My Lasko electric heater stopped working and I thought it just played out so I replaced it with another heater that worked fine for a while, but when I went back to check it was also not working. A fan is on the same circuit and has been that way for years, the fan still works fine. Is this maybe a grounding problem or a bad breaker? I don't want to try another heater for fear it might blow up too. How can I check to see if it is safe for a new heater?