“There are moments when troubles enter our lives and we can do nothing to avoid them.
But they are there for a reason. Only when we have overcome them will we understand why they were there.”
― Paulo Coelho
Tell the BG engineer to follow these instructions.
Switch off power.
Gain access to PCB, identify potentiometer marked 'Max R' turn this from the 5 O'clock position to to the 11 O'clock position.
Reassemble in reverse order.
Switch power on.
BP 8)
You need to measure Zs
refer to table 41.5 page 50 17th edition and you can choose your RCD from the chart , observe the voltages!
Personally I'd use a 100mA time delayed RCD
Consumer unit split load board with 2 x 30mA RCD