Quote
However, he is now selling single-module RCBOs from CHINT for £6.30 each!
I'll second Alan's question -- Never seen them that cheap before. And where or what is CHINT, or is that a typo? [Linked Image]

Quote
With an RCD protecting all of the circuits in a TT system, how do you get around the problem of appliances and other equipment, tripping the RCD, due to leakage currents to earth, caused by the equipment itself?
You just have to hope that the total leakage is under 30mA! [Linked Image]

Seriously though, on a small domestic installation you will find a main 30mA RCD feeding everything, and it does lead to tripping problems once you get a few heating elements starting to go leaky.

On larger commercial installations a solution is to break the system up into sections, each fed by an appropriate RCD. If there is a need for main RCD protection (e.g. bank of RCD's at the end of a sub-feeder) then it can be a time-delayed type of higher trip current (e.g. 300mA).