You need to be careful about mounting a light bulb in a confined space such as under a stairs. If the bulb is too close too an inflammable surface (e.g. any kind of timber product) if may well start a fire. It is easy to forget about a light bulb being left switched on in such a cupboard etc.
A light bulb of less than 100 W needs to be at least 0.6 m away from any flammable material, bulb holders marked T1 - intended for bulbs of 60 W or less should not be used and bulb/lamp holders should not be mounted directly on flammable materials like chipboard.
J
May 2009