2 way wiring diagrams showing flow of circuit

Hi

Hopefully somebody can help explain a headache I've got with 2 way & Intermediate switching. I'm on C&G 2330 & the principle of how the electric is flowing around a circuit is confusing me. I think I'm confusing myself by looking into it too much, but cannot see the Wood for the trees on this.

Anybody help with some simplified explanations of what is happening when a switch is turned on/off & how the direction of the current travels round the circuit? I have some diagrams of how to wire up this without the connection block method, although couple of lads on course seemed to think this was easier to grasp than the way I've been doing it. Feels like I'm putting square pegs in square holes without understanding exactly the principles.
Cheers
Andy

its in the wiki, in colour too

Yes. Thankyou. I do have some of those printed off, but I can't clearly see what happens when the switch is on/off how the current is leaving/returning & its effects on each of the wires. The diagrams do not have directional arrows to help here?

Sorry if I'm asking Dumbass questions but I'm either confusing everybody or just myself...
Thanks
Andy

Start by trying to understand what is happening with the schematic diagrams at the top of wiki page.
//www.diynot.com/wiki/electrics:two-way-lighting

Current flows from +ve to _ve via a load, if a switch is open it will not flow if it is closed it will, if it flows from a closed switch to an open switch it will stop flowing. With 2-way & intermediate switches changing the state of any one of them will either open or close a path for the circuit to flow through. I always used to imagine electricity as being water & switches taps & folllow the flow until it got to a place where it could continue to flow or flow no further. Hope this helps because it is something you are really going to have to understand if you want to make the grade.

In practical terms, the current flows from the source of the Phase (live) to the end of the Neutral, via switches and loads. So, all you have to do to understand a wiring diagram is find the source of the live supply, which is usually indicated by a fuse or CB on a busbar, and follow that line to the end of the Neutral. If there is no end to the Neutral or if the line is broken by a switch, current cannot flow. On most diagrams, the end of the Neutral is not shown. There is an assumption, on diagrams, that a connection to any Neutral will complete a circuit. In reality, the Neutral wire must be connected to the Neutral supplied by the power source.

On 2 way switch diagrams, the focus is on the route of the live supply to the load. While the light is on, one route will always be live and the other will always be dead. The dead route is not neutral, its is simply an unused route. Selecting either switch to the opposite setting will break the live supply to the light, but it will also prepare the other switch with the ability to transfer the supply onto the previous dead route. This design ensures that both switches have full and independant control of the light.

Hope this helps.

The diagrams do not have directional arrows to help here?

Click to expand...

Directional arrows have no place in AC circuits because the current flows both ways. You might find it better to think about connections rather than directions. If you can follow an unbroken line from live at the CU through wires, fuses and switches to a light bulb and BACK TO NEUTRAL, the bulb will be on. If there is any break in this complete circuit it will be off.

PS: I once knew an electronics engineer who got himself completely lost with a simple circuit involving a 24V AC supply, a myriad of switches and a relay coil. When he couldn't follow the badly drawn circuit any further through the switches I suggested that he start from the ground side of the 24V supply and, hopefully, get to the relay coil from that end. "But it's AC", he said with a puzzled look. "It doesn't have a ground side."

kevnurse said:

While the light is on, one route will always be live and the other will always be dead.

Click to expand...

Sorry but that's wrong. It's true for old two-way circuits where the live supply goes to COM on one switch and switched live comes from COM on the other. It is NOT true for circuits where the switch terminals are connected like for like through three core cable. In this case all three terminals are live when the light is on.

Hey

Had somebody show me the water technique with matchsticks...
OK! Sounds basic to all with knowledge but I got it in 10 mins...
Cheers
Andy