Grounding: Earth And Zero Connected

[mistitikimikis]

I discovered that here (BKK suburbs) the "electricien" combined in a new installation earth and zero which I don't like too much. The zero by the way isn't earthed at every pole of the electricity-provider.

I also discovered that, the current(s) are not equal in the phase and zero feeding my house.

On top of that I measured a current of 3 Amp. in the line going to the earth-rod.

The earth-rod, although no earth-resistance checked of course, is three meters and on top of that I incisted to connect the (general) earth-line with the iron floor-foundation of an extension of the house, what I was used to do in Spain.

Although normally the ground-water level is quit high here I am getting a bit frightened of the earthing.

I know that, besides of the shower / pump installation, there is a small change to get electrocuted (for that reason I did not fitted an instant-heater but an old-fashioned boiler). Even an expensive fridge, brand Hitachi, wasn't equiped (I think by the importer) with an earth-plug.

Somebody can give me some hints??

[craigt3365]

I think you'll do better with this over in the real estate and housing forum.

Topic Moved.

[Crossy]

What you have (N - E connected) is a TN-C-S supply with MEN (Multiple Earthed Neutral). This is the normal connection for a new installation in Thailand (and you probably had it in Europe but just didn't know, it's standard in the UK but the N-E connection is hidden in the service head).

However, your 3A in the earth path is very worrying and I would remove the N-E link now. How did you measure this current? With the link out what is the N-E voltage?

[Crossy]

UPDATE.

WARNING Will Robinson.

If you really have 3A going to earth it's possible that you have L & N transposed (3A @ 220V is about 73 Ohms, a reasonable value for an earth stake).

Be very careful when handling even the neutral and ground connections.

Turn off your main breaker.

Disconnect the ground stake and measure voltage between it and the incoming L & N wires. Report back here.

[leogerritsen]

I hope he reports back

[mistitikimikis]

Thanks! No, I'm not (yet) electrocuted but started some investigations.

The (road)-supply is 3x380 Volts plus zero which should have been earthed near every pole which is, of course, not the case.

My (1x220 Volt / zero) connection goes first and for all to the bi-polair main-breaker, and after there the zero has been connected with the earth, which I want to split when I sorted out the main-question about the current at the zero / earth.

The failure isn't the house-installation because the current disappears when I switch-off the main-breaker; leaving the main-breaker connected and switching-off every single sub-breaker doesn't cut the current.

This means clearly that I am (partly) functioning as an earth-connection for the electricity-supplier on his general zero-supply.....

Upto now I was only able to measure the current but I want to check the tension (in between the earth and the zero from the road) also when I am ready to do that; I'm very curious about that!

I started to-day with another test and made an earth-pole near the (road)-entrance of the installation but as the soil is a big lump of very dry clay and this connection is still very amateuristic I got "only" 0.3 A. there until I started "watering" the pole; it went up rapidly until about 1 Amp.

However it shows that my standard earth-installation is proper there it showed "standard" about 3 / 4 Amp. until a bit of an hour later when it went up to about....................10 Amp.!

I want to change that situation now asap BUT when I cannot get rid of that problem with the "zero" I'm a bit afraid to split zero and earth which is my intention. And to get the electricity-supplier "helpful", well, you know yourself: TIT! I don't like the idea to have a zero under tension fed by the provider.

I'm measuring the current with a Kyoritsu digital clamp meter (2017) with which I worked already in Europe.

I really don't like this whole situation very much and I'm very near to the idea to switch-off the (Grundfoss)-pump and boiler before showering! Better low water-pressure than no blood-pressure.

Why I'm a bit slow in answering? I was studying how I can (re)build the whole louzy installation around the breakers and want to make first a general switch near the road to prefent that I have to climb a ladder to reach the meter to deconnect the wires................

Thanks already for your previous reactions!

[Crossy]

Carefully, disconnect the ground stake from the E bar (wear shoes and stand on a wooden stool) and measure the voltage between it and the bar.

If you get more than a few volts do NOT re-connect it and call your sparks immediately!

[mistitikimikis]

Carefully, disconnect the ground stake from the E bar (wear shoes and stand on a wooden stool) and measure the voltage between it and the bar.

If you get more than a few volts do NOT re-connect it and call your sparks immediately!

I get around or < 3 V. AC and, well a very tiny spark I have. The "sparks" you mention are not able / willing to come (khlong Samwa and even not from Koobon) and when they are too easy-going / without proper knowledge and, for sure they will point at the electricity-supplier who will have the same attitude. For me it's the electricity-supplier who has to do something.

Here is the breaker-case: http://www.antoni-uni-photography.com/THAILAND/TECHNICAL-STUFF/electricity-thailand-antoniuni/11216846_2GR4wv#!i=1762345678&k=592Jwv6&lb=1&s=A

It's not very easy to get proper people out, even to find all the professional material................ (Don't recommend a certain "professional" outlet in shopping-malls please!)

[Crossy]

OK, with <3V you don't have a polarity reversal which I was very worried about.

But that does not fit with your excessive ground current, ground rods simply don't get anywhere near 1 Ohm.

You have no RCD, get one fitted ASAP.

[mistitikimikis]

Well, that's why I want to split the earth and the zero! I brought it from Europe but they didn't install it (30 mA) plus some spark-protectors. What I have learned always is that one need a separate earth and zero for this device. I'm curious when installed it doesn't trip with the incoming "pollution". When I changed everything I'll hammer some more ground-pools in because the groundwater-level is very low. Next week I'll try to get somebody from the electricity-supplier ............

Only one thing still borders me is that I measured about 3 Volts at 3 Amp but wasn't able to measure the voltage when I read about 10 Amp.! Might be the far higher current-rate can have something to do with the weekend: more houses occupied in the compound, somewhere sending earth-faults back into the zero.

Sorry I am/was a bit cynical about the services but I have seen and experienced already too much in more than six years!

Anyway, thanks very much for your responses. Nice weekend.

[Crossy]

RCDs work just fine on TN-C-S / MEN systems, it's just important that the link between N and E is on the supply side of the RCD. The neutral for all your circuits is separated from the incoming neutral by the RCD.

The instructions that came with your ABB CU show numerous configurations including some with surge arrestors (we have the same unit bought in Thailand).

Good luck finding a sparks who can read a diagram, I know ours can't, check out my Housebuilding Thread

[mistitikimikis]

RCDs work just fine on TN-C-S / MEN systems, it's just important that the link between N and E is on the supply side of the RCD. The neutral for all your circuits is separated from the incoming neutral by the RCD.

The instructions that came with your ABB CU show numerous configurations including some with surge arrestors (we have the same unit bought in Thailand).

Good luck finding a sparks who can read a diagram, I know ours can't, check out my Housebuilding Thread http://www.thaivisa....uilding-thread/

Lucky I can! I was always working with Hager

http://www.hager.co.uk/products/energy-distribution/protection-devices/7946.htm

OBO

http://www.obo-bettermann.com/downloads/en/prospekte/bss_basisinfo_en.pdf

and

Simon

http://www.simon.es/

True what you said.

[Crossy]

My considered advice would be to get your local sparks to install a separate breaker on your incoming supply (even one of the Chang brand knife switches would do the trick).

Then you can open said breaker and safely work on the CU and do the job yourself and get it right.

[necronx99]

Carefully, disconnect the ground stake from the E bar (wear shoes and stand on a wooden stool) and measure the voltage between it and the bar.

If you get more than a few volts do NOT re-connect it and call your sparks immediately!

I get around or < 3 V. AC and, well a very tiny spark I have. The "sparks" you mention are not able / willing to come (khlong Samwa and even not from Koobon) and when they are too easy-going / without proper knowledge and, for sure they will point at the electricity-supplier who will have the same attitude. For me it's the electricity-supplier who has to do something.

Here is the breaker-case: http://www.antoni-un...92Jwv6&lb=1&s=A

It's not very easy to get proper people out, even to find all the professional material................ (Don't recommend a certain "professional" outlet in shopping-malls please!)

Is that a record for how many different colored wires in a box?

[Crossy]

Is that a record for how many different colored wires in a box?

Probably not, what is rather alarming is the number of non-white wires on the neutral bar and the white wires in breakers. No recognisable colour code has been used except maybe green for some earths.

EDIT. Have a look at the other images in his gallery, scary!

[necronx99]

Is that a record for how many different colored wires in a box?

Probably not, what is rather alarming is the number of non-white wires on the neutral bar and the white wires in breakers. No recognisable colour code has been used except maybe green for some earths.

EDIT. Have a look at the other images in his gallery, scary!

I wonder how many electrocution deaths per year here.....

Anyway, I'm glad I did my pool area myself.

All three pin and earthed!

[mistitikimikis]

Is that a record for how many different colored wires in a box?

Probably not, what is rather alarming is the number of non-white wires on the neutral bar and the white wires in breakers. No recognisable colour code has been used except maybe green for some earths.

EDIT. Have a look at the other images in his gallery, scary!

I wonder how many electrocution deaths per year here.....

Anyway, I'm glad I did my pool area myself.

All three pin and earthed!

There is always a wat nearby for a last ceremony!

There are for sure lots of humans and even elephants electrocuted every year but it almost never reaches the press or it must be a farang.

The last one I heard of was the tragic death of a tourist touching the handrail of a foot-bridge over a small pool. In Spain (Catalonia) we were not allowed to make electrical contacts and other stuff at less than three meters from the pool and every metal construction around had to have a proper (visible) earth-connection leading to an earth-rod next to it. The lights in the pool (12 Volts) were proper protected in the engine-room and fed by a heavy separating-transformer, i.e. separated windings.

This installation I saw by coincidence somewhere in the lower Sukhumvit-area (Bangkok). Might be satisfying working for it's purpose but one push and.............: http://www.antoni-uni-photography.com/THAILAND/TECHNICAL-STUFF/electricity-thailand-antoniuni/11216846_2GR4wv#!i=1742030248&k=Zhd34GG&lb=1&s=A

When I have a bit of time I'll start some warning-topics concerning domestic-electricity and locally sold electric household-appliances which are not too safe or are only safe after a special treatment.

[necronx99]

Is that a record for how many different colored wires in a box?

Probably not, what is rather alarming is the number of non-white wires on the neutral bar and the white wires in breakers. No recognisable colour code has been used except maybe green for some earths.

EDIT. Have a look at the other images in his gallery, scary!

I wonder how many electrocution deaths per year here.....

Anyway, I'm glad I did my pool area myself.

All three pin and earthed!

There is always a wat nearby for a last ceremony!

There are for sure lots of humans and even elephants electrocuted every year but it almost never reaches the press or it must be a farang.

The last one I heard of was the tragic death of a tourist touching the handrail of a foot-bridge over a small pool. In Spain (Catalonia) we were not allowed to make electrical contacts and other stuff at less than three meters from the pool and every metal construction around had to have a proper (visible) earth-connection leading to an earth-rod next to it. The lights in the pool (12 Volts) were proper protected in the engine-room and fed by a heavy separating-transformer, i.e. separated windings.

This installation I saw by coincidence somewhere in the lower Sukhumvit-area (Bangkok). Might be satisfying working for it's purpose but one push and.............: http://www.antoni-un...hd34GG&lb=1&s=A

When I have a bit of time I'll start some warning-topics concerning domestic-electricity and locally sold electric household-appliances which are not too safe or are only safe after a special treatment.

I cant make it out, what is under the umbrella?

[Daffy D]

Click to enlarge:-

Edited March 25, 2012 by Daffy D

[necronx99]

Click to enlarge:-

that's my pool , I was talking about his link

http://www.antoni-un...hd34GG&lb=1&s=A

Edited March 25, 2012 by necronx99

[mistitikimikis]

I don't think it's the main-filter installation, I think it's an invention, an automated chlorine dosification I pressume

[mistitikimikis]

Are you kidding??? THAT'S your pool????

[necronx99]

Are you kidding??? THAT'S your pool????

lol, no. everyone hopes it was an internet joke.

[mistitikimikis]

Well, to be honest.................... (not pointing at you) but there are lots of @#$%& not knowing what they are doing and thinking to be sufficient protected by whatever technical device....................

[dhrobertson]

With such a high current flowing to ground from the neutral, I think there is a problem with the system ground at the transformer star point. Neutral is generally bonded to ground at the transformer and then every third pole in Thailand. Get local PEA to check this.

TN-C-S is strongly recommended as it is very difficult to get god enough ground performance from local ground rods. Link should be not less than 50% size of the feeders and should be made at the origin of the supply only (at your main load panel). Local ground rods should also be installed. Add rods until you get a resistance to earth of less than 5 ohms.

ELCB/RCD/RCBO protection is required for all types of water heater in Thailand. You may want to consider adding a main ELCB (Safe-T-Cut or similar) to protect the entire installation.

[Crossy]

A thought, since the N-E link is in the CU and therefore on the consumer side of the meter are those 3 Amps going to cause the meter to spin?

[mistitikimikis]

With such a high current flowing to ground from the neutral, I think there is a problem with the system ground at the transformer star point. Neutral is generally bonded to ground at the transformer and then every third pole in Thailand. Get local PEA to check this.

TN-C-S is strongly recommended as it is very difficult to get god enough ground performance from local ground rods. Link should be not less than 50% size of the feeders and should be made at the origin of the supply only (at your main load panel). Local ground rods should also be installed. Add rods until you get a resistance to earth of less than 5 ohms.

ELCB/RCD/RCBO protection is required for all types of water heater in Thailand. You may want to consider adding a main ELCB (Safe-T-Cut or similar) to protect the entire installation.

I took the decision to contact the electricity-supplier on Monday, but............... Another weak point in the supply is that when we have a heavy downpour all of a sudden (only our phase) starts going down onto about 160 Volts or dies, so that explains already something, and that for more than three years and the company (I think) comes, does something centrally and goes. Real solving the problem? No, TIT! So when they come for my main-issue I ask them to change my house-connection onto another phase, and who knows, the main problem has been solved as well!

Speaking about that branch of the electricity-supplier (Minburi): in Koobon (Ramintra) we have with a heavy down-poor a heavy explosion in a transformer nearby and electricity down. This is already for years; nothing cured up-to now...............

Apart of that my steps are now:

1. take a ladder and unscrew the wires of the meter

http://www.antoni-uni-photography.com/THAILAND/TECHNICAL-STUFF/electricity-thailand-antoniuni/11216846_2GR4wv#!i=1763459699&k=kLkL6nL&lb=1&s=A

2. install a general switch for the house-supply in the garden

http://www.antoni-uni-photography.com/THAILAND/TECHNICAL-STUFF/electricity-thailand-antoniuni/11216846_2GR4wv#!i=1763470589&k=vRxgQsk&lb=1&s=A

3. Redo the main-breaker part, including splitting the earth from the zero

http://www.antoni-uni-photography.com/THAILAND/TECHNICAL-STUFF/electricity-thailand-antoniuni/11216846_2GR4wv#!i=1763474034&k=qFvQmh2&lb=1&s=A

4. and start messing around with the whole further system

http://www.antoni-uni-photography.com/THAILAND/TECHNICAL-STUFF/electricity-thailand-antoniuni/11216846_2GR4wv#!i=1762345678&k=592Jwv6&lb=1&s=A

Here I can show you how "water-proof" the main-connection was:

http://www.antoni-uni-photography.com/THAILAND/TECHNICAL-STUFF/electricity-thailand-antoniuni/11216846_2GR4wv#!i=1763419027&k=FVDhfd3&lb=1&s=A

Thanks all for your helpful comments / ideas / suggestions!

[mistitikimikis]

dhrobertson can you give me a hint about the best way how to measure the earth-resistance. I don't have the old-fashioned megger anymore, just have now a digital universal meter with which I can go up-to 40 Meg.

[dhrobertson]

So, you are fitting a new 40A 2P type C breaker at the origin. Cables look like 10mm2 so that's oK. Then you have an RCD which currently is not connected to the load. What is the trip current of this RCD? For shock protection, this should not exceed 30mA. Then you have some small surge protection devices? I cannot see the spec of these.

Do be careful with phase/neutral polarity.

I still suspect a problem with inadequate ground bonding of the neutral. This must be bonded to ground at the transformer, at least every third pole and (in my opinion) at the origin of every residence connected.

If, you decide not to continue with TN-C-S ground, disconnecting the N-G link, and rely upon your new RCD, you must still have the local ground rods connected to the ground bus bar. Ground rod impedance must be less than 5 ohms.

The problem with this solution, and a problem with using Safe-T-Cut is that you may well get nuisance tripping. Maybe you have some landscape lighting with some water ingress problems. OK, the RCD will trip but then you have no power anywhere! Safe-t-cut users often dial in protection of 500mA thus stopping the nuisance tripping but disabling bthe protection from shock.

No, the solution is to fix the main problem.

If you disconnect the phase (black) at the meter, but leave the neutral (grey) connected and with your main breaker on, what is the current flowing to ground?

[dhrobertson]

To measure ground rod resistance to the main body of the earth requires a special instrument. A multimeter or a Megga won't help. However, as you are getting such high currents to ground, I suspect there is not much of a problem there!

You could try measuring the voltage between the incoming neutral and ground with your main breaker switched off. Then measure the current in the ground conductor with the main breaker on but all the final circuit breakers off. Then you can do V/I =R. How does the ground current change as you switch on each final circuit breaker?