Getting a tingle off all my metal frame appliances?

[JohanB]

Only concerning to your last question; i had a power book and a windows laptop leaking, now problem, real low voltage, some prickling, some surprise effect, but not hurting (i don't care about earthing, i use circuit breakers, worked well for the last 20 years, only a modem once retired after our power lines got stroke by lightning).

Circuit breakers are typically 20AMP and primarily to protect the premises wiring from overload not protect from electrocution.

If you are the part of the circuit and all the current is running through you, you will have to carry more than 20AMP before the breaker trips out. 5KW. You are toast.

Only a correctly wired RCD (Residual Current Device that senses leakage to earth) will protect you but they do nothing without the electrical installation being properly earthed.

Your'e wrong!

You're talking of the old fashion and now obsolete ELCB (Eart Leakage Circuit Braker) that needed a ground connection to work.

A RCD (Residual Current Device) compares the currents in live and neutral!!

If the difference in L/N is more than f.ex. 30 mA it shuts off both live and neutral in milliseconds. Need no earth or earthed appliancies to give full protection.

So if you install a modern RCD you do not need earthed circuits.

But a ground rod is sometimes usefull to eliminate the tickeling feeling from leakage currents in computers etc. These currents are unpleasant but not dangerous and will not trigger the RCD.

[MadMuhummad]

Broken or damaged neutral from the street or high resistance ground. Trying to keep it basic....

[Crossy]

OK, let's introduce a modicum of decorum here.

1. A polarity reversal is easily checked using a 20 Baht neon screwdriver. Buy one!
2. A MEN system with no rod and a polarity reversal won't give you a tingle, it will kill you! *
3. A MEN system with a rod and a polarity reversal will make your meter go round pretty fast even if the main breaker is open (N-E link is on the hot side of the breaker) and may still kill you. *
4. A rod, any rod (big screwdriver in the lawn and a length of speaker wire) connected to a case screw on the appliance will kill the tingle from a Class-1 device. Try it, if the problem goes away you can source a permanent fix
5. A mat / slippers will likely kill the tingle, but they won't save you when a real L-E fault occurs in a Class-1 device with no ground.
6. The amount of current flowing during a tingle from a mains filter is < 1mA, it won't open even a 10mA RCD.

* Part of the reason I'm not a lover of TNC-S (MEN) on an aerial supply system, but the local supply authorities require it to provide a permanent supply. A properly grounded TT system with a quality RCD would be my preference, TNS would be better but isn't going to happen here.

To our OP:-

Try a temporary earth, report back.

If you don't have an RCD, install one.

[Forkinhades]

Just hijacking this tread don't wont to open another one

I have a electric hot water storage system for my shower

all pipes are plastic from the system to the shower

can I still get zapped ?

PLEASE START A NEW THREAD!

[louse1953]

All Class-1 appliances leak to some extent, some more than others, older refrigerators and aircons can go leaky, same with electric ovens and rings, they don't actually have to have a mains filter.

It gets worse, because even just a floating ground wire can pick up enough by capacitive coupling from the live wires to give you a significant nip.

A proper ground rod will bleed all this leakage to earth, usually (unless something is seriously wrong) without opening the RCD.

Please check your rod, if you're not sure if you have one, a big screwdriver in the lawn will suffice to check if it helps.

He has checked his rod and it is not connected,so bloody obvious isn't it.Re wire coming up.

[Crossy]

All Class-1 appliances leak to some extent, some more than others, older refrigerators and aircons can go leaky, same with electric ovens and rings, they don't actually have to have a mains filter.

It gets worse, because even just a floating ground wire can pick up enough by capacitive coupling from the live wires to give you a significant nip.

A proper ground rod will bleed all this leakage to earth, usually (unless something is seriously wrong) without opening the RCD.

Please check your rod, if you're not sure if you have one, a big screwdriver in the lawn will suffice to check if it helps.

He has checked his rod and it is not connected,so bloody obvious isn't it.Re wire coming up.

I missed that post in amongst the noise.

Agree 1000%

[Forkinhades]

Indeed there was a lot of that

[Tatertot]

Check this

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

[TPUBON]

When I had our house built, I said to ground all the outlets. All my receptacles are three pronged. Much later I had to go into the attic to check something. I noticed that the wiring coming from the outlets all had the ground wire cut. Didn't go anywhere. The only things grounded are my two hot water heaters. Why they did what they did remains a mystery. When I discovered this, the house warranty was long expired.

[BlindMagician]

...and you're a qualified electrician? Maybe give yourself a call, get an overpriced quote to not fix the problem. Nice little earner.

[Forkinhades]

Look people please read the pinned thread

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

How to make your Thai electrics safe

[JohanB]

Look people please read the pinned thread

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

How to make your Thai electrics safe

Already in figure 4 you have put in the deadly MEN-connection and call it safe! How do you think!

Thai DB4.png

Do'nt you understand what happends when neutral/live is interchanged from the grid!

I can tell you if you don't know:

When the ground rod has cooked away (no fuses in the current path) you'll have all 'grounded'' appliances included your shower carrying mains voltage!

This is a death trap and ticking bomb ready to go!

Don't trick people to follow your instructions on installations here in Thailand!

Even when unknowingly people think they're safe with an installed RCD, your figure 4 will kill without protection or fuses, as the live voltage on the neutral is comming from before the RCD.

If you try to connect the MEN after the RCD, it will immediately trip on the neutral/ground spurious voltage.

Only a TT connection + RCD without MEN or any connection between Protection Ground and Neutral is safe here in Thailand.

[Shiver]

I used to get a tingle from devices which I'm guessing would have been around 50V floating voltage (negligible amps of course). I got a local odd jobs man to install an earth and put in 3 pin sockets where I wanted them most. What he did was put a wood screw into the grout between tiles, and found that the only way to make it work was to put a wet paper tissue over it. Eventually I found someone who would put a proper copper spike in the ground and never had a problem since.

[Crossy]

JohanB, whilst I understand your sentiments, I suggest you are scaremongering.

How many polarity reversals actually occur? It can only happen at the meter, usually when some unauthorised work has been done.

MEN is not deadly per-sé, every home in Australia and many in the UK (it's called PME there) have it.

There are indeed circumstances where a MEN installation can become unsafe and I'm not a great lover of it on aerial supplies but it is required in Thailand in order to gain a permanent supply to a new installation.

If worried, and you know what you are doing, by all means TT your installation once the PEA inspector has gone.

EDIT My general advice regarding MEN (it's actually TN-C-S with MEN), is, and has always been - "If you don't have it, don't add it. If you do have it, don't remove it."

EDIT 2 There's a good discussion of the various earthing systems here https://en.wikipedia.org/wiki/Earthing_system

In Thailand we have TT and TN-C-S (with MEN), there are reports of some villages being IT (possibly because the star-point earth has rotted away) and condos with their own transformers may be TN-S (ours was but it's the only one I've actually checked).

[JohanB]

I am not going to read it all as most of it will be rubbish anyway.....

ARE YOU SURE the active and neutral aren't reversed, it's happened twice to me. Being at work, not paid the bill, removed meter. Pay bill install new meter. Go inside house and check polarity . Not gonna happen. Both wires going into the house are black, so I guess a 50/50 chance...

If you have no ground rod and the place is MEN then guess what..... YEP ALL the metal is alive!!!!

Welcome to 200 Baht a day electricians company VERY Limited, schooled at Somchai school of engineering (have selfie with hat), 6th rice paddy on the right, Nakon Nowhere......

Now making BIG money from Farang

Crossy, here is one more example of reversal L/N that really happend by autourized service in this thread!

Repair of broken overhead wires is an other situation that happend to me, made by PA peple!

In a normal country thai home with no earth at all. nobody really notice if L/N is interchanged.

I bet there are 10-thousends + or even more homes in Thailand with reversed L/N. Nobody cares about it as everything seems working normal. But when something happend (f.ex. short to ground) there are no fuses in the live line and the wires will burn.

As RigPig wrote above, there are in many cases a 50/50 chance/risk that the 2 black wires are mixed up when changing meter or doing other work on the grid. Unatourized or autorized dont really matter, the education level is low.

You have to much confidence in ordinary thai, by PA autourized servicemen on the road.....

I have been in the electronic engineering for over 40 years and understand fully how MEN (multiple earthed neutral) works in Australia UK and in my home country Sweden, but this is Thailand!

[Forkinhades]

I will echo this

For new installations it is a requirement of the PEA to have MEN implented on the CONSUMER side, otherwise you are not getting connected.

If you already have a connection, but do not have MEN, we do actually advise to leave as is.

However for my dwelling in LOS, I insisted on it mainly because the impedance values were lowered significantly, thus under fault conditions the MCBs will open within the required time by any regs. So in effect making Front End Safety-cut redundant, but that said my install has 2 RCDs protecting 5 circuits each. Which also let's me have 3 security circuits that are not protected by RCDs. Which I know will open in time under fault conditions.

[Forkinhades]

^ I will edit the sticky with regards to MEN connection for old installations.

If the PEA was supplying reversed polarity, then I thought the meter ran backwards?

[Forkinhades]

@ Crossy, I'm sure we could come up with a polarity indicator that was connected to the supply, with just an led and 25k ohm resistor?

[Crossy]

@ Crossy, I'm sure we could come up with a polarity indicator that was connected to the supply, with just an led and 25k ohm resistor?

One of the 20 Baht neon screwdrivers will do the trick, finger on the end, it lights on live, doesn't on neutral. If it also lights on earth you have a problem.

With reverse polarity the meter still runs forwards, so no easy way to reduce your bill.

[RigPig]

Nothing wrong with an MEN system ...AS LONG AS IT IS DONE PROPERLY!!

And there in lies the problem.

The Neutral and main Earth should be conneced together at the main switchboard.

The resistances of Earth wires should be low enough to be in spec.

How many Thai 'electricians" Even know what an insulation resistance meter (Meggar) is let alone have one? As for an Earth loop impedance tester

BUT the bottom line really is how much are you willing to pay for your safety, $80 an hour same as back home? No I didn't think so....

[JohanB]

I will echo this

For new installations it is a requirement of the PEA to have MEN implented on the CONSUMER side, otherwise you are not getting connected.

If you already have a connection, but do not have MEN, we do actually advise to leave as is.

However for my dwelling in LOS, I insisted on it mainly because the impedance values were lowered significantly, thus under fault conditions the MCBs will open within the required time by any regs. So in effect making Front End Safety-cut redundant, but that said my install has 2 RCDs protecting 5 circuits each. Which also let's me have 3 security ecircuits that are not protected by RCDs. Which I know will open in time under fault conditions.

OK, so you put in the MEN connection to be able, by the lower impedance in the Neutral, to trip the 3 MCB's outside the Safe-Cut RCD, if the fault condition is a short between live/ground. A more common fault case is internal short between L/N and that needs no MEN-link to work. That is how everything worked before RCD's were implemented.

According to your wireing on the picture from your pinned thread, the connections are very confusing.

No neutrals going in to the secondary RCBOs, all neutrals going out from the RCBOs are connected together!!

This will upset the function of the whole system and I can't calculate how it works, if it works at all.

Each live line out from the RCBO must have their own return through the neutral in the same RCBO.

How you can connect them together on the neutral bus-bar I can not understand!

Have you really tried this?

[Forkinhades]

We want to get the earth value as low as possible. RCBOs do not detect L-N faults, and any MCB will open in such case. We are looking to protect against L-E faults (Neutral is also a live onductor). With TT systems your impedance values in Thailand will be about 20 ohms, so on the C curve of an MCB under fault conditions they will not open in time, if at all. This is why Safety-cut is used, as only 30mA of fault current is required to open it.

RCBOs mostly come with with fly leads for the neutrals and earths to go back to their relevant bars. The neutral load of the circuit goes to directly to RCBO.

Hope this makes it more clear.

Yes it works perfectly fine.

EDIT: Added another paragraph

[JohanB]

We want to get the earth value as low as possible. RCBOs do not detect L-N faults, and any MCB will open in such case. We are looking to protect against L-E faults (Neutral is also a live onductor). With TT systems your impedance values in Thailand will be about 20 ohms, so on the C curve of an MCB under fault conditions they will not open in time, if at all. This is why Safety-cut is used, as only 30mA of fault current is required to open it.

RCBOs mostly come with with fly leads for the neutrals and earths to go back to their relevant bars. The neutral load of the circuit goes to directly to RCBO.

Hope this makes it more clear.

Yes it works perfectly fine.

EDIT: Added another paragraph

OK, the 4 blue neutrals from the bus are neutral inputs to the 1 pole RCBOs.

But what is confusing about your circuit is that there are 4 blue lines from the bus, going to the left, that appears to be neutral return connections for the 4 RCBOs and no neutrals shown comming out from the RCBOs.

[Forkinhades]

Yes indeed you are correct, I will modify the picture.

Thanks for the observation.

[Crossy]

A agree it's a bit confusing Johan, we have the browns going off to the circuits but no matching blues

EDIT I posted at the same time as Forkinhades.

[Crossy]

To show the absolute requirement for MEN in Thai installations here is a scan from the installation manual for an ABB consumer unit, note that every illustration shows the routing of the incoming neutral via the ground bar, Thai MEN implementation (actually the same as the NEC method), not a TT in sight

[Forkinhades]

The pinned thread has now been edited, thanks to an observation by JohanB, who will indeed be credited for such.

@ JohanB if you want to continue this discussion either by another thread, or a pm to me and Crossy,I (we) would be very happy to do so, and if you have any other suggestions on the pinned thread please do pm me.

OK now lets get the thread back on topic.

Thank you

[JohanB]

I had similar problems when our place was wired by Thai electricians (On their mother's side) - we had some neutrals wired to live and some lives wired to neutral, we were getting weird junk out of some of our sockets, like 130V etc. Nightmare on Somchai Street! Then we had the local EGAT come out doing some work on the high voltage cables outside on the street when they installed a new step down transformer - They reconnected everything but had the polarity reversed, live became neutral and neutral was no live!

I have a three pin socket in my kitchen that no one uses, I have it marked with indelible ink as to which terminal I neutral and which one is live - everytime EGAT fiddle around on our road I like to double check as you never know what to expect - At least they cannot change my Earth to live or neutral!

Crossy, I sure belive you on new installation should be done by the PEA-red book, but I remarked that it is not safe to have a MEN-connection together with overhead wiring on the countryside.

I questioned the safety, not the regulations.

Just notice the above experiences from another member here in this thread......and consider....

[Forkinhades]

We have always said that out in the countryside on old installations one should make enquiries about whether MEN can be done in ones home. We advise to contact the local PEA and ask for confirmation.