The answer to 'why is my surge protector dimming lights' is that a faulty or overloaded surge protector can cause the connected lights to dim. This is typically due to the surge protector not providing enough power to the lights, often because it is being overloaded with too many devices or has an internal issue.
Some common causes include the surge protector being old and failing, having too many high-wattage devices plugged into it, or a problem with the surge protector's internal circuitry. If you notice your lights dimming when connected to the surge protector, it's best to unplug the surge protector, test the outlets, and consider replacing the surge protector if the issue persists.