The majority of our space heaters pull 1,500 watts on high and 900 watts on low. This equates to about 12.5 amps on high and about 7.5 amps on low. Because of this high draw, if you are running a heater on a breaker line that also has a TV, DVD player and anything else and the line is a 15 amp breaker that will likely exceed the threshold for that line and will trip the breaker. The first thing you should do is try the heater in a separate outlet in a different room to see if the same thing occurs. If it does, take note what other items shutoff along with the heater. Based on that information you will be able to determine if this is something that might be a defect or that the unit is being used on a line that exceeds the amperage allotment for that breaker. As a means of testing, you can also plug the heater into a bathroom as they typically have 15+ amp breakers and are dedicated. If the unit trips that breaker, please contact our Customer Support Specialists for more assistance.