I am searching to increase the sensitivity of my RCCD to induce more frequent tripping and saw this forum...totally opposite of what i m looking for but here is my comment...Increasing RCCD beyond 100mA is dangerous, please avoid doing so, RCCD is installed to save lifes.
If it is due to lightning, a good surge protection device (SPD/TVSS) will be able to solve the problem, increase in surge will be absorb by the device, look for 1 with 10 modes protection if tripping is too frequent, otherwise 7 modes protection device is sufficient for a house and choose 1 with the longest warranty (rules of thumb..length of warranty=quality), my problem was sorted out...using an american brand, Sine Tamer.

Hi sifus

My new house RCCB 63A 0.1A  tripping randomly.
Did the usual diagnosis and trace the problem to one line supplying the front lights.
When the MCB (6A) for this in ON, cannot reset the RCCB, trips immediately.
When I OFF this MCB, then only can reset the RCCB. 
After sometime however can reset back with that MCB ON.

The problem is transient, sekejap ada, sekejap OK.

The faulty line has a timer switch, which I thought was causing the problem, so call back the wireman.

He checked and found that the one line is carrying 33 light points (including 16 T5s and 10 mLED downlights) and 1 fan.     
But I very seldom on everything. usually max 7-10 lights only.

He thinks it overload, and 'partition' some load over to the nearby 20A MCB. Don't know what it means.

But the RCCB still trips randomly. Although now can reset.

Any ideas how to approach?  I suspect some wire are overheating, that why after a while cooling down the problem goes away, only to happen again later.