Universal Rotary Cam Selector Changeover Switch, SZW26-20/D202.2D, 660V 20A, ON-Off-ON, 3 Position 2 Phase 8 Terminals, with Master Switch Exterior Box,(Standard Box)

I installed this in my camper, to switch between a battery inverter and mains. Get the the large back box version as wiring is made a lot simpler. I installed an extra gland as there are only two supplied. Wiring is straight forward, although the instructions could be a more helpful.

Very cool item

These are a decent build quality. They only come with two glands, so be aware of that. Can't figure out how to install the included jumper bars. Really they need a bit more space to connect the earth cables, but they are much more compact than triple pole versions. They look tidy and have a very nice, positive click.

Seems well built. Not much space for your wires once the back is on and all tight but easy to wire up, and feels solid. You could remove the switch from the box and panel mount if you needed. Used in my case to power a diesel heater from one of two sources.

Being in regular use for 6 months works great can't fault it nice and compact but enough room to get the wiring in nicely Highly recommended

This switch is designed for housing electrics & it comes with all the bits you will need & a few extras. I am only using it to switch between speakers & it does that very well, overkill some might say but I like it. I'm running it one in two out, two in two out is the default but you can wire it how you wish. It is very sturdy & has a great feel to it. The one I got DID come with a wiring diagram unlike some other reviewers have stated.

My only grip, as others have observed too, is that the mounting box is a little too small IMO. Cables can only just be fitted in place within the mounting case. The kit includes all that you need but it's strange that only 2 cable outlets are provided when you really need 3 surely? (Power in, power out 1, and power out 2). The lack of an earthing option also means that you need to provide your own connection block for the (3) earth cables and then squeeze this in too. However, it all worked and I was just about able to then secure the rotary switch to the casing (just) - albeit I used 1.5mm heat proof cable. My use was to be able to select 1 of 2 power options for my immersion heating element in the Hot Water tank: Solar control, or (overnight cheap rate) grid power.

I used this to control 1xSupply & 2xLoad as the immersion heater circuit controlled the immersion and a show pump through a socket. So as not to breach the supply current I used this DP switch to totally isolate one from the other. My connections were; 1) Supply Live. 1&3) bridged Live 2) Load position1 Live, 4) Load position 2 Live, 5) Supply N, 5&7) bridges Neutral, 6) Load position1 Neutral & 8)Load position2 Neutral. There is a tiny square piece of paper supplied labelled tip which shows these connections. Even though position 0 is off, I have a spare water heater DP isolation with a neon which I installed between the supply and this switch. I also ordered the larger back box version and agree that this should be the standard size especially when using 2.5mm T&E and wage or other connectors.