Andrew Gabriel wrote:


80A is a common contact rating found on RCDs, but 80mA isn't
a common trip rating. Are you sure you read that right?


Quite right. I miss-remembered the rating. It's an MK LN6180 item:
100mA trip, rated at 80A


For the benefit of later contributors, and with apologies for being
economical with the information earlier, this is the setup:

LN6180 feeds one CU which supports kitchen, GF, 1F and attic ring mains,
and oven, immersion heater and outside socket.

Second CU (no RCD) supports GF and upstairs lighting, freezer and fridge
supplies, boiler and garage (via it's own 30mA RCD CU).

I suspect that the LN6180 was installed by the previous owners because
of frequent nuisance tripping - but I cannot be certain.

Richard