Electric shocks operating RCDs

[scousespark]

You will struggle finding any stats relating to the causes of electrical accidents. Part P was suppose to prevent 7 deaths per year. When the review took place it was reported that Part P had been a total success and saved hundreds of lives. Hardly what most would call reliable recording or reporting.

 

[JohnW2]

You will struggle finding any stats relating to the causes of electrical accidents.

Indeed. In the past I've been involved in some very serious attempts to find useful/reliable data about this, and it's essentially non-existant. The ESC, and various other organisations, quote all sorts of statistics, but (apart from data deriving from official death records, and even that is far from faultless) most of them are based on surveys which leave a lot to be desired.

Part P was suppose to prevent 7 deaths per year. When the review took place it was reported that Part P had been a total success and saved hundreds of lives. Hardly what most would call reliable recording or reporting.

Quite so. Officially-recorded deaths due to 'domestic/leisure' electrocution have hovered around 20 or so per year for many years - so go figure about these 'hundreds of lives saved' in the past 8 years! IMO, even '7 per year' was a very optimistic prediction/target.

Of course, it's not all about death, but finding any reliable data on non-fatal injuries due to electricity is even more difficult. Probably the best data available relates to burns, something like 3% of the significant burns treated in the UK being electrical burns. As I've already mentioned, attempts to find data on injuries (even deaths) secondary to electric shock is all but impossible.

Common sense tells us at least two things. Firstly, RCDs have got to result in some reduction in injuries (both minor and serious), perhaps even deaths, due to electric shock. Secondly, since there are apparently so few deaths due to electric shock, RCDs could never result in 'dozens', let alone more, lives being saved each year. I obviously may be wrong, but I personally suspect that, of the very small number of deaths, a fair proportion probably result from mechanisms that would not involve an RCD operating. If that's true, the opportunity for RCDs to 'save lives' reduces even further.

Kind Regards, John

 

[JohnW2]

Fine for a workshop. For anybody who would like emergency lights on landing/stairs/hall, note that any fluorescent light with its own ballast can be converted to an emergency one if you want.

Another approach which can be useful in some situations is something like this:

Untitled

• JohnW2
• 13 May 2013
• 1

The rechargeable LED torch remains charged up, switches itself on automatically if the power fails and can simply be lifted out and used for wandering around in the dark. I have a couple similar to that in my house, plugged into sockets on different RCDs, so that one will come on if either RCD operates (and both will come on if there is a total power failure).

Kind Regards, John

 

[viewer]

I once stuck my arm down inside a washing machine having pulled out the wrong plug at the back. My elbow and fingers touched live and earth. Small shock; RCD tripped.
Similar event with colleague but no RCD; result several months of skin grafts.

 

[JohnW2]

I once stuck my arm down inside a washing machine having pulled out the wrong plug at the back. My elbow and fingers touched live and earth. Small shock; RCD tripped. Similar event with colleague but no RCD; result several months of skin grafts.

It's good to hear of examples of them having done their job. As I've said, it must happen sometimes, but it would still be nice to be able to get a handle on how often! You also illustrate what I said about it not only being about 'saving lives'.

Kind Regards, John

 

[ban-all-sheds]

Similar event with colleague

You stuck your arm inside a colleague having pulled out the wrong plug at the back?

 

[viewer]

 

[leeco]

I got a shock today on a circuit protected by a type s 100A 100mA RCD and it never triped.

 

[JohnW2]

I got a shock today on a circuit protected by a type s 100A 100mA RCD and it never triped.

Probably just as well ... >100mA for 500ms would have definte potential to be fatal.

Kind Regards, John

 

[viewer]

Perhaps worth noting that the idea is not to prevent shocks but to prevent injury/death. This point also emphasises that RCDs" deal" only with electrical injuries; a small shock on a ladder, holding petrol, etc could cause a fatality. This links back to the original posts because the cause of death could be (say) multiple injuries due to fall from height and would not be electrocution.

 

[JohnW2]

Perhaps worth noting that the idea is not to prevent shocks but to prevent injury/death. This point also emphasises that RCDs" deal" only with electrical injuries; a small shock on a ladder, holding petrol, etc could cause a fatality. This links back to the original posts because the cause of death could be (say) multiple injuries due to fall from height and would not be electrocution.

That's all very true. It's also worth noting that, partricularly with high current shocks, a standard (not Type S!) RCD may reduce the shock duration to such an extent (potentially to 40ms or less) that some of those 'consequential injuries' (due to falls etc.) may be much less likely to happen.

Kind Regards, John