Hopefully someone here can help me out.

After realising the transformer powering the 6 low voltage lights in my dining room had blown i have gone about replacing it. I have found the transformer and was just going to replace it with another of the same rating voltage etc, but a mate reckons i need to replace the entire lighting wiring that connect each light, as he says the length of wire is important to the amps drawn (something like that!)

I really don’t want to have to replace the whole low voltage wiring as it will be a real pain in the ass, so am i ok just replacing the transformer and being done with it?

no need to change wires

Thanks, do you know at what point the cable becomes to long and cause the lights to suffer a voltage drop?

I presume this depends on bulb wattage, transformer rating etc?

You normally have a maximum length of wire permissible – on the chaepo ones I have it was 1m.

1m? Do you mean 1m extra to what is already supplied?

what lenghts are the cables, what rating are the lamps 20 / 35 / 50watts

sorry but I think low voltage lighting is not the best

You normally have a maximum length of wire permissible – on the chaepo ones I have it was 1m.

It’s not like 0.99m will work and 1.01m won’t. Unless the transformer / voltage converter is really rubbish and relying on the inductance / capacitance of the wiring, the only difference the length of the wiring makes is how much voltage drop there is along it. If you want to make longer wiring runs you can simply use lower resistance cable – though since to get lower resistance you need more copper, the wire will be thicker and therefore more expensive.

Was the original ikea? My sparky has told me they are crap.

No harm in up-rating?

1m total length – they were cheapies tho

If you want the lights far apart it is better to use individual transformers for each light

Does each light have its own transformer or is there one transformer for all 6 lights?
Volt drop along cable should be no more than 3%, so for the lighting run from fuse to the transformers (assuming 1.0mm twin and earth in a plasterboard ceiling with less than 100mm of insulation, and all six 50w lights are on the same circuit), the run can be approx. 120m before volt drop falls below the 3%.
For the weedy cables from the transformer to the lamp its a bit sketchy (the calcs run out at 15.7m but that’s rubbish), so as a rule the transformer should be as close to the light as possible, but at least 9 inches away to protect against the lamp heat. Also clear insulation from around the transformer as this is a killer. Pulled many a melted pliable transformer out of a nice bed of insulation.
On a money note, switch from lv downlights to a single centre light. Elec is paid in watts used not volts, so 6x50w = 300w of chargeable elec versus 1x60w centre light or a 5ft 58w fluorescent. Yeah yeah, i know, downlights are v. pretty and sparkly….