RCD/Circuit breaker Demo

Discussion in 'Supporting Physics' started by Paul, Feb 7, 2019.

  1. Hi

    Does anyone have a RCD/Circuit breaker Demo they do (preferably using a power pack not mains) want to show how it works.

    the teacher has watched this.

  2. We bought a pre-made demonstration. Possibly Lascells brand or similar It uses two power packs - one for a light bulb and one for the solenoid.
  3. We got this one last year - seemed to work ok (no complaints/whinges)
  4. I have purely electromechanical RCD which works perfectly well on 12V AC except that the test button does not create enough current unbalance to trip the device. I have fitted a lower value internal resistor so even that works.

    Extract from Demo. attached.

    Attached Files:

  5. Isn't a C60N an MCB not an RCD?
  6. I made this ant NWNE technicians a few years ago. 12v in. 12v bulb to indicate kettle is on. Red 12v bulb to indicate electric shock.
    Just a circuit breaker (no RCD or RCBO) but demonstrates earthing. Green/Yellow wire plugs in/out. Brown with Red terminals simulates a fault.
    I cut a breaker in half, (replacing the cover with a bit of acrylic) to show the inner workings... but it isnt a reliable demo.

    Attached Files:

    Andrew Goloskof and KeithD like this.
  7. I'm having trouble getting the required 6A to trip it with a bulb in circuit.:(
  8. You could swap the bulb for a rheostat - and as you decrease the resistance the current will increase - with a 12V supply - down to 2 ohms should give you approx 6A - the standard rheostat is approx 11ohms at full
  9. Your little man lights up in a better place. Our Fuse Wire Fred has an LED right on his crotch! One physics teacher insisted he had a paper skirt and changed to Fuse Wire Freda
  10. So now her crotch lights up - illuminating the skirt from underneath???
  11. It looks more like her belly button!
  12. With what circuit? With an earth fault the "Live" to earth (Negetive) should be zero bypassing the bulb and the current maxing out your PSU.
  13. the trip on the power supply goes not the breaker.
  14. what is the current rating on your power supply?
  15. The one I made had a fuse. The element in the kettle is a coil of wire and there is a layer of silicone mat glued on to the backing board.
    Pictures are:
    no earth, no fault - working kettle
    no earth, fault - electric shock
    earth, fault - fuse blown

    image1.jpeg image2.jpeg image3.jpeg
  16. All you need now is a teacher who can change a fuse!!!
  17. I got it going in the end, I find the power supplies trip far too easily to be helpful.
  18. That was in my last school - no non-physicists in the physics department - for this school, I will need a circuit breaker!
  19. I use a piece of NiCr wire as a fuse - it limits the current, glows red, and slowly melts.