Lighting fuse keeps blowing.

I hope this question isn't too mundane for the group:
I have an Ikea Beryll light fitting http://www.ikea.com/gb/en/catalog/products/70043483
fitted with four 20W halogen bulbs. I'm based in the UK so I have a 240v mains supply.
With 4 bulbs drawing 20W @ 240v I've got a total draw of 80W @ 240v. I make that 0.333 amps. (W/V = A, or 80/240 = 0.333).
So why do the 8 amp, 250V, quick blow fuses I'm fitting into this light fitting keep blowing after a few hours operation?
--
-Toby
Add the word afiduluminag to the subject to circumvent my email filters.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Toby Newman wrote:

The link takes me to a description stating 12v, not 240v, lamps.
Which is important, because it means that the mains supply is connected to a transformer, not directly to the lamps.
The rest of this is written on the basis that there is a transformer in the base of the lamp fitting.
That it runs for several hours before blowing the fuse puts the suspicion on the transformer. Something with a bit of thermal mass is needed to produce that sort of delay.
What I suggest that you do is take the fitting down and inspect what wiring you can get to, to see if there are any bare wires that could move and touch something.
There are other tests that can be done to prove that the transformer is faulty , but they either need test equipment that you probably don't have, or need test methods that should be done under the supervision of someone qualified and experienced.
Unless you have such tools and/or the expertise, all you can do is replace the transformer, or the complete light fitting.
It would probably be possible, and cheaper, to replace the transformer with an external one, extending the 12 volt wiring from the lamp fitting to reach the nearby transformer. However, this will prbably mean that the 240v wiring would need to be extended too - so best left to someone experienced in such things.
--
Sue

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.