Is the maximum audible noise from power supplies regulated in Europe?
As far as I am aware of, there is no requirement for noise of electronic devices per se. But there are regulations of noise levels at various work environments. I.e. if you want to sell your devices for a specific environment, you have to ensure that its noise level is below the one specified for that environment. I don't think I have seen any such noise level regulation for home environments, but I might be mistaken.