Electricity

[tatom]

I read that many of us are concerned anout the danger of the older electric systems here. I also have an older ungrounded system.

When living in the US, I was zapped several times, 110v, 220v, and I was even struck by lightning twice, the last time I was outside standing in a puddle of water. The only damage was a headache.

Touching a live, grounded wire, has only resulted in a good jolt. If one was to touch a live ungrounded wire here, would it be worse, even cause death?

Also, if one were to get electrocuted, what would be the likely cause? Normally, we dont have any direct contact with electricity. We turn on the light switch and appliances and thats about it.

[Gimbo]

The danger is if the current run trough your brain or heart. 110 and 220v is plenty enough to stop your heart. Normaly when people touch something electric and get a shock, it only run trough the hand or fingers, and your bodies reflexes make you close the hand and pull it away, same as when you touch something hot. So you simply do not get shocked long enough to do any damage.

[kmart]

"The Green Mile" movie was on UBC (again) yesterday. Please remember to "wet the sponge" before turning on switches and stuff, won't you?

[helitool]

The ground wire from an electrical plug is connected to the metal chassis of the device that is plugged into the receptacle. This is to allow any electrical leakage to the metal chassis to find its way to ground and not be a danger if someone touches the metal part of the device. If a device has no metal parts exposed to the operator then a ground is not needed. Many small electrical appliances such as hair dryers do not have grounded plugs because there is no danger of coming into contact with the electrified parts of the appliance because the housing is plastic.

In western countries house floors are usually wood and do not conduct electricity to ground unless they are very wet. Also most people wear shoes in the house there which provides additional insulation preventing the person who touches a hot wire from being shocked severely enough to be fatal. Unfortunately here in Thailand people who come into contact with electrical hot wires are usually barefooted and often standing on tile or cement floors with sweaty feet which provides an excellent ground plane for the electricity to travel down the arm and through the heart on the way to the foot.

My brother tried to pull a plug out of a socket recently and received a shock even though he only touched the plugs plastic housing because the humidity was high and he was barefooted on a cement floor. His house BTW has a modern properly grounded system. When I was in Kwajaline atoll the humidity was so high that we had to use a stick to unplug and plug-in electrical devices of we would receive a very bad shock.

Another problem here in Thailand is that hot and neutral wires are often swapped when going from outlet to outlet. To sum up a grounded plug is only useful if there is an electrical leak to the metal part of an appliance and the person happens to touch the metal while providing an opportunity for the current to find a ground through him.

[frenchFARANGbkk]

Hi,

I found this interesting website about grounding in Thailand:

http://www.thailandguru.com/grounding-eart...electrical.html

They say:

A ground is not any of the following:

* A ground is not a wire screwed into the wall

* A ground is not a wire stuck into the dirt

* A ground is not a wire connected to just anything metal and big

So I wonder why my washing machine has a wire screwed into the wall ?! Completely useless or better than nothing ?

Thanks.

[stateman]

Touching a live, grounded wire, has only resulted in a good jolt. If one was to touch a live ungrounded wire here, would it be worse, even cause death?

Also, if one were to get electrocuted, what would be the likely cause? Normally, we dont have any direct contact with electricity. We turn on the light switch and appliances and thats about it.

I have read numerous times in the news about people killed by electrocution. These tend to be small news, as it is not the stuff that sells newspapers. However, I like to make a mental note when I read them.

I think if there is an electrical leak, or a short circuit, the metal appliance body carries live electricity. Touching that can give a jolt and an electrocution. Example: one child I remember reading wanted to drink at a hospital fountain, got killed. Too bad, the way it was dealt with in the land of "mai pen rai" is basically, well, too bad. Then life goes on as usual.

So I wonder why my washing machine has a wire screwed into the wall ?! Completely useless or better than nothing ?

That wire is to make "you" feel good. It is not meant to really effectively carry the current along to a proper ground and down to earth. I used to get jolted when I stood on the wet floor operating the washing machine. Never liked it!

[Crossy]

99 times out of 100 you'll get away with touching the live wire, over the years I've had numerous belts, mains, 220V DC, 25kV DC (low current), 115V 400Hz (that HURTS), 115V 1100Hz (that hurts A LOT).

The problem occurs when you are in the 1% group.

You can die from a 12v car battery, if all the bad circumstances add up (very, very unlikely).

EDIT To our OP, in the US you are very unlikely to get a 'real' 220V shock because of the way 220 is delivered to the home as a bi-phase 110V system.

Edited December 12, 2007 by Crossy

[stateman]

99 times out of 100 you'll get away with touching the live wire, over the years I've had numerous belts, mains, 220V DC, 25kV DC (low current), 115V 400Hz (that HURTS), 115V 1100Hz (that hurts A LOT).

Crossy: Thanks for sharing! That is a rare experience that most of us don't have.

[yorkman]

99 times out of 100 you'll get away with touching the live wire, over the years I've had numerous belts, mains, 220V DC, 25kV DC (low current), 115V 400Hz (that HURTS), 115V 1100Hz (that hurts A LOT).

The problem occurs when you are in the 1% group.

You can die from a 12v car battery, if all the bad circumstances add up (very, very unlikely).

EDIT To our OP, in the US you are very unlikely to get a 'real' 220V shock because of the way 220 is delivered to the home as a bi-phase 110V system.

With all the talk about Voltages, there is an old saying "Volts jolt and mills kill" (mils referring to milliAMPS, presumably just to make it rhyme ) Hence the possibility of a 12V battery killing you, although unlikely as you say. Hurts though!

@ frenchFARANGbkk, completely useless if the earth wire is just screwed onto the wall. The earth needs to be carried using a heavy (minimum resistance) wire to a proper earth sunk into the ground, assuming you have no house earth. What constitutes a "proper" earth is a different conversation methinks as it is a bit complicated.

Which is why there are frequent reports of people killed in Thailand using instant water heater showers. The earths are usually a minimal attempt, especially considering you are stood in water at the time . A local farang died last year for the very same reason.

[GuestHouse]

As Crossy says perhaps 99 times out of a hundred you will not have a problem - but you only need killing once for it to matter.

It is also worth noting that just because an individual got away with a few zaps in the past, it is not safe to believe they will continue to do so. There are many factors that influence how lethal an electric shock is - Voltage and Frequency has been mentioned (DC is particularly dangerous because of the reaction of the body's muscles to DC Current - far more like to lock muscles and prevent the normal reflex recoil - hence leaving the individual still in contact with the source of the electricity - perhaps even gripping on tightly to it).

But there are others too. - Issues relating to the health of the person and then back to basics - Conductivity.

Our skin is normally a pretty good insulator - if it is dry. If it is wet with a salty liquid that we call sweat then the conductivity of our skin rockets upwards increasing the likelihood of any electric shock becoming dangerous.

(Point to note when working with live circuits in hot sweaty environments - Your sweat can also form a conductive film over hand tools, and added to that a slippery surface too. So periodically wiping hands and hand tools with a dry cloth is always a good idea where you are dripping sweat - for example when the Air conditioning packs up).

Likewise any creams or lotions on your hands can increase conductivity, so washing hands with soapy water and drying them throughly before working with electricity is not a bad idea.

Another problem with older installations is Fusing - Fuses are very slow to react in comparison with modern Circuit Breakers and when they do blow they blow at significantly higher rating than what is written on the fuse (Yes folks your bog standard house fuse that says 10A does not blow at 10A - Somewhere around 15A is more likely)- They may also be oversized, have been replaced with wire, wrapped in aluminium foil or simply in the wrong side of the circuit.

And then there is what is perhaps the biggest cause of death relating to electricity - FIRE.

Typical causes of electrical fire are:

• Botched electrical connections - example wire twisted together and covered with tape (or Band-Aids) (or no covering at all).
  
• Loose electrical terminals (loose screws) that cause the terminal and insulation to heat up
  
• Poor quality electrical connecting devices - cheap pugs/sockets and extension cables made of undersized wire.
  
• Poor quality cable and wiring - Undersized and or damaged wire insulation
  
• Over sized appliances - particularly things like light bulbs that are over rated for the wiring and or lamp shades etc.
  
• Overloading extension cables and multi-sockets
  
• Using electric extension cables with the cable wound onto the drum (always unwind all the cable off the drum before using it).
  
• Over rated fuses/circuit breakers or fuses replaced with bits of wire/wrapped in aluminium foil or as I said above, connected in the wrong side of the circuit.
  

What to do about all that?

• If you have an old style fused type installation, consider changing it out for a modern Circuit Breaker system - There are several very reasonable options on the market, the most commonly used is a RCB (Residual Current Breaker) combined with Circuit Breakers. RCBs article from Wikipedia
  
• If for some reason you don't want to got that route, you should at least check your fuses to ensure that they are not over rated and that they have not been made useless with bits of wire or aluminum foil. And also get a check done that the fuse is in the Live side of the circuit.
  
• Go around your house and check for botched electrical connections.
  
• Throw out that cheap extension cable you have sixteen plugs stuck into and buy a better quality extension lead - Don't stack plugs in sockets.
  
• Never use a cable extension coil that is wound onto the drum - always fully unwind the cable before using any extension cable.
  
• If you need more sockets get them installed.
  
• If you have mains electric sockets or wall switches in your bathroom get them moved to outside the bathroom door.
  
• If you have sockets near taps get them moved to at least a full arm stretch away from the taps/sinks etc
  
• If you have children get socket covers installed to keep little fingers out
  
• Inspect electrical cords and flexes on household appliances regularly for damage
  

Many of these things you can do yourself, others you'll need help with - but help is available and cheap. Ask around your local community for a recommendation of a good local electrician and then ask to see some of his/their work.

You do not need an expensive expat to do this work, there are plenty of good, well trained Thai electricians about - Despite the efforts of Jobbing Expat Sparkies to instill fear of Thai workmanship and hence dependence of the expat.

Edited December 12, 2007 by GuestHouse

[stateman]

I was even struck by lightning twice, the last time I was outside standing in a puddle of water. The only damage was a headache.

I read Danion Brinkley's book where he was struck by lightning twice and became clairvoyant. I think he was knocked out by it.

Just think if you got a larger jolt, you too might become clairvoyant!

[GuestHouse]

^If he'd had a larger jolt he might need a clairvoyant to post here in TV on his behalf.

I had an aunt who died by a lightning strike while she was playing golf in what was then Zimbabwe

[astral]

It is current that kills. not voltage.

As little as 50mA can be lethal.

Good rubber soled shoes, or even rubber gloves.

I saw an Electricity Board guy in the UK move a live mains

feed from the street, no fuses, wearing rubber gloves.

NOT recommended unless you know what you are doing.

Topic moved for comment from our electrical experts.

[astral]

It is current that kills. not voltage.

As little as 50mA can be lethal.

Good rubber soled shoes, or even rubber gloves.

I saw an Electricity Board guy in the UK move a live mains

feed from the street, no fuses, wearing rubber gloves.

NOT recommended unless you know what you are doing.

Topic moved for comment from our electrical experts.

[Crossy]

As Crossy says perhaps 99 times out of a hundred you will not have a problem - but you only need killing once for it to matter.

I wish I'd thought of saying that An excellent post guesthouse

As others have noted, it's the current that does the damage. The actual value of a lethal current seems to be re-defined every year but it's always a few 10s of milliamps.

No fuse or circuit breaker will even blink at that, which is why an ELCB / GFI / RCD / RCCB / Saf-T-Cut (they're all the same device) is absolutely VITAL in your electrical installation, this will pull the supply in the event of a fault current of 30mA or less and do it in one mains cycle (20ms) an absolute lifesaver. BUY ONE TODAY

Edited December 13, 2007 by Crossy

[johnnyk]

As Crossy says perhaps 99 times out of a hundred you will not have a problem - but you only need killing once for it to matter.

I wish I'd thought of saying that An excellent post guesthouse

As others have noted, it's the current that does the damage. The actual value of a lethal current seems to be re-defined every year but it's always a few 10s of milliamps.

No fuse or circuit breaker will even blink at that, which is why an ELCB / GFI / RCD / RCCB / Saf-T-Cut (they're all the same device) is absolutely VITAL in your electrical installation, this will pull the supply in the event of a fault current of 30mA or less and do it in one mains cycle (20ms) an absolute lifesaver. BUY ONE TODAY

crossy,

Can a GFI be installed at/near/in the service panel? I thought I saw something saying one could be put there.

Could you supply a few details please?

Thanks.

[Crossy]

crossy,

Can a GFI be installed at/near/in the service panel? I thought I saw something saying one could be put there.

Could you supply a few details please?

Thanks.

Assuming that by 'service panel' you're refering to the 'consumer unit', 'distribution board' or 'fuse box', yes, that's the correct place. The ELCB would be the first device in line after the meter / utility fuse. A combined MCB / ELCB would fit in place of your existing main breaker with no extra wiring required.

If you buy a Saf-T-Cut it comes in a nice box with clear installation instructions (electrician installation only).

Have a look here http://www.crossy.co.uk/wiring/Consumer.html for some wiring details.

Edited December 13, 2007 by Crossy

[monty]

Pretty much correct everything mentioned above.

The SafeTcut's you can buy in Thailand are actually pretty good, you can set them as low as 5 mA! At that setting you get a jolt and out pops the SafeTcut. Been there, done that, no harm done...

You do need to have pretty good appliances all round your house, just 1 with a tiny little bit of leakage will constantly trip the SafeTcut. Take your time to weed out the appliance and trash it, that is hoping the fault is not in the wiring. In that case you'll need a rather smart electrician to start tracing the problem!"

In general, human's reaction times will save you from electrocution, just like you won't get seriously burnt by touching something hot. Your natural reflexes will make you pull away from harm.

The biggest danger in getting electrocuted, is the fact that electrical current can contract your muscles, so if you touch a live circuit in an unlucky position, the contraction of the muscles in your hand might result in you gripping the live part and simply not being able to release your deathly grip!

For this reason it is absolutely important to cut the source of electricity before you try to pull away a victim. Many a parent has been killed by trying to pull away their child to safety!

[GuestHouse]

It is to be noted that whatever Electrical Protection devices you put into your home they are all useless if you and your family do not follow the very basic electrical safety tips I have mentioned above.

It never ceases to amaize me how little respect people give to Electricity - The silent, invisible killer.

Walk around your house now and have a look to see how many plugs you have sticking into extension cables? How many Bht120 extension cables are you using (that have wire that is more suited for use as HiFi Speaker wires than for carrying mains power)?

How many botched electrical connections have you around the house? Visibile and hidden behind the covers of switches and sockets?

Have you got electric sockets and switches in your bathroom?

[Crossy]

I posted this on another thread, worth puttng here too although not Thailand, the newly 'installed' fan in the office kitchen here in Bangalore

India also allows power outlets on the lighting circuits, pretty well every light switch has a 15A power point too.

[Naam]

Have you got electric sockets and switches in your bathroom?

yes! because not all of us are paranoid Brits or Aussies whose wives go with their dryers to the kitchen or the living room to dry their hair instead of using the bathroom. some of us less paranoid ones don't like to brush their teeth or shave in the garden by using an external socket and most of us (less paranoid ones) do not use a toaster when having a shower or an electric hair dryer when sitting in a bath tub.

moreover, some of us have placed these sockets and switches in their bathrooms that no harm can come from them except when used by some brain-amputated person.

[wpcoe]

Typical causes of electrical fire are:

• Botched electrical connections - example wire twisted together and covered with tape (or Band-Aids) (or no covering at all).
  

This may sound stupid, but here goes: Are "wire nuts" (as they are called in America -- they are slightly cone-shaped plastic covers on a threaded metal inner part that you twist aound a pair of bare wires to join them -- from the US, which are intended for 110v systems, okay to use with 220/240v wiring? I have a large set of them that I have in my tool kit and have wondered if they were safe to use here.

The only time I've actually seen "wire nuts" here in Thailand are with ceiling fan kits, and the one time I had my ceiling installers put up a fan, they used black electrical tape. The several times I've installed ceiling fans here, I've used the included wire nuts.

(If my description of wire nuts is still perplexing, I can photograph some and attach a pic.)

[GuestHouse]

moreover, some of us have placed these sockets and switches in their bathrooms that no harm can come from them except when used by some brain-amputated person.

Well we can live in hope.

[GuestHouse]

This may sound stupid, but here goes: Are "wire nuts" (as they are called in America -- they are slightly cone-shaped plastic covers on a threaded metal inner part that you twist aound a pair of bare wires to join them -- from the US, which are intended for 110v systems, okay to use with 220/240v wiring? I have a large set of them that I have in my tool kit and have wondered if they were safe to use her

I know exactly what you mean.. I've seen these used in Thailand for the lighting circuits of an Oil Refinery Control Room (based on US Standards).

The reason I spotted them was we were investigating faulty lighting circuits - the fault was in one of these 'Wire Nuts'.

I don't like them and would not personally use them in Thailand - My reasoning relates to what Crossy has said about US Domestic Power Systems - The US Voltage is 115 either side of Ground - The Thai Voltage is 220V above Ground. This is a significant difference and as you say these devices are designed for use on 110V circuits.

I would therefore throw them in the bin and use wiring termination boxes suited to the voltage.

[Gimbo]

We use those wire nuts in Norway and those are 220 volts. But there are different sizes so important to use the right size not for thickness of the "bundle" of cables you connect.

Else I am having my washing machine in the bathroom. Both outlets, one for shaving machine and one for washing machine are grounded.

Light switch and separate switch for outlets are otside the room, and the outlets have splash proof lids on them, and placed 1.5 meters above floor level. Should be safe enough.

Shower cabinet is insulated from the floor, it is raised on 10 cm feet and has a oplastic bottom, so no water from the shower is splashing around in the room. The washing machine also sits on a wooden platform, about 20 cm above floor level, so no real danger. And should the room flood, we can cut power from outside the room.

I think thats safe enough. And follows Norwegian safety standards for a wet room.

[elkangorito]

We use those wire nuts in Norway and those are 220 volts. But there are different sizes so important to use the right size not for thickness of the "bundle" of cables you connect.

Else I am having my washing machine in the bathroom. Both outlets, one for shaving machine and one for washing machine are grounded.

Light switch and separate switch for outlets are otside the room, and the outlets have splash proof lids on them, and placed 1.5 meters above floor level. Should be safe enough.

Shower cabinet is insulated from the floor, it is raised on 10 cm feet and has a oplastic bottom, so no water from the shower is splashing around in the room. The washing machine also sits on a wooden platform, about 20 cm above floor level, so no real danger. And should the room flood, we can cut power from outside the room.

I think thats safe enough. And follows Norwegian safety standards for a wet room.

Does Norway use an "Earthed" (grounded) electrical system?

BTW, more about "wire nuts" later.

[Gimbo]

In homes, only wet rooms bath room/ shower room and what is refered to as a moist room in regulations, f.ex kitchen, need to be grounded in Norway.

Living rooms, bedrooms etc do not require it.

Fuse box or whatever it is called in english these days is also grounded. Wall outlets is the standard two prong euro plug.

Edited December 13, 2007 by Gimbo

[elkangorito]

In homes, only wet rooms bath room/ shower room and what is refered to as a moist room in regulations, f.ex kitchen, need to be grounded in Norway.

Living rooms, bedrooms etc do not require it.

Fuse box or whatever it is called in english these days is also grounded. Wall outlets is the standard two prong euro plug.

Do you think that the electrical rules of Norway, apply in Thailand?

[elkangorito]

I've just finished speaking to a friend, who is a "working" electrician in the USA. He has informed me & supplied me with info regarding "wire nuts" as currently used in the USA.

These "wire nuts" are rated for a minimum of 300 volts, therefore "safe" to use on Thai voltages. They are "twist on" & do not use screws unlike the Australian variety, which do use screws.

At the end of the day, the reason why these devices fail is because the person who installed them used too much force (either screwing or twisting) OR did not twist the wires OR twisted the wires incorrectly. This all goes back to "training". Actually, most electrical "connection" problems are caused by people (electricians), who have either forgotten/ignored their training or have not received adequate training in this regard.

This begs the question, "Why are 99% of the 'wire to wire' connections in Thai domestic situations (not oil rigs) twisted together without the use of any mechanical device?"

Of course, the "high quality" workmanship in Thailand would never allow this.

BTW, I only know of one Thai electrician whom I would trust...he lives in Klaeng & he charges 300 Baht per hour (as he should).

[GuestHouse]

This begs the question, "Why are 99% of the 'wire to wire' connections in Thai domestic situations (not oil rigs) twisted together without the use of any mechanical device?"

99% !?

Even taking into account the removal of Oil Rigs from your estimation - 99% is a very large percentage.

Are you sure that 99% of the 'wire to wire' connections in Thai domestic situations (not oil rigs) are twisted together without the use of any mechanical device?

I think there is no real basis for the question you beg to ask ... excepting a need to run down Thai workmanship in the hope of drumming up trade for yourself.

Anyway, nice to see you have found at least one good Thai Electrician - There are plenty of them around.

Last year we had a Thai electrician do a complete rewiring of a house and not only did he do a first rate job, including megga-testing the wiring (and using the correct terminations and housings) but he did it the whole job at around Bht 1200 a day.

A bargain.