Electricity-those with houses in Thailand

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PeteC
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Electricity-those with houses in Thailand

Post by PeteC »

Again need advise. This pertains to houses with 3 phase wiring.

Currently in Pattaya, the house I'm in has a meter rated at 30-60 amp 75 KWH. On this we run several aircons, a bore pump, house pump, pool machinery etc.

Where I'm going and building, the meters available are 15-45 amp 80 KWH, or 30-100 amp, and I don't know the KWH at the moment.

So, If this new house will run basically the same things the Pattaya house is running, which meter should I get at the new place, 15-45 or 30-100? Thanks again to the electricians out there. Pete :cheers:
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Post by Norseman »

Hi Pete.

On a 10 Amp circuit you can pull 2,200W of power.
A 20 Amp circuit 4,400W.
30 Amp 6,600W.
60 Amp 13,200W.

Add all your Air Cons and other power hungry products, use OHM's law, http://en.wikipedia.org/wiki/Ohm's_law and you'll find the answer.
Remember that we have 220V in Thailand and not 110V as in the USA.
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Post by Nereus »

Norseman wrote:Hi Pete.

On a 10 Amp circuit you can pull 2,200W of power.
A 20 Amp circuit 4,400W.
30 Amp 6,600W.
60 Amp 13,200W.

Add all your Air Cons and other power hungry products, use OHM's law, http://en.wikipedia.org/wiki/Ohm's_law and you'll find the answer.
Remember that we have 220V in Thailand and not 110V as in the USA.
Norseman: It is not quite that simple for a couple of reasons. With AC current you have to take into account inductive loads, such as pump motors and aircons, as opposed to pure resistance loads such as an oven or water heater. Pete has also said that his existing supply is 3 phase, and the voltage there will be, I think in Thailand, 380 Volts, plus the amps calulation is a different critter.

The Thai system of quoting an amp range for the meter is very strange, I have never been able to get a staight answer about it. The first thing to establish is the load going to require a 3 phase supply? If you are running a bore pump it may be a better to have a 3 phase pump, but other that that I can not see the point. A so called 100 amp single phase supply should be more than adequate, providing the cabling is sized accordingly. There seems to be more problems with low voltage supply from the street, and undersized cabling, than with what the total calulated load will be.

Do not forget that the size of the supply / meter, is directly connected to the size of the deposit required! :cheers:
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Post by PeteC »

I have no choice concerning the 3 phase as that's the way the entire development is set up.

I brought up the issue with the developer as the wiring is different (at least from meter to house) with the two different sizes and if I make a mistake initially, it's a big problem to change it later. Something like 4 x 16 vs 9 x 25. Unfortunately, I'm the only one there with a bore and pool so can't compare to other dwellings.

In any event, this is a good start. Thanks again. Pete :cheers:
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Post by Nereus »

prcscct wrote:I have no choice concerning the 3 phase as that's the way the entire development is set up.

I brought up the issue with the developer as the wiring is different (at least from meter to house) with the two different sizes and if I make a mistake initially, it's a big problem to change it later. Something like 4 x 16 vs 9 x 25. Unfortunately, I'm the only one there with a bore and pool so can't compare to other dwellings.

In any event, this is a good start. Thanks again. Pete :cheers:
Not to sure if you have a typo or bad advice concerning the cables.
4x16 will refer to 4 conductors of 16 sq mm area. 9x25 should be 4x25, which again refers to the area of the cable. There is no hard and fast rule concerning the amp capacity of a conductor, many variables have to be taken into account, such as if it is enclosed in a conduit, if so how many conductors, the length of the run, (most important to calulate the volt drop), if the cable is overhead in open air ,etc., are just some of them.

I would recommend you have them install 4x25 sq mm. There is no exact size conversion from AWG for this size conductor, but as a a guide #4 AWG is 21,5 sq mm and a "ball park" ampacity of 105 amps, and #2 AWG is 33.5 sq mm, with a "ball park ampacity of 120 amps. So 25sq mm falls in between. It is always better to have more, rather than less, or minimun. You will then have to use the larger size meter quoted.

As a side I am always a bit concerned about 3 phase supplies in a complex such as you are talking about. The single phase loads are connected from 1 phase to the neutral and have to be divided up around the 3 available phases. It is very difficult to arrive at a "balanced" distribution in such a system, and the result can be out of balance circulating current(s) flowing around causing head scratching problems. Not much you can do about it as a consumer, just ensure that they install a good earthing (ground) system from your distribution board.
:cheers:
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Post by PeteC »

All noted Nereus, thanks. Yes it is a "4". I was looking at the engineers handwriting and his 4 looked like a 9.

Concerning 3 phase, yes it can be strange, like my place in pattaya. Sometimes only one of the phases goes out and only certain ceiling fans, lights, aircons run in the house and others don't. We can tell what phase goes out as once it will be one set of things that will run, then the next outage it is the other set.

This entire development I'm goign to is part of a golf course resort/estate and everything is underground. So much so I can't even find the pole where the transformers are. Either they are far away, or in one of the large metal locked containers scattered around the area. Pete :cheers:
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