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Wiring PIR sensors, Extractor fans, LED panel lighting, overide switch. In one circuit

Former Community Member
Former Community Member
Hi,


I am currently level 2 Qualified 2365 and beginning my level 3. 

​​​​​As my interest in the field increases I always observe electrical installations, I noticed one day in a public toilet, the ceiling panels were lifted and the Extractor fan, PIR sensor, Panel lighting, and override switch we're all wired in one circuit using wago connectors. 

Now I can't help it but I really need to work out how this was wired in a wiring diagram, I have an idea as to how, but not sure.


But my question is, as normal do we calculate the whole load of this circuit and then use the correct rated mcb, and if anyone could provide me with a wiring diagram or explain how it works. I think I even noticed some resistors used. 


Thanks for your help
  • 0

    esMoses:

    Is there are a book that has unorthodox wiring diagrams? I've got the basic college one's, but there seems to be multiple ways of wiring circuits. 

    I suppose you just pick it up with experience




     

    Yes, I am sure that experience helps - if you have done something 100 times, you don't have to work out the 101st. However, as a novice, try drawing the circuit, then you will understand it, and then you will become an expert.
  • 0
    Although in the real world. will a 3A fuse blow before a 6A MCB would?
  • 0

    ebee:

    Although in the real world. will a 3A fuse blow before a 6A MCB would?




    It is a Manufacturer's instructions' requirement ebee. We don't really need to think beyond that. I suppose that the makers just do not want their fans fused at 13 Amps or more.


    Z.

  • 0
    Agreed Zoom lad, I was just stating the obvious
  • 0

    Although in the real world. will a 3A fuse blow before a 6A MCB would?



    It's possible. On the wiring side we tend to think of faults being of negligible impedance, but once you're inside an appliance, possibly on the far side of some controlling electronics, things can look rather different. The current due to a fault can be limited by how far down a motor winding a short occurs or the constrained by rapidly warming semiconductors. Certainly the fuse would open long before the MCB for currents in the 4A-7A range.


       - Andy.
  • 0
    Colour coding the three core and earth cable-


    BROWN- permanent live


    BLACK over-sleeved brown at the terminations - switched live.


    GREY over-sleeved blue at the terminations - neutral


    Bare circuit protective conductor over-sleeved green/ yellow  at the terminations - circuit protective conductor.


    Please do not use any other colour coding.


    Andy Betteridge.
  • 0
    Or black, the old N, over-sleeved blue; and grey for switched line, over-sleeved brown. Same applies for 2-way lighting.
  • 0
    Sorry Chris I disagree.

    I` do it as Andy Sparking chip says
  • 0

    Chris Pearson:

    Or black, the old N, over-sleeved blue; and grey for switched line, over-sleeved brown. Same applies for 2-way lighting.




    No, that's not good practice,  it may comply with the regulations, but is not considered correct as it is continuing the idea that black identifies the neutral. 


    Andy Betteridge. 

  • 0
    Looking at it another way.

    Three Phase L1, L2 & L3

    Was Red, Yellow, Blue.

    Is now Brown, Black, Grey.

    Therefore Red becomes Brown, Yellow Becomes Black & Grey Becomes Blue.




    Oh, I still prefer the old (proper) clours though.

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