Electric Shocks In Thailand

[Guest IT Manager]

Delta Star Transformers in Thailand are badly installed, the secondary neutral should be connected to the earth electrode. Bad Phase/Impedance 3 phase problems persist due to bad planning. Neutral should be near zero potential.

Reverse the 2 pin sockets to avoid shock. If that does not work create your own ground.

I think Thailand should be made a compulsory D.C. system as Edison himself championed!

Wilson dear a transformer is EITHER star or delta wound. Thank you for your input but it isn't both.

[Pink Mist]

Delta Star Transformers in Thailand are badly installed, the secondary neutral should be connected to the earth electrode. Bad Phase/Impedance 3 phase problems persist due to bad planning. Neutral should be near zero potential.

Reverse the 2 pin sockets to avoid shock. If that does not work create your own ground.

I think Thailand should be made a compulsory D.C. system as Edison himself championed!

Edison may have championed DC (must admit hadn't heard that) and its fine for lighting purposes but a lot of equipment wont work properly or at all. Just briefly to name a few, there are far too many problems associated with DC.

Induction motors, transformers dont work at all. Devices such as SCR's and thermionic valves dont work properly, DC coils burn out unless special circuits are utilised. DC can be used for transmission of high currents but not in a local infrastructure, think of all the pole top and pad mount transformers you see used for local distribution. High voltage DC links are used for undersea cable transmission in lots of locations ie North and South island of NZ uses one and many others world wide.

I have worked with DC most of my career and if I had a choice of shock, something I avoid religously, it would be AC a similar DC voltage really burns.

IT you do have star delta trannies, they are used extensively in my game for three phase rectifiers.

I enjoyed this little spuell getting the brain going again for next year course.

Bronco

[wilson steer]

######;

Three Phase transformers have six windings, three primary, three secondary, they can be described as;

Delta Delta

Delta Star

Star Delta

Star Star

The actual connections used depend upon the applications required.

There are many advantages of AC over DC, yet HVDC transmission is definitely more efficient and without EMF problems that HVAC transmission has.

Back to the original thread; Long Copper Pipes banged into wet earth will do the job, I have used this method many times.

I think the most alarming electrical malpractise I have witnessed in Thailand is regarding electric shower units, truly shocking!

[Pink Mist]

Yes wilson HVDC is the way to go in under sea transmission lines.These cables by the nature of their construction have a very high capacitance when AC is used, this means if the cable is more than a few kilometres in length the capacative reactance is so high that the cable useless.

In 3 phase arial transmission lines the upper limit was generally accepted as about 400k volts, experimentally these figures have been exceeded but problems are associated with the design of these lines. DC transmission lines can operate at megavolts and you only need 2 conductors.

One other use is Zero length DC links ie join two AC systems of a different frequency such as used in Japan between Osaka 50 hz and Tokyo 60hz, current can flow between these 2 systems for more economic use.

Back to original thread I shudder to think of some devices used without an earth especially instantaneous hot water services.

[lopburi3]

I think the most alarming electrical malpractise I have witnessed in Thailand is regarding electric shower units, truly shocking! 

Agree. Although believe they all have built in GFI they are almost never grounded (just like refrigerators) and some have/had GFI that can fail. I have five units and latest does have large red letters on front advising that it must be grounded. But I still had to do it myself after electricians decided it didn't need it.

There are two problems I have had with these units. One had direct metal to metal connection to shower hose. When GFI failed (due to soap scum preventing switch from activating) the hose became hot and when the other hand was used to adjust metal tap serious shock occurred. That unit was immediately destroyed as it had leakage in heater unit. Two things learned.

1. Make sure there is non conductive connection to hose when I look at new units - the current model of the unit I had now uses this.

2. Test the GFI to make sure it is free to operate. The current models have changed the mechanical linkage so this would not happen.

[the gentleman]

Just got one - and another -doh!

[Pink Mist]

Just remember lopburi that even though water is an insulator we are talking about pure water. Most town water supplies are filtered somehow but would still contain minerals and be conductive so you still have an earth path, you. If your water is not distilled then you could be in for a shocking experience if things go wrong.

Best idea for the 152nd time earth the premesis.

I have put stakes down in Qld where the electrical inspector actually watches you drive the stake into the ground in some areas with hard soil (just incase you might have decided to cheat and cut the top of the stake off)

[lopburi3]

Just remember lopburi that even though water is an insulator we are talking about pure water. Most town water supplies are filtered somehow but would still contain minerals and be conductive so you still have an earth path,

That's true but suspect the surface water we are drinking here in Bangkok has more chemicals than minerals.

The big problem was that the shower and hose was metallic so it made the holder a really great ground when holding it covered with water on a tile floor. So item three would be never use metallic shower hose on electric heater. And of course ground it.

[Guest IT Manager]

hi lopburi,its all a bit conFUSING to say the least,

Watt do you mean?

[KenUdon]

This says it all really!...http://www.takeonthailand.150m.com/page2.html

[lopburi3]

http://www.takeonthailand.150m.com/page2.html

Text is so true; but the photo is misleading as the foreground wires are not electric.

[KenUdon]

http://www.takeonthailand.150m.com/page2.html

Text is so true; but the photo is misleading as the foreground wires are not electric.

Lop...Never said they were. Just a general indication of the quality of the wiring.....any wiring... Still looks pretty colourfull when it rains!

[dhrobertson]

All good stuff but not so helpful to the average expat methinks.

There is nothing intrinsically wrong with a two wire system IF the appropriate safety equipment is in place. Such systems have been standard in Scandinavia for decades.

Sadly, in Thailand there is no such word as safety.

What you need is a RCD (otherwise known as an earth leakage breaker). Essentially this limits the current that can go to earth through your poor little body to just 30 milliamps. As it takes 40mA to kill you, you're as safe as houses. (you need the high voltage just to get across your skin resistance).

If you are wiring a new place in Thailand, do it to 16 edition UK regulations. These are the safest in the world.

You will end up with 3 wire ring and lighting circuits, RCD and the appropriate MCBs. That takes me onto another point. In Thailand, little or no thought seems to be given to choosing fuses (MCBs) of the correct rating TO PROTECT THE CIRCUIT WIRING from fire hazard. I've seen loads of cases where an ancient 100A breaker is "protecting" a circuit which is essentially bell wire. It's no wonder, excluding insurance jobs, that there are so many fires here. It is essential that MCBs be chosen for the correc trating to protect the circuit in question.

If you are in no position to get the wiring done correctly, consider this:

In most cases the shock you get from touching the casing of a two pin device is due to charge build up. By all means ground the casing by running a single core cable from the metal casing to a ground point which can be a 2m copper rod hammered in to the ground.

However, many devices REQUIRE to be grounded and must have a three wire connection. The lack of a ground in these cases is a serious hazard. In my view the sale of devices, which should be grounded, in Thailand, together with a two pin lead is criminal.In these cases you MUST ground the device either by running a separate earth cable to the device or installing a three pin circuit.

Incidently it is important that neutral and live are not switched over for many appliances. With reversable two pin plugs this is close to impossible to keep track of. Often the on/off switch is only in the live circuit. Switching live and neutral thyerefore can create a hazard where the appliance is still live even though switched off.

Finally, there seems to be no regulation here concerning neutral/ground bonding. Generally I expect neutral, earth, and equipotentential bonding all to come together at the consumer unit or where the supply comes in to the building. Anyone know what is supposed to be the rule in Thailand?

Keep Safe!!

[maerim]

Anyone know what is supposed to be the rule in Thailand?

The rule here is there are no rules, or if there are they are optional.

I know of one young man or knew him anyway when one Sunday afternoon worse the wear with too much "lao khow" decided to kill some fish in a pond by elctrocuting them it works well on human beings as well.

His cremation was three days later

[Georgie-Porgie]

Wow. What a bunch of burly-men. I never suspected!

[lopburi3]

There is nothing intrinsically wrong with a two wire system IF the appropriate safety equipment is in place. Such systems have been standard in Scandinavia for decades.

And then you go to cite a perfect example (items that require ground) of why a ground system is required. RCD/GFI have been talked about and recommended but they can and do fail (just as circuit breakers fail). The ground is an important added layer of safety at very little cost. Don't wire today's home without it.

I've seen loads of cases where an ancient 100A breaker is "protecting" a circuit which is essentially bell wire. It's no wonder, excluding insurance jobs, that there are so many fires here.

Agree with the breaker point but do not believe there are that many fires here caused by this. The normal open/surface wiring in wood construction and natural resistance to fire in brick construction limits the number of fire greatly IMO. In 30 years I have never even seen a building fire here.

In my view the sale of devices, which should be grounded, in Thailand, together with a two pin lead is criminal.In these cases you MUST ground the device either by running a separate earth cable to the device or installing a three pin circuit.

Agree completely.

Finally, there seems to be no regulation here concerning neutral/ground bonding. Generally I expect neutral, earth, and equipotentential bonding all to come together at the consumer unit or where the supply comes in to the building. Anyone know what is supposed to be the rule in Thailand?

Meters are normally placed on a power pole (rather than home) and there is a ground wire there. Don't know if this is always the case.

[dhrobertson]

Meters are normally placed on a power pole (rather than home) and there is a ground wire there. Don't know if this is always the case.

Thanks for the advice. In this particular case the meter is indeed on a pole outside the house. However, there is no ground point. Also the supply comes off a single phase transformer and I can see no grounding there either.

Guess I'll just have to tie neutral to ground myself.