# Using US 120V Electrical Devices in BKK



## emanmb

We're 6 mos. or so away from moving lock stock and barrel to BKK from Chicago w/my Thai wife who has US citizenship. She has family there and we'll be setup pretty well once there.

This is my first post here and has to do with what electrical gear should I sell and what is worth bringing. 

I know computers should be OK but what about external hard drives, scanners, monitors, and printers?
I have a lot of power tools which I assume would be cooked by the Thai 220V. Correct?
We have a lot of appliances, 42" TV, stereo, etc. as well. All the usual things a homeowner would have here in the US a lot of which we'd like to bring but not if it's just going to get fried as soon as it's plugged in.
I've also got an entire B&W darkroom, timers, enlargers, a Jobo processor and so on to either sell or bring. Also all kinds of photo gear bought in the US with battery chargers for my flash and camera batteries. 
Will a US iPhone charger work there?

I've done a basic search on Amazon for electrical converters and read mixed reviews depending on the load and if it is 'downsizing' the current or upping it. For our uses it will be 'downsizing' the current for our US devices.

Any help is appreciated!

Thanks.

Eric


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## stednick

Eric: check the nameplate data of each individual piece of equipment for the required electricity. That will tell you the specific electrical voltage the equipment requires along with the current consumption (amperage) the equipment will consume. You must decide if it makes sense to purchase a transformer to run the equipment on Thailand electricity. Transformers have slight electrical losses so they cost slightly more to run. You also must make sure you do not exceed the transformers power capacity (amerage) or it will burn up. Another consideration is if you will be hit with an "import" tax. All in all the decision to bring equipment depends on how old it is, what you can sell it for, shipping cost, import taxes, price of converting transformers and what it cost to replace it in Thailand. Good luck with your move.


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## stednick

*sizing transformers*

Power, Electric Power, or as we know it, Electricity, is used to run electrical equipment, be it low power consumer electronics, such as radio's, TV's, computers, or, medium power consumer appliances containing motors, such as Refrigerators, Washing Machines, Air Conditioners, or, high power commercial equipments found in manufacturing plants.

This deals strictly with the low and medium power single phase electrical equipments found in a typical household. I will attempt to describe this in basic terms. Much more advanced and specific electrical formulas and calculations are performed by our electrical engineering folk. 

All electrical equipment will have an "informational tag" which will include the manufacturers name, model number and serial number. It will also include the equipments electrical power specifications. These specifications will include it's allowable input voltage, and, either it's current consumption in amperes or its power consumption in watts. This "informational tag" is called the Nameplate and the information is called the Nameplate Data.

Electricity. In basic low power single phase equipments typically found in a standard household, the following formulae apply:

voltage times current equals power
Voltage (E) times Current (I) = Power (W)
E X I = W

Practical usage: A United States vacuum cleaner rated at 120 Volts and 12 Amps is:
120 Volts X 12 Amps = 1,440 Watts

This vacuum cleaner requires an input voltage of 120V. Uses 12 Amperes of electrical current and consumes 1,440 Watts of electrical power. (1.5 kilowatts, 1.5 kW)

Specific to your query:

To operate the above vacuum cleaner in Thailand you will need a 1,500 Watt, 2:1 Step Down transformer. The transformer will step down the voltage from 220V to 110V. You will receive a voltage of approximately 220V from the electrical power receptacle in Thailand. You may, or may not, need to use a power plug adapter to connect the step down transformer's input to the Thailand receptacle. The transformer will output a voltage of approximately 110V. Again, you may, or may not, need to use a power plug adapter to connect the vacuum cleaner to transformer's output receptacle.

Note: you do not need to be concerned with the discrepancy in the voltage 125V nameplate data and the 110V output of the step down transformer. This equates to approximately a 15% difference. Also be aware that all electric power voltage levels fluctuate to some degree. What you do need to be aware of is the fact that you are on the edge of the 1,500 Watt transformers rating. If the voltage level drops to much, the current will increase to maintain the vacuum cleaners power rating. It is possible that the current level will increase to a level beyond the transformer capacity. In this case the transformer may "burn up" or br destroyed. You need to pay serious attention to make sure you do not exceed the transformers rating. Not only will you destroy the transformer, you may well start a fire. You could also ruin the equipment you are operating on the transformer if a significant power surge or voltage spike occurs when the transformer fails.

Therefore, it is suggested that you purchase transformers that exceed the power rating of the equipments you will be running on them. Also, if you are running more than one equipment on a converting transformer you must add the capacities of the connected equipment when sizing the transformer.

I would not run the vacuum cleaner used above unless it was running on a 2,000 Watt transformer. Nor would I run the transformer without an adequate over-current protection device, circuit breaker or fuse on the transformers input circuit, and don't forget you earth ground to protect against electrical shock. 220V electricity can and will "hold" you. Don't become a statistic.


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## emanmb

Thank you very much stednick for the excellent detailed reply. I was confused about electricity with the amps, volts, and watt-not  and your formula helps out a lot.

I had guessed (but didn't know for sure) about the amount of watts needed for the converters. Given their size and cost I'm debating what if any of our appliances are worth bringing. 
Since we'll be living in a condo, power tools won't be a necessity but handy to help at the in-laws house or where ever. A Thai guy here who works in construction complained that the tools in Thailand weren't as good as those in the US which is what got me to thinking I should bring mine. It won't be how I will make a living (hopefully) but us guys know when you need a drill or jigsaw, you just need one!


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## lovelg10

Remember that Thai power is 50 Hz. and that the transformer can only change voltage levels, not frequency. You will need voltage cconverters, not transformers, in order to properly power your equipment.


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## emanmb

So if a device states that it is 60Hz, it won't work, or will it get damaged by using it with the converter? High powered devices are going to be left behind or sold at this point and it would be silly to try to run a hairdryer with a converter. It's the more delicate devices that I'm concerned about.

Speaking of selling of stuff, I wonder why Craigslist is barely used there in Thailand? I checked the Thai version of the site and there's not nearly the number of listings as here in Chicago.
Here in the US it's wildly popular and a LOT of what we own came from there (buying used) saving us tons of $. Is there an equivalent that is used there more than CL?


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## stednick

*50 Hz - 60 Hz*

Do not consider this to be all inclusive or a broad brush stroke encompassing all electronic equipments. 

The 50 Hz - 60 Hz regards the frequency of the alternating current electrical power. 50 Hz (Hertz) is 50 cycles per second and 60 Hz is 60 cycles per second. 
The electrical current alternates this many times per second.

This will impact clocks. In that a 60 Hz electric clock will only advance 50 minutes in an hour when operated on 50 Hz power. That is unless the clock is timed by a crystal, as many are today. 

Most electronic equipments in use today have "switching" power supplies that compensate for the voltage difference. The alternating current is converted to DC, direct current, such as is found in a battery. The electronic components are typically powered with the DC that leaves the switching power supply. 

It is possible that sensitive electronic equipment may be adversely affected by the 60 to 50 hertz frequency difference. There is no safe way to predict an individual piece of equipments tolerance to the frequency difference without actually trying it. 

For any high cost sensitive electronic equipment I would suggest you call the manufacturer and speak to an applications engineer to address the power concern before powering up the unit in Thailand.


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## lovelg10

Check each nameplate for the following ratings:
120/240Vac
50/60 Hz.
If so stated, you will have no issues. If not, the safest solution is to not use the item in Thailand.


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## emanmb

Thank you lovelg10 and stednick!
Some devices like my camera battery chargers will be OK but the darkroom stuff is precision gear and set at 120/60 only. I'd rather sell them here than risk them frying or just not working properly so giving ebay/craigslist some serious thought for those items.
Thanks for all the detailed and helpful info!
Eric


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## hydroman

You are very passionate about this subject I would guess that you are an Electrical engineer. You are needed there, I have never seen such bad electrics, I bought a microwave it states this needs to be earthed my home is quite new and has 3 pin plugs (and RF I do know a lot about) they supply with a 2 pin plug and a piece of wire 2 foot long. I also bought a cooker I work out the Amps I think about 60 Amps looked at my fuse box and the max trip was 45 Amp so called out a professional. I thought I would save some time took myself to Home Pro bought 6mm sq wire, the professional came through my wire in the bin used 2.5mm sq. There is worse one night and my home is only 3 years old all went dark up stairs down stairs TV. I looked at my fuse box only 1 has tripped it was a 8 Amp tripped my whole house was out. Thai electrics are a little behind and what we should be saying is sell your bits don’t spend a fortune bringing .


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## stednick

*Thai electricity*

Hydroman:

Beware the three prong plugs. Although your house is new and has three prong plugs installed by no way guarantees that the third (grounding) prong is actually connected to a wire. Even if you find that the third prong is connected to a wire there is no guarantee that the wire is bonded to a valid and safe earth ground. 

As per your post you are correct, I have spent my life earning a living with electricity and electronics. I have had the good fortune of observing and practicing electrical maintenance in several countries in North America, Europe and Asia. In all instances I have found both good and bad (you can't have one without the other). There are many solid and qualified professionals with a few unqualified bad eggs mixed in to keep us on our toes.

You have a good firm grip on what is needed from an electrical safety platform. Supervise for yourself and demand a good safe installation. You have the ultimate responsibility for the work performed by your chosen subcontractors as it is your house, possessions and personal safety that suffer should you get one of the bad eggs mentioned above.

Good luck to all, Tom


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## emanmb

I wouldn't be surprised at bad workmanship after seeing what happens here in the US!

Thanks for the tip Tom.


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## emanmb

I wish I knew about electrical work as then I could have some decent money coming in!

Thanks for the warnings!


hydroman said:


> You are very passionate about this subject I would guess that you are an Electrical engineer. You are needed there, I have never seen such bad electrics, I bought a microwave it states this needs to be earthed my home is quite new and has 3 pin plugs (and RF I do know a lot about) they supply with a 2 pin plug and a piece of wire 2 foot long. I also bought a cooker I work out the Amps I think about 60 Amps looked at my fuse box and the max trip was 45 Amp so called out a professional. I thought I would save some time took myself to Home Pro bought 6mm sq wire, the professional came through my wire in the bin used 2.5mm sq. There is worse one night and my home is only 3 years old all went dark up stairs down stairs TV. I looked at my fuse box only 1 has tripped it was a 8 Amp tripped my whole house was out. Thai electrics are a little behind and what we should be saying is sell your bits don’t spend a fortune bringing .


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