If you have a modern consumer unit, how is it possible to still get a shock - what wiring faults can bypass the RCD protection? Can faulty appliances give you a shock even if you a have correctly installed circuit with a modern consumer unit? Cheers, S
Electric Shock
- Thread starter seanpk
- Start date
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1) An RCD will do nothing for you if you put yourself between L & N.
2) An RCD will limit the current which can flow through you to earth, but not stop it altogether, and what does flow could still be fatal.
3) Why do you ask?
2) An RCD will limit the current which can flow through you to earth, but not stop it altogether, and what does flow could still be fatal.
3) Why do you ask?
We're having an extension built and we're starting with a period certificate test - I'm the sort of person who needs to understand the process and don't like when I feel myself slipping into the blank stare when an electrician is talking to me!
So what sort of fault could put "...yourself between the L&N"?
Cheers, S
So what sort of fault could put "...yourself between the L&N"?
Cheers, S
Working on stuff without isolating it.
Handling a damaged flex.
Putting your fingers behind an old plug with unshrouded pins as you insert it.
Sticking a finger into a lampholder.
Handling a damaged flex.
Putting your fingers behind an old plug with unshrouded pins as you insert it.
Sticking a finger into a lampholder.
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TBH you should be more worried about checking the relevant qualifications of the people doing the work, what they are and aren't allowed to do depending on their level of qualifications (are they part P and will any work done dictate that they should be) will they notify the council of works to be done if needed, what certification will they provide and when etc. Can you see examples of past work (from the sparky, not the builder) etc.
I can see that getting between the L&N your basically becoming the load, but usually the load (the motor in an appliance say) is isolated from earth, in these cases; Working on stuff without isolating it, Handling a damaged flex, Putting your fingers behind an old plug with unshrouded pins as you insert it, Sticking a finger into a lampholder - isn't the current running to earth and therefore should trip the RCD?
Only if it flows through the earth wire to the RCD in the CU, if it flows to earth through you instead then no RCD protection exists! If there is a fault with the earth protection then the RCD may never activate etc.
Your questions seem very specific, have you had a shock?
That's incorrect. You will be earthed to a certain extent which will operate the RCD.
You are talking about the CPCs but any earth path will do.
No it won't. It will limit the time for which a current above a threshold level (e.g. 30 mA) can flow.
No haven't had a shock (luckily) was just under the misconception (just armed with some basic physics) that new fangled circuit protection on a correctly wired system had made electric shocks a thing of the past, obviously they still a have a way to go,
You'll never get away from the situation where you can get a shock as long as you have an electrical installation (and live in a faraday cage)!!
All you can do is limit the shock to a safer level, using RCDs to limit the duration of a fault and correctly installed circuits which will also help limit duration.
All you can do is limit the shock to a safer level, using RCDs to limit the duration of a fault and correctly installed circuits which will also help limit duration.
Well put it this way, my mums house has a reasonably modern mem memera 2000 board with RCD protected circuits. I still managed to get a good shock from that before it tripped. Singed my fingertip too! ...hey ho
A (true) anecdote from some years ago. I put my hand down the back of a washing machine thinking that it had been unplugged. It hadn't the cables from washing machine and dishwasher crossed over and I didn't check.
I touched a live point and my elbow touched the machine body which was earthed. I got a shock. Made me jump. RCCD clicked out.
The same week a lady in my class did exactly the same thing, only there was no RCCD. She had a year of skin grafts to her burned arm and still had movement problems.
Conclusion from experience: you get a shock yes, but are saved from serious injury (because the current flows for a very short time). However, as stated before, if we had touched live and neutral (rather than earth) then the RCCD would not have tripped as the in/out current would have balanced. Like many safety devices there is a tendency for some people to think that they are 'protected' and therefore become careless or complacent: my mistake could have been fatal even with a RCCD and nobodies fault but my own.
I touched a live point and my elbow touched the machine body which was earthed. I got a shock. Made me jump. RCCD clicked out.
The same week a lady in my class did exactly the same thing, only there was no RCCD. She had a year of skin grafts to her burned arm and still had movement problems.
Conclusion from experience: you get a shock yes, but are saved from serious injury (because the current flows for a very short time). However, as stated before, if we had touched live and neutral (rather than earth) then the RCCD would not have tripped as the in/out current would have balanced. Like many safety devices there is a tendency for some people to think that they are 'protected' and therefore become careless or complacent: my mistake could have been fatal even with a RCCD and nobodies fault but my own.
Only if you are levitating.
You, too, are thinking CPC rather than earth.
What about the current flowing through you to EARTH and not flowing through the Neutral?
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