Installation of outdoor wiring systems
The presence of water in gardens means that for safety reasons electrical circuits in the garden have to be protected by 30mA RCD. This means that any earth faults that develop on the circuit will cause the circuit breaker to trip before anybody receives a fatal electric shock.
Any light fitting, transformer or electrical equipment used outside has to have a minimum IP (Ingress Protection) rating. Equipment with the correct IP rating and correctly assembled will ensure that moisture does not get into the installation and this will prevent earth faults causing nuisance tripping of the RCD.
Mains voltage electrical cable burried in the garden must be mechanically protected against damage and laid at a safe depth. This is normally achieved by using Steel Wired Armoured cable laid at 500mm deep and terminated with the correct glands at the junction boxes.
It is often sensible to fit 12v Extra Low Voltage lighting if 'Spike Lights' or 'Path Lights' are being positioned in flower beds. This allows the cable to be left on the surface or covered with bark chip or mulch and means that the lighting can be moved easily, if required, as the seasons change.
All work on outdoor circuits is deemed notifiable to building control. Any additions or alterations have to be inspected, tested and certified during installation and on completion to confirm that they conform to the Wiring Regulations - BS7671 2008. The client is issued with an Electrical Installation Certificate and the local building control must be informed. This is all completed by a suitably qualified electrician registered with a competent person scheme like Elecsa.