In House Electrics, Where Do I Go From Here?

[elkangorito]

Yes they are.

I will provide an answer shortly.

[david96]

Once you have your max demand calculated you would be advised to contact the PEA/MEA first for your energy metering requirements. Then see if they require a MCB as a main switch along with any requirement to instigate an MEN on your main switchboard.

[david96]

All your socket outlets should be RCD protected not just some of them.

A socket outlet in a Thai style bathroom is not advised. There is no reason to have a socket outlet in a bathroom at all.

[david96]

An RCD will minimise the effects of electric shock and automatically disconnect the supply from the following.

A broken PE conductor in the cord of a defective appliance (indirect contact).

A damaged appliance cord with an exposed live conductor (direct contact).

A broken active pin of a 3 pin plug top exposed in a socket outlet (direct contact).

Damage to a 2 core and earth cable, damage will generally involve the earth with the line or neutral conductor.

An incorrectly wired 2 core and earth extension lead or appliance (line or neutral to earth).

Most electrical fatalities are caused by indirect contact.

Earthing will not protect a person from the effects of electric shock from direct contact. ( Unless the circuit is protected by an RCD.)

A 10mA RCD will disconnect in less than 0.04secs, a 30mA RCD will disconnect in less than 0.2/0.3secs. An RCD must operate between 50% and 100% of its rated current in mA. In practice the sensitivity is about 70% of rated mA.

An RCD must be used where the earth impedance is not sufficiently low enough to trip an overcurrent protective device within the required disconnection times ( 0.4secs).

RCDs should be used on final subcircuits where the integrity of the earthing system cannot be guaranteed.

Edited April 1, 2010 by david96

[eraymos]

All your socket outlets should be RCD protected not just some of them.

A socket outlet in a Thai style bathroom is not advised. There is no reason to have a socket outlet in a bathroom at all.

Outside of Thailand I have never seen a bathroom that doesn't have some kind of electrical outlet. In the states the socket has it's own RCD buit in (with test button), and in Norway most bathrooms have 1 outlet (with a cover) built in to the light over the sink and/or an outdoor socket with a cover.

How do you tell your Thai wife that she can't use a hair straightner or blowdryer? Where do you plug in your electric razor?

[bankruatsteve]

Yah - just to throw in my opinion... having ALL sockets RCD protected is WAY overboard - and probably cause more nuisance trips than you want to live with. Proper grounding (they call it "MEN" in this forum - in the states it's just normal) is sufficient for most in-house circuits. You want the GFI protection in areas where there is potential for accidental earthing of live device. Around here the RCBO seems to be the preferred method - but like you I am only familiar with the in-socket (GFI) device. I wonder what statistics there are for people being accidentally electrocuted here in Thailand with the (to most of us) sub-standard methods? Maybe it's not the horific situation we might imagine.

[elkangorito]

Your Maximum Demand is about 64 amps without adding 20% for future usage. If you add this percentage, it will be about 77 amps. Essentially, this is normal for most western style homes of your chosen size.

As per my suggestions & moving from left to right, top to bottom of your drawing (not more than 2 x DGPO's in each bedroom):

Kitchen - 2 x DGPO. 1 x SGPO (range hood plus exhaust fan). 1 x combination light/fan. 1 x oven. 1 x cooktop.

Bathroom - 2 x lights. 1 x exhaust fan. 1 x SGPO.

Laundry - 1 x hot water heater. 1 x DGPO. 1 x light.

Master bedroom - 2 x DGPO. 1 x combination light/fan.

Bathroom - 1 x light. 1 x exhaust fan. 1 x SGPO.

Bedroom - 2 x DGPO. 1 x light.

Carport - 2 x DGPO. 1 x light.

Living room - 4 x DGPO. 6 x lights.

Hallway - 2 x SGPO. 1 x light.

Sunroom - 2 x DGPO. 1 x light.

Foyer - 1 x DGPO. 1 x light.

Bedroom - 2 x DGPO. 1 x light.

Bedroom - 2 x DGPO. 1 x light.

Outdoor - 2 x DGPO. 6 x lights.

Recommended strongly & other assumptions. Please read the following carefully.

There is no way on god's earth that you will need more than 2 x DGPO's per bedroom unless you have more than one person permanently in each bedroom.

I have assumed that all combination fan/lights will not exceed 150W.

I have assumed that all exhaust fans will not exceed 60W & will be the "plug-in" type. It is NOT recommended that small exhaust fans be 'hard wired'.

I have assumed that no light (fitting) exceeds the capacity of housing a lamp rated at more than 60W.

I have assumed that the oven & cooktop are 'fixed' (cannot be moved e.g not on wheels).

I have assumed that each 'downlight' (not 'drop light') will not exceed 60W & are not transformer operated.

I have assumed that you will not be using any form of insulation in the walls or the ceiling.

I have assumed that the outdoor lights & power outlets are not affected by weather (rain).

Total number of outlets - 47.

Total number of lights not exceeding 60W each (this includes exhaust fans) - 27.

3 zone hob - 6kW.

Oven - 3.3kW.

Hot water heater - 2.5kW.

Air conditioner - 1 x @ less than 10 amps.

Please feel free to ask any questions, no matter how silly they may seem to you.

I will make further recommendations according to your next reply.

Edited April 2, 2010 by elkangorito

[eraymos]

Your Maximum Demand is about 64 amps without adding 20% for future usage. If you add this percentage, it will be about 77 amps. Essentially, this is normal for most western style homes of your chosen size.

As per my suggestions & moving from left to right, top to bottom of your drawing (not more than 2 x DGPO's in each bedroom):

Kitchen - 2 x DGPO. 1 x SGPO (range hood plus exhaust fan). 1 x combination light/fan. 1 x oven. 1 x cooktop.

Bathroom - 2 x lights. 1 x exhaust fan. 1 x SGPO.

Laundry - 1 x hot water heater. 1 x DGPO. 1 x light.

Master bedroom - 2 x DGPO. 1 x combination light/fan.

Bathroom - 1 x light. 1 x exhaust fan. 1 x SGPO.

Bedroom - 2 x DGPO. 1 x light.

Carport - 2 x DGPO. 1 x light.

Living room - 4 x DGPO. 6 x lights.

Hallway - 2 x SGPO. 1 x light.

Sunroom - 2 x DGPO. 1 x light.

Foyer - 1 x DGPO. 1 x light.

Bedroom - 2 x DGPO. 1 x light.

Bedroom - 2 x DGPO. 1 x light.

Outdoor - 2 x DGPO. 6 x lights.

Recommended strongly & other assumptions. Please read the following carefully.

There is no way on god's earth that you will need more than 2 x DGPO's per bedroom unless you have more than one person permanently in each bedroom.

I have assumed that all combination fan/lights will not exceed 150W.

I have assumed that all exhaust fans will not exceed 60W & will be the "plug-in" type. It is NOT recommended that small exhaust fans be 'hard wired'.

I have assumed that no light (fitting) exceeds the capacity of housing a lamp rated at more than 60W.

I have assumed that the oven & cooktop are 'fixed' (cannot be moved e.g not on wheels).

I have assumed that each 'downlight' (not 'drop light') will not exceed 60W & are not transformer operated.

I have assumed that you will not be using any form of insulation in the walls or the ceiling.

I have assumed that the outdoor lights & power outlets are not affected by weather (rain).

Total number of outlets - 47.

Total number of lights not exceeding 60W each (this includes exhaust fans) - 27.

3 zone hob - 6kW.

Oven - 3.3kW.

Hot water heater - 2.5kW.

Air conditioner - 1 x @ less than 10 amps.

Please feel free to ask any questions, no matter how silly they may seem to you.

I will make further recommendations according to your next reply.

Thanks alot ! I know that 4 DGPO's per bedroom is an overkill. It is not so much that we need/want 8 outlets per BR, it's more about the placement and the eventual use of ext.cords. Do you know of any way around this???? I have 3 kids under the age of 5 and ext.cords are accidents waiting to happen.

As for the exhaust fans in the bathooms I had thought to have them wired with the lights so that when you turn on the light so does the fan.

Only 2 x DGPO's in the kitchen? What about the fridge and dishwasher?

I have been looking at OSRAM DULUX downlight 10-17 W, is this OK?

What about the water pressure pump?

Do you see anything I'm doing wrong? Is there any way you see that could be done to bring down the MD?

OK, let's say that we do things as you say, what recommendations would you have as to what kind of consumer unit and types/amounts of switches?

I/we do appreciate all the help you are giving us

[elkangorito]

My comments in blue.

Thanks alot ! I know that 4 DGPO's per bedroom is an overkill. It is not so much that we need/want 8 outlets per BR, it's more about the placement and the eventual use of ext.cords. Do you know of any way around this???? I have 3 kids under the age of 5 and ext.cords are accidents waiting to happen.

Almost all houses in Australia have a maximum of 2 x DGPO's per bedroom. Of course, if the bedroom is full of electronic equipment &/or very large (which may therefore require many outlets), the cheapest solution is a 'power board'. Electronic equipment generally draws a small amount of current.

As for your kids, I have no suggestion other than you educate your kids accordingly. Saying 'no' now is significantly better than saying 'no' at the hospital or at a funeral. Then again, if you are happy with the extra expense, I will recalculate according to your desires. This may prove expensive as the size of consumer mains cable jumps significantly after 16mm squared.

As for the exhaust fans in the bathooms I had thought to have them wired with the lights so that when you turn on the light so does the fan.

No problem.

Only 2 x DGPO's in the kitchen? What about the fridge and dishwasher?

Adding another 2 x DGPO's in the kitchen will not affect your MD.

I have been looking at OSRAM DULUX downlight 10-17 W, is this OK?

The light fitting is important...not the lamp size. Lamp sizes only become important if the light fitting can house lamps that are greater than 60W each. For example, if you have a light fitting that is capable of accepting 3 x 60W (maximum wattage) lamps, it does not matter what lamp you choose to use as long as the wattage of the lamp does not exceed 60W.

What about the water pressure pump?

I have assumed that this is a "plug-in" unit that will be plugged into an outdoor outlet. Right or wrong?

Do you see anything I'm doing wrong? Is there any way you see that could be done to bring down the MD?

I have already reduced your MD by allowing only 2 x DGPO's per bedroom.

OK, let's say that we do things as you say, what recommendations would you have as to what kind of consumer unit and types/amounts of switches?

Before we go into 'consumer units', we must establish that you are happy with the current proposal.

I/we do appreciate all the help you are giving us

My pleasure.

[eraymos]

My comments in blue.

Thanks alot ! I know that 4 DGPO's per bedroom is an overkill. It is not so much that we need/want 8 outlets per BR, it's more about the placement and the eventual use of ext.cords. Do you know of any way around this???? I have 3 kids under the age of 5 and ext.cords are accidents waiting to happen.

Almost all houses in Australia have a maximum of 2 x DGPO's per bedroom. Of course, if the bedroom is full of electronic equipment &/or very large (which may therefore require many outlets), the cheapest solution is a 'power board'. Electronic equipment generally draws a small amount of current.

As for your kids, I have no suggestion other than you educate your kids accordingly. Saying 'no' now is significantly better than saying 'no' at the hospital or at a funeral. Then again, if you are happy with the extra expense, I will recalculate according to your desires. This may prove expensive as the size of consumer mains cable jumps significantly after 16mm squared.

What do you call jumping significantly? What would 16mm (m2) be compared to something larger?

I'm sure I will need extra power in the future as we are thinking to one day have a pool (pump, lighting, etc)

As for the exhaust fans in the bathooms I had thought to have them wired with the lights so that when you turn on the light so does the fan.

No problem.

Only 2 x DGPO's in the kitchen? What about the fridge and dishwasher?

Adding another 2 x DGPO's in the kitchen will not affect your MD.

I have been looking at OSRAM DULUX downlight 10-17 W, is this OK?

The light fitting is important...not the lamp size. Lamp sizes only become important if the light fitting can house lamps that are greater than 60W each. For example, if you have a light fitting that is capable of accepting 3 x 60W (maximum wattage) lamps, it does not matter what lamp you choose to use as long as the wattage of the lamp does not exceed 60W.

I understand all light fixtures 60 watt or under. As I am in Norway for now it makes i kind of hard to look at electrical ratings for lighting i Thailand

What about the water pressure pump?

I have assumed that this is a "plug-in" unit that will be plugged into an outdoor outlet. Right or wrong?

From what I understand , you removed the outlet 1xSGPO

Do you see anything I'm doing wrong? Is there any way you see that could be done to bring down the MD?

I have already reduced your MD by allowing only 2 x DGPO's per bedroom.

If going to a larger consumer mains cable, could I then change the amount of DGPO's?

Is all this just a pipe dream from my side? Am I just making more problems for myself and/or will I then have problems with the electric company?

OK, let's say that we do things as you say, what recommendations would you have as to what kind of consumer unit and types/amounts of switches?

Before we go into 'consumer units', we must establish that you are happy with the current proposal.

I/we do appreciate all the help you are giving us

My pleasure.

[bankruatsteve]

To me the test for how many plug sockets you want (I like every 2 meters or so) is to recall the situtations where you have to use extension cords b/c a socket isn't available. Just b/c you have a socket in the wall doesn't mean you HAVE to have something plugged into it nor does having many vs few necessarily need to increase the MD. It's what you plan to USE - and where - that should be the factors.

Back to extension cords... most of those sold in Thailand ought to be banned. Those roll up things are really scary. Much much better to have a proper wall socket where you MIGHT need it than rely on extensions.

[Crossy]

Got to agree with steve, much better to have too many outlets than too few and have to use trailies.

It is important to estimate your MD so that you have an idea just how big a supply you need, or to ensure you don't exceed the capability of the supply you've got stuck with in the wilds of Thailand. However, there are as many ways of guestimating the MD as there are countries (or for that matter sparkies).

In the UK the MD calculation does not involve the number of outlets but instead uses the number of outlet ring circuits (or in Thailand radials). A UK ring can have pretty well as many 13A outlets as you want, there are limits but in a sensible sized home you'll not approach them. Each ring is fused at 32A so we assume that's the max load for that circuit (Thai radials would have 20A breakers) before applying diversity.

A simple means used for determining the MD of an existing installation is to total the breakers then multiply by 0.4 (to account for diversity). We should be able to apply this to our new installation by applying a little common sense.

This being the case, it's easy to reduce your potential demand simply by fusing down (say to 10A) some radials, your bedroom is never going to get near 20A, neither is the lounge, IMHO the only radial that really needs to be 20A would be the kitchen.

To be honest, I may even suggest that loads other than aircon, water heating and kitchen appliances could be neglected (or assumed to be say 10A total) in a normal domestic installation

Thoughts?

[eraymos]

I have thought the way that bankrautsteve and Crossy are talking about. I thought that how much power is being used from the contacts was what is important. Being weak i electronics is why I started this in the first place. Like you say Crossy not to much power going out of 2 nightlights, clock radio etc. I do want and value the input of the experts. WHERE DO I GO FROM HERE?

[Crossy]

WHERE DO I GO FROM HERE?

I would go ahead with placing your outlets where you want and have as many as you wish, there is no danger of overload unless you decide to start welding in the bedroom (grinding is different and uses no electricity).

The MD calculation / estimate is there to ensure that your incoming supply is in the correct ball park, it's not a be-all and end-all, hence my suggestion that only major loads need apply (unless you have 10kW of external lighting, but that would be a major load). Provided you don't do something dumb like replacing your incoming breaker with a larger one you will not over-stress the MEA / PEA supply. In the event that you do exceed the ratings all that will happen is the incoming breaker will trip.

There has been a great deal of controversy on the IEE forum regarding the calculation of domestic MD and the application of diversity (how much load you can ignore). The argument is a practical one. Having calculated an MD if you place a clamp meter on the incoming supply set to measure the peak current and leave it there for a month the actual peak current drawn is rarely anywhere near the calculated MD and the average current is less than 5A. NOTE we are talking domestic here, restaurants / light industrial is a different kettle of fish.

A classic example. Back in 2002 we lived in Rome in a 2 bed apartment. We had 3 aircons, storage water heater, washing machine, toaster, kettle, telly etc etc. Our incoming supply breaker was 15A!! We probably had to re-set the breaker once or twice a month. You soon learn to live within the available power, make the toast before the tea, don't iron whilst the washer is heating up etc. Nothing caught fire, nothing exploded.

EDIT Incidentally, our home design has four double outlets in the bedroom. One each side of the bed for lamps, clocks, phone charger etc. one near the dressing table (high level) for her hair dryer and one other for the TV. Maximum total loading in the bedroom about 7A (drying hair whilst watching TV).

[bankruatsteve]

Actually, one BIG question is where do you live? I had experience (here in LOS) where I had to beg for 30a meter - finally got it (I have 4 A/C units, 4 water heaters, and otherwise normal stuff). BUT - could I run 4 A/C's the same time? Hardly ever = brown outs. So much for MD. Now it's a bit better but no way I will get the max of 60 some amps until maybe the community gets a lot bigger. I don't have much experience with grid stuff so just don't know about that.

The main question, in my opinion, is how to break out your circuits. I know the "ring" is popular in England - but I only like in special cases. For me, radial circuits are preferred (I could give my reasons if you like.) But, a lot of circuits and fault protection can get expensive. Again, my opinion is to have at least 2 circuits for the kitchen area and put ALL major appliance on single circuit ie: A/C, water heaters, oven, range, etc. Otherwise, divide things up based on how you imagine to use or what fits the house design. Again, the rough calc is total watts divide by 220 is the size breaker and WIRE you need for the circuit. Fault protection should probably be in wet areas (incl. outside) but I just don't think it's that necessary otherwise. (My opinion OK?)

If you're doing it yourself, get the code book for Norway (or England or US or wherever) and that should help you with most of this stuff. If using local "electrician" it shouldn't take long to know if they know what their doing after reading all these posts and Crossy's info.

In any case, hope you have fun getting involved - at least it's always been fun for me. Cheers.

[bankruatsteve]

Forgot to say... lighting circuits should be separate from socket circuits. Several reasons but big one is expense ie: smaller D wire can be run for the lights.

And, hope you don't mind me saying: looking back at your posts, you should probably NOT be doing this yourself b/c there's LOTS more you need to know for the rough-in, hook-ups, etc. that it sounds you're not familiar. Use this forum to get some guidelines and thus informed you should be able to at least supervise getting things done to the standards you want to have.

Here's a suggestion: give a go at laying out circuit design over your floor plan. Use multiple pages (like for each size breaker or just so it doesn't get "busy"). Show where you want the DGPO's (why single I wouldn't know), switches, lighting fixtures, where you want 2-way switches, 3-way?, switching on outlets, etc. Show that to your builder/electrician and, if the eyes glaze over, try again. Watch how they install - or better see what they have done before. For new build, you shouldn't see the wires stapled to the wall or connections made by twisting wire and covered with black tape. Make sure proper wire size is used for the breaker. ie: 5a wire CANNOT be used with 10a breaker. If you're doing grounded outlets (I hope) make sure they actually put the green or bare copper wire in the system and hooked up properly. Stuff like that. Good luck.

[eraymos]

Forgot to say... lighting circuits should be separate from socket circuits. Several reasons but big one is expense ie: smaller D wire can be run for the lights.

And, hope you don't mind me saying: looking back at your posts, you should probably NOT be doing this yourself b/c there's LOTS more you need to know for the rough-in, hook-ups, etc. that it sounds you're not familiar. Use this forum to get some guidelines and thus informed you should be able to at least supervise getting things done to the standards you want to have.

Here's a suggestion: give a go at laying out circuit design over your floor plan. Use multiple pages (like for each size breaker or just so it doesn't get "busy"). Show where you want the DGPO's (why single I wouldn't know), switches, lighting fixtures, where you want 2-way switches, 3-way?, switching on outlets, etc. Show that to your builder/electrician and, if the eyes glaze over, try again. Watch how they install - or better see what they have done before. For new build, you shouldn't see the wires stapled to the wall or connections made by twisting wire and covered with black tape. Make sure proper wire size is used for the breaker. ie: 5a wire CANNOT be used with 10a breaker. If you're doing grounded outlets (I hope) make sure they actually put the green or bare copper wire in the system and hooked up properly. Stuff like that. Good luck.

Everything is going inside conduits, so I sure hope I don't see any wires stapled to the walls. Plans on alot of junctionboxes and wire nuts. I do know a little about grounded outlets and some basics. From Crossy's web pages I have learned about cable size and the likes. I am not 100% sure about what size switches should be used for everything. The electrician I am going to use does alot of work for the ampur so I hope he knows his job. He says he knows about grounding and consumer units. All the conduit and boxes for light switches and sockets are already in the walls. So it' just to figure out how to tie everything together in the attic and down to the consumer unit. I am thinkinkig to use the K.I.S.S method for myself and the electrician.

Thanks for the help.

Good luck you say, if it was not for bad luck I would not have any luck at all!

[bankruatsteve]

OK sounds like you are comfortable with the project. Again, I will strongly suggest you get them to put more plug sockets than they would do otherwise. More is better. And your wife will thank you for it at some point.

[bankruatsteve]

Again forgot to mention... RE switches: DO make sure you get both switches and sockets that are RATED (in amps) for the size breaker/circuit they are installed. This is an expense item but money well spent. I like the "rocker switches" (and they are usually the higher quality/expense ones). Don't go cheap on this. Cheers.

[eraymos]

Again forgot to mention... RE switches: DO make sure you get both switches and sockets that are RATED (in amps) for the size breaker/circuit they are installed. This is an expense item but money well spent. I like the "rocker switches" (and they are usually the higher quality/expense ones). Don't go cheap on this. Cheers.

Thanks again. I don't have an unlimited supply of money but I know this is not an area where I should be cheap. I do wonder what the cost of things are. My inside electric budget (around 40K not including light fixtures) is for consumer unit, circuit breakers, grounding rod, wires/cables, sockets and switches, and conduit, junctionboxes, wirenuts etc. Anything I have forgotten???

[bankruatsteve]

What?? I thought you are "farang"? Don't they have money trees in Norway? Same as the states?

OK - it sounds like you contracted this out already so I wonder why you ask what YOU forget? I don't know - just be involved: after all the info from everyone, you should have a basic understanding of what you are searching. Let us know how everything turns out.

[eraymos]

What?? I thought you are "farang"? Don't they have money trees in Norway? Same as the states?

OK - it sounds like you contracted this out already so I wonder why you ask what YOU forget? I don't know - just be involved: after all the info from everyone, you should have a basic understanding of what you are searching. Let us know how everything turns out.

No, I have not contracted it out. I have an electrician that says he can wire everything together and that's it. When I get back to Thailand, I have to run around and buy everything that I need and tell him how I want things done. I just figure around 40k, but what do I know?

[longball53098]

I think you will get a "shock" when you start to buy the material and pay to have all the work done. 40k will get you a really nice Consumer Unit

[eraymos]

I think you will get a "shock" when you start to buy the material and pay to have all the work done. 40k will get you a really nice Consumer Unit

Are things that expensive? Can you give me an Idea on what thing cost? When I had all the conduit, light and socket boxes put in the walls I paid about 5-6K installed. I thought the consumer unit is about 10-12K. I get this price from what I have seen on the internet (7-A company Thailand) and here in Norway I can get a AEG consumer unit / with switches for around that price. Am I that far off?

[longball53098]

I can give you some info but first if you have time visit this link to my electrical installation. You can view the nice work my Sparky did and the types of equipment I used. It will take me a few days to track down the prices I paid for what you see.

Electrical

Electrical 2

Electrical 3

Electrical 4

[david96]

Yah - just to throw in my opinion... having ALL sockets RCD protected is WAY overboard - and probably cause more nuisance trips than you want to live with. Proper grounding (they call it "MEN" in this forum - in the states it's just normal) is sufficient for most in-house circuits. You want the GFI protection in areas where there is potential for accidental earthing of live device. Around here the RCBO seems to be the preferred method - but like you I am only familiar with the in-socket (GFI) device. I wonder what statistics there are for people being accidentally electrocuted here in Thailand with the (to most of us) sub-standard methods? Maybe it's not the horific situation we might imagine.

You should read my post #34 closely, they are all reasons that justify the the use of RCDs.

Also in high risk areas connection of permanently connected equipment should be considered.

[eraymos]

I can give you some info but first if you have time visit this link to my electrical installation. You can view the nice work my Sparky did and the types of equipment I used. It will take me a few days to track down the prices I paid for what y

Thanks longball, nice house! Your pics show me that I am not so far off with what I am thinking to do. I'm not so sure that the race track is something I want, it seems to me it would make it harder to keep control of where each wire is coming and going. A ball park figure on what things cost would be greatly appreciated .

[eraymos]

Yah - just to throw in my opinion... having ALL sockets RCD protected is WAY overboard - and probably cause more nuisance trips than you want to live with. Proper grounding (they call it "MEN" in this forum - in the states it's just normal) is sufficient for most in-house circuits. You want the GFI protection in areas where there is potential for accidental earthing of live device. Around here the RCBO seems to be the preferred method - but like you I am only familiar with the in-socket (GFI) device. I wonder what statistics there are for people being accidentally electrocuted here in Thailand with the (to most of us) sub-standard methods? Maybe it's not the horific situation we might imagine.

You should read my post #34 closely, they are all reasons that justify the the use of RCDs.

Also in high risk areas connection of permanently connected equipment should be considered.

I'm thinking that the 3 wet rooms , kitchen and outside electrics are going to be protected. The hob/oven, hot water tank and A/C are going to be hard wired. Do you see any problems with this? I value your input

[Forkinhades]

Just install a dual RCD Distribution Board, as is the standard in the UK, and make sure you have a earth at any outlet that will have a possibility of having something plugged in that has a metal casing, and any wet areas.

Also cable sizes here in thailand should have a factor of about .85 multiplied due to ambient temperature, so in effect the current carrying capacity of the cable is reduced, and also factored in should be the length of the run of cable so as the volt drop does not exceed 5%

[Forkinhades]

An RCD will minimise the effects of electric shock and automatically disconnect the supply from the following.

A broken PE conductor in the cord of a defective appliance (indirect contact).

A damaged appliance cord with an exposed live conductor (direct contact).

A broken active pin of a 3 pin plug top exposed in a socket outlet (direct contact).

Damage to a 2 core and earth cable, damage will generally involve the earth with the line or neutral conductor.

An incorrectly wired 2 core and earth extension lead or appliance (line or neutral to earth).

Most electrical fatalities are caused by indirect contact.

Earthing will not protect a person from the effects of electric shock from direct contact. ( Unless the circuit is protected by an RCD.)

A 10mA RCD will disconnect in less than 0.04secs, a 30mA RCD will disconnect in less than 0.2/0.3secs. An RCD must operate between 50% and 100% of its rated current in mA. In practice the sensitivity is about 70% of rated mA.

An RCD must be used where the earth impedance is not sufficiently low enough to trip an overcurrent protective device within the required disconnection times ( 0.4secs).

RCDs should be used on final subcircuits where the integrity of the earthing system cannot be guaranteed.

Agreed mostly, but will point out that earthing WILL protect a person from direct contact if the value of the earth has a low enough impedance, (which is very difficult to get here in thailand)

Also would like to point out that I have installed a dual RCD DB in my house here in Thailand, so every circuit is protected by an RCD, and when I did the changeover, I found that I had 3 'borrowed' neutrals. Now while this is not considered a problem when everything is up and working, it WILL become a problem for you budding DIY enthusiasts. For when you isolate a circuit that has a borrowed neutral, (for upgrades repairs etc etc) although the 'live' cable is dead, the neutral will become live, and there is a very high risk of shock, but if you had a DUAL RCD DB, installed, then when you touch the 'live' borrowed neutral, the RCD will trip and protect you, but if you split 2 neutrals and hold one in each hand, then you ARE dead! even an RCD will not protect you!

Edited April 6, 2010 by Forkinhades