Electrical

[electau]

If one goes to the PEA website http://www.pea.co.th/th/eng/ and the download the link "Instructions on the Use of Electricity" and gives some insight into their requirements.

The document is dated 10 June 2009 so it is recent. It is in PDF.

It mentions the Thai Electrical Code.

It also states that one can contact the PEA for further information.

[Crossy]

Thanks for finding that Electrau.

But it really says absolutely nothing (I see a 2 page letter to electricity users) that would not be considered common sense in a Western situation (not that all Westerners are endowed with even a modicum of common).

What we really need is the Thai version of BS7671 (hopefully not so restrictive) or the Aussie regs (the document number escapes me at present). Sadly whilst a Thai Electrical Code is mentioned in many places I've never found anyone who's actually seen it, I doubt that such a standard actually exists for domestic installations

This file from the same site is most definitely useful http://www.pea.co.th/pdf/groundwire.pdf (for some reason I can't attach the actual file).

EDIT and this one is worth downloading for our Thai family http://www.pea.co.th/pdf/SB-B02-5001.pdf

[electau]

Thanks for finding that Electrau.

But it really says absolutely nothing (I see a 2 page letter to electricity users) that would not be considered common sense in a Western situation (not that all Westerners are endowed with even a modicum of common).

What we really need is the Thai version of BS7671 (hopefully not so restrictive) or the Aussie regs (the document number escapes me at present). Sadly I doubt that such a standard actually exists for domestic installations

This file from the same site is most definitely useful http://www.pea.co.th.../groundwire.pdf (for some reason I can't attach the actual file).

EDIT and this one is worth downloading for our Thai family http://www.pea.co.th...SB-B02-5001.pdf

But it might make sense if you are Thai, para 1. mentions earthing and the installation of RCDs. In other words earth equipment and install an RCD/RCBO. Earth here is a very general term and presumably it will be found in the Thai Electrical Code and most probably refers to a direct earthing system.

And that Thai Electrical Code may have examples of Thai earthing practice.

I think what that document is trying to say is fit an RCD and earth equipment in high risk wet areas in other areas earthing is optional. The RCD becomes the basic protective device for earth faults.

One would agree a copy of AS3018 Domestic Installations and translated into Thai would be the way to go.

I tried to download those two other PDF files but their must be a serious slow down in the internet at present in Thailand on that PEA website

[Pib]

That PEA letter mostly stated items that should be common sense, but common sense is sometimes a rare item. Maybe it should have also included the statement, "Do not bite into live electrical wires."

[elkangorito]

This file from the same site is most definitely useful http://www.pea.co.th.../groundwire.pdf (for some reason I can't attach the actual file).

This is the booklet that I had translated in an earlier thread (somewhere).

[Crossy]

This file from the same site is most definitely useful http://www.pea.co.th.../groundwire.pdf (for some reason I can't attach the actual file).

This is the booklet that I had translated in an earlier thread (somewhere).

Yeah I thought it was Elk (I couldn't find the thread either).

I does have some good stuff, although it concentrates on MEN / PME connections, no mention is made of IT or 3-phase 3-wire which are known to exist here. I don't really like what appears to be the standard Thai N-E method of connection, as there is no means to remove the N-E link for testing purposes.

It's one of those 'for the masses' documents that actually needs good technical knowledge to really understand and interpret

[elkangorito]

An update:

After work today, I spent about an hour with the Thai electrical teachers. I asked them if there was any such thing as the "Thai Electrical Code". They did not have such a thing in their possession so they searched for almost an hour on the internet.

The end result was: Thailand uses a mixture of the NEC & IEC rules (I was shown some Thai books with references to this).

Exactly what this mixture is, is anybody's guess.

There is only one more avenue to try, which I shall do shortly.

They also showed me some very interesting books (in Thai), which outlined the distribution systems here. I did not see any mention of IT, TT, TN etc. The books did outline the voltages/tx configurations used so I may just copy a few of these pages.

So, everything is currently pointing to: "The Thai Electrical Code doesn't exist" as an individual document. I hope I can prove this wrong.

[Crossy]

Keep us informed Elk. You seem to have the best interfaces with the local 'real' (rather than the twist-and-hope brigade) sparkie community.

Let's restrict this thread to the discovery of the Thai regulations, plenty of others discussing wiring and grounding etc.

[electau]

I find it strange that the electrical teachers do not know if the LV distribution system neutral conductor is earthed or not. How would they answer the question if asked?

And it would seem that the PEA/MEA do not know either. And there must be drawings of the LV distribution system showing any earthing arrangements.

The drawings in the groundwire PDF document show an MEN system of earthing and it would seem that this is applicable to new residential electrical installations connected to supply after 2003/2546.

The connection diagram shown does not provide easy disconnection for testing purposed.

One requires 3 links, one for the main neutral, one for the earthing conductors and one for the RCD protected circuits. The main earth connects to the earth link/bar and the MEN link connects between the main neutral link and the earth link/bar.

And the other drawing SB-B02-5001.pdf shows 2 pole fuse switches and 2 pin flat blade plug tops which of course exist in older installations.

And it would be interesting to know what the Thai concept of protective earthing is from a practical electrical standpoint.

And if the PEA requires an MEN in new installations how does it permit 2 pin plug tops and 2 core leads to be still used with equipment without a protective earthing conductor?

　

[Crossy]

Agreed Electau, I think we're all on the same page now

Two-pin, two-wire plug tops are fine as long as they are attached to Class 2 appliances which don't require an earth.

[electau]

Agreed Electau, I think we're all on the same page now

Two-pin, two-wire plug tops are fine as long as they are attached to Class 2 appliances which don't require an earth.

But in fact most are Class1and are fitted with 2 pin plug tops, eg irons, extension leads, rice cookers

[electau]

Here are some questions that should be asked and they should be addressed to a competent person within the PEA/MEA.

The Thai LV distribution system.

1. Is the neutral earthed?

The consumers electrical installation.

1. Is the main neutral required to be earthed?

2. If the main neutral is not required to be earthed RCDs are mandatory.

3. Are individual protective earth conductors to seperate electrodes permitted?

4. Are alternative protective earthing arrangements permitted where 2 pin socket outlets are installed?

And the answers initially should be a direct YES or NO to each question.

Then each question can be addressed in detail as required.

The questions should be able to be referenced to an existing current Thai code or standard.

[David006]

Here are some questions that should be asked and they should be addressed to a competent person within the PEA/MEA.

The Thai LV distribution system.

1. Is the neutral earthed?

The consumers electrical installation.

1. Is the main neutral required to be earthed?

2. If the main neutral is not required to be earthed RCDs are mandatory.

3. Are individual protective earth conductors to seperate electrodes permitted?

4. Are alternative protective earthing arrangements permitted where 2 pin socket outlets are installed?

And the answers initially should be a direct YES or NO to each question.

Then each question can be addressed in detail as required.

The questions should be able to be referenced to an existing current Thai code or standard.

perhaps we could also inquire as to how Thailand licenses or tests to classify class 1 and 2 appliances for sale in Thailand ( something equiv to IEE code of practice), especially since the electrical code is a bit nebulous? From what I have seen there is no superior insulation in class 2 appliances to rate them as such, never saw any relevant inspection logo of any sort....

Is there a body responsible...?

[electau]

In answer to your post david006 there is an entity known as the Thai Industrial Standards.

( TIS). They administer approvals and certificates for Thai electrical products only. But TIS standards do not comply with AS/NZ or IEC standards. TIS products are for the Thai domestic market.

Thailand manufactures electrical equipment for export but they comply with the importing countries standards, AS/NZ or IEC, BS etc.

They will be fitted with a 2 core and earth lead and a 3 pin plug top. They are class1.

Class 2 are double insulated (the logo is a square within a square) they have a 2 core lead and 2 pin plug top.

If the equipment has not got the DI logo regard it as class1.

Thai standards appear to be based on the JIS ( Japanese Industrial Standard).

[electau]

http://www.st.gov.my/

the downloadable pdf file is onthe right hand side of the page under Electrical Safety

Requirements for Electrical Wiring in Residential Buildings.

This document is the requirements for Malaysia, and is referenced to IEC, BS and MS.

They use the TT earthing system.

Compare that document with what is available in Thailand.

[elkangorito]

It appears that the Engineering Institute of Thailand does, in fact, publish a Thai Electrical Code.

Click on the link below & then click on 'Book store online'. Then, look for 'electricity' in the 'section' column. The book is listed as 'Standard installation of electricity for Thailand, BE 2545'.

http://translate.goo...l%3Den%26sa%3DG

I'm not sure if the book is in Thai or English. Nor am I sure if it is the legislated code. It is, however, the only electrical code that I can find.

I do believe that other posters have mentioned this document.

I will now endeavour to find out if this code is actually cited & used by vocational colleges.

[stgrhe]

Elk., Please let us know what you find out.

[bankruatsteve]

Here are some questions that should be asked and they should be addressed to a competent person within the PEA/MEA.

The Thai LV distribution system.

1. Is the neutral earthed?

The consumers electrical installation.

1. Is the main neutral required to be earthed?

2. If the main neutral is not required to be earthed RCDs are mandatory.

3. Are individual protective earth conductors to seperate electrodes permitted?

4. Are alternative protective earthing arrangements permitted where 2 pin socket outlets are installed?

And the answers initially should be a direct YES or NO to each question.

Then each question can be addressed in detail as required.

The questions should be able to be referenced to an existing current Thai code or standard.

Just to get a hopefully healthy discussion re: "earth"/"grounding", here's my input/opinion...

I don't really understand the relevance of your questions to consumer protection wrt grounding.

First #1 - The neutral MUST be earthed in the grid somewhere else nothing would work.

2nd #1 - Neutral connect to earth at the CU just helps make a healthier system. However, if it is/isn't doesn't make a twit of difference to the CU grounding - and circuits within the CU connected thus to ground.

#2 - RCD's don't care about ground - so why are they mandatory if N is not grounded?

#3/4 - don't understand the question but if you're talking about separate ground with a device from the CU grounding - so what? Shouldn't be necessary but could protect from high impedence earth faults - which are vary rare.

Discussion?

[elkangorito]

Elk., Please let us know what you find out.

After a lengthy 2 hour discussion today, it appears that nobody at my place of work knows of any such Thai Electrical Code. I showed them the book available on the EIT website & still nobody knew anything about it. People stood scratching their heads about this. The only thing that came close to a 'wiring Standard' was someone mentioning the PEA booklet, which I have had previously translated.

Here are some questions that should be asked and they should be addressed to a competent person within the PEA/MEA.

The Thai LV distribution system.

1. Is the neutral earthed?

The consumers electrical installation.

1. Is the main neutral required to be earthed?

2. If the main neutral is not required to be earthed RCDs are mandatory.

3. Are individual protective earth conductors to seperate electrodes permitted?

4. Are alternative protective earthing arrangements permitted where 2 pin socket outlets are installed?

And the answers initially should be a direct YES or NO to each question.

Then each question can be addressed in detail as required.

The questions should be able to be referenced to an existing current Thai code or standard.

Just to get a hopefully healthy discussion re: "earth"/"grounding", here's my input/opinion...

I don't really understand the relevance of your questions to consumer protection wrt grounding.

First #1 - The neutral MUST be earthed in the grid somewhere else nothing would work.

2nd #1 - Neutral connect to earth at the CU just helps make a healthier system. However, if it is/isn't doesn't make a twit of difference to the CU grounding - and circuits within the CU connected thus to ground.

#2 - RCD's don't care about ground - so why are they mandatory if N is not grounded?

#3/4 - don't understand the question but if you're talking about separate ground with a device from the CU grounding - so what? Shouldn't be necessary but could protect from high impedence earth faults - which are vary rare.

Discussion?

I'm sure that electau will have lots of fun replying to this post. I could reply now but I won't.

I await with baited breath.

[electau]

Here are some questions that should be asked and they should be addressed to a competent person within the PEA/MEA.

The Thai LV distribution system.

1. Is the neutral earthed?

The consumers electrical installation.

1. Is the main neutral required to be earthed?

2. If the main neutral is not required to be earthed RCDs are mandatory.

3. Are individual protective earth conductors to seperate electrodes permitted?

4. Are alternative protective earthing arrangements permitted where 2 pin socket outlets are installed?

And the answers initially should be a direct YES or NO to each question.

Then each question can be addressed in detail as required.

The questions should be able to be referenced to an existing current Thai code or standard.

Just to get a hopefully healthy discussion re: "earth"/"grounding", here's my input/opinion...

I don't really understand the relevance of your questions to consumer protection wrt grounding.

First #1 - The neutral MUST be earthed in the grid somewhere else nothing would work.

2nd #1 - Neutral connect to earth at the CU just helps make a healthier system. However, if it is/isn't doesn't make a twit of difference to the CU grounding - and circuits within the CU connected thus to ground.

#2 - RCD's don't care about ground - so why are they mandatory if N is not grounded?

#3/4 - don't understand the question but if you're talking about separate ground with a device from the CU grounding - so what? Shouldn't be necessary but could protect from high impedence earth faults - which are vary rare.

Discussion?

The LV distribution system.

1. The neutral may be earthed in some areas mostly it is not. Verification by visual checks. This is the responsibility of the PEA/MEA.

The consumers electrical installation.

1. It would appear that earthing of the neutral it is not mandatory in Thailand and is subject to PEA/MEA requirements.

2. It would appear that RCDs are not mandatory on existing installations but may be on new installations subject to PEA/MEA requirements.

3. It would appear that they are permitted on existing installations for protective earthing conductors.

4. Alternative protective earthing requirements permitted, it would appear so eg, earthing an item of electrical equipment to the steel work of a building.

I have based this information on what is known of Thai electrical wiring policy and what appears to be accepted practice.

It should be remembered that many electrical installations in Thailand have no earthing or minimal earthing and no RCDs. And the neutral is not earthed.

Now, to answer your questions,

#1. Where the distribution neutral is not earthed there is a low enough impedance to earth per kilometre for a RCD to operate at a consumers individual electrical installation.

#2 Connecting the neutral to earth, the fault current will return to the distribution transformer by way of the neutral conductor, not through the general mass of earth. This is a low impedance fault path. The unearthed neutral is a high impedance fault path.

With a high impedance earth the value of fault current will not operate an MCB with in the required disconnection time of 0.4sec. An RCD will.

#3 and #4. This type of protective earthing is not permitted under the wiring regulations of many other countries (AS, BS, IEC etc) but appears to be permitted in Thailand.

　

　

[bankruatsteve]

Here are some questions that should be asked and they should be addressed to a competent person within the PEA/MEA.

The Thai LV distribution system.

1. Is the neutral earthed?

The consumers electrical installation.

1. Is the main neutral required to be earthed?

2. If the main neutral is not required to be earthed RCDs are mandatory.

3. Are individual protective earth conductors to seperate electrodes permitted?

4. Are alternative protective earthing arrangements permitted where 2 pin socket outlets are installed?

And the answers initially should be a direct YES or NO to each question.

Then each question can be addressed in detail as required.

The questions should be able to be referenced to an existing current Thai code or standard.

Just to get a hopefully healthy discussion re: "earth"/"grounding", here's my input/opinion...

I don't really understand the relevance of your questions to consumer protection wrt grounding.

First #1 - The neutral MUST be earthed in the grid somewhere else nothing would work.

2nd #1 - Neutral connect to earth at the CU just helps make a healthier system. However, if it is/isn't doesn't make a twit of difference to the CU grounding - and circuits within the CU connected thus to ground.

#2 - RCD's don't care about ground - so why are they mandatory if N is not grounded?

#3/4 - don't understand the question but if you're talking about separate ground with a device from the CU grounding - so what? Shouldn't be necessary but could protect from high impedence earth faults - which are vary rare.

Discussion?

The LV distribution system.

1. The neutral may be earthed in some areas mostly it is not. Verification by visual checks. This is the responsibility of the PEA/MEA.

The consumers electrical installation.

1. It would appear that earthing of the neutral it is not mandatory in Thailand and is subject to PEA/MEA requirements.

2. It would appear that RCDs are not mandatory on existing installations but may be on new installations subject to PEA/MEA requirements.

3. It would appear that they are permitted on existing installations for protective earthing conductors.

4. Alternative protective earthing requirements permitted, it would appear so eg, earthing an item of electrical equipment to the steel work of a building.

I have based this information on what is known of Thai electrical wiring policy and what appears to be accepted practice.

It should be remembered that many electrical installations in Thailand have no earthing or minimal earthing and no RCDs. And the neutral is not earthed.

Now, to answer your questions,

#1. Where the distribution neutral is not earthed there is a low enough impedance to earth per kilometre for a RCD to operate at a consumers individual electrical installation.

#2 Connecting the neutral to earth, the fault current will return to the distribution transformer by way of the neutral conductor, not through the general mass of earth. This is a low impedance fault path. The unearthed neutral is a high impedance fault path.

With a high impedance earth the value of fault current will not operate an MCB with in the required disconnection time of 0.4sec. An RCD will.

#3 and #4. This type of protective earthing is not permitted under the wiring regulations of many other countries (AS, BS, IEC etc) but appears to be permitted in Thailand.

　

　

#1 - Huh? The distribution neutral IS earthed somewhere. What that has to do with RCD operation isn't clear.

#2 - Nope - those electrons don't need to return "home" - they have plenty of cousins in the "earth" to take their place. There is nothing high impedance in a properly grounded CU. Connecting ground to N is "healthier" - like if your ground rod should somehow end up dangling in a sink hole. But, a ground fault will take the ground wire path to ground AND (if signigicant) will trip the MCB almost instantaniously (as in a short circuit overload). The RCD might be a few microseconds faster but that's about it.

#3 and #4 - Are you saying separate ground of equipment is not allowed most places. Hmmm.

Cheers

[Crossy]

OK Gentlemen.

As noted in post #8 I'd like this thread to stay on track for discussion of Thai electrical REGULATIONS not to discuss the pros and cons of the various distribution and grounding systems.

Steve. I suggest you refresh your understanding of TT, IT (particularly relevant to some regions in Thailand) and TNC (or TNC-S) systems.

If you want to carry out in depth arguments, please post on one of the other electrical threads (there are many) or start a new one.

Further off-topic discussions in this thread will be deleted.

[bankruatsteve]

OK Gentlemen.

As noted in post #8 I'd like this thread to stay on track for discussion of Thai electrical REGULATIONS not to discuss the pros and cons of the various distribution and grounding systems.

Steve. I suggest you refresh your understanding of TT, IT (particularly relevant to some regions in Thailand) and TNC (or TNC-S) systems.

If you want to carry out in depth arguments, please post on one of the other electrical threads (there are many) or start a new one.

Further off-topic discussions in this thread will be deleted.

OK. I would just like to say that, perhaps in my opinion only, the grid system does not matter for the local CU grounding. Ground faults to ground can be handled by the local CU and whatever "system" there is in place is for the grid. I thought the topic said "discussion" so I do appologize for doing that if nobody wants to hear mine.

Cheers

[Crossy]

^^^ Steve, your opinions are always welcomed, but let's keep technical discussions in the other threads and reserve this one for any information we locate on the actual regulations

[dhrobertson]

This is certainly an area where a little knowledge can be very dangerous. Please consult qualified engineer if in doubt.

Conformance with the Thai EIT code is a legal requirement here. The PEA/MEA are responsible for enforcement but usually fail to do so.

The EIT code is difficult to obtain. I got our copies from Chulalongkorn university bookshop. I don't know any Thai electrical contractor who has a copy.

Code is based on American NEC code, which is unwise since USA has 110V for one reason.

Most Western residential electrical codes are becoming harmonised with IEC 60364. This why you will find ASNZ3000, BS7671:2008, German and French et al codes are all very similar.

Our Thai clients now require installations complying BOTH with EIT code and international IEC standard based codes such as BS7671. EIT is actually more stringent in some areas such as the requirement for RCD protection of water heaters.

Distribution in Thailand is usually 3 phase, 3 wire at MV (6kV, 12kV, 22kV and 33kV). Distribution transformers usually are 3 phase, 4 wire output at 230/400V. Neutral (transformer star point), tank and MV screens are all bonded to ground at the transformer. Requirement is less than 5 ohms to main body of earth.

Ground system at individual villas or developments is a lottery. Typical set up is TT. Requirement here is again 5 ohms(up to 25 ohms in sandy soil).

We always implement TN-C-S at origin only , with a back-up ground rod triangular array of 3 x 3m x 5/8" copper clad steel ground rods. If in doubt about N/G link size and ground conductor size use 50% of main feeder size.

I will respond to specific queries on <email removed>

(Moderator, this is a safety issue. Please permit me to give the above contact email address. I get called as an expert witness in electrical accidents. I would like to reduce this element of my work!)

[Crossy]

I am being rigorous in moderating this thread, as previously stated I want to keep this one for discussion of the actual regulations. I've removed some off topic posts which would normally be allowed to stay.

dhrobertson, I've not removed your email address yet, we don't normally allow emails in posts because they are a potential spam problem for the owners of said address. PM sent.

[InterestedObserver]

Conformance with the Thai EIT code is a legal requirement here. The PEA/MEA are responsible for enforcement but usually fail to do so.

The EIT code is difficult to obtain. I got our copies from Chulalongkorn university bookshop. I don't know any Thai electrical contractor who has a copy.

Code is based on American NEC code, which is unwise since USA has 110V for one reason.

The US National Electrical Code (NEC) regulations cover voltages above anything used in Thailand for residential and light industry. 120/240/480/600VAC are some of the common low voltages covered by the NEC.

[Deke]

I have a copy of the EIT code that dhrobertson refers to in PDF format. It's a large file (>15 MB) but if anyone wants a copy, send me a PM and I'll upload it to some file sharing site for you.

The document is in Thai, of course.

[Kwasaki]

This seems like a rave from the grave I am sure regulations would apply to large buildings in cities like Bangkok etc.

I repect the the enthusiazem that many on here display.

I recently got into this forum wondering where " Elk " had gone with his diagram.

When it comes to individual houses I really believe that regs don't count for much in Thailand.

I got hold of a couple of of guys that do electrical work in our village and they say they are trained electricians and ask them why the neutral wiring in my house was black they said that was right, I think that says it all.

[electau]

With reference to post by dhrobertson.The basis of any electrical installation standard for buildings should be based on IEC 60364, thus eg, AS3000/2007 can be used for guidance purposes. As Thailand uses the nominal 220/230- 380/400 50Hz system

The LV distribution system earthing is covered by other legislation as required and should be enforced by the PEA/MEA.

Earthing requirements for electrical installations are covered by IEC 60364, AS3000. or BS7671.

If the TT system is used RCDs must be installed on all final subcircuits. The main earth electrode need only to be 13mm copper clad, 1.2/1.8 metres into the ground. MEN link at the main switchboard.

Those figures that you have given along with earthing requirements appear to be NEMA requirements.

There is a demarcation line between the definition of "electrical installation" and the service conductors, protective devices and distribution system of the PEA/MEA.

One requires a standard that can hold up from a legal perspective in a court of law. AS and BS standards meet this requirement in the own respective countries.

A note also that to use these standards one must be able to interpret them within the meaning of the standard used. And that requires one to have formal qualifications.

Electrical safety is the priority here, that is why standards are used to minimise the risk of fire and shock within an electrical installation.

　

This EIT code, how can it be used if it is not generally available to the electrical contracting industry, the electrical industry and electricians so they know what is required of them?