#Concrete encased duct bank design install
#Concrete encased duct bank design software
#Concrete encased duct bank design professional

All direct buried conduit shall be rigid hot dipped galvanized steel.Ĭ. Rigid metal conduit shall be used for underground installations whenever an extra high-strength installation is required such as in equipment foundations.ī. Conduit that runs under building slabs or roadways shall extend 1.5 meters beyond the building slab or edge of road.Ī. The minimum bending radius shall be 10 times the conduit diameter.į. In general, the depth of a conduit duct bank shall be established by the bending radius of the largest conduit in the duct bank. Where the conduit stubs up, the concrete envelope shall extend at least 150 mm (6 inches) above grade and shall be sloped.Į.

The top of the concrete envelope shall be located a minimum of 610 mm (24 inches) below grade.

#Concrete encased duct bank design install

Do not install any portion of the duct bank in the 45° cone of deflection from the low point of foundations.ĭ. In general, underground conduits and duct banks shall be installed below sewer lines and other piping.Ĭ. The location of all underground runs shall be selected with consideration for future structural installations in the area.ī. Underground Installation Requirements Underground RoutingĪ. Conduit material (RGS or PVC) for use in duct bank applications shall be selected per the requirements of this document.Duct banks shall be constructed with the use of concrete forms or by the use of precast duct banks.Conduit and/or cable for direct burial shall be selected per the requirements of this document.Plowing of cable or conduit directly into the earth is not permitted. Direct buried cable or conduit shall be installed in prepared trenches as defined in this specification.The following underground installation types are acceptable. Underground installations of electrical conduit, cable, conductors or duct bank systems must be approved by company.

Data output flagging critical and marginal cable temperatures.

Data Input of physical characteristics of the cables, soil, and duct bank parameters.

More information about the ETAP program can be found at The steady-state temperature calculation is based on the IEC 60287 or the NEC© accepted Neher-McGrath method. The ETAP cable thermal analysis program provides five types of calculations for cable derating analysis, namely, steady-state temperature calculation, uniform-ampacity cable ampacity calculation, uniform-temperature cable ampacity calculation, cable sizing, and transient temperature calculation.

#Concrete encased duct bank design software

For an existing system, the cable thermal analysis software examines cable temperatures and determines their ampacity.

#Concrete encased duct bank design professional

Many AHJs will require thermal and ampacity calculations performed and stamped by Professional Engineers.Ĭable derating analysis is an important part of power system design and analysis. Our study determines the proper size of cables to carry the specified loads. Sections 310.16(A)(1) and 310.60.(B) states that the ampacities shall be permitted to be determined by the tables or under engineering supervision, as provided in 310.60(C) and (D). Many times, design engineers and contractors cannot design and install underground duct banks as shown in the 2011 NEC© Tables 310.15(B)(16) as well as Figure 310.60 & Tables 310.60(C)(77) to 310.60.(C)(86).

We use ETAP’s state-of-the-art Cable Thermal Software Module and accurately determine the ampacity and thermal limitations of different underground raceways and duct banks.This program is especially beneficial for our clients who are designing duct banks that deviate from the NEC© duct bank tables. A Underground Duct Bank Cable Ampacity and Thermal Calculation Study will determine if your duct bank design will support the loads and not cause conductor over heating.