jackrae:
Slightly off-topic but if your house has either 100mA or 300mA RCD protection then it effectively offers no personal protection against electrocution. These currents are far more than required to cause fatality.
Why would anyone install a 300mA RCD ?
My shed, built by me, was wired to the then current UK 'regulations' (not actually legal requirements) which specified 30mA RCDs. That was maybe 20 years ago.