Uno Memento

This is a piece of underground high-voltage electric cable that was put into service in May 1976 and recently was replaced and rerouted in May 2010 to make way for a new underground parking structure in downtown Ann Arbor, specifically along South Fifth Avenue between Liberty and William streets. For 34 years, this 4,800-volt cable served the Ann Arbor Federal Building. It has three copper conductors, each insulated with layers of paper insulation, wrapped in a lead sheath to maintain a water-proof seal and covered in neoprene jacketing. This type of cable is installed in conduit that runs between cable vaults (manholes) beneath the city streets and sidewalks. Today's underground cable cost, for similar types of cable, is about $1 million per mile, or $190 per foot. Thanks to Paul Ganz, DTE Energy's regional relations manager in Ann Arbor, for sharing this piece of history.