Lighting is relatively simple to layout, but you've got to understand what your doing. Even experienced electricians are sometimes unsure of quite what components to use and where, as often they will not have encountered low volt garden lighting systems before, but don't worry, help is at hand. Lets start with this diagram below:
I would not advise DIY installation of mains systems (in fact this is now largely illegal), this should be left to a qualified electrician. However, you can use pre-assembled DIY garden wiring kits, such as those supplied by Armadillo. Get the main armoured cable installed with junction boxes as required for the transformers, then you can tackle the low voltage side yourself and without danger. Alternatively, use these diagrams to show an electrician what you want done, and get them to install the lot. Remember, safety first and if in any doubt, consult a professional!
A simple layout showing two spotlights running from one
transformer
- Mains armoured cable
- Junction box
- Transformer
- Junction box
- 12 volt exterior cable
- cable joint kit
- light fitting
The essential ingredients of this layout are listed at right:
We could add more lights to this, as shown below. The ingredients remain the same, we just use more of them.
We've now added extra mains armoured cable (from the first junction box), an extra transformer and more lights.
You might wonder why I have not shown more lights being run from one transformer, instead of adding a second one. There are two reasons for this - firstly, it is important to keep the low voltage cable runs as short as possible, as voltage loss occurs on longer runs. I would say cables should be no more than 3 - 5 metres long. Secondly, the comfortable maximum number of lights that can be wired from one junction "A Box" is five. It is possible to run seven, but the wiring gets very difficult!
A last, important point to note is that you cannot use ordinary cable for low voltage use, it must be specifically designed for 12v exterior use. Ordinary cable soon becomes brittle with exposure to the elements, resulting in breakdown.