Intermittent 12V spotlights Ask questions and find answers to many subjects relating to electrics and electrical work

[u33446z]

I have 5 12V spots in each of my bath and shower rooms which usually all come on when first switched. But after being on for a few minutes and then switched off, an immediate switch on can result in only one of the five in one room coming on.

Any ideas? Are transformers prone to intermittency?

[ericmark]

Some transformers or inverters do have in built protection devices but also 12 volt lights have high amps in the extra volt voltage side and any bad connection can cause these problems. The little pins that go into the socket for these lights get very hot and the sockets and pins are prone to faults sometimes just swapping lamps around can cure problem as the pins are gripped slightly different by sockets.

[u33446z]

Thanks. In this case I had checked that all lamps lit when just offered to the best socket. At the end of my experimentation I had only one of 5 positions working. I left them for a couple of hours, then switched on again, and they all lit. After a minute, I switched them off, and immediately switched on again, and only one(the reliable one) lit!

[ericmark]

From what you say it seems to be some type of protection device that has cut in. This may be because of overload, lack of cooling, or faulty units. It is highly unlikely that as remote we will work out what is wrong. There seems to be a move away from extra low voltage as the cold cathode lamps are only available as 230 volt and LED is not really bright enough so with the proposed withdraw of lamps with less than 40 lumens per watt the old tungsten bulbs will soon be unavailable. Reminds me I must get some spare projector bulbs before they are withdrawn.
Eric