Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove rear control panel cover to expose main PCB

Measurement:

Disconnect controls interface connector marked H7 on the main PCB.
Test 1:
Measure resistance across the live (brown lead) and
neutral (blue lead) connection on the connector.
Test 2:
Measure resistance across the live (brown lead) and suitable Earth.
Expected resistance O.L or greater than 1MOhm on both tests.