DIYer needs advice

[Mandi]

Hi,

I've signed up for advice as I live in Thailand where electrical safety is a joke. I need some advice on an extensive re-working of a TT earth system in our house, but I appear unable to start a thread in the DIY section. How to proceed?

 

[Sintra]

Hi Mandi

I have moved your thread to the DIY forum and given you access to post.

 

[Mandi]

OK I see a kindly moderator has moved the topic for me, so I'll begin. . .

The safety issue here in Thailand is so screwed up. Even if you want to have things done properly, there simply aren't any competent electricians available. Thailand has electrical codes, but they are ignored, there is no enforecement at all. The only way forward is to educate oneself as best as possbile and make the best of what one has to work with. I'm profoundly aware of the dangers associated with DIY electrical work and I have a very healthy fear of electrocution, but believe me when I say that in this location, sorting this mess out myself really is the best way forward. Whatever I do, it's going to be immeasurably safer for me and my family that what we have here at the moment. To give you an idea of what I'm working with, here is a picture fron the loft. . .



The issues are multiple. Everything is connected together with nothing but black electrical tape. No attention has been paid to wiring colour, and there are actually mixed and reversed colour cables on the same circuit all over the place, even mixed gauge wires. In one part of the building the idoot who installed this even used green earth wire on a live circuit. Compounding this is that no effort was make to protect the cables from rats and there are exposed conductors all over the place due to rats nibbling. It's not even safe to enter the loft at all without disconnecting the supply altogether.

It's basically a full rewire job, from the supplier side right through to the consumer plugs and switches i.e. everything.

We have three houses, all on the family land out in the middle of nowhere, and the electricals in all three houses are in this state. We are supplied what I have deduced to be a TT earth system, supplied by two overhead conductors from a pole mounted tranformer, a couple of hundred yards down the road. I 'think' the transformer case is grounded at the pole, here is an image, there appears to be a ground cable coming from the case and running on the back of the pole, but I've been unable to get to the other side to check for sure. . .



Further down the road, and right outside out house, the uninsulated neutral appears to be grounded again before it enters our property. I have highlighted the bond. . .



The low voltage supply for our house continues down to the next pole but appears to go nowhere. This is where the live and neutral appear to be connected with some kind of device, highlighted in the next image. What is that, some kind of noise supression?. . .



I have many, many more questions about the consumer side grounding, but I want first to get some feedback on the supply side of the earth. Thanks in advance. . .

 

[Marvo]

What electrical testers do you have access to Mandi?

 

[Mandi]

I have a good quaility Japanese multimeter but that's it. Any ground/earth resistance testing is going to be improvised. At the moment, as an emergency measure, I've got a number of ground rods around the building to at least get an earth connection to nearby equipment until I can do the full rewire (the house has three pin plugs, but behind the plates there are only the live/neutral connections made). The internal wiring is a joke (not a funny one) but I'll come to that later. I want to establish before anything that I really do have TT coming in.

 

[Marvo]

Did they link the earth connection to the neutral at the back of the sockets when they connected them or is the earth connection just empty and unused?

 

[Marvo]

Also can you attach some photos of the sockets and the main fuse board please.

 

[Mandi]

No link to Neutral in the sockets, nor in the consumer unit (regarding the consumer unit, I assume there should be no earth bond to neutral, assuming this really is a TT system).

Note that the electricians here are mostly 'have a go' types that have no training, have no certifications, they're just builders that throw in shabby electrics as part of the house build. None of them really have any concept of the different earthing systems, let alone the importance of earthing in the first place. Three pin plugs with just the LN wires connected is very common here, it's actually the norm believe it or not.

 

[Mandi]

. . . yes, I'll get some pics of the main fuse box for you in the morning, it's 02:45 HRS here now, I don't want to wake everyone up

 

[Marvo]

No problem, wait till morning. In certain African countries they use a system that also has no earth and in every socket they link the neutral to the earth terminal so the neutral performs both functions. It's a very poor system so I'm not suggesting you should do this but I thought it maybe the way it was done already.

It would be nice if you can attach photos of the electrical meter and the cabling around it (if it's accessible) as well as the fuse box and it's surrounding wiring.

 

[Engineer54]

This thread may be of some use to you. Similar circumstances to those you are asking about now. You never know he may even be a neighbour of yours!! lol!!

http://www.electriciansforums.co.uk...448-need-advice-domestic-instal-thailand.html

 

[Mandi]

Perhaps the title of this topic could be changed to something a little more descriptive e.g. 'Expat in Thailand need some DIY electrical advice'.

Here's a picture of the consumer unit(s). . .



At the top is the main breaker for the whole house. I have uncovered it as I want to talk about that below.

The house is presently set up with a botched split system. On the right you can see there is a 2-pole RCBO, which supplies the larger CU in the middle. This supplies most of the sockets around the house, and most of the lighting.

The smaller CU at the bottom bypasses the RCBO completely and is supplied directly from the main breaker at the top. This CU supplies all the air conditioners. Each air conditioner has been assigned it's own earth rod by whoever set this system up, driven into the ground near each compressor. Alarmingly, the bathroom appears to be on one of the circuits supplied by this CU (which has no RCBO protection)

Regarding the main breaker. . .



It appears to be just single pole, and as this is a TT system, there is apparently no way to isolate neutral as well as live. Further, this breaker box is itself not even grounded, and those cables you can see have just a wrap or two of insulation tape around them. I don't know if that bar at the top is supposed to be an earth bar, but it looks like it's been repurposed for connecting etiher a live or neutral 'splice' for the split system i.e. the two separate consumer unit supplies. I can't be sure as I dare not touch anything until I can get this isolated form the mains altogether.

There is no breaker upstream of this. The only way to cut the power will be to go outside to the meter near the road (in Thailand the consumer has to supply the meter and is responsible for it) and unscrew the live cables. When the time comes to proceed, I have it planned, I will use armoured gloves with a couple of layers of rubber gloves on top of that. I will use some kind of isolation platform to stand on, and use insulated screwdrivers. Doing it scares the hell out of me but I believe in the physics.

I'll get the other pictures requested when I can get outside in daylight hours.

 

[Marvo]

The house is presently set up with a botched split system. On the right you can see there is a 2-pole RCBO, which supplies the larger CU in the middle. This supplies most of the sockets around the house, and most of the lighting.

The smaller CU at the bottom bypasses the RCBO completely and is supplied directly from the main breaker at the top. This CU supplies all the air conditioners. Each air conditioner has been assigned it's own earth rod by whoever set this system up, driven into the ground near each compressor. Alarmingly, the bathroom appears to be on one of the circuits supplied by this CU (which has no RCBO protection)

It's actually not as I feared it might be given your location....

Firstly can you tell us what the two white wires are around the main circuit breaker and where they come from? I realise it's probably 4 in the morning again but is there any chance of a photo of both the CU's with their covers removed? Be careful because I see uninsulated exposed busbars in at least one of them so play it safe and isolate power at the main circuit breaker first.

I wouldn't be too concerned about the air conditioners being on a non-RCB supply but I'd make re-supplying the bathroom from the RCD board part of the master plan if I were you.

Regarding the main breaker. . .

It appears to be just single pole, and as this is a TT system, there is apparently no way to isolate neutral as well as live. Further, this breaker box is itself not even grounded, and those cables you can see have just a wrap or two of insulation tape around them. I don't know if that bar at the top is supposed to be an earth bar, but it looks like it's been repurposed for connecting etiher a live or neutral 'splice' for the split system i.e. the two separate consumer unit supplies. I can't be sure as I dare not touch anything until I can get this isolated form the mains altogether.

The main breaker is definitely single pole so there is no way to isolate the neutral but I'm still not convinced this is a TT earthing arrangement which is why I want to see more of the incoming supply cable and the earth and neutral bar in both CU's. I'm guessing/sensing it's TN C S / PME and the bar above the main MCB is both the main earth terminal and your neutral but I might be wrong.

There is no breaker upstream of this. The only way to cut the power will be to go outside to the meter near the road (in Thailand the consumer has to supply the meter and is responsible for it) and unscrew the live cables. When the time comes to proceed, I have it planned, I will use armoured gloves with a couple of layers of rubber gloves on top of that. I will use some kind of isolation platform to stand on, and use insulated screwdrivers. Doing it scares the hell out of me but I believe in the physics.

I'll get the other pictures requested when I can get outside in daylight hours.

I can't really comment on this suggestion. I'd be tempted to urge you to get one of the local cowboys to do your disconnection and reconnection if I were you. It's not so much about just standing on a rubber mat whilst wearing insulated gauntlets, it's as much about all the other places you could contact an earth or neutral or even another phase. If we work live in marshaling or meter cabinets we sheet off the entire cabinet first and it should only be done following a full risk assessment and as a last resort by a competent person.

 

[Mandi]

Firstly can you tell us what the two white wires are around the main circuit breaker and where they come from? I realise it's probably 4 in the morning again but is there any chance of a photo of both the CU's with their covers removed?

I will take off the covers in daylight later and post images for your examination.

Regarding the white cable, I'm pretty sure the bar above the main breaker is the neutral (but I haven't tested to be sure yet). The black cable on the far left of the box, (thicker at the bottom) is the main incoming neutral feed. It joins that bar at the top, where two other cables leave the bar to supply the two separate CUs. At the bottom of the breaker, two cables thus feed the phase to the two CUs. There is no provision for earth as far as I can see. Further, I have continuity tested the live bus bar to the ground bar in the CUs and there is no bond to earth. That in itself means nothing though, as the person fitting the CU clearly had no clue what he was doing.

Following is an image of the meter outside. Sorry it's blurred, the area around it is heavily overgrown and I was too busy watching out for snakes, we have some extremely dangerous varieties here, including Banded Kraits. . .



Two wires in, two wires out, that's it, there is no earth. On the right, the consumer side, the two wires go around 60 metres to the main breaker already pictured. On the left side, the supplier side and the two cables go to the poles on the opposite side of the road, pictured in my original post.

 

[Engineer54]

Don't assume that all the Thai electricians are clueless, i've had the pleasure of working with more than just a few very competent Thai electricians on overseas projects. Why not make some enquiries with locals you can trust, to find a competent electrician. I know that it may be a lot more difficult if you are in a remote rural location, but they are about, you just have to make the effort to find one.... lol!!