Princeton, IL – Small City, Big Modernization Plans

Converting Overhead Utilities To Underground With HDD, HDPE
March 2010 Vol. 65 No. 3
The city of Princeton is helping the environment while protecting its citizens.

For Mangrich and his crew, the job is also easier and quicker because the pipe comes in coils so hundreds of feet can be installed without stopping, greatly increasing productivity. The length of the coil depends on the size of the pipe. For example, as much as 6,000 feet of two-inch diameter HDPE pipe can be delivered on one reel.

“The HDPE pipe also enables us to use one pull to put in three different sizes - one inch, two inch and a two-and-a-half inch,” Mangrich explained. “The two-inch is used for primary conductor; the two-and-a-half is used for secondary conductor; and the one inch is for future fiber and is empty. This is all done in the same bore. We use a six or eight inch back reamer and pull them all at the same time. This year we also installed some four-inch diameter conduit. Basically what we’re doing is using the HDPE conduit to cut its own the pathway in the soil.” The electrical cable is then pulled through the conduit.

Blue Diamond LLC (Lexington, KY) manufactures the HDPE conduit pipe used for Princeton’s modernization. The conduit pipe has pre-installed pull tape, which makes it easy for Mangrich’s crew to run the power cables.

The conduit is RUS/USDA listed and meets all ASTM specs for SDR, SIDR and NEMA rated duct. It is also listed to UL 651 for the protection of cable and wires. The pipe’s high tensile strength-to-weight ratio, superior crush resistance and low coefficient of friction for cable installation makes it preferable for directional boring.

The main power line is generally run under the backyard of a house. The service line is run underground to the house with the homeowner paying an electrician to make the connection.

Safety, security and eye pleasing
Aside from providing the citizens of Princeton with a state-of-the-art utility system, Mayor Keith Cain knows the disappearing power lines reduce eye-pollution. “Our population loves the idea,” he said. “As we continue to bury underground services, they get even happier because they like the improvement in how their community looks. We all want Princeton to look clean and carefree. No one wants the poles and the wires sticking up through the trees throughout our community.”

Mayor Cain, who started the overhead to underground conversion during his early years as mayor, also realizes the other benefits.