We had a halgen floodlight + separate p.i.r. put on our barn about 18 months ago that has been v. unreliable - lamps blowing, light often not coming on, etc. The light is fed by a switch inside the house connected via an armoured cable of around 40 metres.
On inspecting the floodlight we found the contacts were very corroded, obviously a very cheap fitting. We had the light replaced with a "low energy" (57W) unit purchased from Alert Electricals. When fitted the unit would flash briefly but would not stay on. The existing PIR was diagnosed as faulty and a new PIR obtained from the local Screwfix. New PIR fitted, walktested and set up for 5 mins operation at dusk. Darkness falls and everything works as expected.
An hour later and light fails to stay on. We can put the PIR into "manual mode" from the switch and the light will stay on (but only after dark).
In "Auto mode" the PIR clicks and the light flashes briefly (less than 1 second) but won't stay on.
Can anyone help as I now have little faith in the electrician.
