electau

You should stick to the PEA recommendations for minimum cable sizes or they may not connect a permanent supply, these are:-

5/15 meter - 10mm² (anything smaller may have difficulty supporting its own weight when strung from poles)

15/45 meter - 16mm²

30/100 meter - 35mm² (yes I thought that was excessive too but they only allow 25mm² to 95A)

Source http://www.pea.co.th.../groundwire.pdf (table on page 11, confirmed by our local office).

50m of 10mm² will provide a volt drop of 4.4V (2%) at 20A.

Single core (Bangkok Cables type THW which is usually used for this application) is available from 0.5 to 500mm²http://www.bangkokca...LOG/THWEN.HTML.

The minimum sizes are most probably based on the fact than there is no protective device ( service fuse) to protect the consumers mains and in the event of a short circuit, ie, at the line side of the main circuit breaker, the cable temperature rise will not exceed the rating for the cable. Fault currents should be cleared in less than 5 secs. Perhaps a HV fuse on the transformer will rupture in the event of a S/C fault or it will just blow itself clear ( and the cable still be alive, a potentially hazardous situation.)

Here are some common HRC service fuse sizes. They do not form part of the electrical installation and are installed by the electricity supplier.

80 amp for 10 and 16sqmm, 125 for 25sqmm. An HRC fuse will carry 1.6 rated current for the conventional time of 1 hour, It will rupture faster than a MCB and carry a higher fault current in kA. They are used to disconnect the installation and provide fault current limiting.

They are not for overload protection.

10 sqmm copper conductor with 20A will give a voltage drop of 3% over 50metres. At 50A you will require 16sqmm. At 63A you will require 25sqmm. At 100A you will require 35sqmm. This is from the point of supply to the main switch board. (The max demand may be the setting of the main circuit breaker (switch) on the switchboard).

If you use 5% voltage drop the sizes of conductor will be: 20A / 4sqmm, 50A / 10sqmm, 63A / 16sqmm and 100A / 25sqmm.

The PEA appear to require a minimum size of not less than 10sqmm depending on the max demand.The cable required is single core copper conductor PVC insulated PVC sheathed 700VAC 70C temp rise.

There is a 3 letter code based on the NEC for this type of cable. Refer to the Thai cable manufacturer.

The UK (British Standard) and some countries that use this standard with local requirements are the only ones that use the 32A ring circuit with spurs at 16A.

The usual power circuit in a typical domestic electrical installation is usually 20A and 2.5sqmm. Each socket outlet is given a rating of 1A. The max demand is the rating of the protective device. For a single permanently connected equipment on a final sub circuit the max demand is the input current of the individual equipment.

A mixed circuit of lighting points and 10A socket outlets may be connected on a 2.5sqmm circuit, this method may be used to supply a small external building on a residential property, eg a garage etc. Now not often used.

Yes, it would be normal wiring practice to install an aircon rated at between 5A and10A on its own circuit,and the cable size may then be 1.5sqmm with a 16A protective device.

Where there is a minimum of 2 power circuits of 10A socket outlets both circuits should be run through the kitchen area of a domestic installation.

Source: AS3000. Other countries standards may vary from this. The ring circuit is prohibited in Aust/NZ along with the 13A BS fused plug top and the !3A socket outlet in permanent wiring as they do not comply with AS/NZ standards for plug tops and socket outlets.

Fibreglass Pink Batts, in clear plastic sleeves, 1200 x 600mm, lay over the ceiling. Do NOT cover recessed light fittings and control equipment. Ideal for a T-Bar ceiling.

Any individual load with a max demand in excess of 10amps should be wired on its own individual circuit from the switchboard.

Small items such as exhaust fans and ceiling fans may be connected to lighting circuits on a 10A MCB, These items are usually 60 watts or less.

You would be better off purchasing the genuine National or Panasonic socket outlets in the long term, you do not know the internal construction of these "Zyberg" or where they are manufactured, Do they comply with current Thai Industrial standards (TIS) ?

You should earth the shower heater to minimise the effects of minor leakage currents. These will not trip an RCBO.

An aircon with a load of 4.5amps can easily be accomodated on a circuit of socket outlets. 2.5sqmm/20A.

The RCBO should be tested by means of the test button at least once every 3 months.

The applicant for the 676 visa did not meet the criteria for the issuance of the visa, she will have received a formal letter from DIAC detailing the reasons for refusal under the Migration Regulations. You should read the letter first, that is if your girlfriend mentioned it to you in the first instance.

Circuit protection must comply with the following.

1. The protective device, ie the MCB or RCBO must be rated equal to and not more than the current rating of the circuit conductors to be protected.

2. The protective device must protect against short circuit, overload, and earth fault conditions.

3. Actual current rating of circuit will depend on the method of installation,eg, unenclosed in air, or enclosed in conduit over 50% of its route length. 2.5sqmm will carry 25A unenclosed.in air. subject to voltage drop.

The airconditioner should be wired on its own circuit if over 10Amps total load. if less ie a 7000BTU unit it may be connected to an existing power circuit by means of a plug and socket. Aircon should be earthed and protection by an 20A RCBO at the switchboard.

Do not use the circuit for the shower heater.

Buyer beware: They may be fake Panasonic electrical products, most likely manufactured in China.

DIN rail mounting RCBOs are available in 18mm module width for retrofitting.

All the big names make them, any information who actually imports to Thailand? My local outlet don't seem to be able to get them.

Try Clipsal (Thailand). part of the Schneider group.

DIN rail mounting RCBOs are available in 18mm module width for retrofitting.

Equipotential bonding and earthing is of unmost importance to minimise voltages between different parts of the pool.

Pool lighting should be less than 50VAC (SELV) RCD protection on all socket outlets, and equipotential bonding within a defined pool area.

To start and run an induction motor of 1.0hp (0,75 kW) output a generator with a minimum output of 4.0kW is required.

Make sure that the generator is 50Hz 220- 240V. If the motor is on a long circuit run you should check that you do not have excessive voltage drop on the circuit. The pump should be earthed.

A standard two way switch wiring is : Line (L) term C, a twin between 1 and 1 and 2 and 2 of the switches, terminal C of the second switch to the line side of the light fitting.

If an intermediate switch(es) are to be added they are installed in the circuit betwen the first two switches, in the twin cable.

Clipsal and HPM switch mechs.

The standard switch SPST is generally single pole 1-C-2 these are used as 2 way switches also.

Intermediate switches, (not often used) are when used for passageway lighting and stairwell lighting. The switching is 1-2, 3-4. and 1-3, 2-4.

DPDT are switched 1-C-2 and 3-C-4

Ref. Clipsal 30, HPM 770 series 10A 250V. Try Clipsal Thailand. You will need the wall plate also.

National may make them also as a rocker type switch.

Do you know the route length of the mains from the metering point to the swirchboard?

I looked at the main cable at the meter and on the black sheathing that encloses the two power wires it says '2 x 10' which I assume to be 2 conductors of 10mm2 cable. It's not a very upscale housing development so makes sense that they would put in the smaller size.

As a note, when I asked the housing project office to check and see what size the cable was I was told "35mm".

Off to get my 50 A RCBO.

Length of the mains? jeez, I'd say about 60 feet or so. Just a guess though.

Therefore your existing mains size is 2 x10sqmm.

The advice you were given was therefore incorrect. 35sqmm may be the minimum for new developments, and this would be aluminium not copper conductor. Again current rating depends on method of installation and voltage drop.

There is no problem with voltage drop for this distance, about 18 to 20metres.

Do you know the route length of the mains from the metering point to the swirchboard?

The cable size should be printed onto the cable sheath at regular intervals. Here are some ratings.

Current rating of a cable depends on the method of installation. An increase in current for any given length will increase the percentage voltage drop.

10sqmm unenclosed, single circuit configuration, single phase 63A. enclosed (eg. in conduit) rating 50A. Ambient temp 40C max.

16sqmm unenclosed, single circuit configuration, single phase 80A. enclosed ( eg. in conduit) rating 63A. Ambient temp 40C max.

Source AS3000.

post deleted due to duplication.

An MCB must trip at 1.45 x rated line current. The convential tripping time is 1 hour. On short circuit conditions the MCB must trip is less than 0.4secs. An MCB will carry short time overloads quite safely with no undue temperature increase on the protected cable.

You rate the main MCB in amps not to exceed the rating of the current capacity of the mains, What is the size of the incoming mains? 10sqmm or 16sqmm.

Yes, installing a RCBO as a main switch will provide earth leakage protection for the whole installation and a single isolation point (main switch).

A 50A or 63A, 2 pole 30mA RCBO. Note: The 50A or 63A will now be the max demand of your installation.

Your peak demand in amps in practice will be less than the actual max demand (MCB rating). For example I have a max demand ( MCB) rating of 63A. but in practice it is never over 25A ( peak load). It is the peak load that is the important figure. It must not exceed the max demand.