TRANSFORMERS - loading etc

happyhero

Hi can anybody advise me. We are looking into doing quite a bit of garden lighting at low voltage, and I heard some where to be aware of loading the transformer correctly ie obviously not to overload but also not to underload it, if there is such a word. I think it said something about not doing the transformer any good. If this is so what percentage should I aim to load the transformer to so that I can select correct transformer sizes? What harm does underloading it do anyway?

Also is it ok to mix wattages of fittings on a single transformer, eg could I have 5x20w lamps, and 5x10w lamps and 1x50w lamp on a 200w output transformer?

And lastly does anybody have any guidance on maximum cable run lengths so as not to get any significant volt drop or any other problems?

Any help appreciated please.

happyhero

apologies if I have done wrong here but I wrote this late last night and my post has disappeared off the front page so fast this morning I don't think anyone has noticed it to be able to answer me.

I would still be gratefull for any advice.