I purchased a 100w LED Transformer (240v - 12v) from LED Hut. It came with no instructions. I contacted customer services and asked if I should switch at the input or output side of the transformer. The transformer has 2 outputs. I also asked LED Hut if each output was limited to 50w or if only one of the outputs were to be used could that be used up to a max of 100w. Their response was that they could not answer the question because they were not trained electricians and that I should consult a professional. I used to be a domestic installer but I career changed so I guess I can no longer class myself as professional. So my question to the professionals is: "is there any regulation that states that accessories such as this should be fitted iaw the manufacturers instructions"? Also is there any regulation that obliges the supplier to provide instructions? And lastly if there is a professional out there that can advise on my 2 technical questions regarding switching and outputs that would be greatly appreciated.