Gangs, ways, and poles!

A double pole switch breaks both conductors. The line conductor and the neutral conductor. So the switch has an incoming line and neutral, and an outgoing line and neutral - 4 terminals. A two way has 3 terminals the common, L1 and L2, so an incoming conductor can be switched from L1 to L2, or vice versa. And yes two way switches are often used as one way switches, just leave one terminal unused. Hope I was helpful. EDIT: Example of a double pole switch:- Main isolator (if installed) which breaks the tails between the meter and the consumer unit. The main switch in the consumer unit. Cooker switch.

As you clearly don’t understand the fundamentals and there are a variety of ways to carry out light switching, I would recommend you retain an approved electrical contractor to carry out the works. Its not likely to be an expensive job. Additionally if you have old wiring there may not be any CPCs at the light switch positions so you you be reducing the safety of the installation if you install any Class 1 equipment into the lighting circuits

A 2 way switch can work as a 1 way as well so perhaps just get these if your not sure? You connect the L1 and common for them to work as a 1 way switch. Double pole are for special circumstances isolating fixed equipment and you probably won't need one of these. If you are planning on replacing double pole switches then maybe get some help in?

Hi Julie. Decorative light switches will always be two-way for manufacturing cost savings. There are too many choices in style and finish to justify making both one and two-way switches, so its just easier and cheaper to manufacture just two-way as it caters for both situations. White switches on the other hand are standard and a lot cheaper so they can be purchased as one or two-way. In practice most electricians would not bother with one-way, unless they were installing hundreds where a cost saving could be significant. The reason for two-way is so that a light fitting, or multiple light fittings, can be switched from two different switches. The switches need to be linked together with wire for this to be possible so they have the terminals needed. One-way switches cannot be linked together because there aren't enough terminals so they would only be used where a single switch is required. In all other situations you need two-way or intermediate switches, for example a hall and landing switch to operate the same landing light. Intermediate switches are needed where more than two switches are operating one lighting configuaration. Intermediate switches would be positioned between two two-way switches. You can have three, four or more switches operating a light using this combination but the intermediate switches are specials, normally you don't need them. As for double pole, I am not aware that double pole switches are really necessary for lights. As the other electricians have explained, it is to switch both line and neutral conductors, really only required for maintenance purposes or for safety where complete isolation is required. To just switch a light on and off there is no need to isolate the light completely so its just the line that gets switched. In fact most of the time you won't see neutral conductors in a switch box. Where they are used they would be commoned up in one connector. Gangs are just as you would expect, one-gang is a single switch, two-gang is a double switch, three-gang is three switches on so on. For the same reason explained above, two gang or more are always two-way (or intermediate) its pointless making multiple- gang switches one-way. Regards, Roy