Museum of Plugs and Sockets logo, small Bayonet Cap (B22d-2)
plugs, outlets and adapters
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BS 546
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 phased out


Bayonet lampholder with 5A 2pin outlets Bayonet adapter with swich BC lighting plug Bayonet Cap plug

BC plug, exploded view

1 B22d-2* bayonet lamp holder with two BS 372 Part I outlets.
* B = Bayonet; 22d = diameter in mm; 2 = double contacts. This type is also known as BC = Bayonet Cap.
Brand name: Anchor, a large Indian plug, socket and switch manufacturing company. Bayonet light bulb mounts are the standard fitting in - among others - India and Bhutan. India uses plugs according to IS 1293, which is derived from BS 546.
2 Two-way BC adapter with switch (red).
3 BC lighting socket plug in accordance with the BS 52 standard. The plug fits in a B22 bayonet lamp holder (see nos. 1 and 2).
The donor of this plug - see Acknowledgments - has added the following comment:
Originally bayonet socket were used in the UK for ‘Lighting’, whereas BS 546 sockets were meant for 'Power'. Lighting and Power were charged at a different tariffs. So everybody plugged the electric iron into the light socket to do it on the cheap. Bearing in mind that B22d-2 has no earth connection, it was a potentially lethal method of saving money.
4, 5 BC bayonet plug that is composed of two parts: an outlet that fits in a B22d-2 lamp holder (bottom right) and a standard 2-pin 5A BS 372 Part I plug (bottom left). Instead of this plug each other 2-pin 5A, or shaver plug can be used. Image no.5 shows and exploded view of this ingenious device. Also this bayonet plug has been donated to the museum, see Acknowledgments.


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BS 546
D i g i t a l   M u s e u m   o f
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P l u g s   a n d   S o c k e t s
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Bayonet lamp