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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
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    However I think second maybe the preferred method as the industry supplies the annotated 3 pole switch, but I have not seen an annotated 2-pole switch.



    Arguably there's little need to produce a dedicated fan-symbol marked 2-pole isolating device - as you can always employ the 3-pole version and leave one pair of terminals unused.  It's the same with simple lightswitches - if you want a 2-gang one you can only get it in 2-way versions - so you just have to leave the extra terminals unused for 1-way switching. The waste of the extra metal etc is far offset by the savings of not having multiple different products (and lower volumes of each).

     

    Another advantage of the 2-pole switched circuit is that it isolates the whole circuit and not just the branch to the extractor.



    But has the disadvantage of isolating the light as well as the fan - which can be a nuisance especially in bathrooms with no window.


      - Andy.
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  • 0

    However I think second maybe the preferred method as the industry supplies the annotated 3 pole switch, but I have not seen an annotated 2-pole switch.



    Arguably there's little need to produce a dedicated fan-symbol marked 2-pole isolating device - as you can always employ the 3-pole version and leave one pair of terminals unused.  It's the same with simple lightswitches - if you want a 2-gang one you can only get it in 2-way versions - so you just have to leave the extra terminals unused for 1-way switching. The waste of the extra metal etc is far offset by the savings of not having multiple different products (and lower volumes of each).

     

    Another advantage of the 2-pole switched circuit is that it isolates the whole circuit and not just the branch to the extractor.



    But has the disadvantage of isolating the light as well as the fan - which can be a nuisance especially in bathrooms with no window.


      - Andy.
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