Wiring diagram help needed

[James]

 

[James]

when you have filled in the lines for ex 2
see if you can figure where this intermediate switch may fit in so that when you change it the light changes from on to off or vice versa.
once you have your head round this, the most complicated part of domestic lighting is sorted.
everything from there onwards is easy, hmm well easy(ish)

 

[7029 dave]

The OP is specifically asking using 3 core and earth for the switching

 

[7029 dave]

see diagram fig...............................

 

[James]

The OP is specifically asking using 3 core and earth for the switching

that is a very good point. but i am trying to help the op understand how this works, not do it for them.
I find the diagram attached to your post difficult to understand as a seasoned spark, it doesn't show what cable is the live in or feed out to the light and is unnecessarily complex for the task in hand.
you only need 2 core and earth for 2 way switching even if it requires an intermediate switch.
if you decide to use 3 core then the extra core can be used for any purpose.
i.e. as a N conductor
or as a way of taking the switched live back to the beginning of the circuit which may be the first light fitting (ignoring the feed from breaker to first light)

 

[7029 dave]

That diagram is the most practical way using 3core and earth between all switches and the most common way in domestic.
Admit it does not give the whole circuit diagram, just the actual wiring between all switches with 3 core and earth, I am only trying to help the OP with his question too.

 

[nicebutdim]

One thing I'll add for the OP's benefit is that understanding how something is wired from a diagram and understanding why it is wired that way are very different propositions and an issue which has troubled every single electrician at one point in their career - in fact some never grasp the principle and insist there is only one way to wire a two way lighting circuit.

Whether it is a task set as part of learning or a real life situation faced in the course of your work, if you don't understand it draw it out and follow the live path to see how it works (or won't work in some instances). This is probably the quickest way to gain understanding of circuits and one day it will stick without you ever realising.

 

[littlespark]

That’s an old diagram Dave…. Pre harmonisation.

Replace red yellow blue with brown black grey.

 

[7029 dave]

That’s an old diagram Dave…. Pre harmonisation.

Replace red yellow blue with brown black grey.

Lol does that really matter should all be sleeved red as per diagram or brown new colours the principal is the same.

 

[FatAlan]

Look up the great John Ward (JW) on YouTube. Seem to remember that he covers it very well. Some of the old GSH electrical videos are good too.