I've successfully replaced many electrical components for 50 years, although ignorant of the theory behind it, but always very careful to replace identically marked parts.

 

I had 4 spotlights to replace in my apartment, the first three were identical, 220V-20W. The last from another room was different, 12V-50W. The lad in the electrical department was made aware of the difference, he produced four new spots, and tested them in front of me. He had the choice of plugging into a number of power outlets (all numbered in Watts).

 

The first three spots worked perfectly, but I forget which outlet he used to test, the fourth spot exploded loudly with a bright flash, and burned the outlet. He then got another replacement spot, and used a different plug board to test it, this spot was to replace the 12V-50w spot. He plugged this into the 220V outlet and it worked perfectly. I told my Thai wife that we needed a 12V spot, and that he's tested it on 220W and that it probably wouldn't work for us.

 

She explained this to him, but he assured her it was fine, and would work for us. Arriving home I replaced the first three spots, and they were fine, however the fourth one which should have been 12V did not work, mind you it did not explode either, which is something I guess.

 

So if anyone can advise me as to how I might fix this problem spot, I will be very grateful. It lights the vanity mirror where the wife does her make up, so in our home it's the most important spot of all!

I've got the troublesome spot light in front of me it clearly says . . .

 

AEC

12V-50W.

 

The 3 that work are . .

BEC

220V-20W.

 

I thought that bulbs for cars are all 12Volts, so I was confused that a household spot light would have the same rating, can there be a transformer in that room with the vanity mirror, can't think why anyone would bother to go to such lengths, for a spot over a mirror. 

Yes you are spot on, I need to get an electrician to test the fitting. I went to Tesco Lotus (avoiding HomePro who said no need for 12V). I found that they do indeed have both 12V and 220V spots, so I bought  12V spot, got home and plugged it in, sadly it didn't work. So as you suggest, time to have it tested.

 

Curiously (to me) next to the switch for the spot, is a single 2 pin plug in, which powers a very small 220V fan, I have much to learn.

 

Many thanks!

The technician for the complex arrived and did almost as you suggest! except he said the transformer was dead (who knows?) so he bypassed it and connected to the regular wiring, so it now works with an LED 220V.

 

My better half is now happy, so all is well.

 

Many thanks for your helpful advice!