Grounded appliances electrocuting me

[Guest StephenB]

Planning to read the pinned topic "How to check your earthing system". I was wondering if those receptacle testers work if the fault is with the wiring of a outlet somewhere. The house was wired with every recepticle in the house to 1 breaker, every light in the house on another breaker, every aircon on its own, etc.

My problem is every applaince with a 3 prong plug is mild to strong electructing if you touch it and have bare feet. Washing machine, Computer case, iron... Could a receptacle tester find the problem when every recepticle is on the same breaker? I think I have a wiring problem as opposed to a appliance problem. Any idea's?

[Crossy]

I'll put money on either:

1. None of the ground pins are connected at all
2. The ground pins are connected but there's no rod

If you can get a correctly configured 220V receptacle tester (not easy) then it will tell you what's wrong, if you have one of the extension leads with a 'ground' light that would be a useful starting point.

Simple visual checks and checks with a multimeter will confirm what's gone adrift.

[bankruatsteve]

One visual check is to take off the receptacle plate and see what the wires are. Hopefully, there will be a green wire connected to the ground pin on the receptacle. If you need to pull out the receptacle to check, turn off the breaker first as it's very easy to touch the live pin.

[Guest StephenB]

Hey Crossy, just took a measurement at the washing machine recepticle,

Neutral (white) to Ground is almost 0v, Line (black) to ground about 220v.

If i put some water on the ceramic tile and measure Volts between the water and the casing of the washing machine I get around 220V. (washing machine plugged in). If I unplug the machine and continuity test ground prong to case it has continuity.

The wall recepticle ground to the water on the floor is 220v. <--- Does that confirm a problem with the breaker box to the ground rod?

[Crossy]

Those are some worrying numbers there Stephen.

Anything other than near zero between the ground prong and earth (water on the floor, a screwdriver in the lawn would be better) is a problem.

Time to verify if you have earth from the receptacle to the breaker box, and from the breaker box to a ground rod.

[Guest StephenB]

Just finished more testing :-)

Using the puddle of water on the floor and the recipticle ground and measuring volts-

Started shutting off breakers, and when I shut (opened) the breaker to a aircon unit the volts on my test went to zero. I suspect the applaince is putting current to ground, and following the path of least resistance. What is the best way to check if the ground rod is working properly? What is the path of least resistance- a person barefoot on cermic tile touching a grounded unit or copper wire to a ground rod? Crossy, do you think I still have a ground rod issue? I did pull a recepticle to confirm the wire colors and that they are in the right place.

I now have zero volts from ground on a outlet to "water on the floor". I will investigate the aircon unit and report back. I have heard of people installing something that will shut off electricity, and is wired before the breaker: GFCI Circuit Breaker. Does that exist in Thailand? lol

I am glad I don't have to take apart 20-30 outlets to check the wires. whew!

[lopburi3]

Do you have a neon light to determine which line is hot? I would not depend on wire color.

[Guest StephenB]

Not sure lopburi, my measurements are (after shutting off the breaker to a aircon)

N (white) to G(green) 220V,

L (black) to G (green) 0V,

N to L 220V

Does that mean Neutral is the hot one? Is that supposed to the hot one? forgive my ignorance.

[MYKTHEMIN]

Typical Thai wiring!!!!! live neutral, they do not seem to know the difference, even when the PEA connected my new house they had it the wrong way round and I had to change it over myself such idiots and would not listen to me

[tifino]

whoever installed the wiring has taken a guess:

50% chance, and got it wrong...

Q: was that the wall outlet that you just measured?, and you are still getting voltage at the wall outlet after shutting OFF the Cct/Brkr!

(more reason for double pole switching...)

Live chassis TVs are another classic killer, when house wiring is installed vicky verka

[Crossy]

Looks like a polarity reversal.

I suggest you find a competent sparks (yes, i know) to look carefully at what's going on here, could be potentially dangerous!

[Guest StephenB]

lol

I shut off power by (opened the circut) flipping a breaker to just a aircon. I think the aircon unit has a fault and was causing every grounded appliance to zap me when touched.

A: Yes that was a wall outlet measured, if I throw that breaker to the wall outet I am using for measurments its 0V across everything.

[tifino]

good to see you are still alive...

[Guest StephenB]

Allrighty, It is supposed to be 220v from line/phase (black wire) to ground?

intresting...

Just pulled the cover to the breaker box.

Measure the same-

Big fat white wire to ground= 220v

Big fat black wire to ground 0V

So is that a confirmed case of reversed polarity? Is the fix as simple as disconecting from the meter and swapping wires around in the breaker box?

Thanks for all the comments so far.

[Forkinhades]

Please take time to read the pinned thread

http://www.thaivisa.com/forum/topic/693630-how-to-make-your-thai-electrical-system-safe/

[Forkinhades]

Allrighty, It is supposed to be 220v from line/phase (black wire) to ground?

intresting...

Just pulled the cover to the breaker box.

Measure the same-

Big fat white wire to ground= 220v

Big fat black wire to ground 0V

So is that a confirmed case of reversed polarity? Is the fix as simple as disconecting from the meter and swapping wires around in the breaker box?

Thanks for all the comments so far.

Pictures please of inside fusebox

[Guest StephenB]

Thanks, I read it.

My Neutral bar in the breaker box has all black wires to it. So mine is not correct.

Bummer.

I was hoping I could just swap the wires at the meter and be done with it.

[tifino]

Live (Active), depending on the current Standard of respective countrys about the world = Brown or Red, for Leads

Neutral, depending on the current Standard of respective countrys about the world = Blue or Black, for Leads

Inner wall house wiring also differs over the Eras, but the Black wire confirms in your case which wire is 'supposed to be' Neutral.

It gets extra bad when the Earthing wire colour is wrong. Supposed to now be Green/Yellow, previously Green.

Malaysian wiring is just as bad...

[tifino]

just saw that latest post about the neutral bar.

I might sit here in neutral till we see those pictures

[Guest StephenB]

Heres the picture attachment.

[Forkinhades]

Thanks, I read it.

My Neutral bar in the breaker box has all black wires to it. So mine is not correct.

Bummer.

I was hoping I could just swap the wires at the meter and be done with it.

Just because they have used wrong colours, does not mean you have polrity issues. Most thai sockets are 2 pin anyway, so you can always have reverse polarity. Depending on which way you plug the socket in.

[Forkinhades]

Heres the picture attachment.

Leave as is, for polarity, you must install an Safety-Cut as a first priority, this is a good example (not for you) of how earthing when done wrong, can cause serious problems.

[tifino]

Thanks, I read it.

My Neutral bar in the breaker box has all black wires to it. So mine is not correct.

Bummer.

I was hoping I could just swap the wires at the meter and be done with it.

Just because they have used wrong colours, does not mean you have polrity issues. Most thai sockets are 2 pin anyway, so you can always have reverse polarity. Depending on which way you plug the socket in.

Often the customer lives because if the transposed wiring is transposed at both ends, then:

'2 Wrongs can make a Right'

For Double Insulated electronics, for lighting, simple motors, it doesn't matter which way the wire connections end up.

But, if the device, such as the AirCon, has Live wiring connected to earth terminal, the OP problem comes up. There are no transformers to isolate the 'Polarity' within.

What if an Auto-Transformer was connected to Incorrect wiring? Simlar result to that of a Live Chassis Tv.

Pity that Isolating Transformers are so expensive. I'd love to have one in each room, just for the peace of mind

[Guest StephenB]

Safety-Cut, I will look into that. I would have installed it or something simialr when the house was built, but I don't think I could have found it +10 years ago.

I am still concerned as why the current was not using the path to the ground rod, and instead traveling through my body (or anybody else) to earth. Does this have to do with the polarity being reversed? white/black

[tifino]

are you sure the Ground Rod is actually connected?

and even if it is, what about the ground (soil) outside - has it been prepared properly to conduct as a building's Earth.

The outside earth connection might be forLightning Earth, not necessarily Building Mains Earth

If the Earth, whatever it is, is not the best - your body becomes the easiest path...

[bankruatsteve]

You do want to put in the Safe-T-Cut, but with, what appears to be a serious ground fault on the A/C circuit, you will need to find that else keep that breaker off (b/c the Safe-T-Cut will trip). Does the breaker box give you a shock with the A/C breaker on? Better to measure voltage from the box to your puddle on the floor or to a screwdriver in the ground. The wires in the upper right corner appear to be pinched. Are they? Is the insulation broken?

[Forkinhades]

Safety-Cut, I will look into that. I would have installed it or something simialr when the house was built, but I don't think I could have found it +10 years ago.

I am still concerned as why the current was not using the path to the ground rod, and instead traveling through my body (or anybody else) to earth. Does this have to do with the polarity being reversed? white/black

Without full inspection difficult to say, an earth rod on its own will not have a low enough value to trip your MCBs. Again read the pinned threads

[Forkinhades]

^ consider this a 10A type C breaker requires 100A of Fault current to open instanteously, so the value of your rod, together with circuit earth, can not be higher than 2.3 ohms, just not going to happen. This is one of the main reason why safety-cuts are installed, as you only need 30 MilliAmps to open it!

[Guest StephenB]

Ok I will get on this tomorrow, I will post how it goes. It kinda sux having 1 breaker feed all the wall outlets, because home remodeling using power tools becomes a chore.

When I call my electrician in the next couple of days (he is a family friend, but not a ace in electronics- he is safe though!), I wlll have him:

-reverse the neutral and line at the meter. (this will put the polarity the right way with line/phase (black) to Neutral (green) @220V

-keep the neutral bar a line/phase bar (even though I am sure there is a reason why the neutral bar is in that location) lol

-Add a saftey-cut device before the fuse box (I have a 30 amp meter connection, so maybe a 30a or 45a saftey-cut device rating?)

-keep the bad aircon unit disabled until I figure out the fault

Does that sound about right?

If I get volts from neutral to ground - it means the ground rod is working right?; it just may have a little extra resistance then it should. (I can't check it visibly as it is now under concrete)

Thanks everybody for the comments.

[bankruatsteve]

Live and Neutral are not determined by the color of the wire. Live is the one carrying the voltage, neutral is the one with relative zero voltage. If, in your box, the white wires are the Live, then DO NOT cross at the meter. Leave it alone as it is wired consistently. Again, please confirm if you only get the shock when the A/C breaker is on? IE: when the A/C breaker is off, I think you said there is no shock - is that right?