Electric Shock with RCD

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Today I experienced an electric shock in my house, after I touched a bare cable, which I had foolishly left exposed. The cable touched my leg and I had a heck of a jolt up my body which pushed me out of the way.
I am now wondering why the RCD did not trip. Last year a contactum split load CU was fitted, the cable which I touched is on the RCD side. Could there be a problem somewhere, or was the shock I had below the trip current?
Any ideas?
Thanks
Andrew
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| Today I experienced an electric shock in my house, after I touched a bare | cable, which I had foolishly left exposed. The cable touched my leg and I | had a heck of a jolt up my body which pushed me out of the way. | | I am now wondering why the RCD did not trip. Last year a contactum split | load CU was fitted, the cable which I touched is on the RCD side. Could | there be a problem somewhere, or was the shock I had below the trip current? | | Any ideas? | | Thanks | | Andrew | Hi
I'd expect that the shock was probably less than the trip current. If that's a 100mA RCD then it's hardly surprising. However, if you're worried re the RCD then best to get it tested. I assume that you have the test records from the installation which show that it was working when installed?
Also, you should take more care! Shouldn't really have exposed live conductors around to touch and circuits should be isolated (and discharged) before working on them.
J
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Yep !!! This one was your warning, the next one might be worse if you carry on exposing live cables in easy reach. Always a good idea, especially if you're going to work on cables that will become live when your testing others that are connected, is to wrap a piece of insulting tape around them before you make the circuits live again for your test.
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You don't say what exactly you touched. If you contacted bare live and neutral, then the RCD "sees" you as a normal and legitimate load, and will not trip. This will only happen if current from either live or neutral finds an abnormal return path, normally via an earth.
Charles Fearnley
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message

Perhaps the old description 'Earth leakage' was more informative than 'Residual Current'
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get the idea and try to connect it across earth.
Like Swiss bankers couldn't understand Lsd, so we had to go metric :-(
mike r
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principle of operation is very different (although the terms are sometimes, incorrectly, used interchangeably)
--
Tim Mitchell

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Earth Leakage Circuit Breaker is generic and covers both types.
RCD is a Current Operated ELCB, whereas the older ones which monitor the voltage on the CPC verses a ground spike are, unsurprisingly, called Voltage Operated ELCB's.
The term RCD resulted from Which? and That's Life! suggesting that the industry adopt a common term, and it needed to be shorter than "Current Operated ELCB" which Joe Public wouldn't understand.
--
Andrew Gabriel

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contribution to electrical engineering. Who would have thought it)
--
Tim Mitchell

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"Tim Mitchell" wrote | >The term RCD resulted from Which? and That's Life! suggesting | >that the industry adopt a common term, and it needed to be shorter | >than "Current Operated ELCB" which Joe Public wouldn't understand.
I've never really understood what RCD actually means. I know what they do and how to use them, but Earth Leakage Circuit Breaker does exactly what it says on the BS EN IP-rated enclosure.
| An interesting bit of history which I didn't know (Esther Rantzen's | contribution to electrical engineering. Who would have thought it)
Well, she did play a major part in getting open-flued gas heaters (the infamous Ascot water heaters, my parents always rather liked theirs when they had one) banned in bathrooms because of the dangers of CO poisoning.
Owain
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police at IEE ("extraneous-exposed-conductive-part" - I ask you!) they came up with this neutral no-name thang. "Differential" rather than "residual" might've been a little clearer. "Current Balance Device" would've been informative, *and* used shorter words. Ah well... no-one asked me, right? ;-)
Stefek
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Stefek Zaba | the nomenclature police at IEE ("extraneous-exposed-conductive-part" | - I ask you!)
I have a sneaky suspicioun they are trying to harmonise us with something German. More bleedin' hyphens than a Twistleton-FFyffe.
Could have been worse I suppose. Microsoft might have given us "My Grounded Metal Thing".
Owain
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No such thing! There are extraneous-conductive-parts [1] and there are exposed-conductive-parts [2]. These are different things, but the twain _should_ meet in your bathroom, via ... (you know the rest).
[1] Non-electrical metalwork which may "introduce a potential, generally earth..." - e.g. metal plumbing & waste pipes.
[2] Earthed metalwork of electrical appliances - e.g. wall heater, electric towel rail.
--
Andy



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two such similar words, deserves to spend a few thousand years in purgatory trapped in a late-1980s helpdesk dealing with Expanded vs Extended memory (come on now! quickly! summarise the differences!) ;-)
Stefek
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Good point. Quad & Quattro LNB's provide another example in similar vein.
--
Andy



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Expanded memory was a system where you could set a window under the 1Mb mark into the expanded memory bank. The window could be moved to expose a different section of the memory. It was developed to help store additional information (particularly spreadsheets) that just couldn't be squeezed in. There was no virtual memory on Intel processors at this time.
Extended memory was simply memory located above the 1Mb mark. This was only available on 286 processors or above, as previous processors only had a 20 bit address bus. (The 286 has a 24 bit bus, and the 386 a 32 bit one). Unfortunately, MS-DOS, the operating system of the time, did not allow the processor to be in the mode required to access this memory, so various memory extenders were required to switch the processor into and out of the mode as required. (HIMEM.SYS later helping out with this task).
Expanded memory come first, when pre-286 processors were common and the 640kB limit at its worst. Extended memory took over by the time 386s came along with their fast context switches (and Windows 386 Enhanced and DOS4GW). It is far easier to work with and much less limited in size and performance (and does not require additional hardware).
Christian.
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"Christian McArdle" wrote in message

... with the Intel 'Above Board', IIRC. I remember buying one at work in 1980-something to run a upgrade release of Touchstone (1.4?) on our 12 MHz '286 PC-AT, with 20 MB HDD! The price for 1 MB ran to 4 figures.
--
Andy



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On Tue, 28 Oct 2003 20:43:52 -0000, "Andy Wade"

When you think about the prices that applied way back then, each of our PCs today would be at least half a million quid today..... ;)
PoP
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Andy Wade wrote:

You exaggerate; the PC-AT was 6MHz. The later AT-X was 8MHz but that had a massive 30MB drive.
--
Laurie R (IBM UK's PC Technical Product Manager 1984-2000)



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Ah. I remember the old AT with the really expensive EGA graphics upgrade. That was the third computer I used, after the PDP-11 and the Spectrum. The PDP-11 was fantastic. I learnt to program on it when I was five. We had two, sitting in the front room, with the teletypes sitting in the back room. I remember the excitement when the first VT100 arrived (must have been 1979). Such modern technology! You can still see the evidence of them now. My parents still have the holes in the floorboards where all the cables ran.
Christian.
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