Micro-tunneling as an alternative to submarine cable

The geography that gives Seattle its beauty can pose unique challenges for the engineers attempting to provide service to the customers who live near or upon these features. Steep, wooded hills and greenbelts create familiar problems of construction and right-of-way maintenance. The waterways and adjoining shoreline zones present a more difficult set of requirements. When Seattle City Light determined it was necessary to install 2-26 kV distribution feeders across the Salmon Bay waterway, they discovered that submarine cables could not be used. Shallow angle directional drilling and micro-tunneling were examined and it was found that a microtunneled duct bank was the best method to use.<>