Adrian Simpson writes
The main RCD was fitted new last December (the previous one had a broken
casing, so it was changed on safety grounds) 30mA trip, 80A capacity.

It is possible to have an appliance [or eg a shower] which works fine
but has a leak of a few ohms between neutral and earth.
This may not normally trip the RCD.
However, when a nearby kettle and the dishwasher are switched on and
draw 20Amps or so, the neutral-to-earth voltage increases enough to
cause a trip.

BTW, does anyone have a smooth safe technique for using an automatic PAT
Tester on showers and ovens? Yes, I know it's a *portable appliance*
tester but...


--
roger

delete x's to email