Domestic Electrical Wiring

[Crossy]

Sorry for such a simple question, but I don't see how you download attachments on posts to this forum, eg the lead post here, an attachment number is given but you can't click on it....

Thanks

You do just click on it, that said, the earliest attachments on this thread have been removed for space reasons. Most of the information is available here:- http://www.crossy.co.uk/wiring/

[leekman]

hi there, ive been reading this thread now for 3 days trying to understand it and im very impressed of the information plus diagrams that it gives.ive learn,t alot by reading all your post,s. alittle about me im not a sparky but i have abit of knowledge in the building trade and i have rewired two of my homes in the uk.so i can understand afair bit of the basic stuff . what my problem is my house in khon kaen is a 2 storey one and its all the 2pin sockets etc and no earth in any of the sockets but there is a earthrod in i paid for that 1 year ago and it is up to the breaker box which is full up off switches not trips i have a safe to cut already installed but the earth off the rod is not to the safe to cut box but to the breaker box or cu.so im wanting to do a full rewire as then i will know i and my family will be safe.

now at pres im in the uk. and i don,t know if the meter says 15/45 but i do know that in the breaker box or cu it does have a 63amp breaker in. so im hoping that the meter does say 15/45. 1 year ago i got my thai handyman so called sparky to fit a earth in the ground and to the breaker box or cu and also told him to make sure that the shower and water heater is earthed up i bought them 1 year ago from global house but looking in the breaker box i only see the thick earth wire on the earth strip.that tells me that nothing is earthed up in the house i think so.i know i can rewire the house myself the only thing im stuck on is installing the men system link never done that but what i have read i believe i can do that myself with help from you knowedgable lads.what i understand is: the earthrod cable must go directly to my safe to cut nuetral inlet first (not my breaker box first) im not sure about this bit does the earth that ive just but into my safe to cut box in my inlet earth/nuetral then loop into my 63amp breaker or does it just go into my safe to cut box.also how will i know before i start any work that my home is men link enabled. do i have to go to my local elec company to find out or can i do it myself .

ill leave it their for now lads and hope to heare from you soon. paul

[Crossy]

Leeky, have a look here, but remember to read the notes on MEN http://crossy.co.uk/wiring/Consumer.html

[leekman]

thanks for your fast reply crossy, ive printed all that info off your site and thank you.

the m e n link diagram shows the earthcable coming from the earthrod straight to the earth bar in your breaker box. i understand that . this is where i get a bit lost in myself unsure. from the earthbar do i take the earthcable straight to the safe t cut box and insert it in the inlet nuetral. then i wil be m e n linked . also what is the easyest way of finding out you are m e n enabled contact the elec company or can you find out yourself easy. thanks inadvance. paul

[Crossy]

thanks for your fast reply crossy, ive printed all that info off your site and thank you.

the m e n link diagram shows the earthcable coming from the earthrod straight to the earth bar in your breaker box. i understand that . this is where i get a bit lost in myself unsure. from the earthbar do i take the earthcable straight to the safe t cut box and insert it in the inlet nuetral. then i wil be m e n linked . also what is the easyest way of finding out you are m e n enabled contact the elec company or can you find out yourself easy. thanks inadvance. paul

Yes, you just link the earth bar to the incoming neutral, use cable at least as big as your incoming supply.

BUT

If you're unsure if you have MEN or not leave the link out, it's safer should MEN not be implemented. To check if MEN is in your area best to ask your sparks, or have a look at your supply poles, every 3rd or so should have a copper bar running down from the neutral (usually the top wire) to ground.

[leekman]

thank you very much crossy for your help i totaly understand the men now .and i know what to look for on the poles ill look at every pole im my soi.

my consumer unit box

im after a CU with about 14 to 16 breakers on the panel. will i have any prob getting one that size in los can i get a bigger panel than 16 so i have spares.

[powderpuff]

The latest thing from Schneider Square D consumer unit (load center/breaker box) this one happens to be 10 circuits but larger ones are available.

What I wanted to show is the Neutral Bus & a Ground Bus. Should you choose to use it. I paid 1140 baht for this today.

[elkangorito]

Many things have been learnt & many changes realised as a result of this learning, since the initial post of this thread back on 2006-04-29 22:17:30.

The evolution of this thread has involved many knowledgable people & this thread would have been far less informative without them. Notwithstanding this, without the questions asked by people who have less electrical knowledge (than others), the thread would be otherwise "uneventful". I offer thanks to all who have responded to this thread.

As this thread is now approaching "4 years old", I would like to provide a synopsis of the thread in order to cover the current "perceived" domestic electrical wiring status of Thailand.

The thread started out with the ideal of providing "realistic & safe" information for foreigners living in Thailand...particularly for those who build their own homes/offices etc. From the onset, it was believed by many that Thai wiring rules, which strictly pertained to the wiring of domestic premises, did not exist. To this day (19/2/10), I am still unaware of the existence of any such wiring rules. Those who claim to have such wiring rules are welcome to reply.

I also might add that "Domestic Electrical Wiring Rules" means the following:

Legislated rules that strictly pertain to the electrical wiring of domestic installations. These rules must be in the form of a "standard" that is recognised & therefore enforced (by legislation) for the country to which they apply. As a result, Thai Engineering Institutes may not necessarily provide any standardised form of "wiring rules" but offer "knowledgable advice" in this regard. This advice is not to be ignored but acknowledged for exactly what it is..."advice".

In the same vein & in the absence of any legislated "Thai Domestic Electrical Wiring Standard", this thread has offered & may continue to offer "advice".

The advice that is offered generally relates to Australian Standards (AS/NZS 3000 Wiring Rules). The reasons for this are as follows:

1] Australian electrical distribution characteristics (general) - 230v, 50Hz (single phase) & 400v, 50Hz (3 phase). Ambient temperature - 40 degrees Celsius. Australia is a Metric country. Distribution system - TN-C-S.

2] Thailand electrical distribution characteristics (general) - 220v, 50Hz (single phase) & 380v, 50Hz (3 phase). Ambient temperature - about 35 degrees Celsius. Thailand is a Metric country. Distribution system - can be TT or TN-C-S.

Today.

Over the years, one of the most alarming & important points was the realisation that Thailand has been (& still is) inconsistent with regard to the practice "earthing" & the "M.E.N. System". Combine this with the apparent absence of an applicable "standard", the lack of appropriate training available to Thai electricians, a lack of the acknowledgment of electrically related deaths/injuries, a general lack of respect for this "silent killer" & you have Thailand as it is today.

It would be relatively simple for Thailand to "adopt", as an interim measure, the standards of another "similar" country until such time as Thailand fully develops it's own standards. The most difficult thing would be the enforcement of these/this new standard(s), as many barriers would need to be overcome.

In the meantime, it may be advantageous to realise that by "doing your own thing" electrically will only confuse matters in Thailand. The people who contribute electrical knowledge on this forum, generally do so under the consensus of an agreed strategy (silently agreed). The thread has seen quite a few battles in this regard but thankfully, most parties seemed to have settled on an agreed level.

After all that has been said & done here, to this date, there is really only one safe way to do things with regard to wiring your home etc. Mind you, it is not cheap & does not necessarily guarantee anything unless the appropriate tests have been done prior to energising any installation. See as follows:

1] Install only one (1) earth rod, which is then connected to the Main Earth Bar in your consumer Unit. This rod must be 100% "electrical grade" copper (98% pure) or be a copper clad steel rod, the copper cladding of which should be at least 1mm thick. This electrode should be a MINIMUM of 2m long. Connection to the rod should be via an appropriate clamp. More details at Crossy's site.

2] Only use double pole circuit breakers, double pole switches & double pole RCCB's.

3] Insist upon tests prior to energisation. The tests should at least include:

a] polarity.

b] earth fault loop impedance.

Written documents should be obtained with regard to the test results.

Unfortunately, most Thai electricians will not have a clue about these tests. My belief is that the more people who demand this to be done, the more pressure will be put on the "system" to provide a safe installation. I don't expect that anybody will get any immediate test results but my hope is that a few years from now, these things will become a possibility.

Further, I would like to acknowledge that I have made mistakes (nobody's perfect) and I praise the patience of others for arguing with me in this regard. I can be a difficult bastard at the best of times (too many engineering reports - unemotional).

Crossy, a sincere "thanks mate" for your unparalleled knowledge...you taught me a thing or 10

BTW, I'm not leaving (I can here the groans as I type) but in my own way, I'm trying to say "thanks" for a great period of learning & a "feeling of progress".

I'm sure Thailand would be worse off had it not been for all the contributors to this thread.

Cheers & stay safe.

Edited February 19, 2010 by elkangorito

[stgrhe]

Elk, I suppose one should also test the order of the phases if one has a 3-phase installation.

[stgrhe]

Forgot to add this question:

Elk, you say that one should use a double pole RCD in Thailand but I have read that this is unsafe if it is a TN-C installation. Can you please elaborate on this?

Most RCDs and RCBOs sold in Thailand are single pole version as I have understood it, and this was also the recommendation given to me by ABB.

[elkangorito]

Elk, I suppose one should also test the order of the phases if one has a 3-phase installation.

Yes, you're exactly right & I did forget to mention this. Phase rotation should also form a part of the "pre-energisation" checks.

Forgot to add this question:

Elk, you say that one should use a double pole RCD in Thailand but I have read that this is unsafe if it is a TN-C installation. Can you please elaborate on this?

Most RCDs and RCBOs sold in Thailand are single pole version as I have understood it, and this was also the recommendation given to me by ABB.

In the recent couple of weeks, at least 2 members have commented about having the active & neutral reversed as a result of some work being done by the PEA/MEA upon their installations. In all honesty, these are the first 2 cases that I have "directly" heard about.

Since "testing" does not seem to form a part of the typical Thai electrical installation, double pole "everything" seems to be the safest option although quite expensive. For example, if you have 24 single pole CB's/RCCB's, they will easily fit into a 24 pole DB. If all of these CB's/RCCB's were double pole, a 48 pole DB would be needed & the cost of the breakers etc would also dramatically increase. (Stgrhe, I know that you understand this...I'm saying this for the benefit of others.)

This is not done in the west since testing is mandatory & most electricians actually do know what they are doing.

If an RCCB is double pole, it will open both the neutral & the active when tripped. This will ensure that there is no power whatsoever on the circuit it supplies until it is reset. It does not affect the function of an M.E.N. connection/system.

[citizen33]

In the recent couple of weeks, at least 2 members have commented about having the active & neutral reversed as a result of some work being done by the PEA/MEA upon their installations. In all honesty, these are the first 2 cases that I have "directly" heard about.

I think this may be more common in Isaan villages but it has happened to me a couple of times. One scenario is that it happens when you have some metal work done and the workman connects his arc welder directly to the electricity meter (which seems to be the norm in the villages). When they replace the domestic supply they guess the connections (even though I had marked my cables with red and black tape). It isn't such a big job to rectify, providing you don't mind risking your life by connecting the tails to the live terminals! The electric company seems very relaxed about it when the security tags on the meter are snipped off. I must admit last time I forgot to check what the guy had been up to, and only noticed something amiss a day or two later when the fluorescent light in the bedroom glowed ever so dimly on off.

[elkangorito]

Sorry to hear about your dramas Citizen

Since you have brought up the fact that certain "tradesmen" (if you can call them that) muck around with the KWH meter connections, a suggestion may to install the meter in a box with a window for the meter reader. I would love to say that this box could be lockable but it may be simpler to allow access by the use of a tool (screwdriver etc) to keep the PEA/MEA happy. I'd even consider puting a sign on it...in Thai. The sign would say something like, "Seek permission from the PEA/MEA or land owner before accessing. Penalty - 1000 Baht (payable to land owner)."

[citizen33]

Sorry to hear about your dramas Citizen

Since you have brought up the fact that certain "tradesmen" (if you can call them that) muck around with the KWH meter connections, a suggestion may to install the meter in a box with a window for the meter reader. I would love to say that this box could be lockable but it may be simpler to allow access by the use of a tool (screwdriver etc) to keep the PEA/MEA happy. I'd even consider puting a sign on it...in Thai. The sign would say something like, "Seek permission from the PEA/MEA or land owner before accessing. Penalty - 1000 Baht (payable to land owner)."

I survived! Having now read the 'Idiots' thread I see that plenty of others have had similar problems. I was wondering what to do about tradesmen coming to use welding equipment though. The box over the meter idea would probably only encourage them to tap in somewhere else (especially if I was away from home at the time) and perhaps overload the domestic cabling. I had been wondering whether to run some fairly substantial cabling from the point where the mains enters the house near the consumer unit to an outdoor socket especially for high current use (I have an industrial IP44 socket spare). Then I could supply an outside cable with proper plugs for tradesmen to use. What I am not quite sure about is what kind of protection to provide for this supply for occasional welding, cement mixers etc. I could bring the supply straight off the 100A switch I have before my 63A RCD, or after the RCD. If the first would I be better to have a separate switch and RCD especially for this purpose and if so what rating? A lot of these single phase arc welders seem to be about 180A. But I think that is welding current rather than supply current, which is much lower. Is that correct? Any thoughts on whether the general idea is viable?

[elkangorito]

What I am not quite sure about is what kind of protection to provide for this supply for occasional welding, cement mixers etc.

It should be RCCB protected. If an appliance trips one RCCB (at 30mA), it's passing current to earth & is most likely faulty.

I could bring the supply straight off the 100A switch I have before my 63A RCD, or after the RCD. If the first would I be better to have a separate switch and RCD especially for this purpose and if so what rating?

Do neither of these things.

If you wish to have a dedicated outlet for outside use, it should be supplied by it's own circuit. In your case, the outlet should be rated at 15 amps. The cable supplying this circuit should be 2.5mm squared copper 2c+e TPS protected by a 20 amp/30mA RCCB with a "Type C" time/current curve, provided that it is no longer than about 65 metres.

If the outlet is exposed to the weather, it will need to be rated to IP54 minimum...IP55 is better.

A lot of these single phase arc welders seem to be about 180A. But I think that is welding current rather than supply current, which is much lower.

Yes, that is welding current. Usually, these types of welders are plugged into a 15 amp outlet.

Edited February 22, 2010 by elkangorito

[citizen33]

What I am not quite sure about is what kind of protection to provide for this supply for occasional welding, cement mixers etc.

It should be RCCB protected. If an appliance trips one RCCB (at 30mA), it's passing current to earth & is most likely faulty.

I could bring the supply straight off the 100A switch I have before my 63A RCD, or after the RCD. If the first would I be better to have a separate switch and RCD especially for this purpose and if so what rating?

Do neither of these things.

If you wish to have a dedicated outlet for outside use, it should be supplied by it's own circuit. In your case, the outlet should be rated at 15 amps. The cable supplying this circuit should be 2.5mm squared copper 2c+e TPS protected by a 20 amp/30mA RCCB with a "Type C" time/current curve, provided that it is no longer than about 65 metres.

If the outlet is exposed to the weather, it will need to be rated to IP54 minimum...IP55 is better.

A lot of these single phase arc welders seem to be about 180A. But I think that is welding current rather than supply current, which is much lower.

Yes, that is welding current. Usually, these types of welders are plugged into a 15 amp outlet.

Thanks. Actually I already have a 20A MCB-protected outdoor circuit with a couple of sockets in the Thai-style kitchen and a water pump in the circuit - so perhaps that is okay for this purpose too. I had thought a welder might need 4mm2 cable, but your advice sounds right. The plugs and sockets I mentioned are the kind they use on construction sites in the UK - yellow for 110V and blue for 240V - but perhaps need to be positioned out of the rain.

[elkangorito]

2] Only use double pole circuit breakers, double pole switches & double pole RCCB's.

I'd like to amend this statement as follows;

Only use double pole circuit breakers, double pole switches & double pole RCCB's where a TN-(C-S) network is not in use.

[boatguy]

I see this is an extremely interesting and informative discussion on Thai domestic electrical wiring. Regrettably I am an electrically challenged person who only understands the very basics. It will take me some considerable time to absorb all of the knowledge contained in these postings...but I will give it a try soon.


Meanwhile I need a basic questioned answered if possible with the info I can supply here. I married a Thai woman that has this ‘lets get it done immediately or yesterday' mentality. I like to do a little research before I start a project. 

Well I mentioned that the stray currents we are feeling on the metal cases of our computers are a result of improper grounding of the house hold receptacles. (NO grounding I assume from the looks of things). So now suddenly I find she has a Thai electrician coming tomorrow to work on our townhouse wiring. Since I don’t speak Thai yet, I can’t communicate with him, and even though she speaks pretty good English I sometimes have a difficult time getting her to communicate what she has in mine. And I have trouble communicating the necessity to slow down for a moment and analysis the situation. It would appear from my limited reading on this forum subject that to do things correctly the first time around that it deserves some study.

We live on the edge of Khon Kaen in a townhouse in a neighborhood across from a technical school. It does appear as though the electrical wiring on the poles is done in a fairly neat fashion (considering its Thailand). I’ve looked up and down the street and I DO NOT see any grounding cables for the power wires. I do see a few for the lower wiring that I assume is for cable TV, internet, phone cabling. There is one power pole up the street that appeared to have a couple of heavy blue cables running down toward the ground, but these have been cut off.

 What we have coming into the house two wires for power. We have a ‘master box‘ downstairs and a master box upstairs. These are not circuit breakers but rather ‘master switches' of the push button type. All of the receptacles in the house are two prong ones with no grounding third hole. We have a refrig and a clothes washer that appear plugged into conventional 2 prong receptacles. We also have 3 air con units that appear to be wired to some sort of ‘braker’ box each. Installation appears neat.

My most basic question to begin with is how simply might we ground this system?

Can we run a HD ground wire to all the outlets, and then ground this too a dedicated grounding rod outside in the garden?

Or is there some necessity to go back to the power pole/system?

If this was done initially we might get rid of the stray discharges from the metal cases of the computers. The refrigerator box does not seem to emit any of these stray electrical currents.

Edited October 1, 2010 by boatguy

[InterestedObserver]

If all you're worried about is the computers, get an isolation transformer or UPS to break the earth (ground) loop. As for the rest of the house you're looking at a major rework if you want any kind of proper grounding system.

[boatguy]

If all you're worried about is the computers, get an isolation transformer or UPS to break the earth (ground) loop.

Have a GIZZ 800VA unit in line with the computer, but that doesn't seem to help

[InterestedObserver]

If all you're worried about is the computers, get an isolation transformer or UPS to break the earth (ground) loop.

Have a GIZZ 800VA unit in line with the computer, but that doesn't seem to help

Then your UPS does not isolate the computer from the line.

Edited October 1, 2010 by InterestedObserver

[Crossy]

If all you're worried about is the computers, get an isolation transformer or UPS to break the earth (ground) loop.

Have a GIZZ 800VA unit in line with the computer, but that doesn't seem to help

Then your UPS does not isolate the computer from the line.

An isolating transformer will remove the ground from the supply neutral and turn it into an IT supply, this will reduce the possibility of shock from a single fault. A true on-line UPS will have the same effect, but at a mere 1550 Baht the GIZZ unit is certainly not a true on-line unit.

[boatguy]

An isolating transformer will remove the ground from the supply neutral and turn it into an IT supply, this will reduce the possibility of shock from a single fault. A true on-line UPS will have the same effect, but at a mere 1550 Baht the GIZZ unit is certainly not a true on-line unit.

This GIZZ unit is one that had been purchased by her son. So you are telling me it is worthless as an isolation unit for the computer? Is it just a temporary power supply?

[Crossy]

This GIZZ unit is one that had been purchased by her son. So you are telling me it is worthless as an isolation unit for the computer? Is it just a temporary power supply?

A UPS is an Uninterruptible Power Supply, its purpose in life is to maintain the supply to your computer during short interruptions to the incoming mains, this the GIZZ will do just fine. It certainly is not worthless in this respect and probably includes a basic surge arrestor too.

However, it does not isolate your machine from the mains, indeed when the power is on it is simply fed straight through the unit and the UPS merely charges its battery. Some units do include an AVR (Automatic Voltage Regulator) which will protect from low or high supply voltage (down to about 160V) but again an AVR does not provide isolation per-se.

I can see no real reason why, in a domestic or small office environment (data centres are something else) you would want to isolate totally from the incoming supply (IT connection).

A good solid ground connection and a quality surge-arrestor (don't forget to include the phone line) will provide protection from indirect lightning strikes which are the most prevalent cause of damage, pretty much nothing will protect your kit from a direct hit

[InterestedObserver]

Has the OP had his computers and the UPS checked to determine if they are defective and the source of the 'stray currents'? Should be interesting to see what the Thai electrician comes up with.

Edited October 2, 2010 by InterestedObserver

[bankruatsteve]

You could also disconnect the power supplay, open the computer and give it a good vaccum. More often than not, the "buzz" you get from a computer case is from cobwebs, dust, bugs, etc. that accumulate inside the unit.

[boatguy]

You could also disconnect the power supply, open the computer and give it a good vaccum. More often than not, the "buzz" you get from a computer case is from cobwebs, dust, bugs, etc. that accumulate inside the unit.

It's definitely some sort of stray current, not just a buzz. Her older computer has one side cover off of it and its clean inside. The newest computer is the IMAC desktop unit I just brought from the US. There is definitely a 'discharge feeling' coming from it

[boatguy]

Don't trust ANY of the power strips you buy here in LOS. I have re-wired at least 3 of them as the units had the live and neutral reversed in all cases. Plus the cheaper ones used such poor workmanship that the soldering of the wires inside came apart. The material used for the plug-in is poorly made and cannot hold a plug tightly after just one or two uses.

Won-Pro seems a bit better and Toshino not too bad but they all cannot be trusted.

How about the power strips labeled "TAG"?? My wife has quite a few of these in use around the house. Of course they are plugged into the std 2 plug receptacles the townhouse has...which I assume are totally ungrounded.

[Crossy]

If you're getting a buzz from your PC it's certainly because of a poor earth.

Desktop PSUs require a ground for the mains filter to operate correctly, with no earth the case can float to 1/2 mains via the input capacitors.

This in NOT a fault with the PC.

Verify you have a good ground.

EDIT I see you have only 2 pin outlets, look here http://www.crossy.co.uk/wiring/2pin.html

[boatguy]

Don't trust ANY of the power strips you buy here in LOS. I have re-wired at least 3 of them as the units had the live and neutral reversed in all cases. Plus the cheaper ones used such poor workmanship that the soldering of the wires inside came apart. The material used for the plug-in is poorly made and cannot hold a plug tightly after just one or two uses.

Won-Pro seems a bit better and Toshino not too bad but they all cannot be trusted.

How about the power strips labeled "TAG"?? My wife has quite a few of these in use around the house. Of course they are plugged into the std 2 plug receptacles the townhouse has...which I assume are totally ungrounded.

Thank you Crossy, you just answered my question about these TAG power strips with your illustration on page My link . Now that is something even I should have realized, but it slipped by me. These TAG units in the house present 'grounded configuration' plugs, but they power themselves with only two pin plugs

Edited October 3, 2010 by boatguy