Validate new Light Switch Replacement

[Andy90]

Had to replace a Light Switch with a faulty dimmer.

The New Light Switch is wired different from the old one but appears to work ok

Can someone with Aus Electrical knowledge tell me why:

- Old Light Switch was wired using Terminal 1 and 2

- Whereas New Light Switch uses only Terminal 1 and C (and works ok) ?

> See Before / After Photos

 

[Avo Mk8]

I'm not an authority on Aus electrics, but it is clear from the photo's that the two wiring configurations are equivalent.

Let's assume that the two reds are permanent live, and the single goes to the lamp (could be the other way round - doesn't matter). The switch needs to join the pair to the single to light the lamp.

In the first case, the dimmer needs to be connected in series with the switch. So one lead of the dimmer needs to be joined to the single red wire. That could have been done with a seperate connector, but has been achieved using terminal 2 as a loop terminal. One can get away with this clever method as when the switch is off, the middle C terminal is connected to terminal 2 anyway (the dimmer terminals get shorted together, but there is no connection to the lamp circuit). It is the connection of terminal 1 to C that closes the circuit.

In the second case there is no dimmer to accommodate, so the single red wire goes into the C terminal instead of having to be looped to a dimmer wire in terminal 2.

Sorry for the verbose explanation. No doubt someone can put this in a clearer way!