I am having a kitchen extension done and want to put spotlights in the ceiling,do they have to be low voltage or can i use 240v spots and do they have to be fire rated,can't seem to find any info on this anywhere.
you can use either mains or LV lights & they only have to be fire rated if there is a particular risk of breaking a fire barrier say into an escape passage above.
The only other consideration is that all wiring in a kitchen is covered by bldg regs part p, see projects section,
You can fit 230 volt spots I see very little advantage with SELV unless you have fluctuating voltage and 230 volt will normally allow used of cold cathode lights (compact florescent), but as to fire hoods I am uncertain as to rules.
I think in the main the idea is to replace the plaster board removed with a hood so a general fire in the kitchen will take longer before it spreads up to the bed room above and is not really to do with heat from the lamp it's self.
Since work on electrics in a kitchen other than replacing like for like will come under Part P I suggest you ask the responsible person either the registered electrician or building inspector.
It would be so easy for me to make a mistake and since they are signing the paper work if they make a mistake you still get the all important paper work.
Do be careful with spot lights I have seen some very poor results where the angle was wrong and never seen so many shadows. Also I do not believe the tungsten halogen lights are any more efficient than normal bulbs and I am sure a lot less efficient than florescent fittings plus the government says they are phasing out the tungsten bulbs and many of the little spot lights will not take the LED or Cold Cathode bulbs without having a big lump sticking out of the holder as they are longer than the tungsten halogen types.