter you may find this book useful in your quest http://www.eit.or.th/book_detail.php?id=17&gid=2 probably 300 Baht well spent.

There used to be an earlier version on the PEA website for free but it seems to have moved, searching now.

Thai Electrical Code 2013

Hard to believe there is such a thing.

It's actually very comprehensive, but concentrates on industrial and HV installations, unlike BS7671 and AS3000 which talk about domestic.

The PEA document linked in my earlier post is as good as we've found for domestic.

[LeeThayer]

Peter, what did you use as your ground reference to check the potential on the green/yellow and other wires?

What equipment did you make these measurements with?

Hi Crossy, I appreciate your response.

As common practise I originally connected the white and black coloured conductors coming out from the wall to the water heater's terminals N and L, the yellow/green one to the dedicated Earth terminal. To my surprise the heater did NOT function. Since I have another water heater installed at a second shower room I checked the connection there and it revealed that the yellow/green conductor was connected to either the N or L terminal, I don't remember accurately, however, not to the dedicated earth terminal of the device. I couldn't believe that and I returned to the water heater to be connected, using a multimeter and taking measures between the yellow/green and the white resp. black conductors, both cases indicated a 220V potential, while taking measures between the WHITE and BLACK conductor indicated a Zero potential. Thus the ground reference was as well the white as the black conductor.

Upon this experience I contacted an external Thai electrician to brighten me up about the strange situation who confirmed the yellow/green conductor as the "live" conductor and he continued rendering the water heater operational by connecting the yellow/green conductor to the L terminal and the white resp. black wire to Earth resp. N terminal. (I described his comment about this previously).

The multimeter used is a commercial type with an int. resistance of 9kOhm/V in the AC range.

1. Is there a ground connected to the breaker panel? There should be a line, rather large coming out of that and leading outside to rod that it is clamped to.

2. If there is a ground connected, you need to inspect the connections inside the breaker panel to see if in fact the line is connected to the correct ground connection in the panel.

3. If the ground is connected in the panel, yet you have 220 on it in the bathroom, somewhere between the panel and the bathroom, an electrician has cross connected the Line and Ground wire, poosibly in a juntion box or from an outlet box. You need to find this cross connection

4. If you do not have a ground connected to the service breaker panel in the house, DO NOT add on until you find the cross connect between the Line and Ground

[RickFarang]

Without a Safe-T-Cut, you are counting on that ground wire to protect your life in case of a failure inside the heater causes current from the line to get to other parts of the heater. I don't know what the electrical code says, but I insist on having a working Ground Fault Interrupter breaker (or Safe-T-Cut) in the line ahead of the heaters in my bathrooms, and I insist on it for my in-laws' showers as well.

Do you want to leave the protection of your life in the hands of the guy(s) who used the yellow-green wire for the live conductor?

[falangadang]

"Are there compulsory rules for grounding electrical devices?"

Yes,... don't trust your average Thai electrician to do the job for you as grounding for most of them is a foreign concept!

When we had our extension done, the builder sent round the carpenter,.. a nice guy and "OK" carpenter (call him Khun T for this story).

Next he sent the gyrpock ceiling guy,... Khun T rolled up again!

Next he sent the brick render/plaster guy,.. Khun T and friend again!

Next he sent the plumber,... Khun T again!

Finally came the day to do all the wiring.... you guessed it,.... Khun T again.

He was a nice guy and well rounded talent wise. Turns out his proper #1 trade was gyprocking/plasterboard which he was very good at.

We had all his work tested by another independent professional electrician that we trusted and it turns out that all was OK (amazing).

When we had our first house built in CM 7 years ago we then had an emergency cut off box installed. It tripped all the power every time we activated it. Long story short,.. we got the trip box selling company rep back with his electrician and it was discovered that none of the wiring on our house was grounded,.. a virtual death trap (and we had little kids too).

The builder said he'd fix it (reluctantly... even though warranty still was valid) and it took two weeks and two separate teams (and dozens of holes in ceilings to be patched) to fix it. The second team turned up to fix the errors of the first team. My wife heard the head electrician foreman of team 2 refer to team 1 as "chimpanzees".

[bbbbooboo]

Lol.....chimpanzees and electricity, sums it all up in the LOS

[recycler]

Never trust anything that has to do with water or electricity in Thailand a shower-heater has both!

In construction and installation they use the cheapest labor they can find, often from Myanmar and Cambodia, they don't know the difference between AC and DC and if the supervisor knows it it's lost in translation. Nobody give a f..k what happens when they are gone and nobody is ever responsible for anything!

If you want to shower safe, there is only 1 way and that is to look at every move the workers make or do it yourself.

[recycler]

By the way, a lawsuit is useless, will keep you busy and annoyed for years and cost you a lot of money with little change of success!

[RonCM]

Hi PeterAlex,

All your assumptions are correct, but as just about everyone has commented the standard wiring rules as we have come to learn in our own countries is not the case here, for example I am from Australia and in my past life I was an electrician, and International standards were met.. But Australia has what is called an MEN System which is Main Earth Neutral Bond, we take the earth wire from a stake (In Thailand this stake must be 1.8mtrs long), the Earth wire must be a minima of 4mm2, and connected to the earth bar in the Switchboard, but in Australia's case we than bond the earth bar to the Neutral bar with wire same size as the mains coming into the building, possibly 10mm2 or 16 mm2, and in my personal experience they use aluminium as the wiring for mains, This isn't a good practice as it adds to voltage drop, so whenever everyone of your neighbours turn on their lights and other appliances at night you will see your lights dim, .

Ok enough off the lessons- their was good advice given earlier - get a Safe- T -Cut Leakage breaker, even if their is no earth in the building the S-T-C will still operate as it looks for an imbalance between the Active (L) and Neutral (N) it does not reference Earth at all. But if current were to go to Earth hence an imbalance between L and N than the S-T-C will operate.

S-T-C's have some idiosyncrasies, the Refrigerator will be a problem, as we as appliances with a lot of water, such as Washing machines. It's a good idea to get the washing machine off the S-T-C obviously if you go away for the weekend you don't want your food gone bad as a result of a trip. But things like Washing Machines and dishwashers it is wise to keep them protected, as safety for the operator.

Ok enough of my ramblings.

Good luck.

[happysoul]

Hello,

We moved in our house in September. I did the electricity myself as i thought there were no requirements and it wouldn't be worse than others. The day came to go ask for the elec. counter (no house on land before). The boss of pea came a few wreks later to inspect. Of course, nothing was in the norm. So electricians came to upgrade what i had done : put all the cables in the ceiling in pvc yellow pipes, distribution in 3mm cables and grounded the house with a 2m copper pole (12mm diam) wired to the safty box with a 10mm copper wire. Regarding the last, they said it was the requirements and it couldn't be done in another way.

So to the op, yes there are rules but no idea where you can get them

Ps : while doing the elec myself, Neighbors came and said oh, you do it yourself, good luck with the pea boss, he's not easy... They were right and it might change from ampoe to ampoe...

Cheers

[RonCM]

Hi Guy's

Correction to my last entry - brain thinking to fast for my typing washing machine and dishwasher should remain on S-T-C to protect the operator, but the refrigerator shouldn't be on the S-T-C, for instance if you go away on holidays or just the weekend and if the S-T-C trips, then the food inside will perish.

Sorry for my earlier entry

[rotary]

That's clear (and scary) now Peter.

Is it your own place or a rental? (do you fix it properly or leave alone as it's working)

Do you have any form of earth leakage protection (Safe-T-Cut)?

It's my/our own place, we took it over in April 2013 from a village developer. I'm not going to fix it myself nor leave it alone as it is but committing the developer to scrutinize the entire electric installation and to remidiate problems, requiring an installation according to state-of-art. I'm determined to file a lawsuit if necessary, therefore it's necessary to know and to refer to relevant statutory basis.When this country is producing and exporting electric devices and appliances then they must certainly follow international safety standards and have their products produced accordingly.

No Crossy, there is no Safety-Cut installed.

Edit: Sorry, I had to revise the Date "April 07" to now "April 2013"

Good luck on that law suit..........you will need it.

[ozyjon]

Erectricity, be careful coming out of the pool and grabbing the metal hand rail, you could die.

[Mudcrab]

Hi PeterAlex,

All your assumptions are correct, but as just about everyone has commented the standard wiring rules as we have come to learn in our own countries is not the case here, for example I am from Australia and in my past life I was an electrician, and International standards were met.. But Australia has what is called an MEN System which is Main Earth Neutral Bond, we take the earth wire from a stake (In Thailand this stake must be 1.8mtrs long), the Earth wire must be a minima of 4mm2, and connected to the earth bar in the Switchboard, but in Australia's case we than bond the earth bar to the Neutral bar with wire same size as the mains coming into the building, possibly 10mm2 or 16 mm2, and in my personal experience they use aluminium as the wiring for mains, This isn't a good practice as it adds to voltage drop, so whenever everyone of your neighbours turn on their lights and other appliances at night you will see your lights dim, .

Ok enough off the lessons- their was good advice given earlier - get a Safe- T -Cut Leakage breaker, even if their is no earth in the building the S-T-C will still operate as it looks for an imbalance between the Active (L) and Neutral (N) it does not reference Earth at all. But if current were to go to Earth hence an imbalance between L and N than the S-T-C will operate.

S-T-C's have some idiosyncrasies, the Refrigerator will be a problem, as we as appliances with a lot of water, such as Washing machines. It's a good idea to get the washing machine off the S-T-C obviously if you go away for the weekend you don't want your food gone bad as a result of a trip. But things like Washing Machines and dishwashers it is wise to keep them protected, as safety for the operator.

Ok enough of my ramblings.

Good luck.

Not sure when you were a sparky in Oz but things have changed somewhat.

MEN = Multiple Earthed Neutral system not Main Earth Neutral Bond.

Can't remember ever seeing aluminium cables in a domestic install, and I've rewired some pretty old houses.

I was interested to see the pinned topics in the electrical forum but unfortunately could not add anything to them.

There is some good info from Forky there but there is some that could also be added.

Many people discuss circuit breakers, MCB's, RCD's etc in terms of their current rating e.g 10 amps, 20 amps, 32 amps etc. This is correct but only tells half the story. All of these devices have a secondary rating known as the kA rating. This is the amount of current that the device can withstand before destroying itself and possibly anything nearby such as the power board or indeed starting a fire.

When a circuit breaker trips and shuts off the power we assume that the current has exceeded the 10, 20 or whatever amps the circuit breaker is rated at. It sure has and in all likelihood could have been in the thousands of amps for a very short (milliseconds) period of time.

Maybe you can now see where the kA rating becomes important. The device has to physically (as opposed to electrically) withstand the tremendous amount of energy generated without blowing up.

There is now a requirement in Australia and New Zealand to calculate the circuit impedance to then calculate the prospective fault current to ensure the kA rating of the circuit breaker is sufficient to withstand the very high fault current.

Sorry to have waffled on into the technical area but it is important for people to be aware. I'd be concerned if a domestic circuit breaker had a rating of less than 6kA as a generalisation.(Agreed I shouldn't generalise)

One other point with the RCD's, safety switch, ground fault interrupts or whatever device or term you use is to test the dam_n things regularly to ensure they are working. Every 3-6 months or so is a good idea. That's what the test button is for!!

I have heard of a case where all three devices connected in series failed and allowed an electrocution.

Edited January 3, 2014 by Mudcrab

[RonCM]

Hi PeterAlex,

All your assumptions are correct, but as just about everyone has commented the standard wiring rules as we have come to learn in our own countries is not the case here, for example I am from Australia and in my past life I was an electrician, and International standards were met.. But Australia has what is called an MEN System which is Main Earth Neutral Bond, we take the earth wire from a stake (In Thailand this stake must be 1.8mtrs long), the Earth wire must be a minima of 4mm2, and connected to the earth bar in the Switchboard, but in Australia's case we than bond the earth bar to the Neutral bar with wire same size as the mains coming into the building, possibly 10mm2 or 16 mm2, and in my personal experience they use aluminium as the wiring for mains, This isn't a good practice as it adds to voltage drop, so whenever everyone of your neighbours turn on their lights and other appliances at night you will see your lights dim, .

Ok enough off the lessons- their was good advice given earlier - get a Safe- T -Cut Leakage breaker, even if their is no earth in the building the S-T-C will still operate as it looks for an imbalance between the Active (L) and Neutral (N) it does not reference Earth at all. But if current were to go to Earth hence an imbalance between L and N than the S-T-C will operate.

S-T-C's have some idiosyncrasies, the Refrigerator will be a problem, as we as appliances with a lot of water, such as Washing machines. It's a good idea to get the washing machine off the S-T-C obviously if you go away for the weekend you don't want your food gone bad as a result of a trip. But things like Washing Machines and dishwashers it is wise to keep them protected, as safety for the operator.

Ok enough of my ramblings.

Good luck.

Not sure when you were a sparky in Oz but things have changed somewhat.

MEN = Multiple Earthed Neutral system not Main Earth Neutral Bond.

Can't remember ever seeing aluminium cables in a domestic install, and I've rewired some pretty old houses.

I was interested to see the pinned topics in the electrical forum but unfortunately could not add anything to them.

There is some good info from Forky there but there is some that could also be added.

Many people discuss circuit breakers, MCB's, RCD's etc in terms of their current rating e.g 10 amps, 20 amps, 32 amps etc. This is correct but only tells half the story. All of these devices have a secondary rating known as the kA rating. This is the amount of current that the device can withstand before destroying itself and possibly anything nearby such as the power board or indeed starting a fire.

When a circuit breaker trips and shuts off the power we assume that the current has exceeded the 10, 20 or whatever amps the circuit breaker is rated at. It sure has and in all likelihood could have been in the thousands of amps for a very short (milliseconds) period of time.

Maybe you can now see where the kA rating becomes important. The device has to physically (as opposed to electrically) withstand the tremendous amount of energy generated without blowing up.

There is now a requirement in Australia and New Zealand to calculate the circuit impedance to then calculate the prospective fault current to ensure the kA rating of the circuit breaker is sufficient to withstand the very high fault current.

Sorry to have waffled on into the technical area but it is important for people to be aware. I'd be concerned if a domestic circuit breaker had a rating of less than 6kA as a generalisation.(Agreed I shouldn't generalise)

One other point with the RCD's, safety switch, ground fault interrupts or whatever device or term you use is to test the dam_n things regularly to ensure they are working. Every 3-6 months or so is a good idea. That's what the test button is for!!

I have heard of a case where all three devices connected in series failed and allowed an electrocution.

Thanks for the clarification on M-E-N, memory failing me, but my reference to aluminium conductors as mains only refers to places I have seen here in Thailand, it is common practice as backed up by a couple of electricians I have come to know.

[Mudcrab]

Hi PeterAlex,

All your assumptions are correct, but as just about everyone has commented the standard wiring rules as we have come to learn in our own countries is not the case here, for example I am from Australia and in my past life I was an electrician, and International standards were met.. But Australia has what is called an MEN System which is Main Earth Neutral Bond, we take the earth wire from a stake (In Thailand this stake must be 1.8mtrs long), the Earth wire must be a minima of 4mm2, and connected to the earth bar in the Switchboard, but in Australia's case we than bond the earth bar to the Neutral bar with wire same size as the mains coming into the building, possibly 10mm2 or 16 mm2, and in my personal experience they use aluminium as the wiring for mains, This isn't a good practice as it adds to voltage drop, so whenever everyone of your neighbours turn on their lights and other appliances at night you will see your lights dim, .

Ok enough off the lessons- their was good advice given earlier - get a Safe- T -Cut Leakage breaker, even if their is no earth in the building the S-T-C will still operate as it looks for an imbalance between the Active (L) and Neutral (N) it does not reference Earth at all. But if current were to go to Earth hence an imbalance between L and N than the S-T-C will operate.

S-T-C's have some idiosyncrasies, the Refrigerator will be a problem, as we as appliances with a lot of water, such as Washing machines. It's a good idea to get the washing machine off the S-T-C obviously if you go away for the weekend you don't want your food gone bad as a result of a trip. But things like Washing Machines and dishwashers it is wise to keep them protected, as safety for the operator.

Ok enough of my ramblings.

Good luck.

Not sure when you were a sparky in Oz but things have changed somewhat.

MEN = Multiple Earthed Neutral system not Main Earth Neutral Bond.

Can't remember ever seeing aluminium cables in a domestic install, and I've rewired some pretty old houses.

I was interested to see the pinned topics in the electrical forum but unfortunately could not add anything to them.

There is some good info from Forky there but there is some that could also be added.

Many people discuss circuit breakers, MCB's, RCD's etc in terms of their current rating e.g 10 amps, 20 amps, 32 amps etc. This is correct but only tells half the story. All of these devices have a secondary rating known as the kA rating. This is the amount of current that the device can withstand before destroying itself and possibly anything nearby such as the power board or indeed starting a fire.

When a circuit breaker trips and shuts off the power we assume that the current has exceeded the 10, 20 or whatever amps the circuit breaker is rated at. It sure has and in all likelihood could have been in the thousands of amps for a very short (milliseconds) period of time.

Maybe you can now see where the kA rating becomes important. The device has to physically (as opposed to electrically) withstand the tremendous amount of energy generated without blowing up.

There is now a requirement in Australia and New Zealand to calculate the circuit impedance to then calculate the prospective fault current to ensure the kA rating of the circuit breaker is sufficient to withstand the very high fault current.

Sorry to have waffled on into the technical area but it is important for people to be aware. I'd be concerned if a domestic circuit breaker had a rating of less than 6kA as a generalisation.(Agreed I shouldn't generalise)

One other point with the RCD's, safety switch, ground fault interrupts or whatever device or term you use is to test the dam_n things regularly to ensure they are working. Every 3-6 months or so is a good idea. That's what the test button is for!!

I have heard of a case where all three devices connected in series failed and allowed an electrocution.

Thanks for the clarification on M-E-N, memory failing me, but my reference to aluminium conductors as mains only refers to places I have seen here in Thailand, it is common practice as backed up by a couple of electricians I have come to know.

No worries

mostly the aluminium conductors these days are used for HV distribution. Aluminium conductor wrapped around a steel core to keep the weight down compared to copper. But you are spot on regarding the voltage drop.

[Mudcrab]

Hi PeterAlex,

All your assumptions are correct, but as just about everyone has commented the standard wiring rules as we have come to learn in our own countries is not the case here, for example I am from Australia and in my past life I was an electrician, and International standards were met.. But Australia has what is called an MEN System which is Main Earth Neutral Bond, we take the earth wire from a stake (In Thailand this stake must be 1.8mtrs long), the Earth wire must be a minima of 4mm2, and connected to the earth bar in the Switchboard, but in Australia's case we than bond the earth bar to the Neutral bar with wire same size as the mains coming into the building, possibly 10mm2 or 16 mm2, and in my personal experience they use aluminium as the wiring for mains, This isn't a good practice as it adds to voltage drop, so whenever everyone of your neighbours turn on their lights and other appliances at night you will see your lights dim, .

Ok enough off the lessons- their was good advice given earlier - get a Safe- T -Cut Leakage breaker, even if their is no earth in the building the S-T-C will still operate as it looks for an imbalance between the Active (L) and Neutral (N) it does not reference Earth at all. But if current were to go to Earth hence an imbalance between L and N than the S-T-C will operate.

S-T-C's have some idiosyncrasies, the Refrigerator will be a problem, as we as appliances with a lot of water, such as Washing machines. It's a good idea to get the washing machine off the S-T-C obviously if you go away for the weekend you don't want your food gone bad as a result of a trip. But things like Washing Machines and dishwashers it is wise to keep them protected, as safety for the operator.

Ok enough of my ramblings.

Good luck.

Not sure when you were a sparky in Oz but things have changed somewhat.

MEN = Multiple Earthed Neutral system not Main Earth Neutral Bond.

Can't remember ever seeing aluminium cables in a domestic install, and I've rewired some pretty old houses.

I was interested to see the pinned topics in the electrical forum but unfortunately could not add anything to them.

There is some good info from Forky there but there is some that could also be added.

Many people discuss circuit breakers, MCB's, RCD's etc in terms of their current rating e.g 10 amps, 20 amps, 32 amps etc. This is correct but only tells half the story. All of these devices have a secondary rating known as the kA rating. This is the amount of current that the device can withstand before destroying itself and possibly anything nearby such as the power board or indeed starting a fire.

When a circuit breaker trips and shuts off the power we assume that the current has exceeded the 10, 20 or whatever amps the circuit breaker is rated at. It sure has and in all likelihood could have been in the thousands of amps for a very short (milliseconds) period of time.

Maybe you can now see where the kA rating becomes important. The device has to physically (as opposed to electrically) withstand the tremendous amount of energy generated without blowing up.

There is now a requirement in Australia and New Zealand to calculate the circuit impedance to then calculate the prospective fault current to ensure the kA rating of the circuit breaker is sufficient to withstand the very high fault current.

Sorry to have waffled on into the technical area but it is important for people to be aware. I'd be concerned if a domestic circuit breaker had a rating of less than 6kA as a generalisation.(Agreed I shouldn't generalise)

One other point with the RCD's, safety switch, ground fault interrupts or whatever device or term you use is to test the dam_n things regularly to ensure they are working. Every 3-6 months or so is a good idea. That's what the test button is for!!

I have heard of a case where all three devices connected in series failed and allowed an electrocution.

Thanks for the clarification on M-E-N, memory failing me, but my reference to aluminium conductors as mains only refers to places I have seen here in Thailand, it is common practice as backed up by a couple of electricians I have come to know.

No worries

mostly the aluminium conductors these days are used for HV distribution. Aluminium conductor wrapped around a steel core to keep the weight down compared to copper. But you are spot on regarding the voltage drop.

A bit more waffle. Be careful of the brand of circuit breaker you buy. I have seen warnings about some of the Chinese knock off brands that are simply a switch - no overcurrent protection whatsoever. Choose what you will but Terasaki is good.

[peteralex]

Peter, what did you use as your ground reference to check the potential on the green/yellow and other wires?

What equipment did you make these measurements with?

Hi Crossy, I appreciate your response.

As common practise I originally connected the white and black coloured conductors coming out from the wall to the water heater's terminals N and L, the yellow/green one to the dedicated Earth terminal. To my surprise the heater did NOT function. Since I have another water heater installed at a second shower room I checked the connection there and it revealed that the yellow/green conductor was connected to either the N or L terminal, I don't remember accurately, however, not to the dedicated earth terminal of the device. I couldn't believe that and I returned to the water heater to be connected, using a multimeter and taking measures between the yellow/green and the white resp. black conductors, both cases indicated a 220V potential, while taking measures between the WHITE and BLACK conductor indicated a Zero potential. Thus the ground reference was as well the white as the black conductor.

Upon this experience I contacted an external Thai electrician to brighten me up about the strange situation who confirmed the yellow/green conductor as the "live" conductor and he continued rendering the water heater operational by connecting the yellow/green conductor to the L terminal and the white resp. black wire to Earth resp. N terminal. (I described his comment about this previously).

The multimeter used is a commercial type with an int. resistance of 9kOhm/V in the AC range.

1. Is there a ground connected to the breaker panel? There should be a line, rather large coming out of that and leading outside to rod that it is clamped to.

2. If there is a ground connected, you need to inspect the connections inside the breaker panel to see if in fact the line is connected to the correct ground connection in the panel.

3. If the ground is connected in the panel, yet you have 220 on it in the bathroom, somewhere between the panel and the bathroom, an electrician has cross connected the Line and Ground wire, poosibly in a juntion box or from an outlet box. You need to find this cross connection

4. If you do not have a ground connected to the service breaker panel in the house, DO NOT add on until you find the cross connect between the Line and Ground

Hallo to all OPs,

many thanks for your valuable advice and contributions.

I checked the CB box and a Ground bar is found which is supposedly connected to the said grounding rod by a heavy green conductor of outer dia. approx. 8mm; onto this ground bar are 5 black conductors (10mm2) hooked up. It can be assumed that using the standardized yellow/green instead black conductors represent the grounding network in further distributions within the home.

Within the CB box 6 white conductors (16mm2) are connected to the N bar, yellow conductors (16mm2) after CBs of the L bus. These main conductors are leading into the attic for further distribution.

It is stated that NO yellow/green conductor is found in the CB box, it can hence be suspected that in a grossly negligent manner yellow/green conductors for the 2 water heaters are joint in the attic with yellow conductors coming from the CB box and, thus becoming to 220V conductors.

I'll verify my suspicion asap and, in any case have the erroneous yellow/green conductors replaced. I am absolutely aware that one should not expect too much about technical perfection in LOS but I hope that the rest of installation complies at least to some degree with the state of art.

I'll keep you updated.

[thomasteve]

The majority of shower heaters sold (reputable brands) now seem to have their own buit in earth leakage (similar to a saf-t-cut) protection device. Presumably these will still work correctly and provide adequate protection regardless of whether there is a correct earth wire connected to a ground rod or just a live and neutral supply connection ? The wire colours being mixed up will also be of no consequence if they are designed to operate by detection of a small imbalance (often 20mA) between the line and return (neutral) conductors ?

If you cannot get the house wiring correctly done,complete with an earthing rod, then at least install an ELCB (commonly sold as a saf-t-cut in Thailand) after the main on/off isolator switch before the rest of the circuits and associated mix-ups.

[Forkinhades]

Hi PeterAlex,

All your assumptions are correct, but as just about everyone has commented the standard wiring rules as we have come to learn in our own countries is not the case here, for example I am from Australia and in my past life I was an electrician, and International standards were met.. But Australia has what is called an MEN System which is Main Earth Neutral Bond, we take the earth wire from a stake (In Thailand this stake must be 1.8mtrs long), the Earth wire must be a minima of 4mm2, and connected to the earth bar in the Switchboard, but in Australia's case we than bond the earth bar to the Neutral bar with wire same size as the mains coming into the building, possibly 10mm2 or 16 mm2, and in my personal experience they use aluminium as the wiring for mains, This isn't a good practice as it adds to voltage drop, so whenever everyone of your neighbours turn on their lights and other appliances at night you will see your lights dim, .

Ok enough off the lessons- their was good advice given earlier - get a Safe- T -Cut Leakage breaker, even if their is no earth in the building the S-T-C will still operate as it looks for an imbalance between the Active (L) and Neutral (N) it does not reference Earth at all. But if current were to go to Earth hence an imbalance between L and N than the S-T-C will operate.

S-T-C's have some idiosyncrasies, the Refrigerator will be a problem, as we as appliances with a lot of water, such as Washing machines. It's a good idea to get the washing machine off the S-T-C obviously if you go away for the weekend you don't want your food gone bad as a result of a trip. But things like Washing Machines and dishwashers it is wise to keep them protected, as safety for the operator.

Ok enough of my ramblings.

Good luck.

There is no reason that a non faulty washing machine, dishwasher, or fridge is more likely to open an rcd

[Forkinhades]

The majority of shower heaters sold (reputable brands) now seem to have their own buit in earth leakage (similar to a saf-t-cut) protection device. Presumably these will still work correctly and provide adequate protection regardless of whether there is a correct earth wire connected to a ground rod or just a live and neutral supply connection ? The wire colours being mixed up will also be of no consequence if they are designed to operate by detection of a small imbalance (often 20mA) between the line and return (neutral) conductors ?

If you cannot get the house wiring correctly done,complete with an earthing rod, then at least install an ELCB (commonly sold as a saf-t-cut in Thailand) after the main on/off isolator switch before the rest of the circuits and associated mix-ups.

• Best not to have any presumptions with electricity
• With no earth the fault path will go through your body, do you really want that when having a shower?

[Forkinhades]

Peter, what did you use as your ground reference to check the potential on the green/yellow and other wires?

What equipment did you make these measurements with?

Hi Crossy, I appreciate your response.

As common practise I originally connected the white and black coloured conductors coming out from the wall to the water heater's terminals N and L, the yellow/green one to the dedicated Earth terminal. To my surprise the heater did NOT function. Since I have another water heater installed at a second shower room I checked the connection there and it revealed that the yellow/green conductor was connected to either the N or L terminal, I don't remember accurately, however, not to the dedicated earth terminal of the device. I couldn't believe that and I returned to the water heater to be connected, using a multimeter and taking measures between the yellow/green and the white resp. black conductors, both cases indicated a 220V potential, while taking measures between the WHITE and BLACK conductor indicated a Zero potential. Thus the ground reference was as well the white as the black conductor.

Upon this experience I contacted an external Thai electrician to brighten me up about the strange situation who confirmed the yellow/green conductor as the "live" conductor and he continued rendering the water heater operational by connecting the yellow/green conductor to the L terminal and the white resp. black wire to Earth resp. N terminal. (I described his comment about this previously).

The multimeter used is a commercial type with an int. resistance of 9kOhm/V in the AC range.

1. Is there a ground connected to the breaker panel? There should be a line, rather large coming out of that and leading outside to rod that it is clamped to.

2. If there is a ground connected, you need to inspect the connections inside the breaker panel to see if in fact the line is connected to the correct ground connection in the panel.

3. If the ground is connected in the panel, yet you have 220 on it in the bathroom, somewhere between the panel and the bathroom, an electrician has cross connected the Line and Ground wire, poosibly in a juntion box or from an outlet box. You need to find this cross connection

4. If you do not have a ground connected to the service breaker panel in the house, DO NOT add on until you find the cross connect between the Line and Ground

Hallo to all OPs,

many thanks for your valuable advice and contributions.

I checked the CB box and a Ground bar is found which is supposedly connected to the said grounding rod by a heavy green conductor of outer dia. approx. 8mm; onto this ground bar are 5 black conductors (10mm2) hooked up. It can be assumed that using the standardized yellow/green instead black conductors represent the grounding network in further distributions within the home.

Within the CB box 6 white conductors (16mm2) are connected to the N bar, yellow conductors (16mm2) after CBs of the L bus. These main conductors are leading into the attic for further distribution.

It is stated that NO yellow/green conductor is found in the CB box, it can hence be suspected that in a grossly negligent manner yellow/green conductors for the 2 water heaters are joint in the attic with yellow conductors coming from the CB box and, thus becoming to 220V conductors.

I'll verify my suspicion asap and, in any case have the erroneous yellow/green conductors replaced. I am absolutely aware that one should not expect too much about technical perfection in LOS but I hope that the rest of installation complies at least to some degree with the state of art.

I'll keep you updated.

Can you post a picture?