Flickering Lights Can Indicate a Few Problems
A loose circuit connection – This is probably the most serious problem because it means that there is dangerous heating that is taking place at the connection point. This not only poses a high risk of electrocution, but a fire as well. Take care of this problem immediately.
A failing switch – While this is not quite a serious a problem, it is still one that requires immediate action.
A motor that is hard to start – The flickering may not have anything to do with your electrical system, but rather a motor in a large appliance such as your furnace or air conditioner. If a motor is experiencing a bearing failure, for example, that will require it to work harder when starting. This, in turn, means that it will draw more current and make any flickering more noticeable.