Abstract: Four employees of an electric utility were replacing the damaged base insulator of a 220-kilovolt circuit breaker. They had positioned two ladders; one on each side of the circuit breaker. One of these ladders was supported by the circuit breaker's head, and one of the employees was working from it. Another employee was working below from the other ladder, which was resting on the metal structure. The base insulator broke because of the extra load imposed on it. As a result, the circuit breaker, the ladder resting on it, and the employee on that ladder fell down some distance until the breaker was caught up by a boom sling. This caused the ladder below to collapse, and the employee who was on it fell. He suffered several broken bones and was hospitalized for his injuries.