Customer was having an issue with the basement rec room recessed lights circuit breaker tripping. I found that the breaker was a combination Arc fault breaker. We tried testing breaker multiple times and it would not trip at all. After the customer and i tried again we were able to get it to test trip. We determined there was definitely an internal issue with this breaker so we removed it and installed a new one in its place. The basement lights are working properly now and were not tripping off while we were there.