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PostPosted: Sun Apr 08, 2018 11:41 am 
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I have just got an electric shock from the lighting cct. No need to go into should have turned power off, I realise that.
The big shock, no pun intended is that no cct breaker/rcd tripped.
Is this because I was touching live and neutral and not earth?
I thought one would trip or was the shock not big enough or long enough to make them trip?

glassescase


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PostPosted: Sun Apr 08, 2018 12:06 pm 
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Depends what you were actually doing, and what you actually have by means of protection.

More info would help, including a picture of your consumers unit.

I suspect I know the answer, but it depends on what you post next

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No such thing as "Thou shalt put this wire here, Thou shalt put that wire there" .............Take a picture BEFORE you do the job.

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PostPosted: Sun Apr 08, 2018 12:48 pm 
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I was connecting a wall light.
As for attaching a picture, not sure how to do that as there is no insert option.
Now someone-else, your reply has made me go and look at the fuse box and I'm going to guess,
I wonder if it is what you suspect, so if I'm right, thank you for giving me the lead

The cct is protected by an MCB, not an RCD. There is the big on off switch on the left, then to the right is my light cct and some other MCB's, further right is an RCD and further right are more MCB's.

MCB is not as sensitive as RCD and I assume I did not draw more then 5 or 6 amps so the MCB did not trip

glassescase


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PostPosted: Sun Apr 08, 2018 12:56 pm 
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Picture still required, and what exactly were you doing at the time. (I know you were connecting a wall light, but what were you doing? screwdriver in one hand? your fingers were?)

Question: Posting pictures, now where could you find help on doing that?

Answer: Read my signature

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Take it easy, a forum is only a collection of opinions. Above, are mine.

Which is correct? Metre or Meter? Click the link. to find out more.

No such thing as "Thou shalt put this wire here, Thou shalt put that wire there" .............Take a picture BEFORE you do the job.

If gloom had a voice, it would be me. :mrgreen:

:idea1: How to post a picture on this forum Click here


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PostPosted: Sun Apr 08, 2018 1:52 pm 
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sorry someone-else I cant recall exactly but I think I was using a screwdriver to push a wire into a hole in the wall while holding the light fitting and or pushing another wire back into the hole with my other hand.

Damn, so easy to add a picture when you know how, thank you
hopefully fuse box picture now attached

glassescase


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PostPosted: Sun Apr 08, 2018 2:45 pm 
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glassescase wrote:
Damn, so easy to add a picture when you know how, thank you


................and its been in my signature for, must be a year now. :welcome:

Back to your question.

You have a misunderstanding of how consumers units and electricity work, no worries, I shall explain.

I would guess that you touched a live wire while another part of you was holding / touching the earthed light fitting. This is how you received the electric shock.

What I suspected ealier is true.
Your consumers unit does have an RCD (But we all knew that) what you didn't realise is that only your sockets (and the conservatory lights) are protected by the RCD as they are all on the right of said RCD. The lighting MCB's (and smoke detectors and garage) are NOT protected by the RCD. If it had of been protected by the RCD then yes, I would have expected it to trip.

All new consumers units (17th edition electrical wiring regulations onwards) have two RCD's so one is for lights and "stuff" and the other is for sockets and "stuff" You used to be able to get consumers units where everything was protected by one RCD (I had one) but the down side is if a lamp failed, sometimes they would take out the RCD, and so all the sockets would be switched off too. Like wise if there was a fault on the sockets at night all the lights would go out too :angryfire: (very annoying)

You are correct when you said
glassescase wrote:
I assume I did not draw more then 5 or 6 amps so the MCB did not trip
If you had, you would not be sitting there reading this, as it takes around 8mA (across the heart) to kill a human. (1000 mA to the Amp) I would also guess you said some unusual words :lol:

However I should point out that when you said
glassescase wrote:
MCB is not as sensitive as RCD
That is a total miss understanding. (Again, no worries, I shall explain)

An MCB (Miniature Circuit Breaker) in plain / simple English is designed to operate in an "overload" situation. Be that you have plugged in too much stuff, or nail through a cable, or a fault to earth etc (in any of the previous examples, more current flows than the MCB is meant to carry)

An RCD (Residual Current Device) in plain / simple English detects current flowing to earth, if this current exceeds 30mA it operates. Unlike an MCB, It will not "mind" if you are using, say 40Amps because all the 40Amps (remember 40A is only an example) are being used, and none are "leaking" to earth.

NOTE: Electricity has no prejudices, it will kill anyone. Always turn off the supply to the device / circuit you are going to work on, and before you touch it, Prove it is dead, not you.

As I said, the above is in plain / simple English, so I have left out the technical bits. :wink:

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Take it easy, a forum is only a collection of opinions. Above, are mine.

Which is correct? Metre or Meter? Click the link. to find out more.

No such thing as "Thou shalt put this wire here, Thou shalt put that wire there" .............Take a picture BEFORE you do the job.

If gloom had a voice, it would be me. :mrgreen:

:idea1: How to post a picture on this forum Click here



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PostPosted: Sun Apr 08, 2018 4:40 pm 
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Good post SE, I found that very informative :thumbright: I am pretty useless with electric issues.

DWD

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PostPosted: Sun Apr 08, 2018 7:01 pm 
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dewaltdisney wrote:
Good post SE, I found that very informative :thumbright:


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PostPosted: Sun Apr 08, 2018 7:42 pm 
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Thank you someone-else that is a good explanation. One question, Can i replace the MCB's on the left with RCD's?

glassescase


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PostPosted: Sun Apr 08, 2018 8:06 pm 
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The answer is in two parts.

1) No, because they will not physically fit. Look at the size of the one you have, and as I already said an RCD and an MCB do NOT do the same thing.

You may be thinking of an RCBO, which is a cross between an RCD and and MCB, and yes it does do both functions. But you have to get ones for your consumers unit (if they make them)

You would need to get a qualified electrician to change them.

2) You do not need them since you will turn the supply off when working on ANYTHING electrical. You are also going to buy a multi meter, learn how to use its basic functions to prove a circuit is dead, better it be dead than.........

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Take it easy, a forum is only a collection of opinions. Above, are mine.

Which is correct? Metre or Meter? Click the link. to find out more.

No such thing as "Thou shalt put this wire here, Thou shalt put that wire there" .............Take a picture BEFORE you do the job.

If gloom had a voice, it would be me. :mrgreen:

:idea1: How to post a picture on this forum Click here


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PostPosted: Sun Apr 08, 2018 9:06 pm 
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I was doing electrics a couple of days ago on a house i just got as the seller had left wires dangling from ceiling. Did all the proper checks, power off, switch off, multi meter testing. Today..........I made a mistake and your right, not one I will make again.


Appreciate all the help and advice someone-else

glassescae


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PostPosted: Sun Apr 08, 2018 9:23 pm 
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Anytime. Happy to be of assistance.

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Take it easy, a forum is only a collection of opinions. Above, are mine.

Which is correct? Metre or Meter? Click the link. to find out more.

No such thing as "Thou shalt put this wire here, Thou shalt put that wire there" .............Take a picture BEFORE you do the job.

If gloom had a voice, it would be me. :mrgreen:

:idea1: How to post a picture on this forum Click here


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PostPosted: Wed Apr 11, 2018 7:03 pm 
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someone-else wrote:


If you had, you would not be sitting there reading this, as it takes around 8mA (across the heart) to kill a human. (1000 mA to the Amp)


Interesting that. I must have no heart... :roll: :roll: I took a 40 + Amp shock from my left hand to my right... and after picking myself up from the floor (and enquiring of Mrs.wine~o why it was still live when I had asked her to switch off) I found the shower circuit (separate CU via henley block ) The rcd was still on, the mcb (40A) had tripped.

I had a great big black burn under my right armpit.

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PostPosted: Wed Apr 11, 2018 8:31 pm 
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Not true. (about you not having a heart)
as I said its around 8mA across the heart. The voltage would have been 240, that with the high resistance of your body means "you felt it" but it wasn't 8mA across your heart.
If the voltage had of been higher then................

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Take it easy, a forum is only a collection of opinions. Above, are mine.

Which is correct? Metre or Meter? Click the link. to find out more.

No such thing as "Thou shalt put this wire here, Thou shalt put that wire there" .............Take a picture BEFORE you do the job.

If gloom had a voice, it would be me. :mrgreen:

:idea1: How to post a picture on this forum Click here


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PostPosted: Thu Apr 12, 2018 6:00 pm 
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someone-else wrote:
"you felt it" but it wasn't 8mA across your heart.
If the voltage had of been higher then................


Felt it alright. :shock: Took me 10 minutes to realise that I was on the floor...

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