The answer to 'junction box burning smell' is that a burning smell coming from an electrical junction box is a serious safety issue that requires immediate attention. This could indicate overheating, loose connections, or even a fire hazard within the box. Symptoms may include a burning odor, visible smoke, or sparking from the junction box.
The main causes are usually faulty or overloaded wiring, loose connections, or water damage. This should never be ignored, as it could lead to an electrical fire. If you detect a burning smell, immediately turn off power to the circuit at the breaker and do not attempt to open the junction box. Call a licensed electrician right away to inspect and repair the issue.