This process is repeated every 10 to 20 feet, depending upon the length of the conduit.ĥ. The pipe is twisted slightly to secure it. Once the pipe is smooth, the correct type of CANTEX PVC Solvent Cement gets applied to the inside of the belled end and the outside of the spigot or “straight” end of the conduit with a dauber.Ĥ. If the pipe has been cut, a reamer tool must be used to remove burrs or debris before cementing. In between each run of pipe, the belled end of the conduit gets cemented to the straight end. A crew begins by digging a trench for the conduit.Ģ. Consequently, the ends of the DB PVC Conduit runs are directed into and terminate in approved electrical devices or boxes. For example, smoother select fill dirt would be used as back-fill and there are no above-ground applications for Direct Burial PVC Conduit. However, since control, instrumentation and communication cables run in separate steel conduit which - if it will be well bonding could create, also, a grounding effective path for power cables in the same duct bank.DB Direct Burial PVC Utility Duct InstallationĪlthough the direct burial installation for DB PVC Utility Duct is very much the same as it is for Schedule 40 and Schedule 80 PVC Pipe, there are some differences in back-fill requirements and performance capabilities. However, in this case, grounding with individual cable ground conductors (see 5.5.3.2) should be considered to avoid installation and bonding complications.' When the cable is run underground, this grounding conductor should be located in the same direct burial or duct bank run as the cable. It is important that the ground conductors be run as close as possible to the circuit conductors, since this reduces the reactance of the fault current return path. The separate grounding conductor is run in the same conduit or cable duct as the outgoing power cable and is also used to ground the conduit or cable duct. Where a single cable leaves the cable tray, a branch grounding conductor is added and connected to the common grounding conductor and to the equipment enclosure or motor terminal box. It is usually a bare stranded copper conductor connected to the main ground bus and fastened to the cable tray. A common equipment grounding conductor could be used for all cables in the same tray (it may also be used to ground the cable tray). From this main ground bus, a grounding conductor is run within the same raceway as the circuit conductors. It should be noted that in systems with impedance grounding, the grounding conductors should be connected to the neutral ground and not to the transformer neutral. This may be the switchgear or the motor control center ground bus to which the supply transformer neutral is connected (solidly or through impedance) and that is solidly connected to the grounding grid. 'It is recommended that a main ground bus be provided.

I am sure it could be also in other standards however this is what I found in 'my collection'.įrom IEEE-665 GENERATING STATION GROUNDING 5.5.3.1 Grounding with common equipment grounding conductor run to the neutral ground.

CONCRETE ENCASED DUCT BANK DETAIL FAA