Most appliance deaths occur via fire, not shock. RCDs do prevent some, but only some.
What does RCD cover cost? Say £50 now for 2 RCDs, about the minimum, per house x 20 million houses (memory vague there) = £1 billion £1b/20 = £50 million spent per domestic shock death. Not great value. In practice its worse, many houses having more than 2 RCDs.
However we need to include reduced fire deaths from RCDs to get a fuller pi cture.
NT
Most appliance deaths occur via fire, not shock. RCDs do prevent some, but only some.
What does RCD cover cost? Say £50 now for 2 RCDs, about the minimum, per house x 20 million houses (memory vague there) = £1 billion £1b/20 = £50 million spent per domestic shock death. Not great value. In practice its worse, many houses having more than 2 RCDs.
Should you not divide the cost of the RCD by the population of the UK and not by the number of houses?
I am unclear about the ?50. I doubt you could get an electrician to add
2 RCDs to an existing installation for ?50 even if it were practicable to provide protection to all circuiits that way. I'd have thought it was more a matter of the cost of replacing a CU with (at minimum) a split-load with 2 RCDs. That seems to start at around ?300 in London but I can well imagine is less elsewhere. And then go up when other things need to be done - uprating main bonding, fixing discontinuities in RFCs and other CPCs, etc etc.OTOH isn't it less than the 23 millions dwellings now there must be a fair few with at least some RCD protection (even if only to 15th or 16th edition)?
The ESC [1] did give figures for the number of houses with RCD protection. They did not say how many of the RCDs failed to work[2]:-)
[1] They have changed their name so my links to them no longer work. [2] Sure they did that one in an earlier article before saying that RCDs are garlic bread.
Oh lordy yes, I forgot that. The ESF[1] quote the 2010 housing survey[2]. That has 63.5 per cent of all dwellings with RCD in consumer unit or separate RCDs. It reckons 46.1 per cent have "all PVC wiring + all modern earthing [sic] + modern consumer unit + MCB + RCD in consumer unit or separate RCDs". Which is a more than I'd have guessed
They also cited a DTI report as showing that 20 per cent of fires could have been prevented with an RCD[2] but that was from 2001 so rather dated.
[1]They did not say how many of the RCDs failed to work :-)
ESF claim "We've found that fixed RCDs are about 97% reliable. This improves if they are tested regularly.[4]" [4]
Thank you.
I recently had an RCBO (from a very reputable manufacturer) fail. I don't know why yet, but I will dismantle it to try and determine what went wrong
John .
In message , Robin writes
But I don't imagine people generally one day go 'oh, I need an RCD, lets get the CU changed.
Ir presumably is more likely to be a job they would being hAving done anyway (rewire, replace an old unit etc.), so it would mostly be money spent anyway
The cost is divided by 20 lives saved to work out cost per life saved.
NT
Have you tried the manufactures tech help line? Smashing it to bits yourself helps very few people
£50 is the cost of 2 RCDs when CU is being replaced anyway. But of course adding RCD cover is a major reason to replace CU, so without RCDs probably a lot of replacements would not occur. That puts the csot up.
around 50% last time I heard
NT
I lost the "lighting" in bad editing. I meant "having/putting lighting circuits on RCDs, especially shared RCDs". I meant that it's dangerous for a domestic lighting circuit to get cut off unless there is a genuinely dangerous problem in the lighting circuit.
People do fail to find their way out in a fire and die. That results from lighting being cut off when there is a genuine earth leakage fault due to smoke. Still safer to leave them on.
Pity I dont have any numbers for this.
NT
Good point. I'll see whether they are interested.
John
Dust is a big killer, And quite often the test button fails but the RCD still works within spec when tested with a RCD tester.
Kind of the reverse actually - they have concluded that there is no real benefit to EQ bonding in a kitchen and hence its no longer required.
So in a new build with plastic plumbing, metal sinks etc would be left floating. On copper based installs however you are obviously left with them earthed due to the (possibly unwanted) fortuitous earthing effect of connecting the pipes.
The proper solution to this is non maintained emergency lighting... that way you always have light when there is a powercut, fire, tripped circuit etc, and since each luminaries has its own supply, no single fault will extinguish them all.
In this specific case, no. The govt figures were only for deaths via electrocution. Most of which were attributed to (mis)use of appliances.
RCDs are more commonly £15/each these days.
We have had this argument before, so I will skip it except to say I disagree.
However lets say that RCDs reduce the number of fires resulting from faults in electrical distribution in the home (i.e. fixed wiring) by 25% (chances are it will do much more than that).
That is a reduction of 1000 fires per year[1]. Now the total numbber of fatalities from the total 45K ish fires / year was 306 in 2010/11. Plus a further 8900 non fatal casualties. If for the sake of argument we allocate those casualties pro rata to the causes, that gives us something like 30 fire deaths, and 890 non fatal casualties.
Then you may well be saving 20 electrocution lives a year, and perhaps another 50 fire deaths. Possibly several 100,000 electrical shock casualties and another 890 fire related ones.
[1]That alone would easily be worth £50 million. Lets face it, local councils will spend that on road improvements that will save two or three lives a year. Its also not a "hard" cost since it would save the NHS a good proportion of the implementation cost each year.
(and remember the installation cost is something paid once, the savings are cumulative)
However, by focusing only on death its easy to ignore the elephant in the room. i.e The number of deaths is almost inconsequential compared to the number of injuries from shock per year.
Suits me. My chrystal radio needs a good earth and mains water piping is ideal.
You should be able to get out of your own house and you should have your own fire escape plan.
And there is one other thing. You are twice as likely to die in a fire if you do not have a working smoke alarm.
Make some up then-:)
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