I agree with the introduction timings, I only knew of one in the early days, late 60's/early 70's we used to run dances in a barn for about 40-50 people, about 1972 the farmer had this massive concrete/asbestos barn added which easily took 200. The new submain (surprisingly 1ph 60A) included a "trip switch thing" which we didn't know about. We ran 2 events then there was a storm and after that our lighting kit kept tripping the RCD. I don't think I saw another until at least early 80's then by early 90's were very popular. I replaced our fusebox around 1994/5 but with a SH Wylex with coloured fuses (likewise a SH 3 way wylex in the new shed around the same time) and then only replaced that when I required additional ways around 5 years later with a split board & one RCD, then converted to RCBOs due to DW faulty mains filter, maybe as late as 2010.
EDIT: I used a number of plug in RCD's for a long time before the RCBOs and maybe only 5 years since I fitted an add-on RCD for the shed sockets.
EDIT: I used a number of plug in RCD's for a long time before the RCBOs and maybe only 5 years since I fitted an add-on RCD for the shed sockets.
