Found this on the oldhouseweb.com bbs.

Hello, I have got a bank of 5 fuses in an upstairs cupboard. They appear to be in line with two wires going to each fuse.
I would like to swap them for circuit breakers. The CB's that I have seen have 3 or 4 connections. I was wondering what I would need to fit them.... An earth line perhaps?

Thanks

John

DIY strikes again. Some people seem to think they can do everything trial-and-error style.