Installing a shower unit is a very skilled job and involves a fair degree of plumbing and electrical work. There are a number of things to think about when planning the electrical installation. The electrical circuit needs to be designed with the current demand of the shower in mind. There are a couple of types of cable used to install an electric shower 6mm or 10mm. The 10mm cable is used on 10.5 and 9.5kw showers and the 6mm cable is used on the 8.5kw showers. Another factor to think about when planning the electrical installation is the length of the cable run.Mcb sizes are also another factor to consider, Mcb stands for mechanical circuit breaker. An mechanical circuit breaker protects the electrical cable from over load and shuts down the power if a fault develops .If you choose the wrong size mechanical circuit breaker for the electric circuit, it can cause the cable to over load and burn out. Or on the other side of the coin the shower will not operate properly. If you are not competent with electrics I would not advise you to attempt to do the electrical installation work. Hire the services of a qualified electrician to do this for you as electric showers can be dangerous if not installed correctly.The plumbing side of the job is a whole lot easier and a lot less dangerous.Every electric shower is connected to the mains cold water supply. To plumb the shower in firstly turn off the water at the stop cock. Then connect the pipe at the shower inlet and plumb the other end into the nearest mains cold pipe. You can use plastic pipe the likes of speed fit or poly plumb as its easy to use. The fittings and the pipe just push together, no blow lamps or spanners required. You can do the pipe work in copper pipe if you like it dose not make a difference to the shower. There is just a little more skill involved to join the copper fittings.