Electrical Service

[Yellowtail]

The building we are in has a three-phase panel, but it is currently wired single phase.

 

The meter has four terminals, I think this is line and neutral in, and line and neutral out, is that correct?

 

There are four wires on the poles in front of the building, that would be three phases and a neutral, correct?

 

The three-phase wiring that went to our panel is still there, but it is stubbed-out at the meter.

 

To get three phase service, I should only have to have a new meter installed and reconfigure the wiring to and in the panel, correct?

 

I would like to start upgrading my aircon to three-phase.

 

Thanks

[bankruatsteve]

Huh?  3-phase to 3 single phase distribution is common practice.  I don't understand most of your OP.  Aircons typically do not use 3-phase.

 

[Litlos]

You would also need the connections made to the other two phases on the supply more than likely.  It is not common in Thailand to use 3 phase for air conditioners domestically as most are splits for a single room which run on single phase as opposed to whole of building units in the US for example.

 

Cheers

[Yellowtail]

2 hours ago, bankruatsteve said:

Huh?  3-phase to 3 single phase distribution is common practice.  I don't understand most of your OP.  Aircons typically do not use 3-phase.

 

Thanks for the response. I want three phase sub-panels on each floor. I would like to start upgrading the AC and be able to run a compressor, a welder and a couple of other pieces of three-phase equipment. 

[Yellowtail]

1 hour ago, Litlos said:

You would also need the connections made to the other two phases on the supply more than likely.  It is not common in Thailand to use 3 phase for air conditioners domestically as most are splits for a single room which run on single phase as opposed to whole of building units in the US for example.

 

Cheers

I think I can have the MEA install a new meter and cut in the leads when they upgrade the service. I'm trying to figure out how big a deal it will be. Once I get it to the main panel I can install sub-panels as I need them, 

 

It is not common now, but I think three-phase is getting more and more common. The big cassette units are offered in three-phase which is what I want to start moving to.

 

Anyone recommend a decent electrician in Lat Krabang?  

[Crossy]

From what you describe it should be a simple task (famous last words) to remove the single-phase kit from the board and reinstate the 3-phase metering. A couple of photos of the relevant bits would help confirm this.

 

I would however caution about using 3-phase equipment generally unless it's absolutely necessary. The most common power failure mode in our area is loss of one phase (invariably the one we are using), you will need to protect your 3-phase appliances from this failure.

 

A 3-phase service may be necessary, but do you actually need 3-phase for your welder and other toys?

[Yellowtail]

1 hour ago, Crossy said:

From what you describe it should be a simple task (famous last words) to remove the single-phase kit from the board and reinstate the 3-phase metering. A couple of photos of the relevant bits would help confirm this.

 

I would however caution about using 3-phase equipment generally unless it's absolutely necessary. The most common power failure mode in our area is loss of one phase (invariably the one we are using), you will need to protect your 3-phase appliances from this failure.

 

A 3-phase service may be necessary, but do you actually need 3-phase for your welder and other toys?

The welder and compressor are three-phase, I could change the motor on the compressor, but the welder I'd have to replace. As much as I would use it, might be cheaper to replace than turn on...

 

We're in greater Bangkok and the power is good. The compressor has a starter that will/should protect it, not sure about the welder.

 

Would not the new airconditioners be protected? I think I want to run one 40K (bedroom floor)  and one 60K (living room floor) cassette AC units each about 12 hours a day. I'll get a couple of photos a little later.

 

Thanks 

[Naam]

34 minutes ago, Yellowtail said:

Would not the new airconditioners be protected? I think I want to run one 40K (bedroom floor)  and one 60K (living room floor) cassette AC units each about 12 hours a day. I'll get a couple of photos a little later.

i side 100% with Crossy. moreover, 48k btu/h units are available in single phase plus using a "lonely" 60k btu/h unit proves that you did not consider an optimal spread of cooled air. another indication for my assumption is that you are planning "floor cooling" which is a futile attempt with one outlet and return air at the same location.

[Yellowtail]

2 hours ago, Naam said:

i side 100% with Crossy. moreover, 48k btu/h units are available in single phase plus using a "lonely" 60k btu/h unit proves that you did not consider an optimal spread of cooled air. another indication for my assumption is that you are planning "floor cooling" which is a futile attempt with one outlet and return air at the same location.

I understand I can get larger units in single-phase, I have a few of them now. I am in the process of replacing one with a new single-phase unit now. 

 

Switching to three-phase is a long term plan. You are correct, a single large cassette unit would not be ideal. Giving it some thought, a ductless multi-split system with cassette style FCUs and a single condenser on each floor would be much better.

 

I think three-phase will lower my peak usage and lower my operating costs.

[Yellowtail]

Pictures:

 

 

[carlyai]

A few of us have incoming 3 phase.

For me the 3 phases are mostly used as 3 seperate phases. I have each phase taking some of my load. So I have the loads from lights, fans, pumps etc across the 3 phases. Each of the 3 aircons are on each one of the 3 phases.

If you spread the lights, power plugs etc across the 3 phases, then if one phase goes down, you still have lights and power.

I have two, 3 phase multi-point hotwater heaters. (They use 2 phases on low heat and the 3 on high heat). So you could still use 3 phase equipment as well as having 3 seperate phase supplies.

Also with 3 seperate phases you have more options and can switch an incoming phase around if that particular phase goes low at 5pm.

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[Yellowtail]

2 hours ago, carlyai said:

A few of us have incoming 3 phase.

For me the 3 phases are mostly used as 3 seperate phases. I have each phase taking some of my load. So I have the loads from lights, fans, pumps etc across the 3 phases. Each of the 3 aircons are on each one of the 3 phases.

If you spread the lights, power plugs etc across the 3 phases, then if one phase goes down, you still have lights and power.

I have two, 3 phase multi-point hotwater heaters. (They use 2 phases on low heat and the 3 on high heat). So you could still use 3 phase equipment as well as having 3 seperate phase supplies.

Also with 3 seperate phases you have more options and can switch an incoming phase around if that particular phase goes low at 5pm.

Sent from my SM-J700F using Tapatalk
 

 

As I understand it, the phases are always separate, so I'm not sure what you mean. 

 

Would I not want to balance the load across the three legs? 

 

As most of the power I use is AC, balancing the AC load using three-phase would provide the most bang for the baht...

 

Where'd you get the 3ph water heaters? I have a 50 gal single phase Rheem I brought from the US.

 

Any gas water heaters around? I wonder if LP would be cheaper heating water than electric...

[sometimewoodworker]

2 hours ago, Yellowtail said:

As I understand it, the phases are always separate, so I'm not sure what you mean. 

They can be a single 3 phase supply to your outlets or wired as 3 independent single phase supply's. The PEA requirement is that the load is roughly balanced across the 3 phases.

2 hours ago, Yellowtail said:

Any gas water heaters around? I wonder if LP would be cheaper heating water than electric...

Yes there are, yes it is

 

 

Edited May 21, 2019 by sometimewoodworker

[sometimewoodworker]

2 hours ago, Yellowtail said:

As most of the power I use is AC, balancing the AC load using three-phase would provide the most bang for the baht...

The original connection is much more expensive, so may be not.

[Yellowtail]

4 minutes ago, sometimewoodworker said:

They can be a single 3 phase supply to your outlets or wired as 3 independent single phase supply's. The PEA requirement is that the load is roughly balanced across the 3 phases.

Yes there are, yes it is

 

With three-phase I think can use one leg and a neutral for 230, two legs for 400 or three legs for 380.

 

I don't know that I can balance the load any better than using three-phase equipment. 

[Yellowtail]

9 minutes ago, sometimewoodworker said:

The original connection is much more expensive, so may be not.

I think all I need to get three-phase is a new meter and reconfiguring the existing panel. 

 

The AC would each need a three-phase drop as well, but they will likely need new drops anyway, so an extra wire is not much of an issue. 

 

To be clear, If it's going to cost a butt-load of dough to get the upgrade I'm not going to do it. As it is now, long-term I think I'm looking at a complete re-wire 

Edited May 21, 2019 by Yellowtail

[sometimewoodworker]

47 minutes ago, Yellowtail said:

I think all I need to get three-phase is a new meter and reconfiguring the existing panel. 

 

The AC would each need a three-phase drop as well, but they will likely need new drops anyway, so an extra wire is not much of an issue. 

 

To be clear, If it's going to cost a butt-load of dough to get the upgrade I'm not going to do it. As it is now, long-term I think I'm looking at a complete re-wire 

Minimum cost from PEA

 

1) Single-phase 5(15)A meter installation fee (Note: (Including 7% VAT))  Fee 728 baht 

 

2) Single-phase 15(45)A meter installation fee (Note: (Including 7% VAT))  Fee 4,621.5 baht 

 

3) Single-phase 30(100)A meter installation fee (Note: (Including 7% VAT))  Fee 12,383 baht

 

4) Three-phase 15(45)A meter installation fee (Note: (Including 7% VAT))  Fee 16,004.5 baht 

 

5) Three-phase 30(100)A meter installation fee (Note: (Including 7% VAT))  Fee 38,754 baht

 

Though if you do not have 3 phase 220V outside your property you may have to pay for a transformer and cables and that can quickly reach into the hundreds of thousands.

 

You will need a new 3 phase CU as you can't just reconfigure a single phase one.

[Yellowtail]

2 hours ago, sometimewoodworker said:

Minimum cost from PEA

 

1) Single-phase 5(15)A meter installation fee (Note: (Including 7% VAT))  Fee 728 baht 

 

2) Single-phase 15(45)A meter installation fee (Note: (Including 7% VAT))  Fee 4,621.5 baht 

 

3) Single-phase 30(100)A meter installation fee (Note: (Including 7% VAT))  Fee 12,383 baht

 

4) Three-phase 15(45)A meter installation fee (Note: (Including 7% VAT))  Fee 16,004.5 baht 

 

5) Three-phase 30(100)A meter installation fee (Note: (Including 7% VAT))  Fee 38,754 baht

 

Though if you do not have 3 phase 220V outside your property you may have to pay for a transformer and cables and that can quickly reach into the hundreds of thousands.

 

You will need a new 3 phase CU as you can't just reconfigure a single phase one.

 

 

I'm MEA, but I imagine the prices are similar. I think the building used to be three-phase, and the existing panel is (I think) three-phase, but it is being used single-phase now. The wire from the meter to the panel seems to still be there as well.

 

I'm not locked into this, I'm just talking at this point, trying to figure out the pros and cons and figure out how to minimize my ongoing cost.

 

My wife owns the building so I don't mind spending a little to get it whipped into shape.

 

 

[Naam]

10 hours ago, Yellowtail said:

I think three-phase will lower my peak usage and lower my operating costs.

it won't.

[Naam]

3 hours ago, sometimewoodworker said:

Three-phase 15(45)A meter installation fee (Note: (Including 7% VAT))  Fee 16,004.5 baht 

i paid something like 17,000 Baht for my 3-phase meter, was told "installation" and got two years later a full refund of this amount. go figure!

[Yellowtail]

24 minutes ago, Naam said:

it won't.

I believe it will absolutely reduce my peak usage, whether or not it reduces my cost is what I don't know.

 

Edit:  only see it reducing peak usage if I move the AC to three-phase. Splitting single-phase units up on different legs I don't think would be much of a benefit. 

Edited May 21, 2019 by Yellowtail
added note

[carlyai]

"Where'd you get the 3ph water heaters? I have a 50 gal single phase Rheem I brought from the US."

I bought the 3 phase multipoint heaters in Thailand. Maybe at Homepro or one of those places. There are pamphlets with all the different single and 3 phase devices available.

Nice rain out here near Mukdahan at the moment.

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[Crossy]

Looking at our OPs photos.

 

Positives:-

• Already has a 3-phase incoming breaker.
• Meter wiring still in place.

 

Negatives;-

• Looks like something is wired to the incoming side of the 100A breaker (what, why?)
• Something that looks awfully like phone cable is wired to the outgoing side of the 100A breaker!!

 

Actions required:-

• Remove that phone cable and wire whatever it feeds properly.
• Sort out whatever is wired on the incoming side, there should be no issue with feeding from the outgoing side of the breaker.

 

Then.

• Install a neutral block next the the breaker.
• Identify and move the incoming neutral to the neutral block
• Ditto for the neutral leaving the breaker.
• You will then have two free poles on the breaker.
• Attache the "spare" wires from the meter to those blocks.
• Call PEA/MEA to re install the 3-phase meter.

 

Once that's done you can set about possibly having one of the existing distribution boards per phase and set up a 3-phase board for your 3-phase kit. 

 

You should also consider installing some form of earth leakage protection. There's a handy-dandy space next to the main breaker ????

 

[Yellowtail]

4 hours ago, Crossy said:

Looking at our OPs photos.

 

Positives:-

• Already has a 3-phase incoming breaker.
• Meter wiring still in place.

 

Negatives;-

• Looks like something is wired to the incoming side of the 100A breaker (what, why?)
• Something that looks awfully like phone cable is wired to the outgoing side of the 100A breaker!!

 

Actions required:-

• Remove that phone cable and wire whatever it feeds properly.
• Sort out whatever is wired on the incoming side, there should be no issue with feeding from the outgoing side of the breaker.

 

Then.

• Install a neutral block next the the breaker.
• Identify and move the incoming neutral to the neutral block
• Ditto for the neutral leaving the breaker.
• You will then have two free poles on the breaker.
• Attache the "spare" wires from the meter to those blocks.
• Call PEA/MEA to re install the 3-phase meter.

 

Once that's done you can set about possibly having one of the existing distribution boards per phase and set up a 3-phase board for your 3-phase kit. 

 

You should also consider installing some form of earth leakage protection. There's a handy-dandy space next to the main breaker ????

 

3

 

The suspicious wires going into the top of the breaker are not connected, they're just stubbed out. The new photo (I think) makes it more clear.

 

Phone wire going to panel light

 

I made a mistake. The top panel is not the main panel. New photo (I think) makes this clear.

 

Thanks for the help

[carlyai]

Sorry for an aside, but does that 3 phase panel have a cover and did you remove the cover for the photo?

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[Crossy]

16 hours ago, Yellowtail said:

The top panel is not the main panel. New photo (I think) makes this clear.

 

Ah, that's even better. So the three incoming wires to the breaker all go back to the meter position with two of them blanked off?

 

Are all the three actually live right now (they're connected togther somewhere to supply everything from a single phase)? Obviously you will need to locate any phase-phase connection but that does make life significantly easier for going back to 3-phase.

 

[Yellowtail]

2 hours ago, carlyai said:

Sorry for an aside, but does that 3 phase panel have a cover and did you remove the cover for the photo?

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Yes it has a cover and I removed it for the photo. In the photo on the previous page it is the one marked Square D Load Center.

[Yellowtail]

2 hours ago, Crossy said:

 

Ah, that's even better. So the three incoming wires to the breaker all go back to the meter position with two of them blanked off?

 

Are all the three actually live right now (they're connected togther somewhere to supply everything from a single phase)? Obviously you will need to locate any phase-phase connection but that does make life significantly easier for going back to 3-phase.

 

 

Yes, the three wires go back to the meter and are blanked off.

 

The three legs do not seem to be connected together. I don't read anything between the legs. Neutral to:

L1 is ~230, 

L2 is ~48

L3 is ~48

 

BUT two of the breakers next to each other are both hot, which seems odd to me. Going down the panel, shouldn't only every third breaker be hot?

 

It seems like the lower three phase panel is feeding the upper panel.

 

I need to get someone in to get it straightened out. Every time I open the cover my wife starts crying...

 

 

 

[Crossy]

OK L2 and L3 are probably showing "phantom" voltages and are just floating.

 

I agree every 3rd breaker should be live with that configuration, if you are seeing hot outputs (are they still hot with the breaker off?) then something odd is going on which needs looking at before you re-connect the 3-phase supply.

 

[Yellowtail]

Ground/Earth: There is a heavy ground wire that I think (but cannot confirm) terminates under the concrete behind the building.

 

Is there any way to check the quality of the ground/earth at the panel?