This seems odd as normally there are 3 amp fuses included within the strip lights. Faulty ballast units can cause overheating and fuses to blow which is why one normally has fuses fitted within the units. My first step would be to check these fuses are fitted and second I would disconnect the lamp at the lamp and see it it still trips and if not I would replace lamp. At the cost of a strip lamp not worth messing with. If you use the garage a lot then many be a HF unit would be better to use less power and get rid of stroboscopic effect but if only used to house car then I would use a cheap type.