By Staff reports The underground construction work causing minor traffic snarls in downtown Charleston is part of a five-year $20 million project to replace electric cables and equipment.Contractors working for Appalachian Power are about one year into the project, company spokesman Phil Moye said.The company currently has about 30 contract workers on the project, which most recently has been focused on Virginia and Capitol streets, Moye said."We have had a fair presence in the city most of this year and we'll continue to as well," Moye said.He said that much of the electric infrastructure beneath the streets is more than 50 years old and needs to be replaced."It's been a very reliable network and we want to make sure it remains that way and the only way to do that is to replace the equipment as it ages," Moye said.The project largely involves replacing cables, but they also constructed a new underground vault recently at the corner of Quarrier and Summers streets."Once the work is completed in one area they'll move to another and, certainly, there are traffic disruptions, but we really can't do the work without getting into manholes and getting into underground vaults," Moye said.