[emeritus]

I have one of those 5A Crabtree plugs. I always wondered why the earth pin was hollow.

The attached extracts from the 1936 Bulgin catalogue may be of interest. They show all the pages that include connectors.

This was apparently the year that the well-known Bulgin 3 pin mains connector was introduced. Interestingly enough, it seems that the enlarged ridge of the female socket was not primarily designed to provide a finger grip. According to the technical data section, it could provide a locking function for the back panel, evidently to ensure mains disconnection before the panel could be removed.


There is also a fused 2 pin 5A mains plug to the normal BS gauge that took 2 x 1" fuses, apparently of the present BS1362 dimensions, but of glass construction. Could this be the first fused mains plug?

Does anyone know what the R.C.M.F was? The fuses are said to comply with B.S.I. and R.C.M.F specifications but searching the web for the initials R.C.M.F. drew a blank.