As a power, it can be done, as long as the load at the exit of the protector is less than or equal to that supported by it. But, and there is always a but, it is not recommended since it does not favor conductivity, and perhaps not in accordance with the country's regulations. Ideally, from the key to cut the entrance, feed two protectors, one for each floor. The latter will give you a better chance of isolating future failures. If you do not have another one, for economic or similar reasons, if you connect it, while the load is in line, it will work for you. (Check the temperature at the thermal outlet every so often) You do not clarify what amperage your thermal is, nor what charge They use your spotlights. In general, 10A goes well for "normal" lighting Greetings from Uruguay