The answer to 'why is my switch circuit overload' is that the circuit has too much electrical current flowing through it, causing the circuit breaker to trip or the fuse to blow. This can be caused by several common issues, such as a short circuit, an overloaded circuit, or a problem with the switch or wiring.
Some common symptoms of an overloaded switch circuit include the lights flickering, the circuit breaker tripping frequently, or the switch feeling hot to the touch. If you're experiencing these issues, it's important to investigate the cause and address it promptly to prevent potential fire hazards or further damage to your electrical system.