Type D Socket And Plug

The Type D plug and socket (BS 546 type), commonly known as the small South African plug and socket, is currently used primarily in India and Nepal.

The Type D plug currently used in India is derived from the British power standard "BS 546" that was in use before 1947. The plug has three round pins arranged in a triangular pattern. The longer, thicker pin is for grounding, measuring 20.6 mm in length and 7.1 mm in diameter. The other two pins for live and neutral are 14.9 mm long and 5.1 mm in diameter, with their centers spaced 19.1 mm apart. The Type D plug is rated for 5 amperes.

In India, Nepal, and Pakistan, in addition to Type D plugs, some large appliances also use Type M plugs (commonly known as the large South African plug and socket). This plug has three pins that are all larger than those of the Type D plug and is rated for 15 amperes. Some sockets can accommodate both Type D and Type M plugs.

Additionally, Type D sockets can, by accident, be somewhat "compatible" with European plugs such as Type C (European standard), Type E (French standard), and Type F (German standard), but this poses significant safety hazards. Although the distance between the two pins of a Type C plug (17.5-18.6 mm) is smaller than that of a Type D socket (19.1 mm), Type C plugs can generally be inserted into Type D sockets relatively easily because the two pins of the Type C plug have some flexibility. However, they usually cannot be fully inserted because the base of the pins is not flexible, and the pins of the Type C plug (19 mm) are longer than those of the Type D plug (14.9 mm). Therefore, when a Type C plug is inserted into a Type D socket, there may be poor contact or sparking, and in some cases, it can cause a short circuit.

If inserting a Type C plug into a Type D socket is unsafe but at least marginally usable, then forcing a Type E/F plug into a Type D socket can only be described as dangerous. The spacing between the two pins of Type E/F plugs (19 mm) is slightly smaller than that of Type D plugs (19.1 mm), and they are not flexible, so they can only be inserted into Type D sockets by brute force. This obviously poses significant safety hazards. First, Type E/F plugs are designed to require grounding, but if plugged into a Type D socket, they cannot be grounded, which can easily produce sparks and cause short circuits. Second, Type E/F plugs cannot be fully inserted into Type D sockets because their pins (19 mm) are longer than those of Type D plugs (14.9 mm). The exposed 4.1 mm of the pins can lead to electric shock. While Type C plugs also cannot be fully inserted into Type D sockets, they do not have this problem because the base of their pins has an insulated section.

The Type D plug is one of the most dangerous plug types in the world because all three pins have no insulation at the base. Imagine if a child accidentally touches the base of the pins while unplugging a Type D plug from a socket—they would be at risk of electric shock. Additionally, Type D sockets are not recessed into the wall, so there is also a risk of electric shock if they are touched.