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Help needed replacing switches

Discussion in 'Electrics UK' started by 600rob, 31 Jul 2014.

  1. 600rob

    600rob

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    I have a couple of switches that i want to replace and had some questions:

    first is the bathroom/hall way switch.
    i have 2 hallway lights controlled by two switches at either end of the hall. A 1 gang 2 way switch at one end of the hall way.

    At the other end of the hall next to the bathroom is 2 gang 2 way switch which controls the hall light on one switch it also controls the bathroom light and bathroom extractor fan off the other switch.
    The extractor fan comes on with the bathroom lights and has a fixed live to keep the fan on overun when the bathroom lights get switched off

    Ive bought a 2 gang 2 way 10ax switch to replace the switch at the bathroom end of the hall.
    I thought i had wired everything up correctly but the bathroom extractor fan comes on and remains on even when the bathroom light is not switched on.
    Other than that the hall way lights go on and off fine, as do the bathroom lights. I just cant work out where ive gone wrong with the fixed live for the fan.

    Heres a picture showing the old switch on the left hand side and its exising wiring. The arrows indicate where i connected the wires on the new switch shown on the right. doing this causes the bathroom extractor to be permanently on regardless of the bathroom or hall way lights




    Can any one help out with this one?

    Second is the fused power switch for my combi boiler.
    Ive bought a 1 gang switched fcu to replace the old switch.

    Heres the old switch

    VS the new one

    All the connections look correct but i noticed that the old switch has a 3 amp fuse in it. ( even though it says on the back has 13/20 amp 250v)
    is this safe/correct? The switch has not been touched since i moved in.
    The new switch comes with a 13amp fuse so i just want to be sure of what fuse i should be using before i change the switched
     
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  3. AndyPRK

    AndyPRK

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    2 way switching will use all 3 switch terminals.

    The bathroom 1 way will only use 2 terminals.
    There are you sure it's labelled correctly?

    Use the 3a fuse for boiler
     
  4. eveares

    eveares

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    Use a 3 amp fuse for the boiler, the info on the back of the fused switch is just the maximum rating for it. (i.e it can take up to a 13 amp fuse.)


    For your lighting, the cable with the red, blue and yellow wires is the cable for your 2 way hall light. The cable with the red and the black wires is for your bathroom light and fan.

    For wiring your new switch as in the position and as shown in your photo, and viewing it as having 2 terminals on the top and 4 terminals on the bottom. (it's really two 2 way switches)

    The yellow wire from the hallway light cable should go in the top right terminal
    The red wire from the hallway light cable should go in L1 on the 3rd terminal from the left.
    The blue wire from the hallway light cable should go in L2 on the 4th terminal from the left.
    The red wire from the bathroom light cable should go in the top left terminal
    The black wire from the bathroom light cable should go in L1 on the 1st terminal from the left.
     
  5. EFLImpudence

    EFLImpudence

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    Don't forget your new switch requires earthing.


    There is nothing on the switch which would alter the fan operation.
     
  6. ban-all-sheds

    ban-all-sheds

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    That's what he's done (well - using L1 where you say L2, and vice-versa, but that will only affect the rocker orientations, not what the switch does).

    Rob - what happens if you put the old switch back?
     
  7. eveares

    eveares

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    EFLImpudence; true - but he may have thought the switch was off when it was on, thus is always better to use L1 when the switch is in the correct way up.

    ban-all-sheds; I know it makes no difference to the way the 2 way switch operates, but common practice to wire red/brown to L1, blue/grey to L2, and yellow/black to common.

    I left earthing out for simplicity reasons, as it is common sense.

    May be the fan has developed a fault?
     
  8. ban-all-sheds

    ban-all-sheds

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    You can't have done - it's not at the switch.
     
  9. securespark

    securespark

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    Am I missing two things?

    1. I can't see any red/black to which people refer in the bathroom switch terminals.

    2. If the blue of the bathroom fan wiring is a N, it will cause a big bang if wired up as it is in the white switch.
     
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  11. ban-all-sheds

    ban-all-sheds

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    Indeed. But he reports the bathroom light as going on and off, so he knows when the switch is on and when it's off.


    The wires don't know what legends the terminals have.

    How do you know that the other 2-way switch has been wired the way you suggest?
     
  12. ban-all-sheds

    ban-all-sheds

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    [​IMG]


    It's not. The switch on the left is the old one, and it doesn't go bang, and it works fine. The OP has got confused about which cable is which, and what each core is, because he doesn't actually understand how any of it works.
     
  13. EFLImpudence

    EFLImpudence

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    The switches are labelled the wrong way round in the picture.
     
  14. eveares

    eveares

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    True, and i don't. Just if you were doing a new install you would use a standard and convention.



    600rob, have you tried taking the switched live wire out of the extractor fan and seeing if it still starts.
     
  15. 600rob

    600rob

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    that's what I thought


    I've replaced the old switch using the original wiring configuration as shown in my original pic.

    Everything works correctly with the old switch...

    Bathroom lights switch on and the fan only comes on when the bathroom light is switched on. It remains on overrun as per its setting then switches off.

    Hallway lights are all fine
     
  16. 600rob

    600rob

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    Not yet, I'll do that when I get a chance and report back
     
  17. 600rob

    600rob

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    The fan is only about 3 weeks old and has been running perfectly without any issues
     
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