BILL Crown bakelite cased switch with four fuses inside
Similar to the metal cased Bill Crown unit, this one has a moulded brown bakelite case.
External view
The exterior is a single piece of moulded brown bakelite plastic.
Two screws secure the cover, which has the maximum ratings 60A and 250V, plus the Bill and Crown logos.
There is no back to the device - a separate white plastic backplate was available which fixed to the wall behind the ceramic inner section.
The earth bar can be seen to the left, with two screws at each end.
Inside
The interior consists of a ceramic piece which would be screwed to the wall or other board behind. This contains the main double pole switch and four ceramic rewireable fuses.
This example has two 30A fuses and two 15A fuses.
Note that some of the brown spots on the fuses are cracked and deteriorating. If these fall out, live screws are exposed.
Fuses and Switch
The fuses are made from a brown ceramic. Circuit wiring connects to the terminal at the top of the top 30A fuses, and the bottom terminal of the bottom 15A fuses.
The terminal for circuit neutrals is at the top right. Incoming supply connects to the two terminals below the switch.
The switch has a mechanical interlock, preventing it from being switched on when the cover is removed. A metal tab which fits over the switch prevents the cover being removed when the switch is on.
Ceramic Closeup
The top section has the two 30A fuses at the left, and the neutral terminal block at the right. Neutral wires are secured with two screws, line with only one.
The lower section has two 15A fuses, with the incoming L and N terminals on the right side below the switch.
The white cloth in the fuse positions is probably asbestos.
Fuses
The rewireable fuses are made from a brittle dark brown ceramic material.
The 30A types have a cloth flash pad and copper blades. The 15A has no flash pad and brass blades.
Plastic Shell
The outer cover is a one piece moulded bakelite item. There are various removeable sections on the top and bottom edges for wiring.
The inside is marked For AC Only, Part No AC 6002, Made In Gt. Britain.
Parts
Another view of the fuses, metal tab, on/off legend and cardboard terminal cover.
