Before packing for your tour, it’s necessary to understand the electricity in China (Tibet), its plug and socket system as well.
Electricity in China/Tibet
Basically there are two main standards for voltage and frequency in the world. One is the standard of 120 volts at a frequency of 60 Hz, and the other is the standard of 220–240 volts at 50 Hz. China/Tibet runs 220V, 50Hz, AC (Hong Kong is 200V; Taiwan is 110V) with a variety of plug types.
Plugs and Sockets
At present, there is no global standard for plugs and sockets. Traditionally the plugs and sockets are classified into several regional standards in the world like American standard, European standard, British standard, South African standard and Chinese standard.
A standard socket in China has two pins on the upper part and earthed three pins on the lower part. You may buy a portable plug adaptor at your home country or here in China/Tibet.
Adaptors and Converters
Make sure you understand the difference between a plug adapter and a power converter. If your plug is not the right shape but rated for 110 to 220 volts, you just need an adaptor to get your plug to physically fit in the wall. If your appliance is rated for 110 volts only and you want to plug it in, you will need a power converter which gives you the right voltage and amperage for your appliance.
Most consumer electronics will be rated at 100 to 220 volts, read the details on your appliance's power supply. Generally cameras, phones and computers may need an adaptor to fit in the plug but not a power converter.
However, if your appliance is not rated for 220 volts, such as a hair dryer using 110 volts, do not plug it in or you will ruin it. Most hotels have hair dryers or will loan you one.