The answer to 'how to test troubleshooting' is that testing and troubleshooting electrical systems requires a systematic approach to identify and resolve issues. As an expert electrical technician, I recommend following a step-by-step process to safely test and troubleshoot electrical problems in your home.
Begin by visually inspecting the electrical system for any obvious signs of damage or wear, such as frayed wires, loose connections, or tripped circuit breakers. Next, use a multimeter to test for proper voltage, current, and resistance at various points in the circuit. This can help isolate the problem area. If you're not comfortable using a multimeter, it's best to call a professional electrician.