I complained to PEA about one phase varying up to 237 V. This was a few weeks ago when I visited them.

Other phases are 222V and and 226V.

A guy came out today and said the normal supply from the transformer is 230V. So 237V is OK.

I said but we should get 220V, he disagreed.

When I asked why the other 2 phases were nearer 220v he said that the other 2 phases are easier to connect to on the pole so most houses are connected to the other phases. 555.

So if we had more connections on the high phase it would be about 220V odd.

I said what about 3 phase equipment as phases aren't equal or near about, he said it's not a problem.

I said what about the pumps etc working at 237v, he said no worries.

I can fix it at our place by changing some gear to a different phase and my AVRs but is PEA speak BS and why tell people BS?

 

Sounds like BS to me. 

 

 

 

 

 

 

 

EGAT and PEA (Provincial Electricity Authority)  220 V ±10% → 198 V to 242 V

 

IEC 60038 Standard

2 minutes ago, Will B Good said:

Allowed Range: 207 V to 253 V

You gotta source or do you moonlight for PEA?

 

220/253 x 100% not 10%

14 minutes ago, carlyai said:

I said what about the pumps etc working at 237v, he said no worries.

Very true.

Most people have the opposite problem like pumps at 190.  I have bought a simple voltage checking device.

Like most it has limits at 160 and 250 Volt.

Just now, carlyai said:

You gotta source or do you moonlight for PEA?

207 is reality for many 😁

5 minutes ago, carlyai said:

You gotta source or do you moonlight for PEA?

On the rush just found this for UK:

In the UK, the declared voltage and tolerance for an electricity supply is 230 volts -6%, +10%. This gives an allowed voltage range of 216.2 volts to 253.0 volts

 

https://www.spenergynetworks.co.uk/pages/voltage_changes.aspx#:~:text=In the UK%2C the declared,216.2 volts to 253.0 volts.

7 minutes ago, carlyai said:

You gotta source or do you moonlight for PEA?

 

220/253 x 100% not 10%

Some sources list Thailand’s single-phase nominal voltage as 220 V, while others use 230 V. Both are technically correct depending on the context and utility region. 

 

You could always get off your fat lazy arse and do your own research of course.

European standard EN 50160 allows +/- 10%.

Hope that some of the experts come to the thread.

And then one has to trust the multimeter he bought at Homepro. 

 

But anyone who worries because he got a reading of 237V has to book for a Gastroscopy as he is likely to have ulcers.

1 hour ago, Peter Crow said:

And then one has to trust the multimeter he bought at Homepro. 

 

But anyone who worries because he got a reading of 237V has to book for a Gastroscopy as he is likely to have ulcers.

Back up your claim Peter. 🙂

My understanding is that PEA is nominally 220V P-N and MEA is 230V P-N, both +-10%.

 

I wouldn't worry too much about the imbalance for your 3-phase kit although induction motors do run with a poorer Power Factor when run at higher voltage than nominal.

 

 

3 minutes ago, Crossy said:

My understanding is that PEA is nominally 220V P-N and MEA is 230V P-N, both +-10%.

 

I wouldn't worry too much about the imbalance for your 3-phase kit although induction motors do run with a poorer Power Factor when run at higher voltage than nominal.

 

 

Thanks. I'm PEA.

Why is there a difference between the two regulating bodies?

 

So if they wanted to bring my high phase back to within 10% do they alter a transformer tapping or what do they do?

 

Is it too difficult?

13 minutes ago, carlyai said:

Thanks. I'm PEA.

Why is there a difference between the two regulating bodies?

 

So if they wanted to bring my high phase back to within 10% do they alter a transformer tapping or what do they do?

 

Is it too difficult?

Balance the load.

TiT I'm afraid for the voltage difference.

 

They would alter the tap setting on the Tx but that might cause other issues if, say, a currently dormant factory came back to life. It's not really a difficult task but ...

*An unnecessary & irrelevant comment has been removed *

On 7/30/2025 at 12:41 PM, carlyai said:

I complained to PEA about one phase varying up to 237 V. This was a few weeks ago when I visited them.

Other phases are 222V and and 226V.

A guy came out today and said the normal supply from the transformer is 230V. So 237V is OK.

I said but we should get 220V, he disagreed.

When I asked why the other 2 phases were nearer 220v he said that the other 2 phases are easier to connect to on the pole so most houses are connected to the other phases. 555.

So if we had more connections on the high phase it would be about 220V odd.

I said what about 3 phase equipment as phases aren't equal or near about, he said it's not a problem.

I said what about the pumps etc working at 237v, he said no worries.

I can fix it at our place by changing some gear to a different phase and my AVRs but is PEA speak BS and why tell people BS?

 

Sounds like BS to me. 

 

 

 

 

Find the secondary 3ph voltage rating of your supply transformer and divide by 1.732 the gives you the nominal single phase voltage per phase at the transformer terminals (normally 400v/1.732 = 230.9v) voltage drop will occur at the connected equipment due to length of cable run from transformer and loads on each phase. 

On 7/30/2025 at 12:41 PM, carlyai said:

 

I said what about the pumps etc working at 237v, he said no worries.

I can fix it at our place by changing some gear to a different phase and my AVRs.

 

I was going to ask if you installed AVR's.  Most wall adapters can handles up to 240V.  If you have sensitive electronics take the reading on the AVR output and make any adjustments if needed

12 hours ago, Cardano said:

Find the secondary 3ph voltage rating of your supply transformer and divide by 1.732 the gives you the nominal single phase voltage per phase at the transformer terminals (normally 400v/1.732 = 230.9v) voltage drop will occur at the connected equipment due to length of cable run from transformer and loads on each phase. 

Thanks

 

I thought MEA was 230v but PEA 220v. 

We are under PEA.

The PEA man that visited us said the supply is 230v.

So does it not matter what area you live in but what the supply authority thinks is the best transformer to feed the power runs?

 

@carlyai I fixed your typos, if your supply was 330V you have other issues

 

We recently had a "new" (it's more rusty than the old one, they could have at least painted it), bigger, village transformer installed to support a couple of warehouses that have sprung up (one supplies teak furniture, Madam has already been snooping, I expect more teak to appear in the house soon). Our PEA supply is now 230V from the previous (perfectly acceptable) 218V or so.

 

 

 

30 minutes ago, Crossy said:

@carlyai I fixed your typos, if your supply was 330V you have other issues

 

We recently had a "new" (it's more rusty than the old one, they could have at least painted it), bigger, village transformer installed to support a couple of warehouses that have sprung up (one supplies teak furniture, Madam has already been snooping, I expect more teak to appear in the house soon). Our PEA supply is now 230V from the previous (perfectly acceptable) 218V or so.

 

 

 

Thanks and sorry for typos. 

Yesterday I changed the garage phase supply over to the lowest phase voltage 222v and installed some 40A breakers in the 2 CUs that feed the EV for charging.

Now have the connectors to reconfigure the EV charger feed. 

I will step the charge current up from 16 to 25A, take some heat sense pics, then step up to 32A.

Initially I'll turn off the swimming pool kit while charging the EV.

 

When I get a chance I'll go have a look at our feed transformer. They have just replaced one in the village and installed the wires and fuses for another.

 

 

 

I'm on PEA with my own single phase transformer, and get normally 235v at entrance of my property.

 

21 hours ago, carlyai said:

Thanks

 

I thought MEA was 230v but PEA 220v. 

We are under PEA.

The PEA man that visited us said the supply is 230v.

So does it not matter what area you live in but what the supply authority thinks is the best transformer to feed the power runs?

 

It is only relative to the transformer secondary nominal voltage, and tap settings (-5, -2.5, 0, 2.5, 5) nothing to do with who the supplier is. Like I said before consumer loads and cable lengths will reduce the transformer terminal voltage. Your maximum phase voltage should not be greater than the transformer secondary voltage rating divided by 1.732 x 1.05.