Any fitting under 230V (eg 12V) is called low voltage and will require a transformer.
If you use one fitting with a 50W lamp then you will need a transformer that can take at least 50W or 50VA. If you have one fitting with 3 x 50W lamps then you will need a transformer with at least 150W or 150VA capacity or three individual 50VA transformers.
Mains voltage or 220-250V fittings do not require any extras aside from the lamp (bulb)
Most light fittings exclude lamp (bulb), transformer (if required) and heat can (if required).
These need to be purchased separately - see respective sections for these.
MAINS VOLTAGE vs LOW VOLTAGE
People often ask why one over the other. It is mainly preference except in situations
like bathrooms where it is preferable, but not necessary, to have low voltage fittings.
Most fittings can now be easily changed to L.E.D. lamps for additional energy saving.
Compact Fluorescent Lamps (CFLs) should preferably be used in fittings specifically designed for
CFLs so that proper light reflection is obtained.
NOTE: From July 2012 it will be mandatory to include, on either the fitting or the packaging, one of the following Class Markings. From July 2012 the only recessed luminaires that may be installed in a residential dwelling are those that possess one of the first FOUR marks. If it possesses the Non IC mark OR it doesn't have a mark at all then it may not be installed in a residential dwelling. This is principally to do with insulation, therefore they are perfectly safe fittings for commercial installations.
For these marks please click on the Marks below for a full description of each mark.