Shock Likelihood at Switch.

An RCD will not provide the necessary shock protection even though by fortuitousness it may operate due to a minor current imbalance and current flow to an earthing point. 

If this was true, RCDs could be omitted without making the installation less safe, and all the agonising over risk assessments for 32A sockets would be moot.

I'm afraid this is not really true, a 30mA RCD is chosen for exactly this reason. The shock current is set by the environment, things like how well earthed you are and how much contact area, but the whole point of an RCD is indeed to limit that shock current to either be less than 30mA, or  less than half a heart beat period, so you are very likely to survive. Without it, and absent some other ADS you are very likely to die.

You and I may prefer a 10mA limit,  or a shorter operating time, (well I would, having once been saved by one, I seemed to have plenty of time to realise what was happening and think about what had gone wrong before it tripped) but they are indeed set to limit the shock; to a very painful but survivable level.


What is true is that the regs in the UK do not recognise an RCD as the sole means of protection against shock, and like to see it backed up by insulation over the live bits and/ or earthed enclosures.

An RCD will not provide the necessary shock protection even though by fortuitousness it may operate due to a minor current imbalance and current flow to an earthing point. 

If this was true, RCDs could be omitted without making the installation less safe, and all the agonising over risk assessments for 32A sockets would be moot.

I'm afraid this is not really true, a 30mA RCD is chosen for exactly this reason. The shock current is set by the environment, things like how well earthed you are and how much contact area, but the whole point of an RCD is indeed to limit that shock current to either be less than 30mA, or  less than half a heart beat period, so you are very likely to survive. Without it, and absent some other ADS you are very likely to die.

You and I may prefer a 10mA limit,  or a shorter operating time, (well I would, having once been saved by one, I seemed to have plenty of time to realise what was happening and think about what had gone wrong before it tripped) but they are indeed set to limit the shock; to a very painful but survivable level.


What is true is that the regs in the UK do not recognise an RCD as the sole means of protection against shock, and like to see it backed up by insulation over the live bits and/ or earthed enclosures.