A conduit is a structure containing one or more ducts. A duct is a single enclosed runway (hole) for conductors or cables. Conduit systems should be located so as to be subject to the fewest disturbances practical. Conduit systems extending parallel to other subsurface structures should not be located directly over or under other subsurface structures. If this is not practical, the rules on clearances should be followed. Conduit alignment should be such that there are no protrusions which would be harmful to the cable. When bends are required, the minimum radius shall be sufficiently large to prevent damage to cable being installed in the conduit. The maximum change of direction in any plane between lengths of straight, rigid conduit without the use of bends should be limited to 5 .

Routes through the unstable soils such as mud or shifting soil or through highly corrosive soils should be avoided. If construction is required in these soils, the conduit should be constructed in such a manner as to minimize movement and/or corrosion. When conduit must be installed longitudinally under the roadway, it should be installed in the shoulder or, to the extent practical, within the limits of one lane of traffic. The conduit system shall be located so as to minimize the possibility of damage by traffic. It should be located to provide safe access for inspection or maintenance of both the structure and the conduit system. The top of a conduit system should be located not less than 36 in...