PARIS—Saying the devastation could perhaps have been avoided with some routine upgrades to modern 200-amp service, investigators announced Wednesday they have traced the cause of the Notre Dame fire to the cathedral’s archaic electrical system, which dates back to the 12th century. “In our examination of the wreckage, we discovered that some of the circuit breakers and sockets hadn’t been updated since the reign of Louis XII,” said lead investigator Jean-Luc Marchand, explaining that many of the fuses from the time of the cathedral’s construction were made of solid oak, while much of the wiring consisted of twisted cords of straw. “The light bulbs we found were so incredibly antiquated that their filaments were made of wool strips dipped in kerosene or whale oil. To make matters worse, Notre Dame’s entire electrical system was hooked into the power company’s transformer on the pole outside with a single strand of hemp twine. It’s a miracle the damage wasn’t worse.” Marchand went on to add that the fire likely started due to a malfunction from one of the rectory’s 14th-century wicker space heaters.