Are there compulsory rules for grounding electrical devices?

[Forkinhades]

^ nice one well done thomassteve. We do not need to get any more technical than that.

[Crossy]

^ nice one well done thomassteve. We do not need to get any more technical than that.

Forky, why not blatantly plagiarise thomassteve's post as a sort of summary for your pinned thread, giving credit of course?

[Forkinhades]

I am thinking about adding that post to the pinned thread, as his own post of course.

Sent from my GT-I9300 using Thaivisa Connect Thailand mobile app

[Piztolapete]

The majority of shower heaters sold (reputable brands) now seem to have their own buit in earth leakage (similar to a saf-t-cut) protection device. Presumably these will still work correctly and provide adequate protection regardless of whether there is a correct earth wire connected to a ground rod or just a live and neutral supply connection ? The wire colours being mixed up will also be of no consequence if they are designed to operate by detection of a small imbalance (often 20mA) between the line and return (neutral) conductors ?

If you cannot get the house wiring correctly done,complete with an earthing rod, then at least install an ELCB (commonly sold as a saf-t-cut in Thailand) after the main on/off isolator switch before the rest of the circuits and associated mix-ups.

I could not find one of the (reputable brands). So I got a Sharp WH-A55 3500 watt. The directions were very specific on the connection points. Connections must be made as to the manufacture's specs. Or a possible result of DEATH by electrocution could occur. If you could give me the models and manufacturers names I would look at that as possibility for future installs if I gift any of the extended family.

By reputable brands I was thinking of Panasonic, Sharp, Stiebel Eltron etc. or others that have a built in ELCB which you can identify by seeing a 'test' button on the front panel. Some of the cheaper models don't have this protection but it's still advisable to have a Safe-t-cut or equivalent fitted rather than just rely on the internal one of the shower.

The shower instructions will emphasise the importance of earthing the unit but this is useless if you find that the earth wire just goes as far as the consumer unit as no earthing rod has been installed by cost cutting builders.

I bought a sharp. at no point does it say you can switch the N and Line. It only says do not switch the two. Or death can result. It has a test button on the front same as any ground fault interrupter. When a manufacture says connect it this way you do it. No questions or hum ha. Otherwise you void you warranty and put people at risk. 21 years as an electrician has learned me this.

Edited January 6, 2014 by Piztolapete

[Piztolapete]

Re : Post 35

Just to be clear and get complete transparency, I do actually agree that earthing needs to done properly, and if not can be more dangerous than if not installed at all. Was hoping you could have given an example.

with reference to the pinned thread 'How to make your thai electrics safe', what we are trying to do is educate people that here in Thailand it is more important to have your Safe-T-Cut installed, than to install earthing without a Safe-T-Cut. Which can become very dangerous indeed.

Regarding the pinned thread it can be summarised as follows :

1. Install a Saf-t-cut or similar ELCB.

2. Ensure appliances and socket outlets are correctly earthed and an earthing rod is installed.

3. Never add a Neutral to Earth MEN link unless you are 100% sure it is required by your supplier.

As for an example of a scenario where earthing can present a danger :

House has no Saf-t-cut or ELCB but has correctly earthed fixed large appliances and socket outlets.

User purchases a metal cased small appliance (rice-cooker, toaster, iron etc.) fitted with a 2 pin plug or Schuko type European plug that does not provide correct earth connection.

This small appliance becomes faulty and the metal casing live but user remains unaware as he is insulated from ground (rubber soled sandals, wooden floor etc.) but then touches another correctly earthed appliance (cooker,fridge) with other hand and will receive severe shock. If there had been no earthing then there would be no potential difference to allow current to pass through user and cause a shock.

I am not advising against earthing but it needs to be done properly and in conjunction with an ELCB.

Very good point. This is why when I upgrade the electrical in I current house and our new house I will ensure all outlets earthed or ground as you would. However my shower is hard wired in the bathroom with no contact from any other appliance. SO I put in ground rods just for the single purpose of the electric SHOWER use. They do not use hair drier or any electric device in shower room.

[Piztolapete]

Your neutral and earth ground are the same point electrically. But they are only suppose to be connected in one place. Usually near you meter or in the closest transformer. There are only certain occasions when it happens in your electric panel located in your home. The reason for only one connection point is to reduce currents in the "ground" wire and make them flow through the identified grounded conductor the neutral.

Edited January 6, 2014 by Piztolapete

[Crossy]

Your neutral and earth ground are the same point electrically. But they are only suppose to be connected in one place. Usually near you meter or in the closest transformer. There are only certain occasions when it happens in your electric panel located in your home. The reason for only one connection point is to reduce currents in the "ground" wire and make them flow through the identified grounded conductor the neutral.

Pete.

Thailand implements TNC-S with MEN in a similar way to the US NEC.

Please have a look at the diagrams in this document http://www.crossy.co.uk/Handy%20Files/groundwire.pdf and at Forkinhades pinned threads at the top of this forum.

You will note that N and E are linked at the consumer unit.

IMPORTANT NOTE Do not link N-E unless they are either already linked or you are certain that MEN is implemented in your area!

[Piztolapete]

The diagrams were barely useful. I do not read Thai. But what I could interpret from the diagrams was that the neutral was earthed in one location. So is it saying I should take my ground for the neutral bar at my distribution to my shower?

Edited January 6, 2014 by Piztolapete

[Piztolapete]

Your neutral and earth ground are the same point electrically. But they are only suppose to be connected in one place. Usually near you meter or in the closest transformer. There are only certain occasions when it happens in your electric panel located in your home. The reason for only one connection point is to reduce currents in the "ground" wire and make them flow through the identified grounded conductor the neutral.

Pete.

Thailand implements TNC-S with MEN in a similar way to the US NEC.

Please have a look at the diagrams in this document http://www.crossy.co.uk/Handy%20Files/groundwire.pdf and at Forkinhades pinned threads at the top of this forum.

You will note that N and E are linked at the consumer unit.

IMPORTANT NOTE Do not link N-E unless they are either already linked or you are certain that MEN is implemented in your area!

I did not do that. only a ground for the shower separate of the distribution. no physical of n and e. just an overall connection in case of water fill of the shower unit and a dead short. No risk to shower taker or kid aiming the head of shower in the wrong place.

Edited January 6, 2014 by Piztolapete

[Forkinhades]

Post removed for inappropriate content

[Forkinhades]

This is Thailand, and we play by their rules.

[Crossy]

OK, several posts giving confusing and potentially dangerous information removed.

A few things to ponder:-

We are in Thailand, diagrams in Thai from the supply authority (PEA) are entirely appropriate.

Consider what would happen if you were the only premises to implement MEN by linking N-E and a neutral fault (open) occurred between you and the transformer (draw it).

It is always better to be TT (no N-E link) with an RCD if unsure.

[thomasteve]

OK, several posts giving confusing and potentially dangerous information removed.

A few things to ponder:-

We are in Thailand, diagrams in Thai from the supply authority (PEA) are entirely appropriate.

Consider what would happen if you were the only premises to implement MEN by linking N-E and a neutral fault (open) occurred between you and the transformer (draw it).

It is always better to be TT (no N-E link) with an RCD if unsure.

I have some further questions about this TT to MEN changeover in the electricity distribution system being implemented in Thailand.

1. Why is it being done ?

2. What are the benefits to the user of a MEN compared to TT system ?

3. If it requires every house putting in a link wire in their distribution box will homeowners be notified and who is going to check that it is done ?

4. If it's not done, what difference will the user notice, if any ?

Thanks.

[Forkinhades]

1. It is a PEA requirement now on all new installations, if you dont have it, then dont do it, unless you are sure the Tx and relevant poles are earthed

2. MEN will give low earth values which should be sufficient to open MCB's in time

3. PEA will not do it, they expect you to. This totally baffles me

4. As long as you have a front end Safe-T-Cut, then nothing.

Best to leave alone if you are unsure.

[Khun Jean]

In the consumer unit i bought recently there is a N-bar and a E-bar. The diagram included shows that the ground stake must be connected to the E-bar and then a connection from the E-bar to the N bar must be made.

The E-bar has only a few connections and are on the top of the unit.

On the bottom there is a N-bar with enough connections left to match the number of breakers with L connections.

The CU contains an earth leak detector.

My question is, when the ground stake is connected to the E-Bar and that is connected to the N-bar, would there still be a need to connect the plugs with 3 wires?

In the CU the Earth and Neutral are connected so practically there are only two connections.

The plugs with three prongs could then theoretically be wired L -> L, N -> N, N -> E.

Is that still safe? Would a third wire add anything?

I have read some more and understand that is called MEN.

It seems that NOT connecting N-Bar and E-Bar together is better as then you can be sure that you are isolated from others and do not depend on if a Earth-Neutral connection is implemented in your direct area.

Confused.....

Edited January 8, 2014 by Khun Jean

[Forkinhades]

Indeed it will add your safety!

Also please make sure that your local Tx are earthed, with every 3rd pole thereafter. If you are going to do the MEN connection.

I will post some pictures of the arrangement.

[Khun Jean]

My only wish is safety.

If one system is better then the other i will use that.

The cost is irrelevant. I see that the other system is called TT. This would mean a 3rd wire to every outlet and appliance and a ground stake not connected to the neutral bar.

If MEN is depended on others i think (as a non electrician) that going for TT would be better.

Is that correct?

[Crossy]

If MEN is depended on others i think (as a non electrician) that going for TT would be better.

Is that correct?

As we often say, unless you are certain that MEN has been implemented in your area, it's far safer to leave the system as TT with an RCD front-end.

Whether MEN or TT you still need that 3rd ground wire to the outlets. Although N and E are at the same potential in a MEN system they are not the same connection, the N at your outlets comes from the controlled side of the RCD.