Minimising 3 Phase Installation Costs

[simon43]

There is a strong possibility that I will soon construct a new 10-room hotel/resort here in Phuket.

One of the larger expenses (500,000 baht) that I incurred with my previous resort was the purchase and installation of the transformer to step down the nearby 3 phase, 480kV supply to 3 phase 220 volts.

I will be working on a rather tight budget this time, and naturally I want to learn from my previous construction experiences, and to minimise any un-necessary costs.

The need for a 3 phase supply is because the maximum load of the resort is higher than supported by a single phase supply, primarily due to the use of air-con units in each guest room and restaurant areas.

What can I due to reduce the installation expense?

I cannot avoid use of air-con units - they are 'de-rigeur' for overseas tourists.

I was thinking along the lines of using a single phase 100 amp supply to provide for the miscellaneous, lower current devices, such as lighting etc, thus reducing the overall current requirement, (and hence transformer rating/cost) for the 3 phase supply.

Any comments on the viability of this or other suggestions?

Simon

[luudee]

Simon,

have you looked at "central a/c" type of systems, or multi-point (one outside compressor

feeding multiple inside units) a/c ?

Those might consume much less power, but might be more expensive to purchase/install.

My feeling is that you can't take short cuts when it comes to your electricity supply. I live

in Pattaya and see every day smoldering cables (r.g. Walking Street) due to overloaded

lines. Overload may cause equipment failure and and is a great fire hazard. Better get

a properly rated 3 phase transformer, and try to make up the cost on some other areas.

Good Luck,

rudi

[InterestedObserver]

Using a separate single-phase supply would not reduce your overall electrical installation costs. The added cost of the 100 amp single-phase meter, cables and distribution panel would not offset the cost of the measly 7.3 kVA per phase increase in the size of the three-phase supply.

[Greenside]

Simon,

have you looked at "central a/c" type of systems, or multi-point (one outside compressor

feeding multiple inside units) a/c ?

Those might consume much less power, but might be more expensive to purchase/install.

My feeling is that you can't take short cuts when it comes to your electricity supply. I live

in Pattaya and see every day smoldering cables (r.g. Walking Street) due to overloaded

lines. Overload may cause equipment failure and and is a great fire hazard. Better get

a properly rated 3 phase transformer, and try to make up the cost on some other areas.

Good Luck,

rudi

Daikin's Multi Units sound like they make the best use of an inverter since they'll be running more consistently.

[MHayward]

There is no doubt about it you will need a good 3 Phase Supply and ''Energy Efficient' Air Con etc is not the answer you require.

Check for the availability of 3-phase at your location as it may well already be there.

I have installed 3 Phase 220V in my house in Surin, even though I was first told it can not be done.

The transformer for our village is 'down the road' somewhere but it supplies 220v to 4 wires (3 phase) up the Main Street which divide to Single Phase (two wires) for each soi.

The Soi houses use just the two wires, however all other houses on the Main Street pick up one of the 3 lives and the single Neutral for their own single phase (two wire) 220 supply. Most are either minimal 5 amp or usual 15 amp.

The Pick up from the 4 wires alternates for each house so as to spread the load over the phases and reduce Voltage Spikes. ie. House A uses Live 1 and Neutral, House B uses Live 2 and Neutral, House C Live 3 and neutral...then round they go again.

I simply had the Electricity Company connect us to all 3 lives and Neutral, thereby giving me a good solid 3 phase supply. With a 45 Amp (3 x 15) meter my house has a good and fairly ''smooth'' supply. You could put in a 90 (3 x 30) or even bigger 135 (3 x 45) Amp Meter as you need, but the Electricity Company will dictate the maximum you are able to have given the existing Transformer.

Limitations are the size of the Village Transformer, but that is their problem not mine and as more demand comes from the village then the Electricity Company will put a bigger one in for us all, but at their own cost !!

I did my own survey, found out what was available and then requested what I needed, it avoided any arguments. Even my Electrician was sceptical, but now he knows.. :-)

Cheers, MH

Edited July 8, 2011 by MHayward

[electau]

Calculate the max demand of your proposed electrical installation first. You will probably require a 80/100A consumers mains 3 phase 4 wire. you can then install single phase split system airconditioners and the balance the loading over the 3 phases. Use solar ( thermal) for your hot water supply.

Install RCDs on all final subcircuits supplying socket outlets.

If upgrading of the PEA/MEA transformer is required you may have to pay for part of the capital cost.

[simon43]

If upgrading of the PEA/MEA transformer is required you may have to pay for part of the capital cost.

In fact, after visiting the electricity office that was responsible for my last hotel installation, I am happily advised that I would have to pay for the complete costs of any transformer, supply poles, cabling etc - the government will not subsidise this in any way.

They explained further that there were many suitable land plots to build new, small hotels, but which currently did not have a suitable 3 phase supply. The first person to develop a site such as this would have to pay the installation costs, (estimated at about 1 million baht to bring the electricity from the nearest point plus the transformer). To rub salt into the wound, the guy who pays for this first install of the power poles etc then see many new resorts being constructed in that area which would use the power poles that he paid for, yet the original payee would receive no compensation or payback!!

It was because of this situation that smaller resorts would only be developed alongside existing 3 phase supply lines...

I'm right by the airport, and unless I stick to the main road for land, there is absolutely no electricity supply, no telephone cable, no mains water or sewage. (This was the sitation when I build my last hotel 6 years ago some 50 meters from the main road to the airport.

This is all very frustrating, because the requirement for 3 phase means that I have to limit my land search to expensive land plots that adjoin the main road.

Maybe I should strike out and build an off-grid eco-lodge in Laos instead??

Simon

[electau]

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.

　

[simon43]

@electau - yes, I understand that I would not own title to the electricty poles/cables etc on public land. What is unfair is that any subsequent users of that new electricity supply line will not pay any additional premium whatsoever for benefiting from my investment in this new supply line. Only a idiot or rich fool would be willing to be the person who finances the initial pole installation.

(For my previous hotel, this was only 30 meters away from a suitable supply, so I did not have to demonstrate a high level of assets or foolishness!)

Simon