My Electrical Nightmare

[nellyp]

My situation is this.

I moved into a property in the school I teach at 1 year ago, and am staying here indefinitely now. I was not prepared to do much to the house as I did not want any expense. Now however because of the long term plan I want the house to be safer electrically,as I am receiving small shocks off my computer, true box and blue-ray player. This has led me to look more closely at the electrics.

I have attached photos so that you can see where I am now.

The first photo is of the meter outside my house,

The second is how the mains connects to the house

The 3rd is the one and only breaker, the clean wire is the wiring that the men who fitted my shower (when they were installing the true sat) fitted. I made my wife tell them to earth the wire which they did. With a meter long copper pole that has the earth wire welded to it (made by Chang, and installed by somebody who has drunk too much of it.

No 4 is the connections inside the breaker, there are no other wires running to or from the board apart from the mains supply and the 4 lines running off the breaker for lights and sockets. By the way there is no fuse wire in here just electrical wire that has been fitted so I have no idea how much they would take to trip.

No 5 is the typical sockets we have. As you can see they are 2 pin (in with light switches)

No 6/7 is the same socket out of the wall, looking at both sides. It looks as though the neutral wires for the lights have been joined (with black tape) to go into the same hole. No earth wires anywhere, but what would be the point? I assume I would need to fit my own 3 pin sockets, but would I need to run an earth cable to an earthing rod?

No 8 I have had 2 sockets fitted with 3 pins (by the same true installers) but as you can see there is no earth wire running to the socket. If I need to run an earth off it where would I connect it on the socket? When I took the plate off the wire came out of the connection hole, as the insulation had been cut too short and would not fit in properly

No 9 is the air-con that was fitted for me to move in. Again no earth on it just the 2 wires going into the side, which look dangerously exposed

The final photo is of the type of adapter plugs I am using.

I will be putting Thai plugs on all the leads, but will I need to have 3 pin plugs on everything or only on things with 3 wires? (I am assuming this is so). My fridge only has a 2 pin connector so i think I will need to run an earth cable to an earthing rod. My washing machine and micro have 3 pin connectors so I will fit them to the wall when the sockets are changed, will I still need to run an earthing cable to the rod though?

I will need to fit a better rod, but do I need to connect it to the breaker and if so how. I will get a box, will I need to connect to that too. When I fit the sockets do I need to connect everyone to the rod separately or can i run a kind of ring, and also with double sockets (really 2 single sockets in the same box) do they need to be done separately? Also do I need to run anything other than the green cable to the rod or should i use different wire and conect the green to it.

I apologise for the length of this (said the bishop to the actress) but Ineed quite a lot of info, and thought the pictures would give you a better idea.

Please help. I need it

[Crossy]

Arrgghhhhh!

I'll have a proper reply later when I get home from the office, but for now have a look at these pages, http://www.crossy.co.uk/wiring/ they should answer some of your questions.

By the way, shoot the person who connected your aircon (or is it the shower) directly to the incoming supply.

EDIT. Does that incoming knife switch have a cover over the 'fuses'?

The phrase 'potentially lethal' springs to mind

[Jdietz]

Nearest fuse is probably near the main transformer... Would "love" to see what happens when your shower shorts out. Hopefully without you anywhere near it. It will look much like the Chernobyl accident, with pieces of the 'reactor vessel' (boiler) landing in the garden.

And no, I'm not really exaggerating either.

So first of all DO install a decent fuse box and RCB while you're at it. Take cold showers until this is done.

The small shocks from your computer and other stuff with cheap switching supplies is nothing to be too worried about, though, it's caused by leakage from the small capacitors in the net filter, which is supposed to be grounded, but isn't. A connection between the ground pin and your 'Chang' ground will fix this.

Edit: Nice example of 'slow blow' home-made fuses there... I'd guess a few hundred amps over a few minutes might actually melt them before the house goes up in flames, but don't be too sure.

Edited March 27, 2012 by Jdietz

[bankruatsteve]

Your "Chang" fuse box is rated for 60 amps. (Crossy, they have protective cover and are safe.) ie: it would take 60 amps and probably a few seconds (if not more) to melt the fuses. So, if that's the only overcurrent protection you have you basically don't have any. And, as others have posted many times, a 3 prong plug doesn't mean it's grounded in Thailand. Most times it's just to fit things that need 3 prong plugs. For example, almost all extension devices in Thailand have 3 prong receptacles but only 2 prong (or if it has 3 is not include the ground) for plug. Yah, TIT.

The shocks you get from your computer equipment could be from dust (which would be eliminated with proper grounding) - try to give them a good clean and maybe it helps.

[nellyp]

Arrgghhhhh!

I'll have a proper reply later when I get home from the office, but for now have a look at these pages, http://www.crossy.co.uk/wiring/ they should answer some of your questions.

By the way, shoot the person who connected your aircon (or is it the shower) directly to the incoming supply.

EDIT. Does that incoming knife switch have a cover over the 'fuses'?

The phrase 'potentially lethal' springs to mind

Yeah there is a cover, and it fits OK too.......unbelievably. I fitted my own shower back in the UK about 15 years ago and we put a pull cord switch in the bathroom and a breaker/isolator between the shower and the main board. I think it was the main board anyway. A long time ago now.I did not even think about the wire going straight into the main supply (wow), I really need to look where that is going tomorrow I'll have a look at the link now. Cheers Edited March 27, 2012 by nellyp

[Crossy]

Yeah Steve, I know they are supposed to have covers, I was concerned that said covers were missing.

[electau]

All final subcircuits must have individual protection by way of correctly sized protective devices rated to the current rating of the cable that they protect.

Install RCD protection on all circuits.

The main switch should be a 2 pole 50A or 63A MCB depending on the current rating of your main incoming conductors.

Earthing where required.

Make sure that there are no exposed live conductors or terminals within the electrical installation.

[nellyp]

All final subcircuits must have individual protection by way of correctly sized protective devices rated to the current rating of the cable that they protect.

Install RCD protection on all circuits.

The main switch should be a 2 pole 50A or 63A MCB depending on the current rating of your main incoming conductors.

Earthing where required.

Make sure that there are no exposed live conductors or terminals within the electrical installation.

Earthing where required is a problem, I don't know where to earth. I feel I should be earthing the main board but do not know where to run the earth from. I am miles from anywhere I can buy a upply board but have loads of wire to earth what I have. I want to eartth the breaker I have (even though it will be replaced. Where would I run the earth from, apparently the earthing rod is longer than I was first told so I will earth to that. Also how doi I earth the sockets I have installed (3 prong) there are no hole to connect an earth to (is this because though thet have 3 holes they are not designed to be earthed?) I feel I should be earthing the washing machine as a separate item, can I just connect an earthing cable to the metal chassis and then to the earthing rod? I hgave loads of questions but I can't trust the workmen here. By the way I can see nowhere around the school that has apole with a lead runniong to earth.

[nellyp]

Arrgghhhhh!

I'll have a proper reply later when I get home from the office, but for now have a look at these pages, http://www.crossy.co.uk/wiring/ they should answer some of your questions.

By the way, shoot the person who connected your aircon (or is it the shower) directly to the incoming supply.

EDIT. Does that incoming knife switch have a cover over the 'fuses'?

The phrase 'potentially lethal' springs to mind

Yeah there is a cover, and it fits OK too.......unbelievably. I fitted my own shower back in the UK about 15 years ago and we put a pull cord switch in the bathroom and a breaker/isolator between the shower and the main board. I think it was the main board anyway. A long time ago now.I did not even think about the wire going straight into the main supply (wow), I really need to look where that is going tomorrow I'll have a look at the link now. Cheers

Yeah there is a cover, and it fits OK too.......unbelievably. I fitted my own shower back in the UK about 15 years ago and we put a pull cord switch in the bathroom and a breaker/isolator between the shower and the main board. I think it was the main board anyway. A long time ago now.I did not even think about the wire going straight into the main supply (wow), I really need to look where that is going tomorrow I'll have a look at the link now. Cheers

I have checked the wire directly connected to the supply and it is running the air-con both the outside exchange unit and the unit in the house. is it possible for me to disconnect it from the supply myself (and then to a supply box) or will I need to get the electric company involved? i suppose the real question here is how do I work on the breaker box I will fit if everything is still connected to the main supply into the house, obviously the aircon people managed it.

Edited March 28, 2012 by nellyp

[Crossy]

Ok. Let's approach this an a practical manner.

You need to provide the following for the safety of yourself and your installation.

1. Overcurrent protection.
   
2. Earth leakage protection
   
3. Grounding where required.
   

in order to achieve the above you must.

1. Disconnect that white cable from the incoming supply.
   
2. Install an RCBO after the knife switch, the knife switch will remain as a main isolator and allow you to work safely. The RCBO will provide overcurrent and earth leakage protection.
   
3. Install an MCB each for, the aircon, water heater, lights/power (I am assuming that your lights and power are on the same circuit in common with most small Thai installations).
   

You have a 5/15 meter, so your RCBO should be rated at 25A with a trip current of 30mA.

Your aircon should be on a 20A MCB as should your water heater (please let us know the power of each before you go shopping, just in case).

Your lighting and power should also be on a 20A breaker, but please confirm the size of wire used on this circuit, if it is smaller than 2.5mm2 (often 1.5mm2) then you should use a 16A MCB.

You should be able to get a small distribution board that this will all fit in. Your local electrical shop ought to be able to supply.

I'm a bit worried that you have outlets with 3 holes but no means to connect a ground, can you upload photos of said items, front and back.

EDIT removed

If you retain the knife switch in front of your new distribution board you will be able to work safely.

EDIT 2 You may find that the main RCBO will trip if you use the water heater and aircon together. Inconvenient, but unless you can upgrade your supply to a 15/45 unavoidable.

[nellyp]

Thanks Crossy, you are the man. I have no water heater in my house so we can ignore that part (the house is an old house in a school grounds, maybe just constructed in old ways though), the wiring all appears to be 2.5 as that is all I saw when tracing the air-con. I think the power and lights are running off the same circuit as I only saw one circuit in the roof space. There are 3 wires coming from the knife switch though so I will investigate that further, as I will the power of the air-con. I would use the existing wiring to re-connect the lighting and power to different circuits, but this would mean me ripping down all the lovely asbestos sheeting that is my ceiling. Will I be able to buy the distribution board with the RCBO and the MCBs already in or will I need to build this (I will probably have a trip to home pro for the bits. In my original post there is a picture (No 8) of the inside of the 3 pin outlets I have, if you click on it it gets big and you should be able to see the connectors, looking at it again I may be able to earth it through the screw on the back (???????) but that could just be connected to the plastic. As for the air-con I'll get a school worker to cut the wires for me (joking, I'll insulate myself first though, with insulation tape all around my cutters, wear wellies and stand on a rubber backed mat). Thanks for this ,but I will upload pictures of the shower connection and the front of the outlet so you can have a closer look. Your site for Thailand wiring is a must read for everybody in Thailand, not just us foreigners.

[prefabs]

Ok. Let's approach this an a practical manner.

You need to provide the following for the safety of yourself and your installation.

1. Overcurrent protection.
   
2. Earth leakage protection
   
3. Grounding where required.
   

in order to achieve the above you must.

1. Disconnect that white cable from the incoming supply.
   
2. Install an RCBO after the knife switch, the knife switch will remain as a main isolator and allow you to work safely. The RCBO will provide overcurrent and earth leakage protection.
   
3. Install an MCB each for, the aircon, water heater, lights/power (I am assuming that your lights and power are on the same circuit in common with most small Thai installations).
   

You have a 5/15 meter, so your RCBO should be rated at 25A with a trip current of 30mA.

Your aircon should be on a 20A MCB as should your water heater (please let us know the power of each before you go shopping, just in case).

Your lighting and power should also be on a 20A breaker, but please confirm the size of wire used on this circuit, if it is smaller than 2.5mm2 (often 1.5mm2) then you should use a 16A MCB.

You should be able to get a small distribution board that this will all fit in. Your local electrical shop ought to be able to supply.

I'm a bit worried that you have outlets with 3 holes but no means to connect a ground, can you upload photos of said items, front and back.

EDIT removed

If you retain the knife switch in front of your new distribution board you will be able to work safely.

EDIT 2 You may find that the main RCBO will trip if you use the water heater and aircon together. Inconvenient, but unless you can upgrade your supply to a 15/45 unavoidable.

Crossy, as one who respects your knowledge and helpfulness tremendously, I am not sure that your first edit should be made public. I would be very wary of passing this idea on to someone who is attempting this for the first time. I would be worried "just in case something happened" after passing this on.

[Crossy]

In my original post there is a picture (No 8) of the inside of the 3 pin outlets I have, if you click on it it gets big and you should be able to see the connectors, looking at it again I may be able to earth it through the screw on the back (???????)

The screw in the middle at the back should be the ground, look for holes to its side for you to poke the wire into.

Local brand Safe-T-Cut make ready configured distribution boards that will do your job just fine. http://www.safe-t-cu...adproduct&id=18

No problem with lights and outlets on the same circuit, that's the way it's done here on small installations.

@prefabs. I thought long and hard about putting that in, our OP wants to do it himself (I would always advise to ask a local) so I made sure that he takes enough precautions to avoid a nasty. I personally would just snip the wires, but I know my cutters have insulated handles and are in good condition. That said, he's now noted that he will get a local worker to do it, so I've edited the edit

[prefabs]

In my original post there is a picture (No 8) of the inside of the 3 pin outlets I have, if you click on it it gets big and you should be able to see the connectors, looking at it again I may be able to earth it through the screw on the back (???????)

The screw in the middle at the back should be the ground, look for holes to its side for you to poke the wire into.

Local brand Safe-T-Cut make ready configured distribution boards that will do your job just fine. http://www.safe-t-cu...adproduct&id=18

No problem with lights and outlets on the same circuit, that's the way it's done here on small installations.

@prefabs. I thought long and hard about putting that in, our OP wants to do it himself (I would always advise to ask a local) so I made sure that he takes enough precautions to avoid a nasty. I personally would just snip the wires, but I know my cutters have insulated handles and are in good condition. That said, he's now noted that he will get a local worker to do it, so I've edited the edit

Thanks for that, Crossy. Your posts are always eagerly read in this household and I would encourage everyone to do likewise

[prefabs]

Global House has a variety of consumer units with integral RCBs in them. I think they are less than 3000 baht. Lets just say 4000 baht for inflation in the last 6 weeks. Surely your life and your family's lives are worth 80 quid. Even a 63 A Safe T Cut was only 3600 baht. Whole house cover in one box. Say another 20 or 30 quid for installation. Must be worth it

[nellyp]

Ok I'm off to the big city (Roi-et), to get some bits. Consumer unit, 3 pin sockets and plugs, and earthing wire. I am assuming if I go to Home Pro I'll get all of these at good prices. Will i be able to buy a reel of earthing wire there? and will the normal green covered wire be good enough for everything I need? Or will I need special wire to connect the unit to the earthing rod? Will they also have the connectors I need for the earthing rod? and if I run earth off the sockets can I connect to the earth wire running to the unit or will they need to connect to the rod and have different connectors on the rod i.e. one each (this could be very messy). One final question, if I use extensions off the sockets is it safe to run extensions off each of the sockets in a double socket, or is there a load rating for each double socket?

[Crossy]

You should run a ground wire (1.5mm2) from each circuit to the ground bar in the consumer unit, and then a thicker (6mm2) wire from the ground bar to the ground spike. Both are readily available in HomePro.

You can run an extension from each side of a double outlet, unless you are running several high power devices (grill, kettle, toaster, microwave) from a single outlet there is little danger of overload. Most decent extension leads have a 10A fuse or breaker anyway so the most you could pull from a double would be 20A.

[nellyp]

You should run a ground wire (1.5mm2) from each circuit to the ground bar in the consumer unit, and then a thicker (6mm2) wire from the ground bar to the ground spike. Both are readily available in HomePro.

You can run an extension from each side of a double outlet, unless you are running several high power devices (grill, kettle, toaster, microwave) from a single outlet there is little danger of overload. Most decent extension leads have a 10A fuse or breaker anyway so the most you could pull from a double would be 20A.

OK thanks, you have been a lot of help

[nellyp]

went to roiet today, bought a new earthing rod will keep the one for the shower connected to that one. new 3 pin sockets, i'll keep the plugs on my appliances for now as (if I am reading this right) they will be ok as long as the multi socket boards are pluged in and earthed ok. i bought 100 meters of earthing wire to connect the sockets up to the distribution board. the board itself I need to wait till next week for as they had no RCBOs for the board I wanted. Should i still use the knife connector as a main switch if the board has one on, or should I not buy a main switch for he board, and just use the knife switch. By the way the wire running through the house is all 2.5mm so I bought 2.5mm earth wire, is that OK instead of the 1.5mm. One more thing while I think about it, does my shower count as a water heater? it's just that it has been fitted to a 25 amp breaker of it's own.

[tim73]

That house looks like it needs complete wiring overhaul unfortunately. Have you checked the wiring inside, it could be totally fuc_ked up! I heard in my house loud bangs from attic once in a while and slight dimming of the lights at the same time. It turned out to be a rat bitten wire making "lovely" sparks! Part of the roof foam insulation nearby was already blackened.

I don't know much about wiring but I think those wires even inside should be covered with something plastic, especially in the attic or anywhere rats and other small animals have easy access.

Edited March 31, 2012 by tim73

[Crossy]

Wise words there Tim, if nothing else a visual inspection for any potential problems is a good idea.

Nelly.

2.5mm2 will be great as your ground, did you get any thicker wire to connect to your rod, if not double up on 2.5 from board to rod.

Retain the knife as an overall isolator, it means you can add your new CU (board) in safety and avoid working on any live wires. So you will actually have two 'main switches' no issue here.

Assuming your shower makes the water warmer it is a water heater and should have its own RCBO in the CU. If it's currently branched off the lighting / power circuit you should extend its cable to the CU itself. If you don't have the cable right now no issue but you may find the lighting breaker pops when you use the shower so should move it ASAP.

[nellyp]

Wise words there Tim, if nothing else a visual inspection for any potential problems is a good idea.

Nelly.

2.5mm2 will be great as your ground, did you get any thicker wire to connect to your rod, if not double up on 2.5 from board to rod.

Retain the knife as an overall isolator, it means you can add your new CU (board) in safety and avoid working on any live wires. So you will actually have two 'main switches' no issue here.

Assuming your shower makes the water warmer it is a water heater and should have its own RCBO in the CU. If it's currently branched off the lighting / power circuit you should extend its cable to the CU itself. If you don't have the cable right now no issue but you may find the lighting breaker pops when you use the shower so should move it ASAP.

This is reply No 4 to this post, internet no good. So it is a lot shorter now. I may double up with the earth to the rod, I was going to do the box as in the attachment, but now there will be another RCBO I do not know where to put it in wiring. I doubt it should go in line with the other one. Does it mean that both the shower and air-con will have their own RCBOs and MCB also will either feed into the light and power circuit ? as that is what I thought I would be doing, (as in the attachment). Sorry this is clippy but am rushing cicuit.docx finally Edited April 1, 2012 by nellyp

[Crossy]

That should do the trick

I was a bit confused as to what you were doing. What you have drawn will be fine.

[nellyp]

That should do the trick

I was a bit confused as to what you were doing. What you have drawn will be fine.

wicked. I was worried that I would have to put another RCBO into it and did not know where to fit it in. If I can get the school to supply the cable, I might have seperate circuits for poer and light thanks again Crossy

[wpcoe]

@nellyp: Are you running your neutral wire via your earthing bar? If I understand what Crossy has been teaching me in other threads, that would enhance your earthing with "MENS".

Here's a diagram from the instruction sheet for the consumer unit in my townhouse:

The neutral wire would go from your knife switch to the earthing bar before it heads to main breaker.

[Crossy]

Rather than using the Thai method it is far better to have a link between the Earth bar and incoming Neutral if you desire MEN, it can be easily removed for testing.

This also means that if MEN is not implemented in your area (or you're not sure) you are not introducing potential hazards to your installation.

[electau]

The neutral earthing method used in the diagram is the US NEC (National Electrical Code).

This is the method that seems to have been adopted in Thailand.

The alternative method eg AS3000 is the install an earth bar in the switchboard, run all protective earth conductors to this bar and then run the main earth to an electrode.

The neutral earth bond is between the neutral link and the earth bar.

US MCBs are plug in type, IEC MCBs and RCDs etc are DIN rail mounted.( clip in type)

The switchboard shown is a NEC pattern type.

[wpcoe]

If the incoming neutral wire goes directly to the ground bar, is that adequate earthing protection even without an earth spike connected to the ground bar?

I'm thinking more of my condo now, where I thought I'd have to run an earth wire up to the metal roof rafters. If I can simply route the incoming neutral wire first to the ground bar (and then to the main breaker), would I be adequately grounded?

With my current townhouse with neutral wire routed via the ground bar *and* (apparently) an earth wire leading up to the metal roof rafters, is that kind of "belt and suspenders" redundancy?

[Crossy]

It is extremely unwise to assume anything about your local electrical system. You need to KNOW what is implemented.

By far the safest grounding system to install in your home initially is TT, i.e. a local ground rod with no N-E connection. RCD protection is vital in this instance but it makes no assumptions about polarity, MEN, or anything else.

Significant safety improvements can be made to the TT system by making it TN-C-S with MEN. However, if your local distribution system is not wired for this system then linking N & E can introduce a potentially lethal situation. If you see the neutral earthed at every third or so pole then it's reasonable to assume that MEN is implemented and you can link N-E, if you do not see this multiple earthing of the neutral assume MEN is not implemented.

Before linking your N and E measure the voltage between them, anything more than a few volts, leave the link out.

I'm deliberately hedging my bets here and erring on the side of safety. Whilst MEN should be implemented on newer systems there are still lots of locations that are TT , IT (where the neutral isn't grounded at all) and even delta (3-phase, 3-wire), where your 220v is picked off between phases, earthing your 'neutral' on a system like this could make other peoples installations potentially lethal.

The common factor between all these potential connections is that wiring it TT with RCD protection is guaranteed to be reasonably safe!

The above is what I would do in MY home, others may be of differing opinions based upon their knowledge. It is entirely up to you what you do in your situation. Measure, observe and make a decision based upon what you see.

[wpcoe]

IF I understand correctly, IF the power company earths the lines every few poles*, then connecting the incoming neutral wire to the ground bar in the circuit box should be adequate. Am I doing okay, so far?

I live in a mooban of townhouses. The previous block of townhouses has eight concrete power poles -- one every two units -- and at the first and last pole appears to be an earth wire. Is that what this is?

It is a twisted-strand wire in a yellow PVC pipe that goes into the ground. However at the top:

It just seems to go into the concrete pole? Is it somehow interfacing with the power lines?

On my block, I'm the second townhouse and the next door (corner) unit has one of those yellow PVC pipes with wire in it connecting to the top of the concrete pole. I walked down the rest of my dead-end soi, and NONE of the rest of the 20 poles have a wire like that.

Without trying to appear even more weird than the usual farang gawking around telephone poles, I looked at the base of most of the poles and saw nothing like a ground stake with wires clamped on. Just the three occurrences of the cables like in my photos, and those were all at corner units.

*When folks say there should be a ground every 3 poles or so, I suspect they are not talking about poles as close together as in my mooban where there's a pole every 8 meters (every two townhouses, each townhouse is 4m wide). BUT, I suspect that one earth wire for the 20 poles in my block would not be sufficient, right? The previous block has two for 30 townhouses (15 on each side of the soi) -- does that sound right? I may have missed one (or two?) on my block, but I looked twice and only saw the one in front of my next door neighbor's unit.