Electrical Wiring In Thailand

[JAS21]

Guys

I have just seen your comments re earthing etc..could you please comment on my set up

I have a new house in Thailand. Basically the live and neutral socket connections are reverse ie live is neutral and neutral is live, as compared to UK.

The incoming cables feed in via an 80amp Mitsubishi Supply Breaker.

This breaker has two outgoing sets of cables L&N) one to the Dist Bd supplying the breakers which supply the Air Conditioning Units.

The other to a SAFE-T-CUT breaker 63amps with setting selections of 5mA, 15mA, 25mA and direct. The tripping time is between 20mSec and 30mSec (not selectable) so is compatable with UK standard of 35mA for 30mSec I think. This feeds the dist bd. which supplies all the house power and lighting circuits. Each circuit has a circuit breaker. So this far is of a simular standard to the UK I think. CB ratings are 10/16/20/32 depending on what they feed.

The wall sockets (power sockets) are rotated 90Deg clockwise compared to the UK. The pin which would be the neutral in the UK (ie now at the top) is actually the Live and the pin which would be the Live in the UK (now at the bottom) is actually the neutral.

Therefore if I plug in a UK appliance (via an extension lead, you can now get these that accept a UK plug) then the live comes in via the neutral pin on the plug and vice versed.

The house is earthed via an earthing rod ..under the floor somewhere I'm told Having an earth is now modern practice in Thailand although many appliances come as two pin. So it is belt and bracers 'I hope' (earth leakage plus circuit breakers).The house is on a guarded complex' and was built by a reputable company. We bought it built so I supplied nothing.

More strange, I purchased, from the same shop in a Mall 'big store' a Electrolux washing m/c and an Electrolux fridge/Freezer. The indicated convention on the plugs was UK convention on the Fridge/Freezer and Thai Convention on the washing m/c ie live and neutral different on each.

Thai plugs do not seem to be fused…haven’t looked in back of appliance to se if there are fuses there.

I realize that I am running computer power supply/vacuum cleaner etc unfused. I guess when we stay here permanently that I need to reverse the wiring on UK plugs..and add a warning to the plug top.

Does my set up sound ok.?

Also could someone give me info on what I should ask the company about the house earth, resistance values etc

I note that the ‘worker’ who ran the cables..ran them all short and so had to put a join in them before the CBs..what a prat!

As the house is still warranted anyone know a ‘qualified’ electrician in Pak Kret area who would give it the once ovr?

.Thanks

[Crossy]

Hi John.

Welcome to our discussions on the 'interesting' wiring in Thailand

OK.

ASSUMING that our Thai friends are using the US way of wiring their 3-pole sockets you are correct. In the US system if the ground pin is at the top then Live is on the left Neutral is on the right (opposite to the UK).

Thai (and US) plugs are unfused, relying on the MCCBs in the dizzy board for overcurrent protection. The plugs are rated at 15A and I expect each spur (they are spurs not rings al-la UK) has a 16 or 20A breaker (as opposed to the 30A you find on a UK ring main).

Most modern appliances are polarity insensitive. The European standard round (Schuko) plug is unpolarised (except in Belgium where a polarising ground pin is fitted) fitting in the socket either way round. I suspect your washer and fridge came with this type of plug (you did get a proper adaptor so that the appliance is grounded didn't you ).

THAT SAID, it would be smart to make sure that the live wire of the appliance actually goes to the live pole of the plug. Some (Chinese) appliances have single pole switches that only switch the live side so reversing the supply could lead to the unit being 'off' but the wiring still live.

Your computer PSU will have an internal fuse. The washer will probably have a thermal trip (look for a red button on the back).

If you are using UK type extension leads for your UK appliances, rather than changing the polarity in the plug tops why not change the extension / adapter so that the UK outlets are correct. The best way of course, would be to replace your UK plugs with local versions, correctly wired to suit the local sockets.

The rest of the installation sounds fine (except the joins in the wiring).

[lopburi3]

As said most of the outlets here are Japanese versions of the normal US three pin and do not mate up well with the European plugs that have now become a standard on locally sold equipment. These plugs are wired with a ground but no prong is provided so can be inserted either way and the only adapter I have found is a cover piece that takes the side bar ground to an external prong (and is so large you can not use two in a two outlet box). As much as I hate cutting off those nice looking plugs I find myself doing that more often, as I run out of outlets; and replacing with US type three pin plugs. As for the two wire/two pin European plugs as sold on power supplies/speakers/small appliances and such find them next to useless as if completely inserted the insulated part of the prong is making contact to most outlet box pins so you have to remove them a bit to obtain contact. A very good idea to replace them also.

[Crossy]

Just a thought about those joints.

How did the man join the wire?? Any joint is a source of resistance and consequently heating, particularly if it's just twisted. Could be a fire hazard. I'd be seriously tempted to moan long and hard if you're still under warranty, see if they will replace (no chance) or re-route the cable slightly so that a joint is not required.

I agree with Lop, those small 2 pin plugs are carp, particularly when plugged into one of the 'universal' sockets. I've removed all mine and replaced them with the regular flat pin jobbies (15 Baht each).

Edited February 15, 2006 by Crossy

[chownah]

"...........

Most modern appliances are polarity insensitive. The European standard round (Schuko) plug is unpolarised (except in Belgium where a polarising ground pin is fitted) fitting in the socket either way round. I suspect your washer and fridge came with this type of plug (you did get a proper adaptor so that the appliance is grounded didn't you ).

.............."

I agree that it matters not what polarity most modern appliances are supplied....but....modern US appliances that have the flat two prong plugs (no third prong ground wire) DO have polarity in that one of the flat prongs is slightly wider than the other and the outlets have one opening slightly larger than the other so that the plug can only be inserted one way. I believe that all appliances currently sold in the US are this way so in effect they all have polarity (even though for most of them it doesn't really matter and is a minor safety issue involving the inaccessable wiring inside the appliance).

[lopburi3]

doesn't really matter and is a minor safety issue involving the inaccessable wiring inside the appliance).

Tell that to someone who has turned the switch off on a lamp and come into contact with the bulb socket which is hot because the switch cut neutral because the plug was not polarized. Yeh, I know he would be dumb not to unplug the lamp but I suspect you can imagine a few friends who might have this happen. I'm sure I have done it at some point. Multiply that by the population and polarization starts to make sense.

[solo siam]

I agree that it matters not what polarity most modern appliances are supplied....but....modern US appliances that have the flat two prong plugs (no third prong ground wire) DO have polarity in that one of the flat prongs is slightly wider than the other and the outlets have one opening slightly larger than the other so that the plug can only be inserted one way. I believe that all appliances currently sold in the US are this way so in effect they all have polarity (even though for most of them it doesn't really matter and is a minor safety issue involving the inaccessable wiring inside the appliance).

I think that Thailand is moving to this type of system now as well, I've noticed quite a few electrical goods now have one wider prong on the plug - I have also seen wall-sockets specifically built for these types of plugs as well.

One of my employees seemed to think that its law now that new appliances etc.... be wired like this.

[JAS21]

I agree that it matters not what polarity most modern appliances are supplied....but....modern US appliances that have the flat two prong plugs (no third prong ground wire) DO have polarity in that one of the flat prongs is slightly wider than the other and the outlets have one opening slightly larger than the other so that the plug can only be inserted one way. I believe that all appliances currently sold in the US are this way so in effect they all have polarity (even though for most of them it doesn't really matter and is a minor safety issue involving the inaccessable wiring inside the appliance).

I think that Thailand is moving to this type of system now as well, I've noticed quite a few electrical goods now have one wider prong on the plug - I have also seen wall-sockets specifically built for these types of plugs as well.

One of my employees seemed to think that its law now that new appliances etc.... be wired like this.

[JAS21]

Thanks guys

After e-mailing the 'big chief' I am getting some quick warrenty work done. Shouldnt really go over the local peoples head but progress was slow. to stop, local 'engineer' just sat on his arse all day.

So today someone came and looked at all the defects.

with regard to electrical..I asked him how do I know that the earth is any good? he said he would check it tomorrow. Please how should he do this?

Can the impedence only be checked by passing a current to earth? I cant remember from my college days?

With regard to appliances the washer and fridge are three pin..just the hoover is two pin

Appreciate a quice reply on checking earth.

I'm told that the rod is buried beneath the floor tiles. i can see the earth cable at the dist board, joined with the circuit earths but then it just disappears somewhere.

Thanks

[chownah]

Thanks guys

After e-mailing the 'big chief' I am getting some quick warrenty work done. Shouldnt really go over the local peoples head but progress was slow. to stop, local 'engineer' just sat on his arse all day.

So today someone came and looked at all the defects.

with regard to electrical..I asked him how do I know that the earth is any good? he said he would check it tomorrow. Please how should he do this?

Can the impedence only be checked by passing a current to earth? I cant remember from my college days?

With regard to appliances the washer and fridge are three pin..just the hoover is two pin

Appreciate a quice reply on checking earth.

I'm told that the rod is buried beneath the floor tiles. i can see the earth cable at the dist board, joined with the circuit earths but then it just disappears somewhere.

Thanks

You really should have the rod accessable so that when the wires corrode you can refurbish the connection. I would install another full service rod and cable which is accessable for inspection and repair.....at least that is what I would do.

doesn't really matter and is a minor safety issue involving the inaccessable wiring inside the appliance).

Tell that to someone who has turned the switch off on a lamp and come into contact with the bulb socket which is hot because the switch cut neutral because the plug was not polarized. Yeh, I know he would be dumb not to unplug the lamp but I suspect you can imagine a few friends who might have this happen. I'm sure I have done it at some point. Multiply that by the population and polarization starts to make sense.

Three part reply.

1. I'd be glad to tell them, just post their email address and I'll inform them!

2. I said "most" modern US appliances...not "all".

3. I think you will find that "most" modern lamps in the US are constructed so that you can not touch the socket unless the light bulb is removed. Thus the situation you suggest is not possible with "most" modern US lamps.

[JAS21]

Thanks guys

After e-mailing the 'big chief' I am getting some quick warrenty work done. Shouldnt really go over the local peoples head but progress was slow. to stop, local 'engineer' just sat on his arse all day.

So today someone came and looked at all the defects.

with regard to electrical..I asked him how do I know that the earth is any good? he said he would check it tomorrow. Please how should he do this?

Can the impedence only be checked by passing a current to earth? I cant remember from my college days?

With regard to appliances the washer and fridge are three pin..just the hoover is two pin

Appreciate a quice reply on checking earth.

I'm told that the rod is buried beneath the floor tiles. i can see the earth cable at the dist board, joined with the circuit earths but then it just disappears somewhere.

Thanks

You really should have the rod accessable so that when the wires corrode you can refurbish the connection. I would install another full service rod and cable which is accessable for inspection and repair.....at least that is what I would do.

doesn't really matter and is a minor safety issue involving the inaccessable wiring inside the appliance).

Tell that to someone who has turned the switch off on a lamp and come into contact with the bulb socket which is hot because the switch cut neutral because the plug was not polarized. Yeh, I know he would be dumb not to unplug the lamp but I suspect you can imagine a few friends who might have this happen. I'm sure I have done it at some point. Multiply that by the population and polarization starts to make sense.

Three part reply.

1. I'd be glad to tell them, just post their email address and I'll inform them!

2. I said "most" modern US appliances...not "all".

3. I think you will find that "most" modern lamps in the US are constructed so that you can not touch the socket unless the light bulb is removed. Thus the situation you suggest is not possible with "most" modern US lamps.

Thanks...not easy to e-mail the company

Would you please send e-mail to me

You can use [email protected]

So how to test earth

So how to test RCD I guess you short to earth via a high resistance..but must need some tioming mechanism. Guess there must be equipment for this..not readily available here I guess.

Good idea to put in a second earth rod. I have done that previously in an old house I owned. Realised I needed it when I sawed through the skirting and a cable behind it. Lost 6 teeth from my saw but supply was still live!

All I did was drill a hole about 1m+, deep hammered the rod in and attached an earth cable. When i rented the house out later an electrician checked it and said ok..cant remember how he did it I also put a new box in with all ccts on RCD.

The guys at work told me how to do it..I worked in Powerstation all my life..more experience on HV than house wiring though.

thanks guys

[dougkos]

Thanks guys

After e-mailing the 'big chief' I am getting some quick warrenty work done. Shouldnt really go over the local peoples head but progress was slow. to stop, local 'engineer' just sat on his arse all day.

So today someone came and looked at all the defects.

with regard to electrical..I asked him how do I know that the earth is any good? he said he would check it tomorrow. Please how should he do this?

Can the impedence only be checked by passing a current to earth? I cant remember from my college days?

With regard to appliances the washer and fridge are three pin..just the hoover is two pin

Appreciate a quice reply on checking earth.

I'm told that the rod is buried beneath the floor tiles. i can see the earth cable at the dist board, joined with the circuit earths but then it just disappears somewhere.

Thanks

You really should have the rod accessable so that when the wires corrode you can refurbish the connection. I would install another full service rod and cable which is accessable for inspection and repair.....at least that is what I would do.

doesn't really matter and is a minor safety issue involving the inaccessable wiring inside the appliance).

Tell that to someone who has turned the switch off on a lamp and come into contact with the bulb socket which is hot because the switch cut neutral because the plug was not polarized. Yeh, I know he would be dumb not to unplug the lamp but I suspect you can imagine a few friends who might have this happen. I'm sure I have done it at some point. Multiply that by the population and polarization starts to make sense.

Three part reply.

1. I'd be glad to tell them, just post their email address and I'll inform them!

2. I said "most" modern US appliances...not "all".

3. I think you will find that "most" modern lamps in the US are constructed so that you can not touch the socket unless the light bulb is removed. Thus the situation you suggest is not possible with "most" modern US lamps.

Thanks...not easy to e-mail the company

Would you please send e-mail to me

You can use [email protected]

So how to test earth

So how to test RCD I guess you short to earth via a high resistance..but must need some tioming mechanism. Guess there must be equipment for this..not readily available here I guess.

Good idea to put in a second earth rod. I have done that previously in an old house I owned. Realised I needed it when I sawed through the skirting and a cable behind it. Lost 6 teeth from my saw but supply was still live!

All I did was drill a hole about 1m+, deep hammered the rod in and attached an earth cable. When i rented the house out later an electrician checked it and said ok..cant remember how he did it I also put a new box in with all ccts on RCD.

The guys at work told me how to do it..I worked in Powerstation all my life..more experience on HV than house wiring though.

thanks guys

hi john45

regarding testing your earth spike you will have to have a earth resistance tester there are different models on the market now, there was the 3-4 wire tester plus earth spikes to test

http://www.hoytmeter.com/earthreslkup/earthreslkup.html

or you can use the clamp tester http://www.multimeterwarehouse.com/M9810.htm

examples as given they will also tell you how to do it

regarding testing your rcd you will have to use a proper tester http://www.pat-services.co.uk/default.asp?prodidsingle=148

dont know how available they are in thailand but should be able to lol your electrical contractor will have done all his tests ready to be given to the inspector before he switches the power on.

there is many different types of testers out there these are just given as a example

dougie

[h90]

in my new house approx 30 % of the lights are so switched that the switch of the N.

Everywhere, but specialy in Thailand you always need to work like every wire would be under power.

A hint, not a recommendation and I don't take any respondsibility: With good shoes with you can thouch 220 Volt and work on it as you are not grounded (but than thouching the N additional is maybe your last mistake).

doesn't really matter and is a minor safety issue involving the inaccessable wiring inside the appliance).

Tell that to someone who has turned the switch off on a lamp and come into contact with the bulb socket which is hot because the switch cut neutral because the plug was not polarized. Yeh, I know he would be dumb not to unplug the lamp but I suspect you can imagine a few friends who might have this happen. I'm sure I have done it at some point. Multiply that by the population and polarization starts to make sense.

[Crossy]

in my new house approx 30 % of the lights are so switched that the switch of the N.

Everywhere, but specialy in Thailand you always need to work like every wire would be under power.

My single most important tool is my neon screwdriver. Gets touched to any wire before my fingers go anywhere near it.

Best 50 Baht I've spent.

And yes, we have some lights with neutral switches (rented cond. so I'm not fixing it).

[Crossy]

Whilst we are on the subject of electrical installation safety, has anyone seen these:-

in Thailand?

If not they are a piece of cake to make. I'm going to make one for myself, if anyone's interested I could make a few (nominal Baht cost). PM me if interested.

Not absolutely foolproof, but infinitely better than nothing.

[elkangorito]

Earth Testing.

There are 2 types of earth testing;

1) a "DC" test, which is done BEFORE the installation (your house) is connected to the Consumer Mains. (before it is powered up).

2) an Earth Loop Impedance test, which can be done at any time & also whilst the installation is energised.

The DC test is a little more complicted to perform compared to the ELI test but is very cheap (an ELI tester is bloody expensive).

The results of the tests normally require to be within the limitations of the areas applied "standards" but generally speaking, if your DC earth resistance is below 1 ohm, your installation is fine. A better result would be 0.5 ohms. Nobody can tell if an installation's earth is ok just by looking at it. It has to be tested in 1 of the 2 ways outlined above.

The testing of RCD's can only be done with an expensive RCD Tester.

I have attached a document to indicate how a DC earth test is conducted. Also note that the document indicates the use of an MEN system, which is what Thailand is supposed to use.

[chownah]

If you want to check your earthing system you might contact the local electric department and see if their inspectors have a tester and would they come by and test it for you.

[elkangorito]

Earth Testing.

There are 2 types of earth testing;

1) a "DC" test, which is done BEFORE the installation (your house) is connected to the Consumer Mains. (before it is powered up).

2) an Earth Loop Impedance test, which can be done at any time & also whilst the installation is energised.

The DC test is a little more complicted to perform compared to the ELI test but is very cheap (an ELI tester is bloody expensive).

The results of the tests normally require to be within the limitations of the areas applied "standards" but generally speaking, if your DC earth resistance is below 1 ohm, your installation is fine. A better result would be 0.5 ohms. Nobody can tell if an installation's earth is ok just by looking at it. It has to be tested in 1 of the 2 ways outlined above.

If you want to check your earthing system you might contact the local electric department and see if their inspectors have a tester and would they come by and test it for you.

I hope the "local electrical department" conducts the test using one of the above methods. If they don't, you might as well talk ask the refrigerator what your earth loop impedance is.

[lingling]

Also could someone give me info on what I should ask the company about the house earth, resistance values etc

I note that the ‘worker’ who ran the cables..ran them all short and so had to put a join in them before the CBs..what a prat!

As the house is still warranted anyone know a ‘qualified’ electrician in Pak Kret area who would give it the once ovr?

.Thanks

My wife's uncle rewired the house for us and he did an excellent job. PM me if you want him to contact you.

Sounds to me what you need are breakers, a couple of more earth rods. It is a good idea to have "heavy" household appliances such as washer, dryer etc on a separate one than the one you use for computers etc. Having just one earth rod means you have a single point of failure and if that fails then your washer can turn *everything* with a metallic casing dangerous...

Also, make sure that water heaters are grounded and connected through a GFI (separate one for each of those is a good idea as they usually get "leak currents" after a couple of years).

[elkangorito]

Also could someone give me info on what I should ask the company about the house earth, resistance values etc

I note that the ‘worker’ who ran the cables..ran them all short and so had to put a join in them before the CBs..what a prat!

As the house is still warranted anyone know a ‘qualified’ electrician in Pak Kret area who would give it the once ovr?

.Thanks

My wife's uncle rewired the house for us and he did an excellent job. PM me if you want him to contact you.

Sounds to me what you need are breakers, a couple of more earth rods. It is a good idea to have "heavy" household appliances such as washer, dryer etc on a separate one than the one you use for computers etc. Having just one earth rod means you have a single point of failure and if that fails then your washer can turn *everything* with a metallic casing dangerous...

Also, make sure that water heaters are grounded and connected through a GFI (separate one for each of those is a good idea as they usually get "leak currents" after a couple of years).

lingling, if you want more info regarding this, read the posts listed under "breaker box wiring". You may find the info usefull.

Also, multiple earths are a bad idea. One earth rod is sufficient if it is sized, placed & connected correctly. Again, more info in "breaker box wiring" posts. In summary, multiple earths can lead to "earth potentials", which can be VERY dangerous. Also bear in mind that RCD's are NOT the answer to bad or incorrect earthing...again, see "breaker box wiring" posts.

By the way, an earth wire may NOT BE JOINED!!! It must remain unbroken. If it is to be joined, then only these 2 methods apply;

1) The earth wires must be soldered together as 1 soldered joint. Mechanically joining 2 separately soldered ends of this cable is dangerous. Solder will "give in" to the mechanical stress and therefore the joint will become resistive.

2) The earth cable can be mechanically joined if the mechanical joining device has a double mechanical function. ie 2 screws clamping the 2 "twisted" wires together. The 2 wires MUST be twisted together appropriately to ultimately form 1 wire. *note* twisting cables/wires in the opposite direction of their "natural" twist is dangerous. This method of joining earth conductors is not desirable.

Edited February 27, 2006 by elkangorito

[astral]

IME many appliances are polarity sensitive.

If they are not plugged in the right way round, then the case becomes LIVE.

Probably only noticeable if you are barefoot, without your usual rubber slippers.

When my house was re-wired I wanted to avoid cutting off the UK fused plugs

on my Hi Fi equipment and computer, so I went to Singapore and bought

UK style boxes and sockets for the computer room and Hi Fi area.

Lots of them to avoid floating plug boards!

Most of the items plugged in there are fused at 5A each.

I had remembered to buy a bag of fuses as well.

All the other sockets are 3 pin with the earth connected, and sensitive items

like the fridge, washing machine and water cooler have 3 pin plugs to make sure they

are plugged in the right way round.

The main distribution board has an integrated Earth Leakage breaker.

This way I feel a lot safer and know that my equipment is well protected.

[elkangorito]

IME many appliances are polarity sensitive.

If they are not plugged in the right way round, then the case becomes LIVE.

Probably only noticeable if you are barefoot, without your usual rubber slippers.

Be advised that the "neutral" & the "active" being reversed DOES NOT result in a "live case". This only can happen if the "active" wire is connected to the "earth" pin on a plug or visa versa.

When my house was re-wired I wanted to avoid cutting off the UK fused plugs

on my Hi Fi equipment and computer, so I went to Singapore and bought

UK style boxes and sockets for the computer room and Hi Fi area.

Lots of them to avoid floating plug boards!

Most of the items plugged in there are fused at 5A each.

I had remembered to buy a bag of fuses as well.

In the UK, the "ring main" (each appliance is separately fused) is normally used. This system is NOT used in Thailand. In Thailand, each electrical "circuit" ia protected by a fuse or a circuit breaker. These devices are used to protect the cable against "fault current", not to protect the device (overload current). This is so because "fault current" is more critical than "overload" current.

Disregarding whether you have fuses protecting individual devices or not, the "fault current" that can be produced is the most critical/dangerous. Appliance fuses do not control "fault current". They cannot do this safely. They control "over current". "Fault Current" & "Over Current" (overload) are 2 totally different things. "Fault current can be controlled by Fault Current Limiting circuit breakers or HRC (High Rupturing Capacity...BS88 standard) fuses.

All the other sockets are 3 pin with the earth connected, and sensitive items

like the fridge, washing machine and water cooler have 3 pin plugs to make sure they

are plugged in the right way round.

This is perfect, provided that the chassis earth of the appliance is connected to the electrical earth of the residence via the 3 pin plug.

The main distribution board has an integrated Earth Leakage breaker. This way I feel a lot safer and know that my equipment is well protected.

This will become a problem later unless the refrigerator & other such "motorised/inductive" devices, are NOT connected through the ELCB. "Motors" have a residual earth leakage current, which increases with age. This is why it is a bad idea to connect things like air conditioners, fridges & washing machines to circuits that are controlled by ELCB's. Generally speaking, if "inductive" devices (electric motors) are to be connected to ELCB's, the ELCB shall have a tripping current of about 100 milliamps. Imagine having an Earth Leakage trip late at night or during the onset of a fire...or during any emergency. If wired the Thai way, all of your power goes off...including lights. In an emergency, you need to find your way out of the building (consider smoke if a fire). If there are no lights, I think you might find it very difficult, if not dangerous in time of an emergency. This is why you must NEVER have your whole house protected by earth leakage. At least half of the lighting circuits can be ELCB protected. None of the "inductive" circuits (motors) must be protected. The rest of the house is ok provided you are connected using the MEN system.

Edited March 2, 2006 by elkangorito