Electric Grounding

[gzu88bv]

...... gave you a little "feel of the juice". Not lethal, but unpleasant.

I confess, I am not an electrician. But I do know that my Misses' computer has to be grounded properly.

She had the hard disk drive of her computer replaced at a shop the other day, and since then one can sense that juicy and unpleasant feeling. Something got hooked up the wrong way.

Can somebody tell me in a few words what these dudes would have to change respectively to re-switch. Thanks.

[elkangorito]

the big problem is that all information is only valuable if your home is not already built. to the best of my knowledge it is nearly impossible or prohibitive expensive to rewire all outlets with proper grounding.

Actually only a single ground wire is required, along with new outlets/ground stake.

????

[lopburi3]

How are you reading "single ground wire"? I am using the term to mean an additional wire to the two that you already have going to each outlet/box. In some cases pulling one strand of wire would be a lot easier than a complete replacement.

[Naam]

the big problem is that all information is only valuable if your home is not already built. to the best of my knowledge it is nearly impossible or prohibitive expensive to rewire all outlets with proper grounding.

Actually only a single ground wire is required, along with new outlets/ground stake. The outlets are the same size and only cost a few baht. If breaker box does not have ground or room to install terminals you might have to replace but most would already be usable.

this "single groundwire" has to be hooked up to EACH and EVERY outlet. my home has 196 six outlets. our resident expert and respected TV-member "El Kangorito" has seen my home, took a look at my installation and found out that my treasured GFCI-switch (which protects the bathrooms) did not work.

rewiring my home (fortunately it is properly grounded) would be a nightmare and cost a fortune.

[lopburi3]

I responded to a general question of cost - and it is not prohibitive for most people (and most people do not have 196 outlets). My single wire, as I pointed out above, was in reference to not having to replace all three wires if you want to do it cheaper. I have done it and it is not that expensive to convert to grounded system for the average home and I seriously hope people will check before they assume it can not be done on a budget.

As for your GFCI not working not sure what you are saying - but if it is that they do not work in general I disagree - they can and do save lives daily around the world and that is with and without grounded systems.

[elkangorito]

Correct Naam . BTW, weren't you "Dr" Naam?

Generally, each circuit must have its own earth wire. Eg if you have 2 x lighting circuit breakers & 1 x power circuit breaker, each of these circuits will require an earth wire (a total of 3 earth cables). And of course, as Naam said, this earth wire must then connect each piece of equipment i.e. light fittings, power outlets etc.

Also, the new Australian Wiring Rules (ASNZS 3000:2007) generally require that each circuit be protected by an RCD. The Wiring Rules also indicate that an RCD is not recognized as a sole means of protection & must be used with other primary forms of protection.

Edited November 18, 2007 by elkangorito

[david96]

AS/NZ3000/2007 will be available in a hardcopy version fro the end of Nov 2007

This edition will be mandatory in Australia and New Zealand from 1 July 2008.

Here is the link to SAA.

http://www.saiglobal.com/shop/script/Detai...=AS0733783910AT

[johnsurin]

You will have to insert an earth electrode/grounding rod (I will use earth electrode as it is the proper term where I come from/UK).

The best way to minimalize your chances of getting a fatal electric shock is to insert multiple earth rods around a circumferance and join them together with an earth/copper cable, this will improve your PSC (prosective short circuit fault current) and provide a much lower resistance that a possible fault current can go to earth, and will result in the circuit tripping much quicker.

This is important as during the dry season as the earth dry's out there is a higher resistance to earth so applying more rods over a greater distance will give you a better chance of getting a better earthing arrangement by spreading the effectiveness of the rods (another method is simply pouring a bucket of water over them or pi**ing on them).

As mentioned before an RCD (residual current device) is the best method. This detects an imbalance of a fault current through your nuetral cable/0v, which is tapped down to earth at it's original source. Therefore any residual/fault current flowing through this is almost instantly detected and trips the circuit. This is a must have piece of equipment considering the thai electrical authority does not offer a PME/TNS/TNCS system. In lamens terms, IF the authority does NOT provide any sort of earthing arrangement coming into your property YOU must do this.

I would advise the best possible way to provide the best protection is to install multiple earth rods with RCD protection (RCD is a must), otherwise everything else is a waste of time.

On reading back alittle and quickly browsing crossy's info and not getting to the end. I don't know how effective ELCB (earth leakeage circuit breakers) are, although it also says RCD's as the same name.

What I do know is ELCB was the old name for what is now an RCD, in turn an ELCB is now banned in the UK as it does not now offer adequate protection to what it's name says. It does not offer adequate protection of a residual current flowing down to earth to disconnect in the alloted time by the british standards, which could be potentially fatal to humans.

Although I must add, the drawing looks correct. I could be wrong and perhaps it is just the name- ELCB has been banned and RCD imposed. But not from my working knowledge (or the JIB/joint industry board of electricians) has <deleted>*ked me up the bum again.

John.....

Edited November 18, 2007 by johnsurin

[johnsurin]

Basically Thailand's electrical distribution system is a little primitave, but similar to the UK's (who says the UK is a modern envireroment)?

They are different wiring and regulations all around the world. If anyone has any questions please feel free to ask.

Installing RCD's to every power outlet socket is the best means of protection, however you should NOT have this on lighting circuits as---- what happens if the power goes at night time and you cannot see because the lights have failed.

Nor should you have protection in a bathroom, you should NOT have socket outlets in a bathroom FULL STOP!!! Condensation=water=electric-sock=DEATH!!!

John.....

[david96]

With a MEN system fault current does not return via the main earth but returns to the transformer though the neutral, the impedance must be low enough to trip a circuit breaker type C in less than 0.4 secs. ( Ref AS/NZ3000 )

If a RCD is used it must be protected by a protective device as an RCD does not have short circuit or overcurrent protection.

A combination RCD/MCB is known as a RCBO. An 30mA RCD must trip in less than 300ms.

Only one main earth is required per instalation connect to a 12.7mm copper clad electrode, main earth conductor 4sq mm stranded max 0.5 ohm (from the main switch board) to the electrode. (AS/NZ3000). Equipotential earth bonding min 4 sq mm.

(The term ELCB was removed many years ago so as not to confuse the residual current device with the old voltage operated type no longer available.)

[david96]

So you may well ask what is the reason for a main earth?

In the event of the main incoming supply neutral conductor breaking or the polarity of the incoming supply being transposed all conductive metelwork and the earth electrode are at the same potential thus minimising the risk of a fatal electric shock. In this instance mild shocks may be received

In the above cases power must be disconnected until the fault is rectified.

Unless the supply authority can guarantee the integrity of their system (polarity) it might be advisable not to connect the MEN link until you get permission from the MEA or PEA in writing.

Your earthing system will be TT.

[Naam]

I responded to a general question of cost - and it is not prohibitive for most people (and most people do not have 196 outlets). My single wire, as I pointed out above, was in reference to not having to replace all three wires if you want to do it cheaper. I have done it and it is not that expensive to convert to grounded system for the average home and I seriously hope people will check before they assume it can not be done on a budget.

As for your GFCI not working not sure what you are saying - but if it is that they do not work in general I disagree - they can and do save lives daily around the world and that is with and without grounded systems.

of course a single additional wire serves the purpose of grounding. but it still has to be connected to all outlets and fixed connections (especially instant water heaters). if the piping in which the wires are laid have two or more 90º elbows or as in my case connection boxes in the attic (below steel mesh and insulation) it's a real hassle to add a grounding wire.

my GFCI does not work as it set to trip at 30 milliamps. however i have a drain of 60-65 milliamps. the electrician mounted the switch (as required by me) BUT DID NOT CONNECT it because it trips when connected i found that out only after opening the casing in which it is mounted.

[Naam]

Correct Naam . BTW, weren't you "Dr" Naam?

i was demoted Kangorito

[Tony Clifton]

Nor should you have protection in a bathroom, you should NOT have socket outlets in a bathroom FULL STOP!!! Condensation=water=electric-sock=DEATH!!!

John.....

We ended up with a socket outlet 30 cm over the washroom's tub.

Ripped that out.

Also, when the electrician installed the shower's water heater, he wanted to install the safety device next to it on the wall.

Worked on something else for a few minutes and the electrician was done and left. He did not even bother checking if it worked.

So, he came back to fix it already and broke the water heater's cover when removing it.

Improvement and improvisation are such similar words.

[JetsetBkk]

We ended up with a socket outlet 30 cm over the washroom's tub.

Ripped that out.

A bit drastic, I think. I have an outlet near all 3 bathroom sinks, and two outlets either side of the kitchen sink. Everyone is still alive - just use a bit of common sense.

It would be different if I had kids, though, especially those without any common sense.

[Crossy]

We ended up with a socket outlet 30 cm over the washroom's tub.

Ripped that out.

A bit drastic, I think. I have an outlet near all 3 bathroom sinks, and two outlets either side of the kitchen sink. Everyone is still alive - just use a bit of common sense.

It would be different if I had kids, though, especially those without any common sense.

Not even remotely drastic, outlets in bathrooms are illegal in the UK for a reason.

People with 'common sense' die all the time, "I'll just dry my hair whilst sitting on the bath", only takes a dribble of water from your hand into the switch of the dryer and you're toast!

[elkangorito]

We ended up with a socket outlet 30 cm over the washroom's tub.

Ripped that out.

A bit drastic, I think. I have an outlet near all 3 bathroom sinks, and two outlets either side of the kitchen sink. Everyone is still alive - just use a bit of common sense.

It would be different if I had kids, though, especially those without any common sense.

Not even remotely drastic, outlets in bathrooms are illegal in the UK for a reason.

People with 'common sense' die all the time, "I'll just dry my hair whilst sitting on the bath", only takes a dribble of water from your hand into the switch of the dryer and you're toast!

Wholeheartedly agree Crossy. (BTW, where have we heard all this talk before?)

Anyway, the Australian regs allow power outlets in wet areas but under strict guidelines. I think that it's a good idea to not have any power outlets in these areas but then again, people will be people & end up using extension leads anyway...which introduces even more dangerous links to an already dangerous chain.

It just goes to show that regulation is somewhat useless against human curiosity & ignorance...it just tries to "cover peoples bums" for one reason or another.

Still, regulations have been tried, tested & proven over the years, so if one wishes to "not listen to them", be it on ones own head. A little bit of knowledge can be a dangerous thing.

[elkangorito]

These are the types of RCD's available in Australia & generally worldwide. I would be selecting .

It should also be noted that most manufactured RCD's have an operating time of 20mS (1 cycle @ 50Hz). This is to be considered normal & the minimum time for maximum protection.

Edited November 19, 2007 by elkangorito

[elkangorito]

I responded to a general question of cost - and it is not prohibitive for most people (and most people do not have 196 outlets). My single wire, as I pointed out above, was in reference to not having to replace all three wires if you want to do it cheaper. I have done it and it is not that expensive to convert to grounded system for the average home and I seriously hope people will check before they assume it can not be done on a budget.

As for your GFCI not working not sure what you are saying - but if it is that they do not work in general I disagree - they can and do save lives daily around the world and that is with and without grounded systems.

of course a single additional wire serves the purpose of grounding. but it still has to be connected to all outlets and fixed connections (especially instant water heaters). if the piping in which the wires are laid have two or more 90º elbows or as in my case connection boxes in the attic (below steel mesh and insulation) it's a real hassle to add a grounding wire.

my GFCI does not work as it set to trip at 30 milliamps. however i have a drain of 60-65 milliamps. the electrician mounted the switch (as required by me) BUT DID NOT CONNECT it because it trips when connected i found that out only after opening the casing in which it is mounted.

Thanks for posting this Naam (formerly known as Dr Naam, which I prefer to just plain, ordinary "Naam").

This is the perfect reason why an RCD should not be installed to monitor your whole electrical installation. Individual RCD's on each circuit are much more effective & give less problems (nuisance trips).

How did I know that this RCD didn't work? I simply pressed the "press to test" button.

[Naam]

Individual RCD's on each circuit are much more effective & give less problems.

that's what i thought i would get had individual ones in my home in Germany as well as in the U.S. of A. but during the construction of my home my eyes were focussed on a zillion other problems than on GFCI switches.

[Tony Clifton]

We ended up with a socket outlet 30 cm over the washroom's tub.

Ripped that out.

A bit drastic, I think. I have an outlet near all 3 bathroom sinks, and two outlets either side of the kitchen sink. Everyone is still alive - just use a bit of common sense.

It would be different if I had kids, though, especially those without any common sense.

Not even remotely drastic, outlets in bathrooms are illegal in the UK for a reason.

People with 'common sense' die all the time, "I'll just dry my hair whilst sitting on the bath", only takes a dribble of water from your hand into the switch of the dryer and you're toast!

Exactly, one example, leave shower head hanging or drop it by mistake and the pressure is strong enough to make it shoot out water at a few feet distance in any direction. PZZZZZZZZZZZZZT!

Nothing is important enough to necessitate outlets in a washroom. Even wall mounted water heaters claim their share.

[JetsetBkk]

Not even remotely drastic, outlets in bathrooms are illegal in the UK for a reason.

People with 'common sense' die all the time, "I'll just dry my hair whilst sitting on the bath", only takes a dribble of water from your hand into the switch of the dryer and you're toast!

Couldn't care less about English regs. In fact, in the UK I found it quite irritating not having electrical outlets in the bathroom, which is where I preferred to shave (electric) rather than in the bedroom.

As for people drying their hair while sitting in the bath - a pretty ridiculous example of "common sense".

I think that it's a good idea to not have any power outlets in these areas but then again, people will be people & end up using extension leads anyway...which introduces even more dangerous links to an already dangerous chain.

And that is why in one of my rented houses I had a trailing lead into the bathroom, up the wall to a 3 way outlet.

Exactly, one example, leave shower head hanging or drop it by mistake and the pressure is strong enough to make it shoot out water at a few feet distance in any direction. PZZZZZZZZZZZZZT!

Nothing is important enough to necessitate outlets in a washroom. Even wall mounted water heaters claim their share.

My showers have a curtain to stop water coming out.

Next silly example please?

[Artisi]

Question for the electricians / electronics guys -- not the "pretenders and experts" -- the wall mounted water heaters available (or most anyway) in Thailand have ELCB fitted, is it still necessary to have grounding on these units.

[david96]

Question for the electricians / electronics guys -- not the "pretenders and experts" -- the wall mounted water heaters available (or most anyway) in Thailand have ELCB fitted, is it still necessary to have grounding on these units.

All electrical equipment protected by a RCD or RCBO must be effectively earthed (AS/NZ3000). In Thailand most are not and rely on the internal 10ma RCD of the water heater only.

[Naam]

Next silly example please?

the outlets in our bathrooms are not connected

[Naam]

Question for the electricians / electronics guys -- not the "pretenders and experts" -- the wall mounted water heaters available (or most anyway) in Thailand have ELCB fitted, is it still necessary to have grounding on these units.

All electrical equipment protected by a RCD or RCBO must be effectively earthed (AS/NZ3000). In Thailand most are not and rely on the internal 10ma RCD of the water heater only.

is that standard with the water heaters sold here?

[Artisi]

Question for the electricians / electronics guys -- not the "pretenders and experts" -- the wall mounted water heaters available (or most anyway) in Thailand have ELCB fitted, is it still necessary to have grounding on these units.

All electrical equipment protected by a RCD or RCBO must be effectively earthed (AS/NZ3000). In Thailand most are not and rely on the internal 10ma RCD of the water heater only.

is that standard with the water heaters sold here?

The 2 units I have in my home have earth-leakage protection -the main reason I selected them.

Edited November 20, 2007 by Artisi

[Crossy]

Question for the electricians / electronics guys -- not the "pretenders and experts" -- the wall mounted water heaters available (or most anyway) in Thailand have ELCB fitted, is it still necessary to have grounding on these units.

Yes.

ELCB / RCD / GFI or whatever you want to call them (they are just different names for the same device [if we ignore the old fashoned voltage-operated ELCBs]) are all electonic / electromechanical devices which can and do fail. Additionally they can get fried by electrical transients caused by lightning. When was the last time you pressed the 'test' button on yours?

Having a proper ground will give you protection in the event that the ELCB does not, it's also likely that the trip will drop out before the 10mA trip current goes through you (and that 10mA will hurt).

IMPO (that's professional opinion) the ELCB is SECONDARY protection and is a back-up to a proper earth as opposed to a replacement, it will give additional safety in the event of certain faults that a ground cannot, such as you getting hold of a live wire when you chop the flex of your lawn mower.

Edited November 21, 2007 by Crossy

[Artisi]

Thanks guys, looks like a roll of yellow/green cable in the suit case when I head back to LOS shortly.

[Crossy]

Thanks guys, looks like a roll of yellow/green cable in the suit case when I head back to LOS shortly.

555, contrary to popular belief (and observation) green cable is available from specialist stores. You'll find it at the back under the empty rice sacks and expired MaMa noodles