LYNN – The Water and Sewer Commission’s director said a subcontractor digging up the Lynnway a month ago might have been responsible for last week’s flooding and traffic jams along the main artery.Daniel O’Neill said workers using heavy excavating equipment to install a plastic conduit line for National Grid may have punctured the cast-iron water line days, even a couple of weeks before the Dec. 30 water break.”It could even have been a pinhole puncture. National Grid has indicated they don’t believe it was their contractor’s fault. We will have to sit down and discuss it with National Grid,” O’Neill said.National Grid spokeswoman Debbie Drew said the pipe break “was not related” to National Grid’s Lynnway project.The break occurred near Marine Boulevard and Shepard Street and filled the roadway with water up to eight inches deep. Repair crews worked around the clock through New Year’s weekend repairing the pipe.The break and repairs, which slowed northbound afternoon commuter traffic to a crawl for two days last week, appear to be near the finish lineWorkers started digging up the north side of the Lynnway on October 22 to install cable and power line ductwork through November 22.The month-long project was part of National Grid’s effort to eliminate power outages in part by allowing service to be shifted throughout the electrical supply system in the event of a mechanical failure.The water break was not the first one to tie up Lynnway traffic or the only pipe break to occur in the city last month.On Dec. 8, a break occurred at the intersection of Broad and Spring streets and, on Dec. 22, a pipe burst on Parkland Avenue.