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Two Way Lighting Methods

  • 05-09-2021 1:19pm
    Registered Users Posts: 3,017 ✭✭✭ John.G

    Posted this in DIY by mistake.

    Any advantages of using one of these wiring

    methods vs the other.?. I think my 49 year old install is the top schematic as no landing light when both switches are either both "up" or "down".


  • Registered Users Posts: 127 ✭✭ Bruthal.

    I used the first one now and again when adding in a second switch to a 1 way setup, or have wired to the first switch and light, but dont want to access the containment again, just continue to the next switch from the first.

    No need to do any wiring to the light or add connectors if changing existing 1 way to 2 way. Just 3 cores & E from the existing 1 way to the new 2 way with all 3 taking the same route, and swap the one way switch to a 2 way.

    You can not tell what method was used by operating the switches. Both up or down together for off is decided by how the L1 and L2 terminals on one switch are connected to the L1 and L2 on the other, or 1 switch upside down.

  • Registered Users Posts: 3,017 ✭✭✭ John.G

    I was able to remove the hall 2 way switch but didn't chance removing the landing one. The hall switch is wired Red, grey, & black. When the light is on, all 3 terminals are "live" as per a phase tester, which might indicate wiring like first schematic, if light is off and assuming both switches at pos 1 then i would expect to pick up two live terminals, com &1 which I am but if light is off with both switches in pos 2 then would expect only one live, terminal 1, but I am still getting two live terminals which are either com&1 or com&2 which might indicate that the wiring is like the second schematic but if so then I wouldn't expect three live terminals with the light on, I am assuming that like both schematics, L1 is linked to L1 and L2 to L2.

  • Moderators, Home & Garden Moderators Posts: 5,648 Mod ✭✭✭✭ Wearb

    Would turning off mcb, removing bulb and then check for continuity be helpful in discovering what method is used.

    Please follow site and charter rules. "Resistance is futile"

  • Registered Users Posts: 3,017 ✭✭✭ John.G

    Possibly would.

    I now got the landing 2 way switch removed.

    Landing switch readings.

    Light on, all 3 terminals live.

    light off, both switches "down", L2 only live

    light off, both switches "Up", L1 only live

  • Registered Users Posts: 3,017 ✭✭✭ John.G

    Once I got enough room to insert the probes for a test lamp and ignore that useless phase tester and even the M.meter which was picking up some low stray voltages I think I have figured it out.

    Its wired almost the same as the lower schematic except that the L1s and the L2s are linked as both switches are orientated the same way and one switch must be up and the other down and vica versa to get the landing light. The phase is connected to the hall switch common and the light which is only a few feet from the landing switch, provides the switching voltage to the com via L1 or L2. Two terminals are always live on the hall switch and two on the landing switch but only when it has switched on, otherwise only one, either L1 or L2 will be live (landing switch).

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  • Registered Users Posts: 127 ✭✭ Bruthal.

    With method 1, one or both l1 and l2 will have 230v on it, one always being at 230v while other goes on and off with the light. Method 2 only one or other of l1 or l2 will have 230v on it. Phase testers are not precise as they can light on the non energised terminal of a floating strapper, but not on the terminal connected to the light when off. Usually brighter on the energised one though.

    So method 1 with light on, all 3 terminals at either switch will be 230v. Method 2, either l1 or l2 will be at 230v but not both.

    Method 2 will only have single conductors in both l1 and l2 at both switches also.

    Another method, and probably the most sure if a phase tester was used, with both lights off, test at either switch. Now switch both switches over, so the lights are again off. Method 1, the live terminal (l1 or l2 depending on wiring) will stay the same. Method 2 it will swap. And because the other terminal will be connected to N via the light, the phase tester or multimeter wont read anything but Neutral voltage.

    Post edited by Bruthal. on

  • Registered Users Posts: 127 ✭✭ Bruthal.

    Method 2 used, which is the sort of traditional method. Method 1, the live terminal would not swap.

  • Registered Users Posts: 3,017 ✭✭✭ John.G