It goes without saying really that one of the biggest electricity consumers for the home at the moment is the electrical shower. Due to revised electrical rules, it could be that you are best hiring professionals to undertake the task of fitting a new electrical shower. However, it is still possible, as you wills see below.
As it is a large electricity consumer it really needs its own MCB or fuse or even its own circuit and there are some rules you must follow when installing a new circuit for your electric shower. Part P covers installing yourself shower circuit by yourself, but you need to consult with and inform building control before you begin work and get the work and area inspected. You may even have to hire a professional to install the circuit so you can install the shower yourself.
If you are only going to be switching the current shower for a similar unit, then you do not need to contact building control You may need to bond the metal pipes in the bathroom and the cables need to run in the permitted zones. The cables you use must be the correct size and thickness and this will depend on the KW rating of your brand new shower, as well as the distance between the shower and the consumer unit. A good rule of thumb for thickness is 10 mm2, but it is best to find out from an electrician which is best.
Shower Must Be Connected To A RCD
An RCD is something that continuously measure the difference between the neutral and live and disconnects the electricity supply if a fault is detected. In a more modern set-up you can connect a RCBO which is essentially combination of RCD and MCB. Any circuit set-up for a shower should have a double pole isolator switch(one that disconnects both neutral and live) that cannot be controlled by someone while they are in under the shower. If you have a particularly small bathroom, this will probably mean you have to install the switch outside of the room. If you have a larger sized bathroom, you may want to install the switch inside and it is crucial that you make it a pull-cord type that comes down from the ceiling. When you are routing the cable it should have a completely separate route from other cables and should not pass through thermal plasterboard or insulation.
You can make the job easier on yourself by feeding the wire into the back box of a double pole switch so all the wires are sitting in their correct places. The double pole switch you use needs to have the correct amperage for your chosen shower. Although there is no harm in using a switch with a higher amperage, you must never use a switch with a lower amperage. There should also be an indicator incorporated into the switch so that you know whether the shower is on or off.
So that you know exactly where the wires go, double pole switches are always marked up on the reverse side. These can sometimes be very confusing and are labelled up as load and feed, some as load and supply and others are more simply labelled as out and in.
The most important connection In the whole set-up is the earth. The earth wire is usually bare and needs to be sleeved with yellow and green sleeving. The earth wire is then fastened very securely to the earthing terminal, which is normally done with a little nut. The cord grip should be tightened firmly so that it grips to the wire and prevents it from ever being removed from the shower. The connections you make at the consumer unit will depend largely on the kind of consumer unit you have. Needless to say, that the shower must be connected to a RCD as not only is this a very practical device, it is very safe too and worth the small investment.
The specific model of shower you have decided to purchase should also come with instructions and guidelines as to how you connect the unit up to a set-up as described above. If you are in any doubt though, there really is no shame in hiring a professional who knows exactly what they are doing when it comes to working with electricity and more specifically fitting modern, electric showers.
You have to weigh up how much possible stress you want to deal with in the set-up stage and whether it is worth alleviating that stress and just hiring someone to undertake the task.