Heschen 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)

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

Although not yet installed it appears to be of a very high quality. Reasonably priced. I would recommend.

This is a very well-made switch with accessible and secure connection terminals. I use it for switching between two standby mains generators before the current one runs out of fuel. If switched quickly the domestic load sees only a very brief interruption, not normally long enough to reset clocks, timers, etc.The central off position ensures that there is no possible short between inputs.This arrangement gives me effectively continuous standby power, necessary in our location from time to time, at the small cost of popping out to the generator shed every 4 hours or so, to switch over, and, after a cooling down period, re-fuel and check the oil level of the standby generator.I have two reservations about the switch:Firstly, the space inside the switch box is very tight. It is difficult to squeeze 3x13 amp cables and links into the available space.Secondly, the switch is provided with only two knock-out holes and weather-proof glands, each capable of accommodating one 13-amp cable, but not two. A change-over switch normally requires one input and two output cables. I used Gaffer Epoxy Putty to create a solid weather-proof seal for two input cables.On the hole, however, this switch is highly recommended - but make sure you figure out the wiring diagram carefully.

I intend to configure a bank of Two 12v Leisure Batteries for occasional 24v operation in my makeshift campervan. At present, my 12v-240v Power Inverter satisfactorily powers a (1200w In) 700w Microwave Oven. Yet, when the former wears out, a replacement 24v P/I might only be available.

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.

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.

Good product, but too compact to enable a good cable installation