Mild Electric Shock From Shower Taps

[loong]

Strange coincidence, he must visit all new houses I guess, but a guy came round offering a safe-t-cut device about an hour ago and showed me, with a hairdryer, some water and my hand, how it works!!! 8500 baht payable over 3 months, pretty reasonable when you consider the possible outcome if one isn't installed.

I don't know about the consumer unit that you have, but changing the breaker that you have for a RCD should only be 1500 to 2000 Baht. So not such a bargain. My HaCO (with 2 dots over the a) consumer unit with everything only cost about 4,000 Baht.

[xerostar]

Just a note to add to the genuine concerns about the lack of electrical safety in Thailand.

Don't trust anyone who calls themselves "an electrician".

And don't expect the wiring to follow any standard (is there one?)

Upon checking the wiring to our instant hot water heater (for the shower)

I found the sparky had used a Green wire for live, Black for Neutral and White for Earth!

This "colour scheme" seems to be throughout the house wiring!

So when I make any additional power points etc I have to be much more careful than normal!

After 40 years of working with Green as Earth in Australia, my brain can hardly accept what I'm seeing.

We had some problems with a "short" in the wiring above the ceiling.

I had added an external security spotlamp (100W) and whenever I switched on my office

light there was a terrible loud buzzing noise from the ceiling and the circuit breaker would trip.

I disconnected my new light and switch just in case I had made a mistake.

(easily done with the strange colour scheme) but but the fault persisted.

I found the fault was inside the conduit leading to the fluorescent light on my office ceiling.

I had pulled on the wiring a little when I installed the new switch for the security light.

Later I found two bare copper wires running inside the conduit.

They had come together and were arcing.

The solid copper wires were vibrating and that produced the loud noise.

I assume the vibration was amplified by the conduit sitting on the ceiling.

The sparky (or his assistant) must have pulled very hard on the wires during installation and they have caught on a sharp edge, stripping the wires bare over 10 cm.!

The fact that they were lying parallel with a slight gap allowed the

circuit to work without a problem, until the wires were disturbed by me.

They got close enough for an arc to form.

Here is photo of the offending wires after removal from the conduit.

You can see the colour changes due to heat build up.

We were lucky that it didn't result in a fire!

[xerostar]

Slow connection tonight - made uploading a pain in the ass!

Third try now!

[Happy Jack]

My experience of Thai wiring is that it's all pretty rough and an earth is generally not installed. Your electrician may have installed an 'earth' but has he actually connected it to anything? or correctly?

For what it's worth - and because in Thailand you inevitably have to do most things yourself if you want them done properly - I have attached a simple diagram of how things should be. I trust of course that OP is intelligent enough to apply this info without electrocution. Phase and also Neutral if a circuit is connected can produce deadly amounts of current so please be careful. Even an earth wire connected to an appliance but not properly earthed could be deadly.

Incidentally - if your plumbing is all copper it should also have it's own earth connection at some point. This can be connected in the same way as the wiring to the earth peg as shown in the attached diagram. If you have fitted a metal shower tray or bench top these should also be earthed. All of these earth connections should be wired back to an earth rail on your main switchboard.

Hope this helps.

Earthing.pdf

[loong]

My experience of Thai wiring is that it's all pretty rough and an earth is generally not installed. Your electrician may have installed an 'earth' but has he actually connected it to anything? or correctly?

For what it's worth - and because in Thailand you inevitably have to do most things yourself if you want them done properly - I have attached a simple diagram of how things should be. I trust of course that OP is intelligent enough to apply this info without electrocution. Phase and also Neutral if a circuit is connected can produce deadly amounts of current so please be careful. Even an earth wire connected to an appliance but not properly earthed could be deadly.

Incidentally - if your plumbing is all copper it should also have it's own earth connection at some point. This can be connected in the same way as the wiring to the earth peg as shown in the attached diagram. If you have fitted a metal shower tray or bench top these should also be earthed. All of these earth connections should be wired back to an earth rail on your main switchboard.

Hope this helps.

Your diagram shows that neutral and earth should be connected. This should ONLY be done if certain conditions exist. I'm not an expert so will leave it for others more qualified to explain.

[Crossy]

Your diagram shows that neutral and earth should be connected. This should ONLY be done if certain conditions exist. I'm not an expert so will leave it for others more qualified to explain.

Agreed, please ensure that MEN or PME (same thing, different names) is implemented in your area before linking ground and neutral.

If done correctly it is very safe, if done incorrectly or inappropriately then there are serious safety issues.

[Artisi]

Your diagram shows that neutral and earth should be connected. This should ONLY be done if certain conditions exist. I'm not an expert so will leave it for others more qualified to explain.

Agreed, please ensure that MEN or PME (same thing, different names) is implemented in your area before linking ground and neutral.

If done correctly it is very safe, if done incorrectly or inappropriately then there are serious safety issues.

Crossy - would you mind expanding on this regarding it being implemented in your area - how do we know - how do we check.

Thanks.

[loong]

..................And don't expect the wiring to follow any standard (is there one?)............................

I found the sparky had used a Green wire for live, Black for Neutral and White for Earth!

This "colour scheme" seems to be throughout the house wiring!

.....................We had some problems with a "short" in the wiring above the ceiling.

I had added an external security spotlamp (100W) and whenever I switched on my office

light there was a terrible loud buzzing noise from the ceiling and the circuit breaker would trip.

................................

I found the fault was inside the conduit leading to the fluorescent light on my office ceiling.

I had pulled on the wiring a little when I installed the new switch for the security light.

Later I found two bare copper wires running inside the conduit.

They had come together and were arcing.

The solid copper wires were vibrating and that produced the loud noise.

I assume the vibration was amplified by the conduit sitting on the ceiling.....................

Here is photo of the offending wires after removal from the conduit.

You can see the colour changes due to heat build up.

We were lucky that it didn't result in a fire!

I'm a bit confused

Green wire for live, Black for Neutral and White for Earth is definitely wrong, but I don't see any green wiring in your photo, ie no live. You were getting arcing between the neutral and earth?

I'm no expert, but in a system where the Neutral and Earth are connected, surely it is impossible for arcing to occur between the 2 ?

Where the earth and neutral are not combined, and enough current arcs to be heard, wouldn't that trip the RCD?

Am I missing something here? I like to be as aware as possible of any safety issues in a country where you can't trust the electricians.

[lopburi3]

I suspect the black/white are hot/neutral and they can short without RCD trip.

[loong]

Thanks Lopburi,

that I can understand, but to quote xerostar

"I found the sparky had used a Green wire for live, Black for Neutral and White for Earth!

This "colour scheme" seems to be throughout the house wiring!"

This is where I'm confused

[Crossy]

Crossy - would you mind expanding on this regarding it being implemented in your area - how do we know - how do we check.

Thanks.

Of course

PME (Protective Multiple Earthing) and MEN (Multiple Earthed Neutral) are two names for effectively the same thing, the neutral is connected to earth at multiple points rather than just at the transformer. MEN is supposed to be implemented in all new installations in Thailand however many rural areas have not yet been upgraded.

To tell if your area has MEN:-

1. Try asking your sparks (move to the next option if you get a blank look)
   
2. Look at your power poles, if you see a copper ground strip running from the neutral down every 3rd or 4th pole chances are you have MEN
   

If you can't tell if you have MEN assume you DON'T, do not link neutral and ground. DO install an RCD device (Safe-T-Cut) on your water heaters and power outlets.

[Artisi]

Crossy - would you mind expanding on this regarding it being implemented in your area - how do we know - how do we check.

Thanks.

Of course

PME (Protective Multiple Earthing) and MEN (Multiple Earthed Neutral) are two names for effectively the same thing, the neutral is connected to earth at multiple points rather than just at the transformer. MEN is supposed to be implemented in all new installations in Thailand however many rural areas have not yet been upgraded.

To tell if your area has MEN:-

1. Try asking your sparks (move to the next option if you get a blank look)
   
2. Look at your power poles, if you see a copper ground strip running from the neutral down every 3rd or 4th pole chances are you have MEN
   

If you can't tell if you have MEN assume you DON'T, do not link neutral and ground. DO install an RCD device (Safe-T-Cut) on your water heaters and power outlets.

Crossy

Thank you for the info', 1 more question just for self learning - If you are unsure what is the effect / problem of connecting MEN at your switch board in a non MEN area?

[Crossy]

Crossy

Thank you for the info', 1 more question just for self learning - If you are unsure what is the effect / problem of connecting MEN at your switch board in a non MEN area?

The hazard is a broken neutral. Should the neutral become open between you and the transformer, with no MEN link the lights go out and you call PEA.

However if you have a MEN link and nobody else does then all the neutral current will attempt to flow down your ground stake. Since the ground stake will have a resistance to ground in the order of 50-100 Ohms it won't be able to handle the current and the potential on all your 'grounded' appliances will approach phase voltage, this is of course something you don't want.

When there are lots of ground points on the neutral, the neutral-ground resistance is very small and the potential rise caused by an open neutral will be limited to a few volts.

The danger of open neutrals is one reason why (in the UK) PME is not implemented on installations supplied by overhead wires, something which the Thais don't seem to have considered.

[Artisi]

Crossy

Thank you for the info', 1 more question just for self learning - If you are unsure what is the effect / problem of connecting MEN at your switch board in a non MEN area?

The hazard is a broken neutral. Should the neutral become open between you and the transformer, with no MEN link the lights go out and you call PEA.

However if you have a MEN link and nobody else does then all the neutral current will attempt to flow down your ground stake. Since the ground stake will have a resistance to ground in the order of 50-100 Ohms it won't be able to handle the current and the potential on all your 'grounded' appliances will approach phase voltage, this is of course something you don't want.

When there are lots of ground points on the neutral, the neutral-ground resistance is very small and the potential rise caused by an open neutral will be limited to a few volts.

The danger of open neutrals is one reason why (in the UK) PME is not implemented on installations supplied by overhead wires, something which the Thais don't seem to have considered.

Crossy, thanks for that information - understood and logged into the memory bank.

[lasiana]

Exactly the same thing happened to me in our new house, when they installed the water heater and an additional air-conditioning unit (both on the same circuit).

Got the sparkies in and when they pronounced it fixed. I said "Okay, go ahead then, have a shower." Which was greeted with smiles and laughter, then they realised I was serious....

They did a few more checks and its been fine ever since!

[Nirvana]

As you seem to only have the one panel I would recommend you buy a new panel to house a main breaker/Safe-T-Cut/your current panel. They do not cost that much and provide room to tap the non RCD breaker if required due to nuisance trips from a leaky air conditioner or refrigerator.

Hi Lopburi3 / Crossy

Would you say that this Panel has RCD and looks to be safe.

We have assurances from our electrician that everything is earthed.3 pin plugs throughout.

Not that it means much if you are a layman when it comes to electrics.

comments / advise well recd.

Thanks

[lopburi3]

Appears to just be an entrance panel with main breaker and sub-breakers but hard to see. Unless it is names RCB or such and has a test button to trip it probably a normal breaker. It seems to have a ground attachment with actual wires on it so you probably do have grounded outlets. But there is no RCD that I can see.

[longball53098]

What I see is a 3 phase panel with main breaker and sub breakers for 12 branch circuits. None of those breakers appears to be a RCBO. There are at least 6 white wires attached to the "N" bar which should be the neutral. The bus next to the N bar is a ground bus and it looks like a heavy black cable is attached to this and runs up and around then down the right side of the panel. This "black" cable may be the ground to the ground rod?

The ground bus bar only has one white cable connected so if the branch circuits are grounded is a good guess.

Some one with expertise needs to inspect this a little closer as it appears not too good of a wiring job. The branch cable size looks big enough but without knowing what each circuit is you can't be sure if the ampacity of the cables and breakers is correct.

Two more cents from an armchair electrician

[Artisi]

I don't see any earth conection on the board although it is possible it is behind the mounting panel.

[Crossy]

I don't see any earth conection on the board although it is possible it is behind the mounting panel.

Yeah, I see a green wire up in the top right but where it goes is anyones guess.

There should be as many green wires as black and white

Definately no earth leakage protection (RCD or RCBO)

Edit I reckon that thick black to the E bar (is that actually the E bar or does the angle deceive?) is the incoming neutral, hopefully there is a nice fat wire between the N and E bars. I don't like this way of providing MEN / PME but it seems to be how all new Thai installations are done.

We need a more 'front on' view of the N and E arrangements.

[longball53098]

Yes, I now see what appears to be a green wire in the upper right. In a closer look I see now what appears a black, dark blue, or possibly that green wire connected to the "E" bar and then maybe straight to the "N" bar? I attach a photo of the area.

As you say Crossy the photo needs to be a straight on view and closer.

[Artisi]

The closer you look the more confusing it seems, there appears to be wires everywhere. Yes, a closeup pic. of the board straight on would be of asistance.

[Nirvana]

Yes, I now see what appears to be a green wire in the upper right. In a closer look I see now what appears a black, dark blue, or possibly that green wire connected to the "E" bar and then maybe straight to the "N" bar? I attach a photo of the area.

As you say Crossy the photo needs to be a straight on view and closer.

Crossy / Lopburi3/ Artisi

Thank you so much for your comments and time spent,sorry for not posting soon, its been a hel_l of a week. I will get some more pics from straight and closer angle and post.

So it seems then definately some work needs to be done here for RCD for a start. Would that be a hard job to install ?

Need to check where green wire goes as you said could be into thin air above the ceiling.

Will revert and if ok, take a bit more of your time.

Thanks

Nirvana