electau

You can also have separate meters for each installation, they will each have a set of consumers mains. Metering will be one location. Each tenant will have their own account.

How is the metering actually connected? One PEA meter and the submeters are PEA with one set of consumers mains ? Or the above?

In reply to post #3.

You will not get a "western" electrical supply until the PEA upgrades its HV and LV network, and that is not likely to occur in the near future.

All you can do is to make sure that your electrical installation complies with the minimum voltage drop requirements with regard to the consumers mains.

It would be recommended that you fit manual reset no-volt relays to each of your airconditioners, they will drop off line when you do get periods of low voltage.

It should be remembered that RCDs must trip between 50% and 100% of the rated trip current, They must not trip at 50%. RCDs generally will trip at about 70% in about 20mS.

If you have a RCD that has 5/10/15/20mA settings, you should take this in to consideration.

Max standing leakage current should not exceed 30% of the rated setting in mA.

And a note on supply failures and low voltage. These are often occur on the HV network, failures can be caused by lightning which trip autorecloser switches which lock out after 2 operations and have to be reset and closed manually. The low voltage can be caused by demand on the system in peak periods on the HV network.

Yes Crossy, I too have tried to access a document pertaining to wiring rules in Thailand. I was able to access the Malaysian standard, they use the TT earthing system and RCDs and they are based on British Standards.

But not Thailand outside of those two PEA documents which are in effect advice for a consumer, the consumer shows this to their electrician and they then comply with the PEA requirements.

From this document it would seem that the (some) following requirements apply.

Minimum size of main earth 10sqmm. MEN connection.

A 2 meter earth electrode.

An RCBO can be used as a main switch. Short circuit rating minimum 10kA at 220V.

Consumers mains minimum size 10sqmm.

3 pin socket outlets to be installed.

PE earthing conductor to be 1.5 or 2.5 sqmm minimum.

One does not see the justification for a 10sqmm main earth (on a MEN system) perhaps the 10sqmm refers to the main earth of a TT system. 10sqmm is used in Malaysia.

It would appear that whoever authored these documents in the first instance might have sourced their information from an engineering textbook, perhaps based on VDE or NEMA requirements.

Nothing about calculating max demand or voltage drop requirements within an electrical installation.

Perhaps cable current ratings and voltage drop requirements may be accessed from Thai cable manufacturers in their cable specifications.

Fixed the topic title electau.

I'm assuming most of your quotes are from the Oz regs which, whilst a good fit for local conditions, are not enforceable.

Thanks Crossy.

The MCB and RCD information is from AS/NZ3000. The TT system is not used under AS3000.

Information supplied is for guidance purposes only. As you stated BS, IEC or AS/NZ3000 standards are not legally enforceable in Thailand.

As per Crossys post..

The 2 pole change over switch should have 3 or 2 positions 1-0-2 or 1-2. It should have a minimum of 10 or16 amps rating and must be connected in such a manner that the generator supply can not feed back into the PEA supply. It should be surface mounted in a enclosure.

The generator frame should be earthed. You may have to get an electrician to install it.

Useful Information. Electrical Installations in General. Thailand.

A customers electrical installation commences from the point of supply. This is generally the energy metering point in Thailand. The LV transformer, distribution conductors, protective devices, service fuses( if installed) and metering are the responsibility of the PEA/MEA.

With any electrical installation one must calculate the max demand in amps first. this can be done by calculation or by the setting of a fixed current MCB. In Thailand service fuses are not generally installed, they protect the consumers mains from short circuit and provide a point of disconnection for the installation. They are not for overload protection. In Thailand a double pole fixed setting MCB is installed, this setting is the max demand of the installation. It also provides short circuit protection on the load side of this MCB. This MCB is generally rated at 6kA at 380V and 10kA at 220V. MCBs for submains and final subcircuits are generally a max of 6kA (1.5kA min). These are prospective short circuit ratings.

Most MCBs will be known as C curve for lighting and power circuits. other types are B and D but these are not used in residential type installations in general.

An MCB must trip on an earth fault in less than 0.4secs, hold a current of 1.2 X rated FL current continuously and must trip at 1.45 X FL current.

An 30mA RCD or an RCBO must trip in less than 0.3 secs at rated trip current in mA on an earth fault.

An 10mA RCD must trip in less than 0.04 secs at rated current on an earth fault.

Conductor installation must satisfy current-carrying capacity, voltage drop and other minimum size requirements for conductors.

With an MEN (TN-C-S) earthing system the earth loop impedance must be low enough to trip an MCB with in the required times. In practice this loop impedance will not be a problem as the requirement of voltage drop will require the installation of larger conductors, thus lowering the loop impedance.

With the TT or direct system of earthing the earth loop impedance will always be high and that is why RCDs must be used for earth fault protection.

Automatic disconection by a protective device must occur if the touch voltage exceeds 50VAC.

Thailand uses both the TT or direct earthing. The MEN system is also used as an option in new installations. Most Thai electrical installations use direct earthing. Mixing of TT and MEN is permitted within an electrical installation.

RCBOs are used as a main switch, thus giving protection to earth faults within an installation, a cost effective way of minimum protection without installing a compliant earthing system.

In reply to post #20.

It does not matter if the socket outlet has the line and neutral reversed as long as the switching is in the line (active conductor). As TIS standard sockets are unswitched unplugging the socket will break the line conductor.

Most socket outlets are marked L, N and E.

If you use 13A BS fused plugs with a TIS adapator the polarity should be changed in the 13A BS plug top not at the socket. As this may not be practicable due to their design you should replace the BS type with a compliant 3 pin TIS one.

AS Crossy states, you most probably have what is known as reversed polarity, the L and N supply cables have been reversed. It could be at the switchboard, the meter or at the connection at the connection of the service. You will have to get the PEA to check.

You should regard this as a potentially hazardous situation. All switching must be in the line (active) conductor.

It was caused by not carrying out a polarity test on connection to supply.

From AS3000, 6sqmm buried direct (unenclosed) is 50A. 10sqmm is 63A. The pump circuit circuit does not carry these currents continuously.

The maximum route length using these values would be dependant on the percentage voltage drop on the circuit.

30 meters from the main switchboard and a 2% voltage drop. 20 amps full load (FL) current you will require 10sqmm cable. For a 3% voltage drop 6sqmm would be the minimum.

　

So Bangkok Cable are taking some liberties with the data?

Another thing I noticed was the roll lengths. 100 m vs 500 m standard lengths. Or will shops cut that to order?

Different cable standards, these may be based on NEMA ratings.

Most cable suppliers will cut 500 meter drum lengths to order, they may charge you a cutting fee.

Whilst the above is undoubtedly correct, I doubt if any of the non-sparks members of this board has a suitable instrument for measuring L-E loop impedance in their toolbox, hence my reference to special kit. Most of us who do any work at all on house wiring will have a cheap multimeter which is adequate for checking earth continuity where the cable runs are relatively short.

A multi meter is a continuity tester on the low ohms range for most practical applications. ( To get an accurate reading one requires a range of 0 to 3 ohms).

Size of the earthing conductor is based on the size of the current carrying conductors for 2.5sqmm this is normally 2.5sqmm except where the earth conductor is laid up in the same sheath as the current carrying conductors. Ref AS/NZ3000. Table 5.1.

The earth loop L to E impedance can be carried out using a standard continuity tester. You have to check the earth continuity as one of the tests before connection to supply.

The PEA/MEA is responsible for they poles and network up to the point of connection to your electrical installation. In Thailand this is usually at the metering point of your electrical installation. After that point the consumers mains, mains switchboard and installation wiring is your responsiblility. You can run the consumers mains overhead or as an underground configuration to the main switchboard. Remember the voltage drop requirements over 130meters. To calculate this you will need to know your max demand in amps.

What where the terms stated in the original supply contract with the PEA?

Take everything with you... We did and everything works just fine with the appropriate converter which costs around 40 Baht each . . .

Equipment such as toasters, rice cookers will draw a higher current and may be subject to overheating and failure over time. System voltage can be 235 to 245volts. There is an approved plug adaptor available in Australia, cost about AUD11 each. Equipment must be earthed, therefore toasters rice cookers etc must have a 3 core lead.

Not advisable. Thai electrical appliances comply with TIS (Thai standards) and are rated at 220volts. Australia uses 240volts. To be used in Australia equipment must have an IEC or AS number on the nameplate. Appliances are cheap enough in Australia at the present time.

Equipment rated at 230 -240V would comply but not 220V.

Your printer and DVD player would probably be OK, check the name plate ratings.

With reference to post # 87

The file is not always sent to Australia as all the information is on the DIAC data base. All the information can be accessed on line in Australia by DIAC.

Bangkok does the first stage of processing, Canberra the second stage. You need to keep them informed of your current postal address in Australia. DIAC will forward some documents to be filled in about 6 to 8 weeks before the date the 309 visa expires.

The Ambassador is a British citizen but he is not a civil/public servant. They represent the UK in an official function, eg at a political level in the host country, they also have diplomatic immunity.

The average British citizen will in most cases never be required to contact the Ambassador, most will use the consular services.

Ambassadors are appointed positions.

I have 3 questions. I've tried to find the answers to them, but have been unable to.

1. If you apply in Bangkok ( as my wife has), is your case officer based in Bangkok? - yes

2. Does the completed application go to Australia? - prior to completion, I understand for the final decision.

3. Is the final decision made in Bangkok? - see above.

Cheers.

If I am wrong someone will correct me.

In answer to your questions.

1. DIAC case officer is in Bangkok.

2. The application does not go to Australia for processing.

3. The decision to approve/refuse the application is made by DIAC in Bangkok.

All the applicants information is entered on the DIAC computer database.

The size of meter (5/15A) is not really the problem, they can take up to 100% overload quite safely, the accuracy may be affected. It only records consumption in kWh, it does not limit the max demand, the MCB does that.

What is the current rating of the consumers mains? They should be a minimum of 32A .The main circuit breaker should be a minimum of 32A.

If you install a 3500watt or 4500 watt type use a 20A MCB as the protective device and wire in 2.5sqmm on a final sub circuit. Earth the water heater. The water heater will probably have an internal 10mA RCD fitted in the unit as an ON/OFF switch.

10A on the 1.5mm² circuit will be fine to protect the cable although I am surprised that 10A is the smallest breaker, UK lighting circuits are usually 5A.

Thanks Crossy.

It may just be Pattaya Home Pro doesn't have smaller.

If I remember correctly, it's 5 amps in NZ as well.

PS. While all my plugs are wired direct to earth, should I also earth the circuit board box?

Yes, if the enclosure is metal. Earth with the same size as the main earth. If you do not have a main earth earth use a minimum of 2.5 sqmm. Connect to the earth bar.Connect the earth bar to the existing earthing system.

AS/NZ3000. 2 core and earth cable. 1.0sqmm 10 amps, 1.5sqmm 16 amps. 2.5sqmm 20amps.

MCBs 10 /16 / 20.

1.0 and 1.5 sqmm for lighting circuits and 2.5 sqmm for socket outlets.

Electau said, "With long shifts they can be problems with fatigue, which can and has caused accidents."

I don't believe that fatigued flight attendants ever caused an accident. They may not have been much help after the accident though. Fatigue in flight crew has caused accidents and that's why Civil Aviation Order 48 dictates flight and duty times. CAO 48 does not cover FA's, but there may be another provision in the CAO's of which I'm not aware. As far as I know, duty times for flight attendants are part of industrial agreements and not law.

Traditionally FA's have not performed well in full blown emergencies, even when not fatigued.

An accident could be an injury to themselves or to a passenger due to fatiguel from long shift times..It could mean that cabin flight procedures are compromised.

That is why airlines have safety management procedures and carry out risk analysis. Airlines have a "duty of care" responsibility to their staff and passengers at all times.

Surge and spike protectors (SPDs), can be fitted within a power board or installed on the switchboard. the switch board types are rated at 40kA per phase for an 8/20 microsecond impluse and a minimum working voltage of 275VAC. Module are plug in replaceable DIN rail mounting, Should be protected by a 32A MCB.

Coarse protection at the switchboard and fine protection at the socket outlet.

Like I said, if the conduit remains dry should be little problem, but the issue would be if any water was to remain in the lowest point.

EDIT It seems that Bangkok Cable's NYY is suitable for direct burial http://www.bangkokca...LOG/NYY2EN.HTML which will remove the issue with getting it into the conduit.

Am I missing/misreading something or can burying that cable actually result is being able to use smaller cable? From that table:

6 mm rating - in ground - 61 amps

10 mm rating - in air - 62 amps

From AS3000, 6sqmm buried direct (unenclosed) is 50A. 10sqmm is 63A. The pump circuit circuit does not carry these currents continuously.

The maximum route length using these values would be dependant on the percentage voltage drop on the circuit.

30 meters from the main switchboard and a 2% voltage drop. 20 amps full load (FL) current you will require 10sqmm cable. For a 3% voltage drop 6sqmm would be the minimum.

Basically you pay for the capital cost but as the equipment is not on your property and is on public land you do not have title to it. The PEA/MEA maintain the equipment at their cost. The idea is that all property holders share in the costs.

Paying for the capital cost or a share of the costs does not consitute ownership.

Generally it is the initial developer of the land who bears these costs and they are passed on in the price of the land to the purchaser.