Domestic Electrical Wiring

[lopburi3]

If you have three wire (ground) electric there is no need for a separate ground for hot water heater - the electric ground connects to the ground terminal.

Metal clad appliances should have a grounded plug so agree most of the cheap cookers and such are a danger. Double insulated (plastic case) gets around this requirement by law but I would still prefer units that are grounded (that knob falls off and you touch the metal shaft and it could be hot without a ground wire). At the least make sure all have RCB protection.

RCB is useful for more than human protection and while using for total lighting is not good practice it is a trade off as that same RCB can prevent most electrical fires. I highly advise using for a refrigerator; your life is a lot more valuable than the off chance of some spoiled TV dinners.

In Thailand I would consider every conductive floor/wall area (most homes) a danger area and worthy of RCB protection. We walk in bare feet and often covered in sweat here making us a very good ground rod.

//RCB should read RCD in above post - also called GFI, ELCB and a number of other names//

[Crossy]

My comments in RED

Ive been doing a bit of scouting around. Its all very well saying that the MEN or PEN system is the safest, but it relies on everyone in the area including the electricity authiority to implement this system. Its no good just going it alone otherwise you may well attract other people earth faults. Personally I ve never seen this implemented in the LOS, but it may well be in the case of new builds in BKK or pattaya? I think its a non starter not for the amateyur to meddle with. Agreed, I do say that your electrician / electrical inspector will be able to tell you if MEN is implemented in your area. It is actually a requirement of the MEA regulations (such as they are), PEA are more woolly in their requirements.

An earth spike at least 2m long inserted into ground that is like to be permanently damp (eg near a cess pit or water storage/ rainwater drainage) is essentail. Yep.

Critical areas like the kitchen and bathroom Shower must be protected with an RCD. Ive seen them in Homepro for 3000 baht (Safe T Cut made in Tahiland!!!!!!!!!!!!!!!!!). Ive also seen The Square D type made to slot into their distribution boards - sounds a better bet and only a 1000 baht. Will try and look at this properly as it was locked away. The DIN rail mounting units are fare nicer than the external beasts.

The bathroom hot shower must have its own separate earth wire going to the spike togetther with a breaker switch OUTSIDE the bathroom (why do they insist on putting it inside next to the shower unit - ludicrous). NO!!!!! It is not acceptable to use a seperate ground for the water heater, all grounds must go to a ground bar and thence via a single cable to the earth spike.

Its possible now to convert over to a 3 pin socket outlet as shown in Homepro (dont know which standard this type conforms to but its common on PC equipment). Schuko is the round plug, I've converted several of my outlets to this type to suit the washing machine etc.

Personally I would recommend removing all socket outlets from the lighting circuits and blanking them off with a new plate or a dummy switch if not available). Then a completely new set of 3 wire power circuit spurs can be added using surface mounted pvc trunking. This can make a neat job. (NB no ring mains as this relies on fused plugs) Then Replace the old knife switch junk with a new Square D Cartridge mcb system. Very neat. After much effort I found some re-wireable plugs for the 3 pin system. Yep

Throw out any old kitchen appliances that have accessible metal surfaces such as the cheap rice cooker. These are potentially lethal. Get the modern totally enclosed plastic variety. Plastic kettle hotpots are great and so on Yep, metal appliances are fine if they are GROUNDED.

NB Dont use an RCD on lighting circuits (replace any metal types with all plastic). Also not adviseable on a fridge (but dont go messy with the metal parts round the back. Yes, but!! We advise protecting MOST of your lighting from a fire protection point of view, leave some 'essential' lights unprotected.

Do use a separate RCD circuit to protect any outdoor/garage power circuits in case you use power tools YES!!!

Any observations on swimming pool electrics please?? Coming soon

[robint]

Hi Crossy

I didnt explain myself properly

QUOTE

The bathroom hot shower must have its own separate earth wire going to the spike togetther with a breaker switch OUTSIDE the bathroom (why do they insist on putting it inside next to the shower unit - ludicrous).

**************************

NO!!!!! It is not acceptable to use a seperate ground for the water heater, all grounds must go to a ground bar and thence via a single cable to the earth spike.

***************************

UNQUOTE

Yes, sorry, that is what I meant to say

All earth wires must go to the earth bus in the Dis unit etc.

BTW I have seen an example of a small RCD which fits inside the standard National Circtuit breaker surface mounted switch. I will post a picture of it. Curiously it looks like the same compact RCD as used inside a Hot water shower. I am wondering if this is some kind of cobbled together assy as itts not in the National catalog?

will take the RCD apart and take some piccies. I dont believe anything in the LOS!!! If it is genuine, then I will try and find a source of supply.

also BTW these Safe T Cut units comprise an enclose about 10 times the size of the nattional unit - I suspect its largely filled with air. Its also a variable leak current type and somewhat disturbingly has a setting called "Direct" Does this mean you bypass thte RCD function completely because of nuisance trips??

Anyone any experience of this locally made product as seen in Homepro? Can you take it apartt and see what is inside

also FYI In the uk you can get a compact RCD that is like an enlarged square pin socket adaptor. Its priced at around 7 pounds ( say 500 baht) just to keep things in perspective

I am going to buy one of these 100 bahtt Square D ones from Homepro and will report back

Edited May 23, 2006 by robint

[Crossy]

Its also a variable leak current type and somewhat disturbingly has a setting called "Direct" Does this mean you bypass thte RCD function completely because of nuisance trips??

AFAIK 'Direct' means no protection!!!

A pointless option!!

I've never looked inside a Safe-T-Cut, but is suspect you are correct, lots of air. It would appear that a bigger box means better, I like the little Square-D DIN mounting units, same width as a 2 pole MCB.

Edited May 23, 2006 by Crossy

[lopburi3]

I have had a Safe-T-Cut 50 amp unit since 1978 and it is still working. The current models are about the same size and that is probably because there is no reason to make them smaller as they are used as a separate unit rather than in a breaker box. If you want a small breaker/RCD would recommend the Oz made Clipsal units which I know are available in Bangkok as have two panels.

As said the direct is bypass and turns on a red light as a warning. It means no RCD protection but all circuit breakers should still work so it may be preferable in the middle of the night when you are brain dead to use until morning, being aware you have no extra protection, than to continue trouble shooting in mummy mode.

[elkangorito]

Please don't just assume that ALL ELCB's are the same. See below;

What to purchase.

It is critical that the ELCB/RCD has a tripping current that does NOT exceed 30mA (milliamps).

Its trip time must not exceed 20mS (milliseconds). Therefore, DO NOT PURCHASE ADJUSTABLE ELCB/RCD’S unless the adjustments cannot exceed these trip currents & trip times.

The ELCB/RCD MUST have a ‘press to test’ button.

Try to purchase a device that will not be affected by;

a. the presence of a DC component upon the normal supply (half wave DC). As an example, most hair dryers use half wave rectification on the ‘low heat’ setting. Some ELCB/RCD’s will not detect an earth fault under these conditions…a potentially deadly situation in a bathroom.

b. the presence of transients or harmonics upon the normal supply. An example of this would be computer power supplies, electronic sound amplifiers & some microwave ovens. These transients/harmonics can cause some ELCB/RCD’s to trip at unacceptably high leakage currents or not trip at all.

c. a broken Neutral conductor or a broken Active conductor (4 wire systems only).

There is normally a substantial price difference between the devices that are NOT affected by the above & the devices that ARE affected by the above.

6. What the ELCB/RCD cannot do.

It cannot protect against an Active & Neutral fault. For example, if you somehow become connected across the Active conductor & the Neutral conductor, the ELCB/RCD will NOT detect an earth fault & will not trip.

It also may not save the lives of people who are very old, ill or who have severe coronary problems.

Don’t forget!!! An ELCB/RCD can never replace a good earthing & MEN system. It is an electronic device that can fail at any time without notice. Test it regularly. If you can’t afford to properly earth your installation, start saving your pennies because earthing (& MEN) is the primary defense system against electric shock.

Edited May 23, 2006 by elkangorito

[robint]

Hi elk

Whilst your advice is top shelf, straight out of the regs, I'm afraid its unlikely to benefit the layman who won't really understand the issues and certainly can't be sure in the LOS of what he is buying. I was really shocked (no pun intended) to read here what I suspected viz that the "direct" setting on the Safe T Cut RCD (made in thailand) mean the protection is bypassed. This is criminal IMHO. Under no account should this device be used. It would never be permitted in the civilised World.

I am pleased to be made aware of the hairdryer problem. Clearly a lethal device that must never be used in a bathroom - period.

What is worse than being aware that you do not have proper earth protection?

Its to think that you have RCD protection when in fact its doesnt work.

On this point let me add my experience which is that a lightning discharge near your house can "blow" and RCD sensitive electrocinic circuitry yet give no visible warning that your RCD is kaput. This happened on my hot shower and I only by change pushed the test button to no effect. We had a strike last week which took out our washing machine.

I wouldnt put a PC on and RCD circuit. They are notoriously leaky due the poor quality power supply inside (its a switched mode type). The only thing you can do is to earth the chassis.

I think the bottom line for the layman is to be aware that any metal parts of electrically connected equipment are potential shocking.(no pun intended). Always treat with suspicion. Try never to grab hold of an electrical device with both hands - very dangerous if there is a leak. If in doubt try the bare knuckle test. Lightly brush your knuckle over a metal part. If its live, you will get a tingle but not a fatal shock (assuming dry conditions). Better still use a good quality neon screw driver - but test it on a live socket to make sure its working first. Dont mess with electrics in bare feet (flip flops are not much better) or in damp/wet conditions.

Unless you know what you are doing, dont mess with live circuits. Remember the idle tizzy (electrician) always walks around with one hand in his pocket for very good reasons.

It would be nice to say "Go and talk to your qualified electrician". Give me a break, whats that in the LOS. Even if you found one, he is likely to be as precious as a quack doctor and certailny not in a position to discuss the finer point of RCD specs even if he understood english or the technology.

Teh only thing they seem good at is pinning cables onto walls neatly.

I had one from the Elec authority come and quote me for an overhead single phase supply 1km long to our farm. He worked out all the pole positions and bill of materials and Tea money ok. When I asked him what power it would supply at 200 vac he was flummuxed. So I did my own quick calc and could draw more than 5A and it was going to cost 100k for this temporary supply. I bought a honda generator instead.

So you penalised by being a Falang. Happens all the time in the LOS. Some days its best to stay in bed.

[bcross2001]

Hi elk

Whilst your advice is top shelf, straight out of the regs, I'm afraid its unlikely to benefit the layman who won't really understand the issues and certainly can't be sure in the LOS of what he is buying. I was really shocked (no pun intended) to read here what I suspected viz that the "direct" setting on the Safe T Cut RCD (made in thailand) mean the protection is bypassed. This is criminal IMHO. Under no account should this device be used. It would never be permitted in the civilised World.

I am pleased to be made aware of the hairdryer problem. Clearly a lethal device that must never be used in a bathroom - period.

What is worse than being aware that you do not have proper earth protection?

Its to think that you have RCD protection when in fact its doesnt work.

On this point let me add my experience which is that a lightning discharge near your house can "blow" and RCD sensitive electrocinic circuitry yet give no visible warning that your RCD is kaput. This happened on my hot shower and I only by change pushed the test button to no effect. We had a strike last week which took out our washing machine.

I wouldnt put a PC on and RCD circuit. They are notoriously leaky due the poor quality power supply inside (its a switched mode type). The only thing you can do is to earth the chassis.

I think the bottom line for the layman is to be aware that any metal parts of electrically connected equipment are potential shocking.(no pun intended). Always treat with suspicion. Try never to grab hold of an electrical device with both hands - very dangerous if there is a leak. If in doubt try the bare knuckle test. Lightly brush your knuckle over a metal part. If its live, you will get a tingle but not a fatal shock (assuming dry conditions). Better still use a good quality neon screw driver - but test it on a live socket to make sure its working first. Dont mess with electrics in bare feet (flip flops are not much better) or in damp/wet conditions.

Unless you know what you are doing, dont mess with live circuits. Remember the idle tizzy (electrician) always walks around with one hand in his pocket for very good reasons.

It would be nice to say "Go and talk to your qualified electrician". Give me a break, whats that in the LOS. Even if you found one, he is likely to be as precious as a quack doctor and certailny not in a position to discuss the finer point of RCD specs even if he understood english or the technology.

Teh only thing they seem good at is pinning cables onto walls neatly.

I had one from the Elec authority come and quote me for an overhead single phase supply 1km long to our farm. He worked out all the pole positions and bill of materials and Tea money ok. When I asked him what power it would supply at 200 vac he was flummuxed. So I did my own quick calc and could draw more than 5A and it was going to cost 100k for this temporary supply. I bought a honda generator instead.

So you penalised by being a Falang. Happens all the time in the LOS. Some days its best to stay in bed.

Hi - you mention runing power lines above to your home.

I have a run of approximately 650 yards - the first 500 to be above ground - the last 150 below ground. I have 220v at the main road and will be installing a 100amp service in our home.

Do you have any ideas on what type and size of wire I will require?

Do I need to place a transformer out at the main highway to insure proper power levels?

I hope someone here has some answers - as the more I continue to read this section the more concerned I become.

Barry

[johng]

Inspired by Crossy's web site,

today I went to 4 Homepro stores looking for an earthing adaptor.

for a "Schuko " plug

After that I went to 2 other hardware stores and still couldn't find one,can anyone tell me exactly

where I can purchase these ..preferably in the Pattaya area.

P.S sorry for stealing your photos Crossy

[lopburi3]

The only place I have seen the adapter is in Home Pro; but not always. They also normally carry a compact surface mount socket here in Bangkok.

[johng]

Yes they had the socket in 2 of the Homepro stores. but no adaptors.

[Crossy]

Yes they had the socket in 2 of the Homepro stores. but no adaptors.

My adaptor certainly came from HomePro (Rangsit). I found it totally by accident so it may be worth showing the piccie to the staff.

HomePro have recently started carrying a modular outlet system that allows you to make up combinations of various outlets, switches, dimmers etc. This range includes a Schuko socket (its piccie has been added to the web page). We've replaced several outlets with these, they are only a few hundred Baht and are a direct fit in the standard Thai wallbox. Unfortunately there is only room for a single Schuko outlet in the standard wallbox

[lopburi3]

If you require the double outlet (for two grounded plugs) you will have to change to the flat pin type as the adapter also covers too much of the standard outlet to plug in a second. But it is really not hard for an electrician to install a second box if you want to keep the Schuko plugs (which do make good connections) and if you convert to Schuko outlets in both you will not need the adapters.

[johng]

Thanks for all the suggestions...think I'll carry on looking for the adaptors,because thats the easiest solution ( I'm a lazy so and so ) when/if I find any I'll post the info here.

[robint]

Hi elk

Whilst your advice is top shelf, straight out of the regs, I'm afraid its unlikely to benefit the layman who won't really understand the issues and certainly can't be sure in the LOS of what he is buying. I was really shocked (no pun intended) to read here what I suspected viz that the "direct" setting on the Safe T Cut RCD (made in thailand) mean the protection is bypassed. This is criminal IMHO. Under no account should this device be used. It would never be permitted in the civilised World.

I am pleased to be made aware of the hairdryer problem. Clearly a lethal device that must never be used in a bathroom - period.

What is worse than being aware that you do not have proper earth protection?

Its to think that you have RCD protection when in fact its doesnt work.

On this point let me add my experience which is that a lightning discharge near your house can "blow" and RCD sensitive electrocinic circuitry yet give no visible warning that your RCD is kaput. This happened on my hot shower and I only by change pushed the test button to no effect. We had a strike last week which took out our washing machine.

I wouldnt put a PC on and RCD circuit. They are notoriously leaky due the poor quality power supply inside (its a switched mode type). The only thing you can do is to earth the chassis.

I think the bottom line for the layman is to be aware that any metal parts of electrically connected equipment are potential shocking.(no pun intended). Always treat with suspicion. Try never to grab hold of an electrical device with both hands - very dangerous if there is a leak. If in doubt try the bare knuckle test. Lightly brush your knuckle over a metal part. If its live, you will get a tingle but not a fatal shock (assuming dry conditions). Better still use a good quality neon screw driver - but test it on a live socket to make sure its working first. Dont mess with electrics in bare feet (flip flops are not much better) or in damp/wet conditions.

Unless you know what you are doing, dont mess with live circuits. Remember the idle tizzy (electrician) always walks around with one hand in his pocket for very good reasons.

It would be nice to say "Go and talk to your qualified electrician". Give me a break, whats that in the LOS. Even if you found one, he is likely to be as precious as a quack doctor and certailny not in a position to discuss the finer point of RCD specs even if he understood english or the technology.

Teh only thing they seem good at is pinning cables onto walls neatly.

I had one from the Elec authority come and quote me for an overhead single phase supply 1km long to our farm. He worked out all the pole positions and bill of materials and Tea money ok. When I asked him what power it would supply at 200 vac he was flummuxed. So I did my own quick calc and could draw more than 5A and it was going to cost 100k for this temporary supply. I bought a honda generator instead.

So you penalised by being a Falang. Happens all the time in the LOS. Some days its best to stay in bed.

Hi - you mention runing power lines above to your home.

I have a run of approximately 650 yards - the first 500 to be above ground - the last 150 below ground. I have 220v at the main road and will be installing a 100amp service in our home.

Do you have any ideas on what type and size of wire I will require?

Do I need to place a transformer out at the main highway to insure proper power levels?

I hope someone here has some answers - as the more I continue to read this section the more concerned I become.

Barry

hi Barry

Your proposed installatio is far from trivial. Assume that your house is already built, ie you are not asking for a temporary supply. You must appply to your local Egat area office and use a registered Electrician. The Egat office will say what they require and the size of cable. Will you really need a 100 amp supply? you should tell them what appliances you will be using particularly heavy current users such as aircons.

When you have done all that, post it on here and maybe some of the contributors can comment. Above all, do not use a suspicious traDEsmen who cannot show proper credentials. Its not woth the risk (course if you are up country you may have to go to a main town to find a proper contractor)

It won't be cheap but at least you can have the job done properly and not go through the agonies of some of the posters on this site.

[elkangorito]

Hi - you mention runing power lines above to your home.

I have a run of approximately 650 yards - the first 500 to be above ground - the last 150 below ground. I have 220v at the main road and will be installing a 100amp service in our home.

Do you have any ideas on what type and size of wire I will require?

Do I need to place a transformer out at the main highway to insure proper power levels?

I hope someone here has some answers - as the more I continue to read this section the more concerned I become.

Barry

Hi Barry,

The answers to your questions are a little complicated but the solution to your situation SHOULD totally lie in the hands of your energy authority.

1.

It is not economical to run cables above ground for a distance & then run them underground for the remainder of the distance. In your situation, running cables underground for a distance of 150 metres will mean that the overall cable size will have to be increased to allow for the extra heat 'held' in the underground cables. Therefore, in your situation, it would be more sensible to run the cables underground the entire length of the run or above ground for the entire length of the run. Underground cables are not seen & therefore not ugly. Overhead cables have their advantages, which are;

Reduced cable size due to better heat dissipation.

Easier to find any faults & therefore somewhat easier to maintain.

2.

The size of the cable will be affected by the voltage drop over a certain distance. For example, if you installed 100 amp cables without considering the length of the run, you may very well end up with a reduced voltage at your house. This is not desirable as it may cause equipment to operate incorrectly or can even damage some equipment. Subsequently, if the correct size cables are installed, there should be no need to install a 'step up' transformer. Be advised though, you may be required to install a transformer at the boundary of your property because the nearest 'domestic supply' transformer may be too far away from your property.

3.

The type of cable used is important.

If your supply is 'overhead', the cables could be 'bare' or 'single insulated' (a single layer of insulation surrounding the wire). They will either be copper or aluminium. Aluminium cables are generally larger for a given current rating, compared to that of copper cables for the same current rating. Aluminium cables are greatly cheaper compared to copper cables.

If your supply is 'underground', it should be laid in appropriately sized PVC conduit & buried at a minimum depth of 600mm. I would recommend this minimum depth in Thailand be increased to 1200mm. The cable(s) inside the conduit can be either single wires or multi-core. Single wires are the cheapest.

Barry, I hope this is not too confusing. If so, ask me & I will try to clarify.

Don't forget...this installation, even though you may be paying for it, should be TOTALLY in the hands of your energy authority (who SHOULD dictate to the electrician, what needs to be done). Maybe I'm wrong? Maybe in Thailand, it is up to the electrician to design the consumer mains from transformer to the 'point of connection'? Maybe somebody can DEFINITIVELY enlighten me on this.

I don't know if or how Thai electricians calculate voltage drop in cables. If there are no clear standards, it would be almost impossible for them to do such a calculation.

[bcross2001]

Hi - you mention runing power lines above to your home.

I have a run of approximately 650 yards - the first 500 to be above ground - the last 150 below ground. I have 220v at the main road and will be installing a 100amp service in our home.

Do you have any ideas on what type and size of wire I will require?

Do I need to place a transformer out at the main highway to insure proper power levels?

I hope someone here has some answers - as the more I continue to read this section the more concerned I become.

Barry

Hi Barry,

The answers to your questions are a little complicated but the solution to your situation SHOULD totally lie in the hands of your energy authority.

1.

It is not economical to run cables above ground for a distance & then run them underground for the remainder of the distance. In your situation, running cables underground for a distance of 150 metres will mean that the overall cable size will have to be increased to allow for the extra heat 'held' in the underground cables. Therefore, in your situation, it would be more sensible to run the cables underground the entire length of the run or above ground for the entire length of the run. Underground cables are not seen & therefore not ugly. Overhead cables have their advantages, which are;

Reduced cable size due to better heat dissipation.

Easier to find any faults & therefore somewhat easier to maintain.

2.

The size of the cable will be affected by the voltage drop over a certain distance. For example, if you installed 100 amp cables without considering the length of the run, you may very well end up with a reduced voltage at your house. This is not desirable as it may cause equipment to operate incorrectly or can even damage some equipment. Subsequently, if the correct size cables are installed, there should be no need to install a 'step up' transformer. Be advised though, you may be required to install a transformer at the boundary of your property because the nearest 'domestic supply' transformer may be too far away from your property.

3.

The type of cable used is important.

If your supply is 'overhead', the cables could be 'bare' or 'single insulated' (a single layer of insulation surrounding the wire). They will either be copper or aluminium. Aluminium cables are generally larger for a given current rating, compared to that of copper cables for the same current rating. Aluminium cables are greatly cheaper compared to copper cables.

If your supply is 'underground', it should be laid in appropriately sized PVC conduit & buried at a minimum depth of 600mm. I would recommend this minimum depth in Thailand be increased to 1200mm. The cable(s) inside the conduit can be either single wires or multi-core. Single wires are the cheapest.

Barry, I hope this is not too confusing. If so, ask me & I will try to clarify.

Don't forget...this installation, even though you may be paying for it, should be TOTALLY in the hands of your energy authority (who SHOULD dictate to the electrician, what needs to be done). Maybe I'm wrong? Maybe in Thailand, it is up to the electrician to design the consumer mains from transformer to the 'point of connection'? Maybe somebody can DEFINITIVELY enlighten me on this.

I don't know if or how Thai electricians calculate voltage drop in cables. If there are no clear standards, it would be almost impossible for them to do such a calculation.

elkangorito

Thanks very much for your reply - I'm looking at 100amps usage for our home - Is there a difference between copper and aluminium? I would assume copper is the better conductor? Therefore my idea is to double the size of the wire required - there must be some way to calculate the resistive load of copper wire lets say 100 meter of wire at a specific wire size is there not.

I would also like to know about the different types of insulation (inner and outer) - I'm close to the sea - have the usual rain and heat factors - and like to be on the safe side.

I have been following your series on grounding and circuit breakers - very good - could you forward to me all the drawings you have at this time - I caught the first one for the MEN - but as I work out of country every now and then I'm sure I have recovered the rest.

I hope perhaps that someone will be around who has done this before and can help as well.

Many thanks

Barry Cross

[elkangorito]

Hi again Barry.

I will try to find out what cable sizes should be used in your situation. It'll take me a little while so please be patient as I do not have ready access to the standards required.

As you are living near the sea, I would suggest using an underground service, if this allowable by your energy authority. Further, I would therefore use copper wire. Again, I will give you the results of the calculation asap. If you wish to use an overhead service, Aluminium cables will be the desired thing. Again, this will take time to calculate sizes etc. I advise against running your service cables overhead for 500 metres & then putting them underground for the last 150 metres. Is there a reason why this should be done?

Further, a 100 amp supply is a good thing, particularly if you plan on living in the same residence for a long time. Although, an 80 amp supply will be more than sufficient for future growth (particularly for a farang). I think you may like to consider an 80 amp supply in instead of a 100 amp supply...it can save you money on install costs. Do you plan on using any 3 phase equipment?

BTW, ALL the information previously posted within this topic can be found at http://www.crossy.co.uk/wiring/

Edited May 25, 2006 by elkangorito

[bcross2001]

Hi again Barry.

I will try to find out what cable sizes should be used in your situation. It'll take me a little while so please be patient as I do not have ready access to the standards required.

As you are living near the sea, I would suggest using an underground service, if this allowable by your energy authority. Further, I would therefore use copper wire. Again, I will give you the results of the calculation asap. If you wish to use an overhead service, Aluminium cables will be the desired thing. Again, this will take time to calculate sizes etc. I advise against running your service cables overhead for 500 metres & then putting them underground for the last 150 metres. Is there a reason why this should be done?

Further, a 100 amp supply is a good thing, particularly if you plan on living in the same residence for a long time. Although, an 80 amp supply will be more than sufficient for future growth (particularly for a farang). I think you may like to consider an 80 amp supply in instead of a 100 amp supply...it can save you money on install costs. Do you plan on using any 3 phase equipment?

BTW, ALL the information previously posted within this topic can be found at http://www.crossy.co.uk/wiring/

Thank you sir - if I had a preference I would run all my heavy appliances from 440V - and leave the lighting up to the 220V - but alas I do not have this opportunity - or so I've been told.

I will await your reply on wire specifications - I to would prefer all underground - however cost still remains a fact. I have a small bridge just prior to the commencement of my property line and therefore thought of running the cable to the bridge - hook up a junction box and then go underground from there - on to my property. Interested in any solutions you may have to this.

Thanks again

Barry Croos

[elkangorito]

Hi Barry,

I would suggest running bare Aluminium cables in 'overhead' configuration, all the way to your house although most Thai overhead consumer mains seem to be single insulated Aluminium cables. This is still ok.

From what you are telling me, I gather that you will only have a single phase service (2 wire)? Correct me if I am wrong.

[robint]

Hi Barry

Let me stress once more that the installation work you want is not suitable for a DIY layman, You must employ a competent electrical contracting company. They do exist but probably only in the major cities. Its going to cost but the work will be guaranteed and fully in compliance with local regulations. Remember you are a falang at the end of the day and if anything goes wrong you will be heeld seriously responsible, so don't take the risk.

I am dissappointed in the armchair experts here who, despite their knowledge of electrical standards, have failed to put forward a professional view point. They should also have recognised that a job like this is not suitable for a "back of the envelope" design and material spec as is being muddled herein. Its fortunate I am not your Engineering Project Manager

BTW Barry, you may not realise this but what you are asking for is a full construction specification. There is far more to it than just a few titbit comments and go and buy a bit of aluminium cable down the local store. I assume that you are a layman, and that is no disgrace whatsoever but you cannot expect a full construction spec for free across this website. Proper design work simply isnt done like that. Remeber also that the construction spec forms the basis of your legal contract with your contractor and is the standard by which work is judged to have ben carried out correctly. Its a great protection for the customer - yourself - both during construction and for liabilities after handover. All too often in the LOS, the hapless Falang gets screwed and this can often be attributed to a lack of propre design and construction specs. Its tempting to assume that an electrician is skilled in the arts. He may well be but its in the nature of construction contractors always to cut corners, build below spec and avoid documantation and consequential liabilites.

Another advantage will be that with a proper spec you can go out to the contractors and get a fixed price bid for construction. The spec will also be sufficiently detailed to allow you to purchase the materials yourself thus saving at least 10% of construction costs (this should more than cover the initial design costs), The spec will also allow you to control the finances. In your case its a small job maybe 2,3 days so stage payments will not be required, not will a downpayment - with a proper company they wouldnt worry because flangs always pay.

Initially I suggested that you post what your designer proposes, so that we all might have a look as much for own own information here as also to assist you.

For example, above, one member proposed the use of pvc conduit below ground. This would not be accepted by EGAT.

There is a purpose made PE (polythene) conduit made for the job. It has a distinctive bright yellow colour and you may see it sticking up around the place.

So that would be your minimum, but we might suggest you add concrete paving slabs just above the sand infill. This gives additional physical protection in case someone gets careless with gardfen tools in the future, a cheap form of guarantee but not in the usual specs. The conduit must be terminated in a housing so that it doesnt fill up with rainwater. Its also a good idea to leave a poly rope inside the conduit incase the cable fails in the future and a new cable must be pulled through. If the cable trench is other than line of sight then a reasonable sketch of its path should be recorded for the future.

Good luck

[elkangorito]

Hi Barry

Let me stress once more that the installation work you want is not suitable for a DIY layman, You must employ a competent electrical contracting company. They do exist but probably only in the major cities. Its going to cost but the work will be guaranteed and fully in compliance with local regulations. Remember you are a falang at the end of the day and if anything goes wrong you will be heeld seriously responsible, so don't take the risk.

I am dissappointed in the armchair experts here who, despite their knowledge of electrical standards, have failed to put forward a professional view point. They should also have recognised that a job like this is not suitable for a "back of the envelope" design and material spec as is being muddled herein. Its fortunate I am not your Engineering Project Manager

BTW Barry, you may not realise this but what you are asking for is a full construction specification. There is far more to it than just a few titbit comments and go and buy a bit of aluminium cable down the local store. I assume that you are a layman, and that is no disgrace whatsoever but you cannot expect a full construction spec for free across this website. Proper design work simply isnt done like that. Remeber also that the construction spec forms the basis of your legal contract with your contractor and is the standard by which work is judged to have ben carried out correctly. Its a great protection for the customer - yourself - both during construction and for liabilities after handover. All too often in the LOS, the hapless Falang gets screwed and this can often be attributed to a lack of propre design and construction specs. Its tempting to assume that an electrician is skilled in the arts. He may well be but its in the nature of construction contractors always to cut corners, build below spec and avoid documantation and consequential liabilites.

Another advantage will be that with a proper spec you can go out to the contractors and get a fixed price bid for construction. The spec will also be sufficiently detailed to allow you to purchase the materials yourself thus saving at least 10% of construction costs (this should more than cover the initial design costs), The spec will also allow you to control the finances. In your case its a small job maybe 2,3 days so stage payments will not be required, not will a downpayment - with a proper company they wouldnt worry because flangs always pay.

Initially I suggested that you post what your designer proposes, so that we all might have a look as much for own own information here as also to assist you.

For example, above, one member proposed the use of pvc conduit below ground. This would not be accepted by EGAT.

There is a purpose made PE (polythene) conduit made for the job. It has a distinctive bright yellow colour and you may see it sticking up around the place.

So that would be your minimum, but we might suggest you add concrete paving slabs just above the sand infill. This gives additional physical protection in case someone gets careless with gardfen tools in the future, a cheap form of guarantee but not in the usual specs. The conduit must be terminated in a housing so that it doesnt fill up with rainwater. Its also a good idea to leave a poly rope inside the conduit incase the cable fails in the future and a new cable must be pulled through. If the cable trench is other than line of sight then a reasonable sketch of its path should be recorded for the future.

Good luck

Robin, thanks for your contribution.

I shall reiterate in blue, what I said in reply to Barry's post about this;

Hi Barry,

The answers to your questions are a little complicated but the solution to your situation SHOULD totally lie in the hands of your energy authority.

...and toward the end...

Don't forget...this installation, even though you may be paying for it, should be TOTALLY in the hands of your energy authority (who SHOULD dictate to the electrician, what needs to be done). Maybe I'm wrong? Maybe in Thailand, it is up to the electrician to design the consumer mains from transformer to the 'point of connection'? Maybe somebody can DEFINITIVELY enlighten me on this.

Where was it mentioned that he should do this himself or even 'manage' this?

I don't think that Barry had any intention of being the 'Project Manager' for his installation. I do think he was seeking advice as to an expected outcome with the purpose of;

1. not being ripped off, and

2. having a safe® installation.

My skin is pretty thick so I can easily cop the 'armchair expert' remark. Please remember that this is not a forum about 'Project Management' or detailed electrical engineering. It purely exists as a guide for a safer electrical installation with the hope that less people will be needlessy electocuted.

In the meantime, could you please provide all the specifications about the polythene conduit of which you mention...available sizes, is it UV protected, can it only be used underground, what chemicals are used to connect the lengths together? Also, how many cables/wires of a certain type can be installed in a certain size polythene conduit (derating)? At what minimum depths should the polythene conduits be buried & under what conditions?

Edited May 27, 2006 by elkangorito

[Crossy]

For example, above, one member proposed the use of pvc conduit below ground. This would not be accepted by EGAT.

There is a purpose made PE (polythene) conduit made for the job. It has a distinctive bright yellow colour and you may see it sticking up around the place.

So that would be your minimum, but we might suggest you add concrete paving slabs just above the sand infill. This gives additional physical protection in case someone gets careless with gardfen tools in the future, a cheap form of guarantee but not in the usual specs. The conduit must be terminated in a housing so that it doesnt fill up with rainwater. Its also a good idea to leave a poly rope inside the conduit incase the cable fails in the future and a new cable must be pulled through. If the cable trench is other than line of sight then a reasonable sketch of its path should be recorded for the future.

Hi Robint

A couple of points, please feel free to comment / disagree. I am UK trained so some Thai regulations may differ, however I would request that you qualify any comments with references to the regulations.

1. YELLOW ducting / piping is universally accepted as being gas / oil / steam.

2. Underground electrical ducting is RED to BS 5252 04E53 - 04E56 with a YELLOW warning tape installed 300mm below ground surface.

3. Telecoms is usually ORANGE or, maybe GREEN

4. Water is BLUE.

5. Ducts may be uniform BLACK with a stripe of the appropriate colour to identify the contents.

6. AFAIK, EGAT do not provide the regulations for LV installations, these are the responsibility of MEA (or PEA in rural regions).

7. Acceptable duct materials are, Polyethylene (PE), polyvinylchloride (PVC or uPVC), chlorinated polyethylene (CPE) or chlorosulfinated polyethylene (CSPE).

I agree with the installation of concrete slab above the duct fill (under the warning tape) in areas where heavy traffic may pass but, since the duct should be at least 600mm below ground level, I doubt that it is really necessary over the entire length.

As Elkangorito noted, the installation as far as the customers meter is the responsibility of the supply authority (even if the customer is paying for it) and it is THEY who should be sizing the cable and directing the installation team.

We are NOT aiming to encourage amateur / unqualified people to perform any form of electrical work. We ARE aiming to make 'Mr Average Joe' aware of the iffy, sometimes lethal, installation practices that are often used by Thai 'electricians'.

The series of posts (earlier in this thread) by Jimmi, who has had his house rewired recently, is exactly how we intend the information contained here and on the website to be used.

Edited May 28, 2006 by Crossy

[elkangorito]

To add a little more confusion to the subject of electrical conduit, Australia essentially uses 2 types;

1. Grey PVC - it is protected against UV & cannot be used underground.

2. Orange PVC - it is NOT protected against UV & can ONLY be used underground. I have seen it used on the inside of some buildings where UV is 'supposedly' non existent. The problem is that some internal lights give off high levels of UV, which can be detrimental to this orange conduit.

At the end of the day, I don't think that burying electrical cables is a good idea in Thailand...unless drawings are created & maintained to reflect exactly where the conduit has been laid. Can anybody tell me if any Thai energy authority does exactly record the location of buried electrical cables for a domestic installation?

[Crossy]

At the end of the day, I don't think that burying electrical cables is a good idea in Thailand...unless drawings are created & maintained to reflect exactly where the conduit has been laid. Can anybody tell me if any Thai energy authority does exactly record the location of buried electrical cables for a domestic installation?

An excellent get out sir :)

I do tend to agree, underground cabling could be a receipe for trouble, no matter what colour the duct.

The stuff that MEA are using in BKK is black corrugated pipe, composition currently unknown, I'll have a look at some tomorrow and report. Since MEA are using it, it would seem reasonable to assume it's 'legal'.

[elkangorito]

Just sidestepping a little, some 'typical' energy saving tips as I posted in another topic but this post is more extensive. If anybody has any other ideas, feel free to post.

1. Don't fill your electric kettle with hot water so that it will boil quicker. You have already paid to have the water heated once...why pay to heat it twice?

2. Defrost your refrigerator regularly. In 'typical' Thai refrigerators, there is usually a red button in the freezer. This button sits approximately 5mm above the surface of the freezer. When the ice in the freezer reaches the end of the button (a 5mm build-up of ice within the freezer), defrost the refrigerator. With Thai refrigerators, defrosting requires the pressing of the button that is normally in the centre of the temperature control knob. Press this button before you go to bed at night & do not leave the door of the refrigerator open & do not not turn the refrigerator off. In the morning, the refrigerator will be defrosted (if there is not more than a 5mm build-up of ice in the freezer when you turned off the fridge. Greater than a 5mm ice build-up may require longer to defrost). Ensure that the door seals are in good order & sealing properly.

3. Use solar hot water. Thailand is an ideal place for the use of this free heating. These systems can be easily 'home built'. Additionally, a pool heating system MAY (but not recommended for drinking water use) be used to heat water. This system usually uses a large plastic matt that is placed upon the roof of your house to heat the water in your pool. This system can be converted to heat your domestic water by adding a small circulating pump & storing the heated water in an insulated storage tank. 2 problems...the water will not be as hot as that of a copper solar system & the water may have a 'plastic' taste to it. Make sure that if you choose to use the 'plastic' system that the plastic used will not be dangerous to your health. Copper is best.

4. Avoid using pressure controlled water pumps. These units will react against the pressure in an air bladder. If the pressure in the bladder reaches a lower limit, the pump is turned on until the pressure reaches the upper limit in the air bladder, at which point, the pump will turn off. Depending upon the size of the pressure controlled unit, the pump can be turned on & off several times if someone has a shower. The problem is that ALL electric motors use 6 to 8 times the amount of energy to 'start' than they need to 'run'.

A sensible alternative is to install a 'header tank'. This tank is ideally 2-3 metres higher than any water outlet within the house. The tank will have 'low level' & 'high level' float switches, which operate the pump as required. Ideally, a minimum 400 litre tank will be installed so that when the 'low level' is reached (maybe at the 100 litre level), the pump will start & run until it reaches the 'high level'. This is much more economical than having a motor switch on & off frequently. This tank will provide good water pressure if it is high enough.

5. Insulate your home.

6. Do not use 'low voltage' lighting. I'm talking about the 12 volt 25/50 watt Halogen lights. These lights generate a significant amount of heat, which makes air con work harder. Also, the transformers that supply these lights with power, are VERY inefficient (a minimum of 45% wasted energy). If you MUST use these lights, try to use 'electronic transformers' to supply this type of lighting with electricity.

7. Use electronic ballasts with fluorescent lighting wherever possible. Also, don't use the cheap fluorescent tubes. If possible, use XL Tri-Phospor tubes. More expensive but will last MANY years compared to that of standard fluoro tubes. They are also almost immune to the life reducing 'switch on, switch off' affect if used with electronic ballasts.

8. Use a microwave oven wherever possible, as opposed to using the electric range. This includes boiling water for drinks etc. Electric kettles are expensive to run compared to microwave ovens.

9. Place the 'compressor/condensor' unit of your air conditioning system, out of direct sunlight & ensure that it has lots of free space around it so that air can move freely. The generated hot air needs to escape. The same applies for refrigerators & freezers (with or without external condensor coils).

10. Do not reduce the air conditioner temperature setting to less than 25 degrees Celsius.

11. Annually, clean the condensor coil (in the 'outside' unit) with compressed air. Be careful not to bend any fins in the process. The same goes for your refrigerator & freezer (if they have external condensor coils).

12. Avoid the frequent turning 'on' & 'off' of fluorescent lighting. This type of lighting absorbs significantly more power in the 'starting' process compared to that of when it is 'on'.

13. If you have the money, buy a 'chilled water' air conditioning system. These units are very efficient but they are not available in Thailand. They can be imported from Italy & Australia.

14. Avoid buying air conditioning systems that are not sized correctly for the estimated heat load. For example, if you have purchased an 'undersized' system, it may run continuously & cost you a fortune in power usage as well as not delivering the proper cooling.

15. Don't wait for your house to get hot before you turn on your air conditioning. Bricks take ages to cool down (insulate your home properly).

16. Avoid the use of 'Instantaneous' hot water systems. Stored hot water (even if not solar) is much more efficient. This only applies to large households (more than 3 people).

17. Restrict shower time to no more than 10 minutes per person.

18. Do not leave electronic equipment such as television sets, video players, DVD players & audio system in 'standby' mode. Switch them off totally. Due to the high ambient temperature in Thailand, this equipment will not suffer a reduced life, which happens as a result of the 'hot/cold' effect.

Edited May 29, 2006 by elkangorito

[elkangorito]

Just sidestepping a little, some 'typical' energy saving tips as I posted in another topic but this post is more extensive. If anybody has any other ideas, feel free to post.

1. Don't fill your electric kettle with hot water so that it will boil quicker. You have already paid to have the water heated once...why pay to heat it twice?

2. Defrost your refrigerator regularly. In 'typical' Thai refrigerators, there is usually a red button in the freezer. This button sits approximately 5mm above the surface of the freezer. When the ice in the freezer reaches the end of the button (a 5mm build-up of ice within the freezer), defrost the refrigerator. With Thai refrigerators, defrosting requires the pressing of the button that is normally in the centre of the temperature control knob. Press this button before you go to bed at night & do not leave the door of the refrigerator open & do not not turn the refrigerator off. In the morning, the refrigerator will be defrosted (if there is not more than a 5mm build-up of ice in the freezer when you turned off the fridge. Greater than a 5mm ice build-up may require longer to defrost). Ensure that the door seals are in good order & sealing properly.

3. Use solar hot water. Thailand is an ideal place for the use of this free heating. These systems can be easily 'home built'. Additionally, a pool heating system MAY (but not recommended for drinking water use) be used to heat water. This system usually uses a large plastic matt that is placed upon the roof of your house to heat the water in your pool. This system can be converted to heat your domestic water by adding a small circulating pump & storing the heated water in an insulated storage tank. 2 problems...the water will not be as hot as that of a copper solar system & the water may have a 'plastic' taste to it. Make sure that if you choose to use the 'plastic' system that the plastic used will not be dangerous to your health. Copper is best.

4. Avoid using pressure controlled water pumps. These units will react against the pressure in an air bladder. If the pressure in the bladder reaches a lower limit, the pump is turned on until the pressure reaches the upper limit in the air bladder, at which point, the pump will turn off. Depending upon the size of the pressure controlled unit, the pump can be turned on & off several times if someone has a shower. The problem is that ALL electric motors use 6 to 8 times the amount of energy to 'start' than they need to 'run'.

A sensible alternative is to install a 'header tank'. This tank is ideally 2-3 metres higher than any water outlet within the house. The tank will have 'low level' & 'high level' float switches, which operate the pump as required. Ideally, a minimum 400 litre tank will be installed so that when the 'low level' is reached (maybe at the 100 litre level), the pump will start & run until it reaches the 'high level'. This is much more economical than having a motor switch on & off frequently. This tank will provide good water pressure if it is high enough.

5. Insulate your home.

6. Do not use 'low voltage' lighting. I'm talking about the 12 volt 25/50 watt Halogen lights. These lights generate a significant amount of heat, which makes air con work harder. Also, the transformers that supply these lights with power, are VERY inefficient (a minimum of 45% wasted energy). If you MUST use these lights, try to use 'electronic transformers' to supply this type of lighting with electricity.

7. Use electronic ballasts with fluorescent lighting wherever possible. Also, don't use the cheap fluorescent tubes. If possible, use XL Tri-Phospor tubes. More expensive but will last MANY years compared to that of standard fluoro tubes. They are also almost immune to the life reducing 'switch on, switch off' affect if used with electronic ballasts.

8. Use a microwave oven wherever possible, as opposed to using the electric range. This includes boiling water for drinks etc. Electric kettles are expensive to run compared to microwave ovens.

9. Place the 'compressor/condensor' unit of your air conditioning system, out of direct sunlight & ensure that it has lots of free space around it so that air can move freely. The generated hot air needs to escape. The same applies for refrigerators & freezers (with or without external condensor coils).

10. Do not reduce the air conditioner temperature setting to less than 25 degrees Celsius.

11. Annually, clean the condensor coil (in the 'outside' unit) with compressed air. Be careful not to bend any fins in the process. The same goes for your refrigerator & freezer (if they have external condensor coils).

12. Avoid the frequent turning 'on' & 'off' of fluorescent lighting. This type of lighting absorbs significantly more power in the 'starting' process compared to that of when it is 'on'.

13. If you have the money, buy a 'chilled water' air conditioning system. These units are very efficient but they are not available in Thailand. They can be imported from Italy & Australia.

14. Avoid buying air conditioning systems that are not sized correctly for the estimated heat load. For example, if you have purchased an 'undersized' system, it may run continuously & cost you a fortune in power usage as well as not delivering the proper cooling.

15. Don't wait for your house to get hot before you turn on your air conditioning. Bricks take ages to cool down (insulate your home properly).

16. Avoid the use of 'Instantaneous' hot water systems. Stored hot water (even if not solar) is much more efficient. This only applies to large households (more than 3 people).

17. Restrict shower time to no more than 10 minutes per person.

18. Do not leave electronic equipment such as television sets, video players, DVD players & audio system in 'standby' mode. Switch them off totally. Due to the high ambient temperature in Thailand, this equipment will not suffer a reduced life, which happens as a result of the 'hot/cold' effect.

I forgot to mention one other thing; if you wish to use standard ballasts for lighting as opposed to 'electronic ballasts', make sure that they are of the 'high power factor' variety. This is easily detected as low Power Factor ballasts will have something like 'Cos 0.5' written upon them. High Power Factor ballasts will be 0.9 or 0.95.

Edited May 29, 2006 by elkangorito

[lopburi3]

13. If you have the money, buy a 'chilled water' air conditioning system. These units are very efficient but they are not available in Thailand. They can be imported from Italy & Australia.

I do not believe any are marketed for home use but chillers are available here and some are even made in Thailand from a quick Google search. I suspect the units you mention from Italy and Oz are a little more attractive than the normal industrial type however.

[elkangorito]

13. If you have the money, buy a 'chilled water' air conditioning system. These units are very efficient but they are not available in Thailand. They can be imported from Italy & Australia.

I do not believe any are marketed for home use but chillers are available here and some are even made in Thailand from a quick Google search. I suspect the units you mention from Italy and Oz are a little more attractive than the normal industrial type however.

The 'chillers' I speak of are designed for domestic use as self contained compact units. As a matter of fact, they are of a similar size to that of DX (direct expansion) units. As you may be aware, these units deliver a more constant air temperature with regard to the 'on/off' cycle of the compressor. With DX units (standard air conditioning), the supplied air is VERY cold whilst the compressor is in operation.

[Crossy]

Had a look at the ducting being used by MEA.

150mm PE, BLACK with a RED tracer stripe.

Stick with a similar spec. and you can't go too far wrong.