Low voltage garden lighting
The majority of modern garden lighting works at 12 volts. To be able to operate these lights at 12volts you will require a transformer. This is a device which alters the voltage usually from 240 volts to 12 volts. There is a very good reason for this reduction and that is safety. If the cable running to the light is damaged it will not harm anyone because the voltage is so low. However, if the cable were 240 volts and it became damaged it could quite easily kill someone.
Low voltage garden lighting still requires 240 volts (up until the transformer) and this is fed by using steel wired armoured cable. This should be buried below the ground (regulation of 50cm/18 inches) and covered with a yellow warning tape. However due to the low voltage cable being 'safe', the cable can be covered with mulch or left just below the soil surface.
Depending on how many lights you are trying to illuminate will determine the size of the transformer. However, low voltage cable may reduce in voltage if the amount of lights fitted extends over a long distance (see voltage drop chart) It is preferable to keep the number of lights used to a minimum, otherwise this will result in a voltage drop and the lights will become dim.
It is important to note that although these lights are low voltage, the fittings can still become hot. This will depend on the wattage of the lamp used i.e. 50 watt will be hotter than a 20watt lamp. The material used for the fitting will also make a difference to the overall heat eg a stainless steel fitting will retain its heat for longer than a aluminium fitting. With any lighting it is advisable to be sensible when changing lamps or moving the fittings. Always wear gloves to change the lamp or when re-positioning the unit if it has been on for some time.
An approved quality light fitting should always carry an IP rating. This indicates how well it will stand up to external conditions.
Voltage drop chart