Two way and intermediate lighting.

[Monkeyblaine]

I understand how 2 way and intermediate lighting works and how to wire it, I'm just struggling to get my head round why it doesn't matter which way round the strapped go from switch to switch. I.e L1 from one switch then into l2 and any other combination. Does anyone have any easy way of explaining why it doesn't matter?? I know this is a pointless exercise as I know how to wire it and I have never had a problem with it. It's just my damn OCD is making me want to know and I can't think of a simple way of thinking about it.

 

[telectrix]

draw it out, then you can see . the intermediate switch switches L1-L1 to L1-L2 and vice versa.

 

[pjcomp]

When you draw it out follow through the path the electricity actually follows to get from one end to the other. Then redraw it with the L1/L2 connections changed and follow the path again. Then you'll see why it doesn't matter, it's just following a copper pathway.

pj

 

[Farmelectrics]

Simple drawing will explain it

 

[7029 dave]

strappers are a continuous copper path does that make it easy?

 

[Richard Burns]

This is a slightly modified diagram I drew when trying to work out using crossover switches as two way switches for an inappropriate application.

This shows the cabling when L1 to L1, L2 to L2 at the bottom and swapped over at the top for each possible switch position.
The state of the load (on or off) is shown below.
If you follow from L along the joined lines to see if a line reaches SL this would be ON.
As you can see swapping the connections reverses the operation but it will still work.

 

[Monkeyblaine]

Thank you all for your input. I do understand how the path works when I draw it out. My brain just doesn't let me understand that no matter how many intermidiate switches you have in a circuit and how many combinations of which way around the strapped go it still doesn't matter. The comment from Dave saying that its just a continuous copper path makes it a little easier to understand. I suppose its just two paths. One is a complete loop to the light and one has a break. And those are goverened by the two end switches of the circuit and not the intermediates, they just send the energised conductor on to a different path?? Correct explanation??

 

[itselectric]

With an intermediate switch all you are doing is swapping the strappers one position the strappers are connected straight through and the other position the strappers cross over. so all you are doing is swapping the route of the live.

 

[Richard Burns]

Thank you all for your input. I do understand how the path works when I draw it out. My brain just doesn't let me understand that no matter how many intermidiate switches you have in a circuit and how many combinations of which way around the strapped go it still doesn't matter. The comment from Dave saying that its just a continuous copper path makes it a little easier to understand. I suppose its just two paths. One is a complete loop to the light and one has a break. And those are goverened by the two end switches of the circuit and not the intermediates, they just send the energised conductor on to a different path?? Correct explanation??

With an intermediate switch all you are doing is swapping the strappers one position the strappers are connected straight through and the other position the strappers cross over. so all you are doing is swapping the route of the live.

Yes MB you are correct as itselectric states with an intermediate switch you are swapping the strappers and, from my diagram, doing this changes the switch from off to on or vice versa.

If there is another intermediate switch this would effectively remove the crossover (or cross back again) and again reverse the operation once more.

The control connections are at the terminal switches and this control is reversed back and forth by each intermediate switch.

 

[Monkeyblaine]

Thanks Richard. That is a great way of explaining it. Intermediate switches in line are just undoing what ever the last one did.