Power
Underground power lines are finding favor with utilities, because of the susceptibility of overhead power lines to storm damage and the continuous maintenance required from “tree topping” and pole maintenance and replacement. Furthermore, underground power lines improve curb appeal and make neighborhoods more aesthetically pleasing.
Although direct bury power cable systems are designed for long life, use of HDPE conduit to encase and protect the power cable from rock impingement is gaining favor as it allows for quick and easy repairs without excavation of the cable. HDPE conduit and innerduct is used to carry low 600V-transformer to end user) and medium (<69kV-substation to transformer) voltage power lines.
HDPE benefits include:
- A wide temperature range for installation, from -20 degrees C to 90 degree C operating temperature for cables
- A low coefficient of friction (20% lower than PVC) to allow for long cable pulls
- Tough, durable and a life expectancy well over that of the power cable.
- Replace or repair cable lines without digging or trenching
- Chemical and corrosion resistance
- Easy installation, HDPE pipe is the preferred material for HDD (Horizontal Directional Drilling), because of its long continuous lengths and high pull strength
- HDD benefits include the elimination of traffic disruption and minimal surface damage
- Can be plowed as opposed to PVC
Smooth Wall Duct
Smooth wall is the industry standard High Density Polyethylene (HDPE)
duct available from Blue Diamond in ½” through 6” in a variety of wall
thicknesses and colors. Standard colors for the power and utility
industry are red, or black with three red stripes. The interior of
smooth wall has a slick finish which delivers a low coefficient of
friction allowing long power cable pulls. It can also be pre-lubricated
at our factory. Cable in Conduit (CIC) means power cables can be
installed in our manufacturing facility during our extrusion process,
saving money by eliminating the need for pulling cable in the field. It
also insures a clean pathway from the factory to the field.Ribbed Wall Duct
Blue Diamonds ribbed wall conduit and innerduct is designed to allow
extremely long pulls of cable by lowering the coefficient of friction.
Lubrication of the conduit is standard on CIC applications.UL Listed Duct
Blue Diamond is also UL (Underwriters Laboratory) listed for power applications. BDI UL duct meets UL 651B Continuous Length HDPE Conduit and BDI is one of only two HDPE conduit manufacturers listed under UL 1990, Nonmetallic Underground Conduit with Conductors. UL 1990 is the specification for UL power cable in UL conduit-CIC. UL listed HDPE is compliant with Article 353 of the 2008 NEC NFPA 70 National Electric Code and NEMA (National Electrical Manufacturers Association) TC 7, Smooth-Wall Coilable Electrical Polyethylene Conduit.UL Listed HDPE conduit is available in EPEC-40 (Schedule 40) and EPEC-80 (Schedule 80) wall thicknesses from ½” through 6”. It is also available from Blue Diamond in EPEC-B (SDR 13.5 wall thickness) in 1 ¼” through 6”.
UL listed conduit from Blue Diamond has a high tensile strength to weight ratio, superior crush resistance and a low coefficient of friction which makes it ideal for HDD (Horizontal Directional Drilling).
- Note: Engineers and contractors often specify a heavier, SDR 11 wall thickness for directional drilling. UL does not recognize SDR 11 in its specifications. If you require a more robust conduit for tough field conditions, BDI recommends specifying UL EPEC-80 (schedule 80) in diameters ½” though 4”. Schedule 80 matches up well with SDR 11 wall thickness through those diameters. Above 4”, SDR 13.5 UL listed pipe is the heaviest wall available.
- Consult the BDI spec sheets.
- UL Listed and NEMA Conduit is not available in ribbed inner wall. UL and NEMA conduit only provide for smooth wall pipe.
