The answer to 'why is my light fixture tripping breaker' is that there is likely an electrical issue with the light fixture causing a short circuit or overload. This could be due to a few common causes, such as a faulty wiring connection, a problem with the fixture itself, or too many lights on the circuit.
When a light fixture trips the breaker, it's a sign that there is an electrical problem that needs to be addressed. This is not something you'll want to ignore, as it could be a fire hazard. If the issue is not resolved, the breaker will continue to trip every time you try to turn the lights on.