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Replacing a one way light switch with a two way light switch

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Full Member level 4
Oct 6, 2002
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Replacing a one way light switch with 2 two way light switches allows one light to be switched on and off independently of the other switch. An example of such a system is in a hallway where the lights in the hall upstairs can be switched on and off from a switch downstairs
Does any body have a schematic for a circuit which i can implement to do this function . or can any body explain the concept of this circuit to me

you can use (NOR, NAND) gate... or electric relay... if you want to use NAnd gate for example you must connect first input to +VCC and let the second Input be connected to the first light wire.. the second light to the output of the NAND gate. so if the input was 1 from light one then the output will be 0.. (OFF). if light one is off... then o/p will be ON.

here is how

You can imagine the two switches as single pole double throw. The two throws of each switch are wired to the two throws of the other switch with two wires. That way the poles of each switch are only connected if they are set to the same throw.

Here is the schematic!


:lol: :lol: :lol:

Can't find

i can't find schemtic , can u plz send it to my pm


You need 2 SPCO standard light switches. Connect the n/o and n/c contacts in parallel with each other. From switch 1 connect a bulb to the switching (moving) contact, and the other side of the bulb to mains live. On the other switch, take the switching contact to neutral. Thats it.

If you draw this out, it will be clear how it works. I am assuming you mean a mains switch, if not, the same principle applies for low voltage.

I would NOT install the wiring as Gandalf proposes due to safety issues!

Both switches must be on the live phase wire side.

See the (very handrawn) little drawing for a circuit which is commonly used.

NEVER switch the neutral (0) side, if the live side is not disconnected at the same time! Also, the bulb thread side (for threaded bulbs) must be on the neutral (0) wire side.

I am quite sure these principles are included in the electrical code in most, if not all, countries.


p.s. pgo's message has a link to a (likely American) wiring example, and it follows the principle I stipulated here.


Silly me. Of course the bulb goes in the neutral side, and live to the switch. Must learn to read it back before posting. Operationally will make no difference of course. Got to be safe though!.

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