The 250 should be closer to the tops of the plants around 2feet or half a meter...most cupboards are up at shoulder height or higher....that means in the summer it will be much much warmer and that could cause a problem to the plant's health.....a 250 is for the most part pretty safe so you most likely would never have any burning probs unless it's touching something. You must have a pretty big cupboard because most are less than 3 feet high, unless I missed something??