Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 44 replies
  • Subscribers 16 subscribers
  • Views 4503 views
  • Users 0 members are here
Options
You may also be interested in
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Too Modest

Former Community Member
Former Community Member
If it can be demonstrated to the scientific community/press/public at large that "the RCD will trip or nary a tingle will be felt", then CBE's, MBE's, Knighthoods or perhaps a Nobel prize will be sure to follow!


This is surely the biggest step forward in Electrical safety since the invention of fuse wire!


In these bleak times the British public needs to hear good news like this.
  • Former Community Member
    0 Former Community Member
    Demonstrate and claim your Nobel prize then.
  • 0
    Coby:

    Demonstrate and claim your Nobel prize then.


    Nobel prize for what?  Showing that a product that has been in use for decades actually does what it is supposed to do isn't going to win you any prizes.


  • 0
    As I have mentioned before, I have received two shocks in my life I would class as 'near fatal'.

    One disconnected by prompt action of a friend, the other by an RCD.

    The first at school, from a flex with a live plug (instead of the more conventional live socket ! ) that was part of the theatre lighting lit. For the several seconds before I was disconnected by the prompt thinking of a school friend with me at the time, I was unable to breath, and apparently I was making a strange growling noise. Afterwards I was shaking for a good half hour, and missed the afternoon's lessons. The burns to the palms of my hands from the entry and exit of the current (the other hand was holding a well earthed fitting at the time to complete the circuit) took ~ 2 weeks to heal. This circuit had no RCD.


    The second was when re-locating the wiring to an immersion heater that ran through the loft of a friends house. - The wiring ran through the loft, and knowing the whole house was RCD wired I carefully cut through the 2.5 mm T & E strand by strand to avoid an earth-neutral trip.

    I was happy in the illusion that I had isolated the correct circuit at the board.

    Only this was the wrong wire - a socket drop from the main ring ran in nearly the same place as the immersion heater, and in the dimness of the loft I had not realised. Once again good contact, this time with tools to sweaty hands, the no-let-go grip, and the same pain and shakes, but only for long enough to think

    "Oh *&%%$ I've had it this time",

    and then at about that point the RCD cut the current off.

    Still the shakes and dizzy feeling, but no burns, and I needed no help to get myself down from the loft after a minute or two of deep breathing.

    I was able to go back and re-connect the mis-cut cable, and solve the original problem, later in the same day.It is possible some of the shock was live-neutral, rather than all live-earth but clearly there was still enough to fire the trip - fortunately the place had a simple TT feed, all tripped at 30mA.


    Yes a 30mA RCD can save you from more serious injury, and no, if the shock is hand to hand, the sensation is very far from painless, but it is at least as good as a friend sprinting across the stage and pulling a big switch for you, and that fact it is probably faster reduces the burns !

    I'd recommend them

    regards Mike .
  • Former Community Member
    0 Former Community Member
    412-06-01 A residual current device shall not be used as the sole means of protection against direct contact.


    Explain please.
  • 0
    Hey, I've just had a brilliant idea, how about if we put some non-conductive material around live conductors, we could call it something like "insulation", as a primary protection, and then in case that fails put some sort of secondary protection in such as an RCD?


    I'll wait for the Nobel prize to arrive in the post...
  • 0
    Only 2 shocks in you life Mike?  I've lost count, it would top one hundred I guess.  The worse was from the final anode of a colour TV (discharge only), it felt like someone had whacked me around the head with a railway sleeper! 

    Many many shocks developing mains powered devices in my early days as an electronic designer and earlier from the Christmas tree lights every year as a child.

    I remember once, at Christmas, with all the adults still sitting at the table, I used to like making sparks with my 12V train transformer, this day I decided to wire a bit of flex to a 13A plug, plug it in then touch live and neutral together - now that was quite a spark and sent the heeby jeebies down me.

    In school we had collective shocks from both Van de Graff and Wimshurst machines, all part of the curriculum in those day!  I made myself an electrophorus which made nice sparks when charged with polystyrene but when I tried to charge it off the static off the TV screen it sent me flying across the room!

    Ahh, the good old days eh.
  • Former Community Member
    0 Former Community Member
    Andy Millar:

    Hey, I've just had a brilliant idea, how about if we put some non-conductive material around live conductors, we could call it something like "insulation", as a primary protection, and then in case that fails put some sort of secondary protection in such as an RCD?


    I'll wait for the Nobel prize to arrive in the post...


    In which case; when your 'primary protection' fails, you are therefore reliant on 'a residual current device being used as the sole means of protection against direct contact'...that doesn't work!


    I think you'll find that primary and secondary 'protection' is provided by 'two layers' of insulation.


  • Former Community Member
    0 Former Community Member
    Rob Eagle:

    Only 2 shocks in you life Mike?  I've lost count, it would top one hundred I guess.  The worse was from the final anode of a colour TV (discharge only), it felt like someone had whacked me around the head with a railway sleeper! 

    Many many shocks developing mains powered devices in my early days as an electronic designer and earlier from the Christmas tree lights every year as a child.

    I remember once, at Christmas, with all the adults still sitting at the table, I used to like making sparks with my 12V train transformer, this day I decided to wire a bit of flex to a 13A plug, plug it in then touch live and neutral together - now that was quite a spark and sent the heeby jeebies down me.

    In school we had collective shocks from both Van de Graff and Wimshurst machines, all part of the curriculum in those day!  I made myself an electrophorus which made nice sparks when charged with polystyrene but when I tried to charge it off the static off the TV screen it sent me flying across the room!

    Ahh, the good old days eh.


    All of this and you still refuse to test your RCD by touching a line conductor?


  • 0
    Coby:
    Andy Millar:

    Hey, I've just had a brilliant idea, how about if we put some non-conductive material around live conductors, we could call it something like "insulation", as a primary protection, and then in case that fails put some sort of secondary protection in such as an RCD?


    I'll wait for the Nobel prize to arrive in the post...


    In which case; when your 'primary protection' fails, you are therefore reliant on 'a residual current device being used as the sole means of protection against direct contact'...that doesn't work!


    I think you'll find that primary and secondary 'protection' is provided by 'two layers' of insulation.




    Only if you're using double insulation.  Class I appliances may contain single insulated wires.  And there's always "reinforced" insulation, to confuse matters.


    And the pedants will argue that most electrical cable doesn't have two laters of insulation - it's "insulated and sheathed" - even though the sheath is made of the same stuff af the insulation.


  • 0
    " And the pedants will argue that most electrical cable doesn't have two laters of insulation - it's "insulated and sheathed" - even though the sheath is made of the same stuff af the insulation. "

    Nothing pedant about clarity and precision. What is the pupose of insulating something twice?  Surely, two layers of insulation becomes either a form of reinforced insulation or as stated insulated and sheathed regardless of insulating material.

    Legh.....?

Community Rules & Guidelines