Thai Electrical Wiring?

[Beachcomber]

Hi

I know a little about electricity. I can wire up a plug and also wire in additional wall sockets.

But some things in LOS are still a mystery to me.

I assume with the wire colors Grey/Black that BLACK is the feed/live/positive?

This assumption is based on an average of wiring in various places I have lived in.

I have one of those neon screwdrivers for testing the positive and use it to put the two pin plug from fridge/toaster/washing machine/kettle in the socket so as not to get a shock from those appliances.

Example; by putting the neon tester on the metal of the fridge it would light up so I put the plug in the other way and I guess that’s how it should be?

On my TV (Samsung) the two pin plug has a flared section on one of the pins. Is this pin positive or negative?

Now for something really weird. In a previous apartment the landlord got an “electrician” to put in separate meters to each apartment.

I use the term “electrician” loosely as his wire connections instead on being twisted together were tied in a knot. Must have been a fisherman before becoming an “electrician”

The weird thing is that the “electrician” grounded the LIVE to EARTH – I checked with my trusty neon tester at the grounding rod and sure enough I got a positive reading – is this possible or only TIT.

[GuestHouse]

There are two problems - Unbalanced Load and Incorrect Routing.

Unbalanced Phases Can cause different voltages, including power on the Neutral.

This occurs when the phases at the local substation/transformer are out of balance.

The local substation will have three phases (You receive one) and the other two are distributed elsewhere. Ideally the load on each phase should be the same, it never is exactly the same, but good management of the system should keep loading balanced.

If your local power distribution is unbalanced the Live/Neutral set you receive can be substatialy drifting from the specified voltage.

Wrong Routing - Live to Neutral and Neutral to Live.

I'd never assume that the Live is in fact Live and the Neutral is in fact the Neutral. They are very very often the wrong way around.

To avoid the problem and risks that arise from these problems I have always used Circuit Breakers

with Leakage Current Cut-Off in all the houses I've lived in Thailand.

Edited April 23, 2006 by GuestHouse

[Khutan]

Unbalanced phases, I did a check with a voltmeter and found 67 volts on the Neutral.

Its particularly annoying as the electricity aurhority made me buy the Extra-Strength Black Cable as I was a Farang with a 2 story house.

Its going to be interesting the day I install the air-conditioner as the village supply is the same rating as the cables going into my (wife's) house.

Its also very annoying when you go to shops or local web cafe's and getting zapped from the chassis of appliances.

[Crossy]

I assume with the wire colors Grey/Black that BLACK is the feed/live/positive? Normally that is true. Bye the way it can be called live, line, phase or hot it is NOT positive You missed the MOST IMPORTANT wire the GROUND / EARTH which should be green.

I have one of those neon screwdrivers for testing the positive and use it to put the two pin plug from fridge/toaster/washing machine/kettle in the socket so as not to get a shock from those appliances. The neon screwdriver finds the live wire. If it is lighting on the metalwork of an appliance then the appliance is incorrectly grounded, reversing the plug is masking the problem it is NOT SAFE.

On my TV (Samsung) the two pin plug has a flared section on one of the pins. Is this pin positive or negative? I'm pretty sure the wide pin is neutral. Modern appliances are polarity insensitive so on something like a TV is doesn't matter which way round the plug is inserted.

The weird thing is that the “electrician” grounded the LIVE to EARTH – I checked with my trusty neon tester at the grounding rod and sure enough I got a positive reading – is this possible or only TIT. Now this is really scary, a hot reading from your ground rod means basically that it aint a ground. This is a potentially LETHAL situation.

[lopburi3]

Will add that the wide pin is the neutral on a polarized plug like the one pictured. And the reason for it is to insure the hot wire it switched off and not the neutral in items that are not grounded.

[Beachcomber]

Thanks for all replies with some good information.

The reason for the questions is I am attempting to get some sort of electrical standard as all the sockets here are only two pin.

I have put in a grounding rod for the computer and with my trusty neon tester think I have got all the plugs in the right way so when I switch off the UPS and everything connected to it the LIVE is off.

I have also attached a grounding rod to the washing machine and hot water shower. Unfortunately the fridge and things like kettle, toaster and small electric oven are on the opposite side of the room so grounding them is not an easy option.

I realize most appliances these days are polarity insensitive but I still don’t like to get a shock off the toaster so while reversing the plug in the socket is not ideal it makes me feel better.

The polarized plug actually plugs in only one way and I wanted to know which way to wire an extension socket.

“Quote”

If your local power distribution is unbalanced the Live/Neutral set you receive can be substatialy drifting from the specified voltage.

Wrong Routing - Live to Neutral and Neutral to Live.

Does this mean the Neutral – Live could change from day to day??????

“Quote”

I assume with the wire colors Grey/Black that BLACK is the feed/live/positive? Normally that is true. Bye the way it can be called live, line, phase or hot it is NOT positive You missed the MOST IMPORTANT wire the GROUND / EARTH which should be green.

So BLACK is normally LIVE - but not necessarily

If you want “SCARRY” you should see my mother-in law’s laundry service set up.

She has about six machines all in various stages of decline all banging away standing in puddles of water on the concrete floor and all connected from a couple of two pin sockets via those cheap roll-up extension cord that are only meant for lights.

Some time ago she just happened to mention that she was getting shocks from most of the machines. I put in a Ground Rod for her and connected all the machines to it. I think that helped but maybe she is just too polite to say if it didn’t. I’m sure we are going to find her electrocuted one day.

[Crossy]

I have put in a grounding rod for the computer and with my trusty neon tester think I have got all the plugs in the right way so when I switch off the UPS and everything connected to it the LIVE is off. Good

I realize most appliances these days are polarity insensitive but I still don’t like to get a shock off the toaster so while reversing the plug in the socket is not ideal it makes me feel better. If you are getting a tickle off your toaster it is faulty!! Some appliances are 'leaky' (PCs, fridges and the like). Toasters should not be leaky.

The polarized plug actually plugs in only one way and I wanted to know which way to wire an extension socket. The wide pin is NEUTRAL (or ought to be).

Does this mean the Neutral – Live could change from day to day?????? Line and neutral are unlikely to change from day to day. However the neutral-ground potential will vary with load, not likely to affect you as you have no ground.

So BLACK is normally LIVE - but not necessarily That's about the size of it

If you don't have one, get a good quality earth leakage breaker (RCD, RCCB, ELCB, Safe-ty-cut). Whilst it is no substitute for a correctly grounded system it will provide a degree of protection from potentially LETHAL shocks.

[h90]

The weird thing is that the “electrician” grounded the LIVE to EARTH – I checked with my trusty neon tester at the grounding rod and sure enough I got a positive reading – is this possible or only TIT. Now this is really scary, a hot reading from your ground rod means basically that it aint a ground. This is a potentially LETHAL situation.

that can not be! The rod if put in the land, can not be on voltage, if connect Live to Earth, you have a short. If you get a voltage on earth, check if it is really connected with the rod in the land or if the earth wire is just a dummy wire.

common is to connect neutral to earth, that is old fashion (say 50 years) but if the earth is really good, it should not be a problem (it is a horror for every technican but normaly nothing happens).

if you only have the earth wire, but no rod (or some idiot disconnected it) than you get neutral on devices with metal housing. If not balanced, than you may get 60 volt on the housing. for weak people that can be letal, but normaly it is not if you young/strong/no heart problems, but I would not test it on your kids or pets (or try at least first with the cat, before you let your son thouch it )

[Crossy]

that can not be! The rod if put in the land, can not be on voltage, if connect Live to Earth, you have a short. If you get a voltage on earth, check if it is really connected with the rod in the land or if the earth wire is just a dummy wire.

common is to connect neutral to earth, that is old fashion (say 50 years) but if the earth is really good, it should not be a problem

I suspect that our OP was not actually measuring directly on the grounding rod, even a really awful ground would prevent the neon lighting. Maybe a poor connection to the rod coupled with a leaky appliance was the cause. To be honest, without actually seeing and checking the installation, who really knows what was going on.

The MODERN way is to ground the neutral at multiple locations (rather than just at the transformer), called variously PME (Protective Multiple Earth) or MEN (Multiple Earthed Neutral).

The idea is that the neutral can never rise significantly above local ground potential even with a bad load imbalance.

In "Western" implementations of PME/MEN there is a link between the ground bar and the neutral bar inside the distribution box, there is NO local earth spike. Thailand is SUPPOSED to use this system, but it seems that most houses have a local ground spike and SOMETIMES have the MEN link.

[h90]

that can not be! The rod if put in the land, can not be on voltage, if connect Live to Earth, you have a short. If you get a voltage on earth, check if it is really connected with the rod in the land or if the earth wire is just a dummy wire.

common is to connect neutral to earth, that is old fashion (say 50 years) but if the earth is really good, it should not be a problem

I suspect that our OP was not actually measuring directly on the grounding rod, even a really awful ground would prevent the neon lighting. Maybe a poor connection to the rod coupled with a leaky appliance was the cause. To be honest, without actually seeing and checking the installation, who really knows what was going on.

The MODERN way is to ground the neutral at multiple locations (rather than just at the transformer), called variously PME (Protective Multiple Earth) or MEN (Multiple Earthed Neutral).

The idea is that the neutral can never rise significantly above local ground potential even with a bad load imbalance.

In "Western" implementations of PME/MEN there is a link between the ground bar and the neutral bar inside the distribution box, there is NO local earth spike. Thailand is SUPPOSED to use this system, but it seems that most houses have a local ground spike and SOMETIMES have the MEN link.

If I mix Earth and Neutral, how the earth leakage breaker should work? Or do they just have two different earth, one after one before the earth leakage breaker???

or do I miss something??

[h90]

If you want “SCARRY” you should see my mother-in law’s laundry service set up.

She has about six machines all in various stages of decline all banging away standing in puddles of water on the concrete floor and all connected from a couple of two pin sockets via those cheap roll-up extension cord that are only meant for lights.

Some time ago she just happened to mention that she was getting shocks from most of the machines. I put in a Ground Rod for her and connected all the machines to it. I think that helped but maybe she is just too polite to say if it didn’t. I’m sure we are going to find her electrocuted one day.

did she make her last will, already?

Or maybe she get rid of the bugs in the water with the electricity???

Anyway 90 % of the time you can stay 220 Volt and mostly it is not full currency. So it may need a year or two.

the earth rod should help, maybe it costs more elctricity??

Measure how many ampere are going true that cable.

[Crossy]

If I mix Earth and Neutral, how the earth leakage breaker should work? Or do they just have two different earth, one after one before the earth leakage breaker???

or do I miss something??

The MEN link is on the incoming side of the ELCB (immediately after the meter) so exchanging ground and neutral will cause a trip as it is supposed to do

Remember a modern (current operated) ELCB does not require a ground connection in order to function unlike the older (voltage operated) units.

[Beachcomber]

Hi

Thanks again for all replies.

Quote: Crossy”

I suspect that our OP was not actually measuring directly on the grounding rod, even a really awful ground would prevent the neon lighting. Maybe a poor connection to the rod coupled with a leaky appliance was the cause. To be honest, without actually seeing and checking the installation, who really knows what was going on.

As I mentioned this was in a previous apartment. I was living in the apartment with my computer setup as usual with trusty neon tester checking the live/neutral feeds to the UPS.

Now normally I wouldn’t worry about the installation of a meter – how difficult can it be? But TIT.

After the installation I rechecked the live/neutral at the plugs and sure enough they were reversed. No problem for me I just reversed the plug in the socket.

My apartment was at the end of the block just where the main power line came in to a box with one of those ‘blade’ switch/fuse thingies. From there I could see and physically follow the wiring into mine and all the other meters also the grounding wire that led along the outer wall down the wall at the corner and was attached to the grounding rod.

I tested the LIVE in the fuse box where it was “tied” to the ground wire. I then whet down to the earth rod and yes sure enough my little neon lit up.

“Quote: h90”

did she make her last will, already? Or maybe she get rid of the bugs in the water with the electricity???

Anyway 90 % of the time you can stay 220 Volt and mostly it is not full currency. So it may need a year or two.

the earth rod should help, maybe it costs more electricity?? Measure how many ampere are going true that cable.

Sorry to say she does not have enough money to worry about a will

Yea! I think about the electricity going trough to the earth but I don’t have an amp meter to measure it.

Next year we will probably all move anyway so as long as she lasts that long it will be OK.

Hopefully in the new place I have the chance to install some basic safety features before he has the whole show set up plugged in and running again; these old dears are so quick sometimes!

[h90]

Hopefully in the new place I have the chance to install some basic safety features before he has the whole show set up plugged in and running again; these old dears are so quick sometimes!

one recommendation (own experience) make the electric long before anything else is finish.

If not they find a thai "specialist" than it may look very bad and noone understand why you want to change something as all lights are working.

Crossy: in my installation, ups wrong, in the installation in my house (it is NOT my installation), at the end they mix all neutrals together, screw it on the housing of the box and screw there the earth, that is of course after all safety devices.

The box for 3 phase electricity does not look much different, but approved from my father as good installation in the 1960s and most probably working safe (considering the long rod and the very wet land for the earth)

[Crossy]

Crossy: in my installation, ups wrong, in the installation in my house (it is NOT my installation), at the end they mix all neutrals together, screw it on the housing of the box and screw there the earth, that is of course after all safety devices. This arrangement means that your ELCB is useless. A live-earth leak will not trip the breaker (a short WILL as it will pull on over-current not leakage). The arrangement as I described it is the correct way to install.

The box for 3 phase electricity does not look much different, but approved from my father as good installation in the 1960s and most probably working safe (considering the long rod and the very wet land for the earth). An installation 'certified' as 'safe' in the 1960s would not pass muster in the 2000s, regulations change. This is not to say your particular installation is unsafe, but I would suggest that after 40 odd years, a rewire would be in order.

[h90]

Crossy: in my installation, ups wrong, in the installation in my house (it is NOT my installation), at the end they mix all neutrals together, screw it on the housing of the box and screw there the earth, that is of course after all safety devices. This arrangement means that your ELCB is useless. A live-earth leak will not trip the breaker (a short WILL as it will pull on over-current not leakage). The arrangement as I described it is the correct way to install.

There is no ELCB installed, but I'll soon do it! Good you point out what it is wrong before I install it useless.

The box for 3 phase electricity does not look much different, but approved from my father as good installation in the 1960s and most probably working safe (considering the long rod and the very wet land for the earth). An installation 'certified' as 'safe' in the 1960s would not pass muster in the 2000s, regulations change. This is not to say your particular installation is unsafe, but I would suggest that after 40 odd years, a rewire would be in order.

Sorry I did not write that clear! It is a brand new installation, direct from the electricity company in thailand (as they told they have to check the installation first, but only will consider it as save when he do it with his private company, which is more expensive, the thai corruption).

What my father said was meant half sarcastic "this is what was considered as safe 1960" meaning it is not absolut crazy and will kill everyone now, but it is far away from modern standards. I should be made different but it is not the first priority.

After reread my own posting that was not clear, after so much house building I can not tell the things clear anymore as automatic I think everyone knows the situation (burn out syndrom??)

By the way, interesting for me: in the old days you did connect neutral to the housing. had in europe a very old machine and grounded the housing, which did not work, housing must be on neutral. I don't know which time 1950/1960??? 3 phase machine which need neutral for the electric.

Edited April 25, 2006 by h90

[Crossy]

After reread my own posting that was not clear, after so much house building I can not tell the things clear anymore as automatic I think everyone knows the situation (burn out syndrom??)

By the way, interesting for me: in the old days you did connect neutral to the housing. had in europe a very old machine and grounded the housing, which did not work, housing must be on neutral. I don't know which time 1950/1960??? 3 phase machine which need neutral for the electric.

No problem

I assume that English is not your first language, misunderstandings are part of life working with 'foreigners', been doing it for long enough now, things still get built wrong

A 3-phase machine should operate just fine with no neutral connection, it is (or certainly was)normal practice to ground the frame and connect the neutral point to the frame too. It's possible that your old machine had a fault on one phase which was masked by connecting the frame to neutral, who really knows ??

Just for your information, the diagram attached comes from 'IEE Regulations 16th Edition, Illustrated and Explained". I've highlighted the correct position of the Neutral-Earth link in red.