Discussion in 'Electricians' Talk' started by DanielQ, Oct 13, 2018.

  1. DanielQ

    DanielQ Member


    Is it acceptable to have a two switches connected with T+E to an intermediate switch and a T+E in between the two switches to connect the COM using one of the wires?
  2. seneca

    seneca Screwfix Select

    Certainly not if you're thinking of using the earth conductor for one of the lives!
  3. DanielQ

    DanielQ Member

    Probably I haven't explain myself well.

    Switch 1 -> T+E to intermediate Switch
    Switch 2 ->T+E to intermediate Switch

    Switch 1 -> T+E to Switch 2 (Only to use one of the wires)

    The earth WILL NOT be used as a conductor.
  4. peter palmer

    peter palmer Well-Known Member

    Think he means the strappers go between each switch: 2 way -> intermediate -> 2way and one core of the 2nd T&E between the two 2 way switches so 2way -> 2way. It will be fine although its a lot more simple with a piece of 3 core and just connect out the common in the intermediate switch.

    I do all my loop connections at the switch nowadays and with each switch having a permanent live and neutral you only need a bit of twin and earth for the 2 way bits, hardly use 3 core and earth at all nowadays apart from fans and smokes. Just as well the price Screwfix charge for it.
  5. MGW

    MGW Well-Known Member

    There are two problems.
    1) Unbalanced transmission lines can cause LED and compact fluorescent lamps to glow or flash.
    2) Running a wire independent with a AC supply can result in a transformer effect where the supply and return goes through independent holes in a ferrous structure.
    At one time is was popular to "borrow lines" and use just two wires between the switches, there is nothing to stop this as long as the two lines come from the same protective device, however it can transmit, and cause mains hum on unrelated equipment. To stop this one should try to run line and neutral together when ever possible.
    retiredsparks likes this.

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