You are most likely to see this 2 way lighting circuit in an industrialcommercial setting where the installation is trunkingconduit based and single core conductors are used. Lighting circuits loop at the switch.
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2 way lighting circuit loop at switch. By wiring a 2 way switch the circuit below shows the basic concept of electricity flow to the load. There is a chance that if your house has these old wiring colours the switch drops may be from a loop in loop out radial lighting circuit done with junction boxes rather than ceiling roses as shown in fig 2. The electricity flows from the hot wire black through the 2 way switch shown in off position and then to the light and returns through the neutral wire white. When i say 2 way swithces i mean a switch with two copper screws. There are different ways to connect up two way lighting circuits if it is a new installation the ideal way is to use a three core earth cable between the two light switches. The switch wiring is all the same but the switch wire cable c leads up to a different set up.
This is a loop in method which can be useful where the light fitting only has three terminals or when using downlighters. 1 look at diagrams of 2 way switching when the loop circuit runs through the ceiling and only the phase goes to and from the switch network. Loop at the switch. This is a completed circuit. 3 think how little it changes if neutral also goes to and from the switch network. Use two 2 way switches to create a two way switch system.
Lets assume the load you are controlling is a light. Logically it cant be done as both switches would need to be on for the circuit to work power the bulb that is but a two way switch system means that either switch should be able to turn on the bulb. If you are doing a new install or replacing a two way switch system go for the three wire control method. Replace the one gang switch with a two gang switch. 2 way light switch wiring 3 wire. The in cable supplies power from the previous light or consumer unit.
Two way light switching schematic using a two wire control. At the ceiling rose brown connects to loop as before black is now the switched line and the third grey wire is connected to. Connect a new cable to the switch to provide power to the new light fitting. The principle is exactly the same as when looping at the ceiling rose or using a junction box. Two way light switch using 3 core cable. The twin and earth switch cable has been replaced with a 3 core and earth cable.
2 see how it works. 4 wonder why you couldnt work that out yourself.
Gallery of 2 Way Lighting Circuit Loop At Switch
