German/thai Student Dies Of Electrocution In Phuket

[dhrobertson]

Thanks, that is what I wanted to know, does the fact that the test button works mean I am safe, and your answer is "no"!

So, I still need to check if the earth wires in my condo are actually connected to earth. Is there a way I can do this with a multimeter or does it require more specialist equipment?

To test the quality of the earth you do really need specialist equipment, to test if you have an earth, you can use a voltmeter, and in this order, set the meter to measure in the 230V range, put one of the leads on the earth terminal FIRST, then the other lead on the live terminal, if you get a voltage of 230V it suggests you have an earth, but will not tell you how good the earth is, more importantly you should be testing the time RCD trips under fault conditions.

A recent job of mine in the UK, I tested a commercial property, which Did not have an earth coming into the site, but there was an earth connected at the Fuseboard, which was then connected to the water pipe, and had an RCCB, under test the RCCB DID NOT trip!! I got the electrician to install a earth rod, got a reading of 3.4 ohms, under test the second time, the RCCB tripped in 38 milliseconds @ 1 x fault current, and tripped in 12 miliseconds @ 5 x fault current.

Hope this makes things very clear

You need a good earth AND a good RCCB which trips within the times

Dear Forkinhades,

Can we discuss this futher offline?

I think a main RCD device is a good solution for dwellings with no CPCs at every node and I do not wish to discourage this. In general we want automatic disconnection in less than 40ms with say a residual current of 30mA.

In your specific examplke, what was the ground system? TN-C-S?

I would be interested to discuss your views further but I suspect this is outside the area of the layman.

Best regards

[Forkinhades]

it was TT, same as most of Thailand. In the example below which you can download, the earth rod has an impedance of 50 ohms, and the Zs can be as high as 1,6777 and this will trip in time ie less than 40 ms, without an earth your trip times will be considerably longer, and possibly fatal

http://static.thaivisa.com/forum/style_ima...e_types/pdf.gif

Quite welcome to have a beer with you anytime

6KW_Shower.pdf

Edited January 3, 2010 by Forkinhades

[robint]

One comment to make about installing an earth rod. One of the best conductors to use is copper, which is why shops sell 2 meter copper earth rods.

Or do they??

When I installed these at my Phuket hotel during construction, I was amazed to see the copper color coming off the earth rods a few weeks later! In fact, they were steel rods painted a copper color!!!

Needless to say, they were all replaced with copper earth rods immediately.

So if you are buying copper earth rods in Thailand, scratch them with a knife to check that they are copper all the way through!

Also, in places like Phuket, the soil is mostly sand for several meters of depth. Then it's very difficult to achieve a good grounding.

Simon

FYI

It is normal for a purpose made earth rod to have a copper coating and steel inside. A pure copper rod would be far to soft and you couldnt drive it into the ground (soft as putty). The quality ones have a sheath of copper about 1mm thick, the cheapo ones are only copper plated. Copper coloured paint is worse than uselss as it would tend to insuate the rod.the rod has to be placed in a damp area to be sure (near a septic tank or well).

This begs the question of what to do if you are in an old appartment block on the 5th floor say. If you found a convenient piece of rebar exposed then you could try to make a contact with it - tricky - but it worked for me when trying to earth my PC. Incidentally you are almost certain to get a belt off an un earthed PC by the way its switched mode power supply is constructed. In theory its a non lethal belt but very irritating nonetheless.

An ELCB (GFI) is essential in such circumstances

You could always opt for a cold shower - not very cold really, or do it the thai way and boil up some water and get you TGF to shower you from a bucket - it works and its safe.

Finally, please remember that an ELCB offers no protection whatsoever against a human contact directly across the live and neutral

Seasoned electricians will often be seen with one hand in pocket when working on live wiring - I do.

And for you TGF doing her hair, some types of hairdryer use half wave rectifier to drop the power to the heater. This saturates the detector coil in the ELCB and it becomes ineffective - ha ha

Edited January 3, 2010 by robint

[David006]

Its scary to even go near water heater for shower or kettle not knowing that it has a safety standard and wiring are being properly grounded and properly insulated again water sip in. A qualified and trustworty electrician will be able to assure you peace of mind for your home. But what about public places like a hotel bathroom? hmmmm..

Luckily most electrical appliances like kettles and toasters are now made from that heat proof plastic. Thus when in LOS don't buy metal appliances; the cheap plastic ones are better as they isolate you.

Not using an electrical shower is probably the best advice; you shouldn't need hot showers unless you spend your life in an aircon coccoon.

Making your own earth is quite easy. A galvinised steel stake in the ground and running an earth lead from the shower to this should be adequate to trip the earth leakage breaker. You can use a jubilee pipe clip for the connection and I coat the connection with grease to stop corrosion getting in and check it from time to time.

Sorry about the DIY advice, but in LOS there are very few standards and hopefully some farang advice will save lives. Lack of education, plus most male folk don't make it to high school, and very few beyond that.

Sound advice ..proper copper amalgam ground rods are cheap enough though...also good idea to check where its driven into the soil...is it dirt or rubble...very sandy or rocky soil could mean very poor ground in dry season>>>if so watering it ( pee is good!) now and then may help..

[dhrobertson]

it was TT, same as most of Thailand. In the example below which you can download, the earth rod has an impedance of 50 ohms, and the Zs can be as high as 1,6777 and this will trip in time ie less than 40 ms, without an earth your trip times will be considerably longer, and possibly fatal

http://static.thaivisa.com/forum/style_ima...e_types/pdf.gif

Quite welcome to have a beer with you anytime

I do not wish to be a pedant, but please consider a situation where we have a dwelling with two pin socket outlets. I maintain that an RCB at the origin set to 30mA can be a life saver even when there is no ground.

As to the shower example, I fully agree that with a ground connection (and we always insist on acceptable ground fault loop impedance at every system node using Fluke 1653 equipment), the ELCB will trip, not just quickly, but without you being part of the circuit.

To re-iterate, I fully agree that adequate grounding is essential. However I do not want to discourage people from protecting themselves with an RCB as this can be readily installed.

As mentioned before, the Thai EIT code requires ELCB protection for all water heaters. They usually fit 10mA RCBOs but these can be too sensitive for other circuits such as socket outlets and landscape lighting.

Generally, we design for TN-C-S with a main neutral/ground bond at the local MDB. We usually specify a local array of 3 x 3m x 5/8" copper clad ground rods such that impedance to ground is less than 5 ohms. All final circuits supplying socket outlets, water heaters, bathroom circuits, landscape lighting circuits and swimming pool control circuits have individual 30mA RCBOs. In this way we comply with both EIT and BS7671:2008 (EIC60364)

As you say, TT is very common here. However a RCD at the origin is the exception rather than the rule. As such EEBADS generally never works (never mind the fact that the MCBs are often incorrectly sized anyway!). Why the Thais make things more difficult by only having "C" characteristic breakers commonly available is a mystery to me!

Where are you based? Are you working here?

Best regards!

[dhrobertson]

It is normal for a purpose made earth rod to have a copper coating and steel inside. A pure copper rod would be far to soft and you couldnt drive it into the ground (soft as putty). The quality ones have a sheath of copper about 1mm thick, the cheapo ones are only copper plated. Copper coloured paint is worse than uselss as it would tend to insuate the rod.the rod has to be placed in a damp area to be sure (near a septic tank or well).

This begs the question of what to do if you are in an old appartment block on the 5th floor say. If you found a convenient piece of rebar exposed then you could try to make a contact with it - tricky - but it worked for me when trying to earth my PC. Incidentally you are almost certain to get a belt off an un earthed PC by the way its switched mode power supply is constructed. In theory its a non lethal belt but very irritating nonetheless.

An ELCB (GFI) is essential in such circumstances

You could always opt for a cold shower - not very cold really, or do it the thai way and boil up some water and get you TGF to shower you from a bucket - it works and its safe.

Finally, please remember that an ELCB offers no protection whatsoever against a human contact directly across the live and neutral

Seasoned electricians will often be seen with one hand in pocket when working on live wiring - I do.

And for you TGF doing her hair, some types of hairdryer use half wave rectifier to drop the power to the heater. This saturates the detector coil in the ELCB and it becomes ineffective - ha ha

I usually work with both hands in my pockets! But then I'm the inspector! Ha!

[Forkinhades]

@ dhrobertson PM for you

[Forkinhades]

has anybody got the link to the Puket Gazette showing this story

[LivinginKata]

has anybody got the link to the Puket Gazette showing this story

http://www.phuketgazette.net/archives/arti...rticle8177.html

[elkangorito]

Actually, the Thai EIT code is pretty good. It is more stringent than BS7671 in that RCBOs are required for all water heaters. Real problem is lack of inspection.

Where can I get a copy of the Thai EIT code?

[dhrobertson]

Where can I get a copy of the Thai EIT code?

Chulalonkorn University bookshop near Siam square. About 350TBT

[elkangorito]

Can you please give me a basic idea of what the book covers? Does E.I.T. stand for the Engineering Institute of Thailand? What does it say about wiring rules?

[Forkinhades]

Actually, the Thai EIT code is pretty good. It is more stringent than BS7671 in that RCBOs are required for all water heaters. Real problem is lack of inspection.

Not going to argue with you buddy, as I have not read the EIT, but in the UK any circuit within a bathroom has to be protected by an RCD including lighting, and all installations have to have a Main earth, although the individual circuits do not require an earth but must be protected by RCBOs

another beer David?

best regards

[elkangorito]

I haven't heard a word about this marvelous EIT Code yet. It must be a secret of some sort.

BTW, Australia follows the IEC, so it has regulations along the same lines as the UK. The only differing points being the exact way the distribution system is earthed in Australia (customers are not supplied with an earth), UK style "ring mains" are not used & the ambient temperature is very similar to Thailand.

[dhrobertson]

I haven't heard a word about this marvelous EIT Code yet. It must be a secret of some sort.

BTW, Australia follows the IEC, so it has regulations along the same lines as the UK. The only differing points being the exact way the distribution system is earthed in Australia (customers are not supplied with an earth), UK style "ring mains" are not used & the ambient temperature is very similar to Thailand.

Engineering Institute of Thailand EIT code was updated last year. It is based on the American code. Only available in Thai but useful for getting cable sizing correct with local ambient conditions. As stated previously, issue is not that Thailand has no electrical code. Issue is that there is no formalised inspection system.

[JetsetBkk]

A couple of weeks ago I was driving past Phuket prison in Damrong road and saw a few cars stationary coming from the other direction - from Thepkrasatri road. Some were trying to do a U-turn.

I then saw a thick power cable lying in the road almost reaching my side of the road, and the end of it was on fire - a flame about 4 to 6 inches high. So the power was still on and it just fell into the street.

Amazing Thailand.

What's the Thai word for "maintenance"?

[Valentine]

Several years ago I was driving along Chao Fa East towards Phuket Town during a storm when 3 or 4 explosions accompanied by bright blue flashes occured on the power lines. Quite a few years back a girl was electrocuted when she leaned out of her balcony & touched some cables. Years ago in my apartment block in Patong a child was killed when he was able to climb on to a transformer which was on the ground & fenced off but unlocked. In Phuket Town, Thalang or Phang Nga Rd, the cables have supposedly all been put underground & certainly makes it look much nicer until one looks at the row of ugly cables stretching the length of the block hanging off the side of the buildings.

Electrical safety standards in this country have a long way to go. I would like to know if there are laws for setting of overhead cables because if they are set according to the current law then it is a disgrace when one can see the state of them throughout the likes of Phuket Town & Patong.

Edited January 23, 2010 by Valentine