spot lights loose connection

[bigal888]

Hi, I'm a newbie so please bare with.

first of all i'm a chippy not a sparky, but i am keen, and i'm pretty handy with electrics, but no pro.

problem:

I have a ring of 5 spots all run off 1 transformer and looped in. recently the spots have started going out after 20mins or so then come back on after about 15mins. so i came to the conclusion i have a loose connection somwhere causing them to over-heat. when i had a closer look the connections have been crimped into a plastic plug-and-play connection (i will try and upload pic)

http://media.diynot.com/175000_174411_38083_78678637_thumb.jpg

all connections appear to be fine but i can't be sure. I also can't get to the transformer as it is screwed to the joist (in a single story extension with no roof space access) any ideas on finding faults?

I decided to buy myself a multi-meter but this has confused the hell out of me and left me with more questions than answers.

any help greatfully recived. thank you[/u]

 

[bernardgreen]

More likely the "transformer" is overheating and shutting itself OFF. When it cools down it restarts.

If you have changed any lamps check the new ones are not higher wattage than they should be, and that the total lamp load is with the "transformers" rated output.

Has anything been done that would reduce the ability of the "transformer" to disipate heat ? Insulation added etc

 

[RF Lighting]

Are they all going on and off together or individually at different times?

 

[bigal888]

hi,

yeah they all go off at the same time, i agree bernard, i think its the transformer, unfortunatly i don't know what the load of the transformer is without cutting a hole in the ceiling.
i think they have had a couple of wrong wattage lamps in their time but they are all right now and yet they still overheat?

 

[dannyboi2003]

What rating lamps are in the fittings now? If they are a pre-made lighting pack then the max rating of the lamp you can fit should be on a sticker on each fitting, can you confirm if you have such a sticker on any of the fittings?

 

[ricicle]

i don't know what the load of the transformer is without cutting a hole in the ceiling.

You mean you have a transformer fitted in an inaccessible position. Is there a liftable floor above ? It is not a good idea and contravenes regulation to have inaccessible terminations.

 

[bigal888]

hi,

yes dannyboi i do have the stickers on each fitting, they say 20w, 12v and the one i don't know the meaning of is 0.5M

the lamps i have in at the moment have this written on them...
m269/bab (which i guess is just a batch number or something similar)
12V
20W
AOT (I'm not sure what this one is either)

hopefully i don't just have the wrong lamps in, and look like a right amateur!

hi ricicle,
yes the transformer is in an inaccessible position, its in the roof space of a single story lean-to extension with no access.

if you all think the tranny is nackerd then i think i will cut it out and replace with indervidual transformers. what do you think?

oh yeah, is there a book on understanding multi-meters?

thanks again