Domestic Electrical Wiring

[robint]

Hi Elk

As a retired professional it would be most unprofessional tto offer half baked specifications on a website like this which is intended for the layman. Many of the issues disussed here are well beyond the understanding of such a layman (which is not discredit to the layman anymore than I would care to speculate on brain surgery)

QUOTE

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?

UNQUOTE

I can only report on what I have seen in recent installations in the Khorat province. Custom and practice as with all things in the LOS varies widely according to which province. I too have seen the corrugated 150mm trunking in bkk. I will look more closely at it and take some piccies.

One must not forget here that the domestic liability for the consumer starts at his meter and the down stream main fuse/knife switch. Up stream of that is the responsibility of the PEA although you have to pay for the installation. If its a simple stringing of a blue 50mm2 ali pair across from a street pole. The PEA will happily do that - usually failry quickly. If its more complicated and a longer distance then you have to employ an approved contractor and carry out the earth works yourself beforehand.

Its ok to discuss the Theoretical issues, but when it comes to the local acceptable installation design and practice, that requires specialist detailed knowledge. Under no circumstances must the Falang ever put himself in this liability chain. The slightest excuse and you will be hung drawn and quartered and even thrown into jail untill you cough up for consequential damages.

[robint]

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?

Can you support this with a technical calculation, it seems to contradict the conservations of energy law

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.

In principle I agree, but then custom and practice in the LOS is that this feature is only available in the more expensive models. Standard models you have to manually defrost and there will be no little red button. This being said you have failed to mention that the fridge should be located in a cool part of the kitchen, ie not against a south facing hot wall or near a gas stove and the back must be well ventialted

3. Use solar hot water. Thailand is an ideal place for the use of this free heating.

Yes indeed, in fact I get a free hot shower simply because I have located my steel storage tank in a south facing location and surround it on 3 side with a simple waal and roof to collect the heat like a sun trap. works a treat

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.

Why on god's earth do you want hot drinking 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.

I havent seen a plastic mat commercially available, do you have any vendor details?

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.

how much energy will your pump use?? how many baht per day???? or will it be cheaper to use an immersion heater

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.

On no account should such a plastic system be used for drinking water. In the LOS there is a food grade polythene that is used to store drinking water, commercial pvc plastice not only have a bad smeel which taints the water but also release cancer causing chemicals

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'.

In many places this is the only option to a roof mounted storage tank. Perhaps you would like to back up your fearsome energy claims with some calculations - are we saving 5 or 10 baht a week here??????

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.

what with in the LOS?

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 the xformers are up in the roof void then no load on the ac. So if we had 10 of these display spots in a kitchen area we would lose say 100W but we gain 50% more Lumens??? as compared with a standard filament lamp

If you MUST use these lights, try to use 'electronic transformers' to supply this type of lighting with electricity.

These should definately be earthed as with any metal casings on the lampholders

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.

I have been using 12vdc electronic starters for use on battery backed lighting. These provide a nominal 220vdc output but I have a suspicion that its a crude square wave which reduces the life of a tube by a hundred fold. I only typical get say 300 hours instead of 3000 hours so I wonder if the EBs made in thailand for 220v use are of a similarly crude nature? FYI it only takes an overvoltage of 10% to reduce a tube life by 50%

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.

Dont agree here Microwave is less than 50% efficient. Do your own calc by timing how long it takes to boil a litre of water, then do the same for a kettle, remembering to correct for the different power consumption. Please publish your own experimental results

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.

Agreed, I leave mine at 28C for my sedentry occupation indoors

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.Dont understand this please explain? What you say is certainly true for an oversized unit

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 properlywhat with).

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).Can you back this up with calcs? - only apppliacable if you have off peak rate for electric usage not applicable in thailand

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

try telling that to a thai

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.

Words fail me here, its the electrical stress and startup currents that shorten life mostly

[elkangorito]

robint, please feel free to provide all the answers to the questions that you put to me, since you obviously feel that my logic is flawed.

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?

Can you support this with a technical calculation, it seems to contradict the conservations of energy law

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.

In principle I agree, but then custom and practice in the LOS is that this feature is only available in the more expensive models. Standard models you have to manually defrost and there will be no little red button. This being said you have failed to mention that the fridge should be located in a cool part of the kitchen, ie not against a south facing hot wall or near a gas stove and the back must be well ventialted

3. Use solar hot water. Thailand is an ideal place for the use of this free heating.

Yes indeed, in fact I get a free hot shower simply because I have located my steel storage tank in a south facing location and surround it on 3 side with a simple waal and roof to collect the heat like a sun trap. works a treat

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.

Why on god's earth do you want hot drinking 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.

I havent seen a plastic mat commercially available, do you have any vendor details?

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.

how much energy will your pump use?? how many baht per day???? or will it be cheaper to use an immersion heater

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.

On no account should such a plastic system be used for drinking water. In the LOS there is a food grade polythene that is used to store drinking water, commercial pvc plastice not only have a bad smeel which taints the water but also release cancer causing chemicals

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'.

In many places this is the only option to a roof mounted storage tank. Perhaps you would like to back up your fearsome energy claims with some calculations - are we saving 5 or 10 baht a week here??????

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.

what with in the LOS?

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 the xformers are up in the roof void then no load on the ac. So if we had 10 of these display spots in a kitchen area we would lose say 100W but we gain 50% more Lumens??? as compared with a standard filament lamp

If you MUST use these lights, try to use 'electronic transformers' to supply this type of lighting with electricity.

These should definately be earthed as with any metal casings on the lampholders

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.

I have been using 12vdc electronic starters for use on battery backed lighting. These provide a nominal 220vdc output but I have a suspicion that its a crude square wave which reduces the life of a tube by a hundred fold. I only typical get say 300 hours instead of 3000 hours so I wonder if the EBs made in thailand for 220v use are of a similarly crude nature? FYI it only takes an overvoltage of 10% to reduce a tube life by 50%

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.

Dont agree here Microwave is less than 50% efficient. Do your own calc by timing how long it takes to boil a litre of water, then do the same for a kettle, remembering to correct for the different power consumption. Please publish your own experimental results

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.

Agreed, I leave mine at 28C for my sedentry occupation indoors

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.Dont understand this please explain? What you say is certainly true for an oversized unit

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 properlywhat with).

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).Can you back this up with calcs? - only apppliacable if you have off peak rate for electric usage not applicable in thailand

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

try telling that to a thai

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.

Words fail me here, its the electrical stress and startup currents that shorten life mostly

[gcad]

Hi guys, first post on this forum for me!

This thread caught my attention because I am also an electrician in Australia, actually a 3rd year apprentice at this stage with another 6 months of trade school to go and another 18 months of on the job experience to finish my time, I wish it would hurry up!

I hate to criticise but the quality of tradesmanship in Thailand from what I've seen is terrible and I wouldn't be surprised if there are a lot of electrical fatalities resulting from ignorant "electricians". To call them electricians is very demeaning to me, it's a respected trade where I come from!

Does anybody know what the licensing or qualification requirements are for electricians in Thailand, if there are any? I found the wiring in Thailand quite amusing and took many photos to show my workmates at home. If the electricians are bad, the linesmen are even worse, some low voltage street mains in Phuket touch the ground and they look like they've been that way for a long time.

I agree with most of what elkangorito has said, although I'd protect my lighting sub-circuits with an RCD (as required by AS/NZS 3000) and wouldn't put any water heaters on RCD protection, unless the unit was right next to the shower, which alarmingly seems to be common practice in Thailand. not to be arrogant but our Australian standards are probably on par with the best in the world and if others could follow our lead then the world would be a much safer place.

Another question, have Thais ever heard of cable ties?

[Crossy]

Welcome to the madhouse we call Thaivisa

Intelligent comment is always welcome, even from Aussies (Soapdodging Brit. here).

Have you had a chance to check out our electrical wiring site at http://www.crossy.co.uk/wiring/ where we are attempting to concentrate our electrical knowledge into something we can all use.

Please feel free to comment on the content (here or on a PM).

Meanwhile, if you want to share your best piccies I'd be happy to include them in our 'rogues gallery'. Post them here or email to me (check my profile for the address).

EDIT. Homepro always has a good stock of cable ties, probably because nobody buys them !!

[elkangorito]

Hi guys, first post on this forum for me!

This thread caught my attention because I am also an electrician in Australia, actually a 3rd year apprentice at this stage with another 6 months of trade school to go and another 18 months of on the job experience to finish my time, I wish it would hurry up!

I hate to criticise but the quality of tradesmanship in Thailand from what I've seen is terrible and I wouldn't be surprised if there are a lot of electrical fatalities resulting from ignorant "electricians". To call them electricians is very demeaning to me, it's a respected trade where I come from!

Does anybody know what the licensing or qualification requirements are for electricians in Thailand, if there are any? I found the wiring in Thailand quite amusing and took many photos to show my workmates at home. If the electricians are bad, the linesmen are even worse, some low voltage street mains in Phuket touch the ground and they look like they've been that way for a long time.

I agree with most of what elkangorito has said, although I'd protect my lighting sub-circuits with an RCD (as required by AS/NZS 3000) and wouldn't put any water heaters on RCD protection, unless the unit was right next to the shower, which alarmingly seems to be common practice in Thailand. not to be arrogant but our Australian standards are probably on par with the best in the world and if others could follow our lead then the world would be a much safer place.

Another question, have Thais ever heard of cable ties?

G'day gcad.

Just a quick question...are you on holidays in Thailand, or not?

Anyway, a word about this thread...it is simply here as a guideline for safer electrical installations in Thailand. This post does not exist in any way, to impose anothers countries rules & regs onto Thailand, although a minimum electrical standard seems to have been realised & silently agreed upon. There are few known 'qualified' respondents to this topic who come from different parts of the globe. As a result, we collectively feel that if we can 'mix & match' our expertise (complete with 'Standards'), we can come up with acceptable & safe suggestions for the domestic installation.

About electrical 'standards' in Thailand? There are some but they don't seem to relate to domestic installations. I've spent hours searching for this info but found bugger all. I'm yet to find out who decided & who still insists upon the way that domestic electrical installations are approved. Thai electrical inspectors seem more concerned about appearence than they are about the 'logical' safety of an installation. I think that they don't even conduct the basic tests of insulation resistance & polarity prior to energising the installation. To think anything about earthing is like thinking of a fantasy...it seems not to be important to the Thai authorities.

So now, you may have some idea of the Thai electrical attitude. Comforting, isn't it?

Since I'm an electrician, the first thing I noticed when I arrived in Thailand, was the atrocious state of all things electrical. All I can hope for is a slow but steady 'awakening' to this situation with all people living in Thailand.

Anyway, have fun & misbehave.

By the way....

[gcad]

Welcome to the madhouse we call Thaivisa

Intelligent comment is always welcome, even from Aussies (Soapdodging Brit. here).

Have you had a chance to check out our electrical wiring site at http://www.crossy.co.uk/wiring/ where we are attempting to concentrate our electrical knowledge into something we can all use.

Please feel free to comment on the content (here or on a PM).

Meanwhile, if you want to share your best piccies I'd be happy to include them in our 'rogues gallery'. Post them here or email to me (check my profile for the address).

EDIT. Homepro always has a good stock of cable ties, probably because nobody buys them !!

Hi Crossy thanks for the warm welcome. I have had a look at your website and it is quite an interesting refresher on domestic wiring, I wish I knew about it when I started my apprenticeship, I might even show some of the industrial boys at work who have never done domestic wiring before because they just don't seem to get it.

One thing that caught my eye, your general rule of thumb of 7 double socket outlets on any one sub-circuit? I find that very interesting because over here we can load up as many socket outlets as we like on the sub-circuits because we rely on the CB to do its job in the event of overcurrent. Obviously for the sake of calculating maximum demand, you wouldn't put all the SO's on one sub-circuit, but nevertheless there is no limit here because it's assumed that not all the SO's will be used simultaneously either. However for a comparison rule of thumb I'd say 10 double socket outlets, or 20 outlets in total, is quite normal, that is allowing 1 amp per outlet on a 20 amp CB with 2.5mm cable.

I think a good addition to your site might include some cabling methods. I noticed that the majority of houses I have been to have slab walls with the TPS clipped on the interior. I know what I'd do in that case, get the angle grinder and chisel drill out and put some dirty big holes in the wall to put the cables in, then render over them. I just can't stand obscene wiring, even if it is clipped neatly and straightly on the inside of the wall, it's still bad!

I'll shoot you a PM too.

[gcad]

Hi guys, first post on this forum for me!

This thread caught my attention because I am also an electrician in Australia, actually a 3rd year apprentice at this stage with another 6 months of trade school to go and another 18 months of on the job experience to finish my time, I wish it would hurry up!

I hate to criticise but the quality of tradesmanship in Thailand from what I've seen is terrible and I wouldn't be surprised if there are a lot of electrical fatalities resulting from ignorant "electricians". To call them electricians is very demeaning to me, it's a respected trade where I come from!

Does anybody know what the licensing or qualification requirements are for electricians in Thailand, if there are any? I found the wiring in Thailand quite amusing and took many photos to show my workmates at home. If the electricians are bad, the linesmen are even worse, some low voltage street mains in Phuket touch the ground and they look like they've been that way for a long time.

I agree with most of what elkangorito has said, although I'd protect my lighting sub-circuits with an RCD (as required by AS/NZS 3000) and wouldn't put any water heaters on RCD protection, unless the unit was right next to the shower, which alarmingly seems to be common practice in Thailand. not to be arrogant but our Australian standards are probably on par with the best in the world and if others could follow our lead then the world would be a much safer place.

Another question, have Thais ever heard of cable ties?

G'day gcad.

Just a quick question...are you on holidays in Thailand, or not?

Anyway, a word about this thread...it is simply here as a guideline for safer electrical installations in Thailand. This post does not exist in any way, to impose anothers countries rules & regs onto Thailand, although a minimum electrical standard seems to have been realised & silently agreed upon. There are few known 'qualified' respondents to this topic who come from different parts of the globe. As a result, we collectively feel that if we can 'mix & match' our expertise (complete with 'Standards'), we can come up with acceptable & safe suggestions for the domestic installation.

About electrical 'standards' in Thailand? There are some but they don't seem to relate to domestic installations. I've spent hours searching for this info but found bugger all. I'm yet to find out who decided & who still insists upon the way that domestic electrical installations are approved. Thai electrical inspectors seem more concerned about appearence than they are about the 'logical' safety of an installation. I think that they don't even conduct the basic tests of insulation resistance & polarity prior to energising the installation. To think anything about earthing is like thinking of a fantasy...it seems not to be important to the Thai authorities.

So now, you may have some idea of the Thai electrical attitude. Comforting, isn't it?

Since I'm an electrician, the first thing I noticed when I arrived in Thailand, was the atrocious state of all things electrical. All I can hope for is a slow but steady 'awakening' to this situation with all people living in Thailand.

Anyway, have fun & misbehave.

By the way....

G'day!

Yes, understood, we're not interested in imposing our rules onto Thailand, it just wouldn't be Thailand without the dodgy wiring! Let's not get started on the road laws.

It is an interesting comparison though, Australia the over-bureaucratic safety first laws in comparison to Thailand's use at your own risk type attitude. I mean it's not even legal to be drunk in an Australian pub for heaven's sake!

I'm not on holidays in Thailand. I just got back from my first visit and I'm hooked, it has changed my life. I'm chucking the aspirations of owning my own electrical company in Australia out the window and going to try get a job on a rig when I qualify so I can get weeks off at a time to spend my spare time there. I was so depressed when I got back to Australia, I cannot even begin to describe how bad I felt! Not that there is anything wrong with this country (hey the wiring is pretty good lol) but it's just so boring in comparison.

Thanks for the welcome and information. I'll send you a PM too.

PS. Sorry that I've drifted away from the topic of conversation but I have to introduce myself to the masses somewhere!

[elkangorito]

In the meantime, just a quick paper about basic lighting.

[Crossy]

In the meantime, just a quick paper about basic lighting.

Cheers for that Elk. I'll add it to the site ASAP, probably over the weekend.

[Crossy]

One thing that caught my eye, your general rule of thumb of 7 double socket outlets on any one sub-circuit? I find that very interesting because over here we can load up as many socket outlets as we like on the sub-circuits because we rely on the CB to do its job in the event of overcurrent. Obviously for the sake of calculating maximum demand, you wouldn't put all the SO's on one sub-circuit, but nevertheless there is no limit here because it's assumed that not all the SO's will be used simultaneously either. However for a comparison rule of thumb I'd say 10 double socket outlets, or 20 outlets in total, is quite normal, that is allowing 1 amp per outlet on a 20 amp CB with 2.5mm cable.

You've got to draw a line somewhere, if we'd left out a figure some bright spark would ask so 7 seemed a sensible medium. My rented place has 3 doubles per breaker, I'll probably wire the house the same, when we get it to be more than a flat piece of swamp that is.

Remember TiT (This is Thailand), you can guarantee that someone somewhere has a double outlet with a welder plugged into each outlet and someone else with a bl00dy great hammer drill nearby. Pop goest the 20A breaker :)

[elkangorito]

One thing that caught my eye, your general rule of thumb of 7 double socket outlets on any one sub-circuit? I find that very interesting because over here we can load up as many socket outlets as we like on the sub-circuits because we rely on the CB to do its job in the event of overcurrent. Obviously for the sake of calculating maximum demand, you wouldn't put all the SO's on one sub-circuit, but nevertheless there is no limit here because it's assumed that not all the SO's will be used simultaneously either. However for a comparison rule of thumb I'd say 10 double socket outlets, or 20 outlets in total, is quite normal, that is allowing 1 amp per outlet on a 20 amp CB with 2.5mm cable.

You've got to draw a line somewhere, if we'd left out a figure some bright spark would ask so 7 seemed a sensible medium. My rented place has 3 doubles per breaker, I'll probably wire the house the same, when we get it to be more than a flat piece of swamp that is.

Remember TiT (This is Thailand), you can guarantee that someone somewhere has a double outlet with a welder plugged into each outlet and someone else with a bl00dy great hammer drill nearby. Pop goest the 20A breaker :)

Thanks dave. What you describe can be typical in Thailand.

The reason why I indicated no more than 7 DGPO's be installed is quite simple. Back in the 'old' days, (before your time, gcad) this number of DGPO's was permitted per circuit. This was purely to reduce the inconvenience to the user (reduced overcurrent trips) & also to assist with Maximum Demand.

Since Thailand seems to be generally unregulated electrically, I thought it to be a good idea to limit the number of DGPO's (as per previous AS 3000 requirements) so as not to give a false impression for the people that read these posts. You are correct in saying that there is no demand limit in Australia but the same logic applied in Thailand would mean constant 'trips' for power circuits. Plus, in Thailand, specific Kilowatt Hour Meters are designated to specific loads. Generally, it is good in Thailand to know your maximum demand to size your meter & therefore your cable(s).

[Crossy]

Prompted by Elkangorito's 'lighting' document (currently being fettled for the website), I noticed some low-energy lamps in HomePro with a very large "Dimmable" on the box, I've not looked closely but I assume you can use a conventional triac dimmer with these.

Anyone tried these?? Comments??

[gcad]

One thing that caught my eye, your general rule of thumb of 7 double socket outlets on any one sub-circuit? I find that very interesting because over here we can load up as many socket outlets as we like on the sub-circuits because we rely on the CB to do its job in the event of overcurrent. Obviously for the sake of calculating maximum demand, you wouldn't put all the SO's on one sub-circuit, but nevertheless there is no limit here because it's assumed that not all the SO's will be used simultaneously either. However for a comparison rule of thumb I'd say 10 double socket outlets, or 20 outlets in total, is quite normal, that is allowing 1 amp per outlet on a 20 amp CB with 2.5mm cable.

You've got to draw a line somewhere, if we'd left out a figure some bright spark would ask so 7 seemed a sensible medium. My rented place has 3 doubles per breaker, I'll probably wire the house the same, when we get it to be more than a flat piece of swamp that is.

Remember TiT (This is Thailand), you can guarantee that someone somewhere has a double outlet with a welder plugged into each outlet and someone else with a bl00dy great hammer drill nearby. Pop goest the 20A breaker :)

Thanks dave. What you describe can be typical in Thailand.

The reason why I indicated no more than 7 DGPO's be installed is quite simple. Back in the 'old' days, (before your time, gcad) this number of DGPO's was permitted per circuit. This was purely to reduce the inconvenience to the user (reduced overcurrent trips) & also to assist with Maximum Demand.

Since Thailand seems to be generally unregulated electrically, I thought it to be a good idea to limit the number of DGPO's (as per previous AS 3000 requirements) so as not to give a false impression for the people that read these posts. You are correct in saying that there is no demand limit in Australia but the same logic applied in Thailand would mean constant 'trips' for power circuits. Plus, in Thailand, specific Kilowatt Hour Meters are designated to specific loads. Generally, it is good in Thailand to know your maximum demand to size your meter & therefore your cable(s).

The thing is if you do calculate maximum demand by limitation, which I think is great for domestic wiring, then you're not going to be posing much of a threat to the safety of the installation whether you have 7 active double GPO's or 70 because the circuit breaker will do its job as intended. I understand the point that if you say it's okay to use 70 powerpoints on one circuit then eventually somebody will do it but feel that it's important for the electrician who is wiring the place to know that provided no more than 20 amps (or whatever the CB rating is) are being drawn then there will be no chance of the circuit breaker tripping unless there is a short circuit somewhere. I think 7 power points is a bit on the cheap side, people are just going to stick powerboards and double adapters on anyway if you under powerpoint the place.

[Crossy]

I think 7 power points is a bit on the cheap side, people are just going to stick powerboards and double adapters on anyway if you under powerpoint the place.

Nobody said anything about only having 7 power points

7 PER BREAKER is what we said, I've got 14 breakers in my 2 bed condo 6 of which are for power outlets, none of them controls more than 3 doubles, most only handle 2, one of the breakers has got only 1 (single Schuko) for the washer.

Lack of outlets is a major problem here, the more the better

Just for the record, the rest of the breakers are:-

3 for aircon

4 for lighting

1 for the water heater (and bathroom outlet)

Please remember, you're not in Kansas Oz any more, we are trying to tailor advice to suit local conditions, what's perfectly ok in one place may be problematic elsewhere.

[gcad]

I don't think anyone would be putting themselves in any danger just because there were a lot of powerpoints in their house on one circuit. Really, it is a waste of resources to have 2.5mm cable going to powerpoints if that copper isn't being used anywhere near its potential current carrying capacity. It might help to split those powerpoints across two circuits if you've got some laundry or kitchen appliances to reduce the load at peak usage times, which is what I'd do, but other than that there is nothing dangerous.

[elkangorito]

I don't think anyone would be putting themselves in any danger just because there were a lot of powerpoints in their house on one circuit. Really, it is a waste of resources to have 2.5mm cable going to powerpoints if that copper isn't being used anywhere near its potential current carrying capacity. It might help to split those powerpoints across two circuits if you've got some laundry or kitchen appliances to reduce the load at peak usage times, which is what I'd do, but other than that there is nothing dangerous.

Hi gcad,

This is not so much about safety but is more about 'convenience'.

The problem is that YOU know this, Crossy knows this & I know this. The other posters aren't necessarily electrically 'up to speed' in the least. Therefore & as a guideline, it is recommended that only 7 GPO's be used per power circuit. One must remember that the installation will be carried out by Thai 'electricians'. At least the consumer will be able to watch carefully & ensure that the 'electrician' carries out their requirements. Thai 'electricians' have been known to do amazing things.

At the end of the day, it would be advisable to not have constant nuisance trips of power circuit CB's, as no doubt, other appliances will also be interrupted by this trip.

With all standard GPO's rated at 10 amps each, how many appliances can be plugged into how many GPO's before the CB trips? Of course this relates to the wattage of the appliance. If people wish to use power boards (that usually have built-in overload protection), this is will not present a problem as the power board overload may trip before the CB does.

I must reiterate that this scenario only applies to Thailand due to the lack of knowledge of some Thai 'electricians' & the lack of regulatory control in Thailand.

What sensible electrician would put in excess of 14 DGPO's on one power circuit? As for me...never. In addition, my personal general rule is to not have any more than 4 DGPO's on any power cicuit, purely to minimise nuisance tripping.

[lopburi3]

Amazing 101

Installation of kitchen exhaust system today. They ask for breaker to hook up to. I ask power requirement. They say 15 amps. I find spare 16 amp breaker on sub panel and remove cover for them. They later start running wire and I notice two conductor 1.5mm so ask them for 3 wire ground from motor to panel. They seem to understand (it was translated) but go out and buy stand alone breaker. Ok if they want we will use that as an expensive switch so be it. Provide them some of our extra three conductor 2.5mm wire. As they are about to connect to panel I open switch/breaker to find old two conductor still run to motor. But what makes me run for panel to stop them is I find they have attached ground and hot together and neutral to the other terminal feeding the breaker. As breaker only has two connections I guess they figure no problem - insert two wires wherever they will fit.

[elkangorito]

Amazing 101

Installation of kitchen exhaust system today. They ask for breaker to hook up to. I ask power requirement. They say 15 amps. I find spare 16 amp breaker on sub panel and remove cover for them. They later start running wire and I notice two conductor 1.5mm so ask them for 3 wire ground from motor to panel. They seem to understand (it was translated) but go out and buy stand alone breaker. Ok if they want we will use that as an expensive switch so be it. Provide them some of our extra three conductor 2.5mm wire. As they are about to connect to panel I open switch/breaker to find old two conductor still run to motor. But what makes me run for panel to stop them is I find they have attached ground and hot together and neutral to the other terminal feeding the breaker. As breaker only has two connections I guess they figure no problem - insert two wires wherever they will fit.

Thank god you were watching Lop

BTW, it must be a bloody big exhaust fan that you installed (3.3 kW?). Be careful that it doesn't suck you or the missus into it

[lopburi3]

Actually am sure the motor draws nothing like 15 amps but it is the large type exhaust system like used in shop house restaurants with turbine fan in stack - all SS construction. They tested it using two wires into an extension cord. Will wait for proper electrician to run wires and complete the install Tuesday. It's not like this is the first system they have installed and perhaps they would not have had a problem with two wires; getting it running. But is sure would not be safe with all the steel directly connected to a motor. And this is Bangkok. One can but wonder what happens in Nakorn Nowhere.

[elkangorito]

Stay tuned.

Coming very very soon...Maximum Demand Calculation, based upon the latest Australian & New Zealand Electrical Wiring Rules (AS/NZS 3000).

[elkangorito]

The below attachment is a 'basic' & simplified indication of how to calculate a Maximum Demand for a 'Single Phase' Single Domestic (residential) Electrical Installation.

If anybody has any questions relating to this document OR if they would like a specific Maximum Demand calculated for other equipment, feel free to ask.

[elkangorito]

The below attachment is a 'basic' & simplified indication of how to calculate a Maximum Demand for a 'Single Phase' Single Domestic (residential) Electrical Installation.

If anybody has any questions relating to this document OR if they would like a specific Maximum Demand calculated for other equipment, feel free to ask.

What is Maximum Demand?

It is the highest current used by an installation based upon an estimated ‘usage’ of each & every electrical fitting/appliance.

How can estimating the Maximum Demand of my installation help me?

It can help to size your Consumer Mains (the cables from the street power pole to your Kilowatt Hour Meter) appropriately. In Thailand, knowing your Maximum Demand will also help you to select the appropriate size Kilowatt Hour Meter.

Maximum Demand does not allow for future expansion, however, any future expansion can be ‘built in’ to an initial Maximum Demand calculation.

[gcad]

Excellent summary of maximum demand elkanga! Can't you do these summaries before I complete the subject at trade school?

I'm keen to see you tackle voltage drop next.

[chownah]

Excellent summary of maximum demand elkanga! Can't you do these summaries before I complete the subject at trade school?

I'm keen to see you tackle voltage drop next.

Gcad,

What question do you have on voltage drop? Do you know about the analogy between water flowing in a system of pipes and electricity flowing in a system of wires? Voltage drop in the system of wires is like pressure drop in a system of pipes.....like when you are taking a shower and someone flushes a toilet and the pressure drops sharply in the shower.

Chownah

[elkangorito]

Excellent summary of maximum demand elkanga! Can't you do these summaries before I complete the subject at trade school?

I'm keen to see you tackle voltage drop next.

Thanks gcad Do you have a copy of the latest AS/NZS 3000? I do...& if you want, I can email you an exerpt from the standard that easily explains Max Demand.

I've also just purchased AS 3008, which will allow me create a brief for voltage drop in 'standard' types of cables.

Let me know if ya want a hand.

Cheers

[elkangorito]

Excellent summary of maximum demand elkanga! Can't you do these summaries before I complete the subject at trade school?

I'm keen to see you tackle voltage drop next.

Gcad,

What question do you have on voltage drop? Do you know about the analogy between water flowing in a system of pipes and electricity flowing in a system of wires? Voltage drop in the system of wires is like pressure drop in a system of pipes.....like when you are taking a shower and someone flushes a toilet and the pressure drops sharply in the shower.

Chownah

I think the 'voltage drop' that gcad is speaking of, relates to specific types of cables installed in various ways.

I will create a 'simplified' paper about these voltage drops in a week or so. It will help a 'home builder' in Thailand to varify that the type, size & installation methods of cables are correct & appropriate. Ya can't trust Thai electricians all the time.

BTW, I've just noticed some 'typographical' errors in the Maximum Demand paper. They are not a huge problem & I'll fix it later.

Crossy...you getting this?

[Crossy]

Crossy...you getting this?

Yeah, getting it mate, just been somewhat overwhelmed the last week or so.

I think these more technical papers can go on the site in their own section as the original .doc files, saves me the work of making them idiot friendly as they are really not intended for idiots :)

[chownah]

Gcad,

So, what information about voltage drop are you looking for?

Chownah

[gcad]

Excellent summary of maximum demand elkanga! Can't you do these summaries before I complete the subject at trade school?

I'm keen to see you tackle voltage drop next.

Gcad,

What question do you have on voltage drop? Do you know about the analogy between water flowing in a system of pipes and electricity flowing in a system of wires? Voltage drop in the system of wires is like pressure drop in a system of pipes.....like when you are taking a shower and someone flushes a toilet and the pressure drops sharply in the shower.

Chownah

I'm well passed that level of knowledge, I'm 3 subjects away from completing my trade certificate in electrical (1080 hours of study). But thanks anyway.