IS 1293 : What are the different kinds of Indian electrical sockets?

I spent a lot of time today reading the specifications of Indian electrical sockets, and since it took me way too long to find this information - here’s a quick summary of what the different kinds of sockets mean. I hope at least one other person finds this useful.

Indian electrical sockets are defined by the IS 1293 specification, as defined by BIS (Bureau of Indian Standards). You can find the contents of the standard here:

• IS 1293 : 2005 - PDF of the third revision of the standard from 2005. This is not the latest version, but this is the only PDF I could find freely available.
• IS 1293 : 2019 - You’d have to create an account to access the latest version from 2019. It is a free download after, for personal use.

The standard specifies the details of plugs and sockets used for household devices (devices which draw up to 16A current). The standard goes into details about almost every aspect of the plugs and sockets, but this article cares only about the different socket layouts.

Plugs and sockets are rated for three current classes in India - 2.5A, 6A, and 16A. There used to be a 10A class as well, but that has since been removed in the 2019 revision (it shared the same socket layout as 6A). All these sockets operate at up to 250V.

Now, onto the different sockets shown in the image above:

• Socket I - This is a 2-pole socket, with no support for earthing. This kind of socket is only rated for up to 2.5A. Both the pins are 5.08mm wide, 15.9mm in length, and 19.10mm apart.

• Socket II - This is a 3-pole socket, which is rated for up to 6A. It is basically the same socket layout as I, but with an additional earth pin, which is 7.06mm wide and 20.6mm long, at a distance of 22.2mm from the other two pins.

• Socket III - This is an outdated socket. It is a combination of standard 6A Socket II, along with an old form of a 2.5A socket which had the pins 16.50mm apart. That latter one was removed from the standard in 2019, and should hardly have any supported devices nowadays.

• Socket IV - This is a 3-pole socket, which is rated for up to 16A. All the dimensions are bigger for this socket - with the live and neutral pins being 7.06mm wide, 20.6mm long and 25.4mm apart. The earth pin is 8.71mm wide, 28.6mm long, at a distance of 28.6mm from the other two pins.

• Socket V - This socket is a combination of socket II and socket IV. Both the plugs can be inserted in the socket, which is rated for 16A.

• Socket VI - This is a common kind of socket found in some places, which conforms to no standard. It attempts to combine many different kinds of sockets from around the world. In India, most of these would be rated for 6A and will be compatible with Socket II. There are a lot of articles on the internet which explain why universal sockets can be unsafe, which you should look up for more info.

And that’s it. This is not my favorite kind of socket layout, but its the one we got. The best one, in my opinion is the British BS 1363 system - which requires compulsory shutters in the sockets, and the plugs have fuses built into them, as well as mandatory insulation at the base of the pins. They are also impossible to plug in sideways due to the rectangular design.