Mike Dolt Enterprises
Mike Dolt Enterprises
User: cyriousn, Location: ME / CT
Asked on: Thursday, April 28, 2011 at 3:50 pm EDT
Answered on: Tuesday, May 14, 2024 at 4:45 am EDT
Question: I may be totally missing something here but I cannot find a code reference to the requirement for concrete encased duct banks? I can see information about depths but nothing about when they are actually required....under roads? medium/high voltages?
National Electrical Code (NEC) Article 300.5(D)
"Raceways installed under roadways shall be concrete-encased"
Additional Guidance
Institute of Electrical and Electronics Engineers (IEEE) Standard 141
Recommends concrete encasement for duct banks installed under roads or parking lots to provide mechanical protection and prevent shifting.
American Public Power Association (APPA)
"Recommended Practice for Underground Electric Power Distribution Design and Construction" also recommends concrete encasement for duct banks under roads.
Reasons for Requirement
Mechanical Protection
Concrete encasement provides additional protection from heavy loads, such as traffic, that may damage or break the duct bank.
Prevention of Shifting
Concrete encasement helps to keep the duct bank in place and prevent it from shifting or moving due to ground movement or other forces.
Seismic Resistance
Concrete encasement can enhance the seismic resistance of the duct bank, reducing the risk of damage during earthquakes.*
Improved Fire Resistance: Concrete encasement can provide additional fire resistance to the duct bank, protecting it from damage in the event of a fire. Flag for review