In Hong Kong, the main electrical wiring system used is BS 1363. In old buildings, the BS 546 system is also common.
Due to its proximity to mainland China, electrical products from there are present in Hong Kong, especially those as a result of cross-border purchase carried out by mainland Chinese immigrants. Nevertheless, even if the product meets the safety requirements in China, they are not necessarily confirmed to BS 1363 standard, thus may have plug and socket compatibility issues when using them in Hong Kong.
Before the enforcement of the Electrical Products (Safety) Regulation, many types of plugs could be found in Hong Kong. Using this old equipment sometimes leads to plug and socket mating problems. Nowadays, virtually all plugs fitted in equipment sold in Hong Kong are BS 1363 compatible.
The 2-pin plugs (with round or flat pins) in mainland China are compatible with the British converter plugs sold in Hong Kong. For shavers and electric toothbrushes that take less than 1A of current, British shaver adaptors can be also used.
Mainland China three-pin plugs cannot be converted with a British standard adaptors, which are commonly sold in Hong Kong. One can replace the plug or the power cord as appropriate. This is also the case for Australian three-pin plugs.
Special attention is to be paid to the earthing of Schuko plugs. Though British converter plugs for Schuko are occasionally found; they are not common. Plug replacement is often necessary. This problem is common for special equipment in optical shops and among the residents of European origin.
There are old electrical plugs that can be inserted into the British sockets BS 1363 or BS 546, but they do not meet the British Standards. Standards "BS 1363" or "BS546" are not marked on such old quasi-UK plugs. Some of them are missing the BS1362 plug fuse or the pins are lacking insulating sleeves, among other problems.
Sockets of BS546 are incompatible with BS 1363 plugs. Compliant adaptors are not available to convert a BS546 5Amp socket to a BS 1363 13Amp one.