Right, where you would have a double insulated tool, which is not capable of becoming live ie made of plastic.
Which is fine for indirect contact/fault protection, but 30mA RCDs also provide protection under direct contact situations - e.g. damage to the appliance's flex exposing the conductors.
It's also hard to control loop impedances where long thin extension leads are in use - it doesn't take a huge amount of 0.75mm² orange flex running down the garden to get to the point where neither the MCB nor the plug fuse will reliably provide 0.4s (let alone 0.2s) disconnection.
Right, where you would have a double insulated tool, which is not capable of becoming live ie made of plastic.
Which is fine for indirect contact/fault protection, but 30mA RCDs also provide protection under direct contact situations - e.g. damage to the appliance's flex exposing the conductors.
It's also hard to control loop impedances where long thin extension leads are in use - it doesn't take a huge amount of 0.75mm² orange flex running down the garden to get to the point where neither the MCB nor the plug fuse will reliably provide 0.4s (let alone 0.2s) disconnection.
