Power Outages Hasten Deere Plant Conversion To Underground

By Jeff Griffin, Senior Editor | October 2008 Vol. 63 No. 10

"Most new installations we are doing are underground," he added. "This project is a little different than normal because of it being a 15 KV project and the age and reliability was called into question with the first failure. The system was serving a large industrial plant, and I am sure costs of down time there was a major consideration in decisions about the new installation."

Maintenance issues hasten change

If there are maintenance issues or the need to change existing feeders, most projects of this nature are planned to convert old aerial plant to underground, Innis pointed out.

"If there is going to be additional load added to existing feeders, there are major costs associated with feeders and gear," Innis said. "Conversion is always examined at that point. In most cases, conversion is selected with the decision based on multiple factors: reliability, costs, future considerations and, in quite a few cases, aesthetics.

“Most of the projects we are dealing with are systems of 480 volt or 208 volt. Due the size of these feeds and the current National Electrical Code (NEC), in most cases the difference in costs to convert to underground is low enough and most of the old 480 or 208 volt systems are being replaced underground."

Innis expects future revisions to the power distribution throughout the plant will all be done underground.

"I cannot imagine seeing another aerial run at this facility," he said.

Innis added that the Deere project was typical of aerial to underground conversions. Most are projects that replace a customer's complete service, usually due to age, required repairs or the need for larger capacity of service entrance to the facility.

"The utility company removes wooden poles and pole top transformers and installs a new pad mounted transformer," he explained. "Our work is to provide concrete pads and all underground conduits and wiring for re-feeding the facility with electricity. On this project, we were required to pothole the entire length of the trench because there were so many existing critical utilities. Potholing was performed by a subcontractor using vacuum excavation equipment."

Baker Electric did all underground work with crews from its underground division."From a cost standpoint, this enables us to directly assist a project owner in the process of making a decision about going underground."