Con Edison Going to Vented Manhole Covers to Lessen Road Salt Damage

When a snowstorm hits New York City, a “salt storm” usually isn’t far behind.

Con Edison is working to minimize the damage road salt does to its underground electrical delivery equipment, and the manhole events and customer outages that can result from that damage.

The company has installed more than 121,000 vented covers on manholes and service boxes that allow gases to escape if underground wiring begins to smoke or catches fire. In addition, the company has an aggressive program to replace underground cable, adding 833 miles of new wiring in 2015 alone.  The replacement cable is dual-layered, insulated with a low-smoke fire-retardant jacket.

Con Edison plans to install another 55,000 vented covers by 2019. The replacement program started in 2005. The company has 246,000 manholes and service boxes in its underground electrical delivery system, which serves 2.5 million New Yorkers.

WHY MANHOLE EVENTS HAPPEN:

When snowmelt and road salt wash into manholes and service boxes, the mix can degrade wire insulation and generate heat. As the insulation burns, it creates smoke and a spark can ignite the gas and lift the cover.