On old Irish boards you usually have a wooden panel on the wall.. with the main supply sealed fuse, meter and diazed fuse board. Some of the oldish ones are pretty much DIN standard so are relatively easy to retrofit with RCDs.
Older boards (usually black in colour) tended not to have a main switch on the board itself, instead having a large double pole high rated switch wired in after the meter. the RCD just goes in as a stand alone unit before distribution board. Most of those old systems wouldn't have hot water or electric cookers just sockets and lights.
Pretty easily done though.
You'll sometimes see extra diazed single fuses added in as individual units too for cookers and showers.
Sometimes there is a single 63amp diazed fuse on its own individual board before the main distribution diazed board too. Depends on the age of the system but they're usually retrofittable without messing around with the distribution board itself too much.
