![]() ![]() We sometimes put two duct banks in a common trench to increase separation, but this is not required by the NEC, AFAIK. It's good practice to keep the 12 kV ducts segregated in one portion of the duct bank. to be located close to the existing 12kV duct banks/manhole in the general. The other option is to provide a barrier of some type within the manhole to isolate the 12 kV from the lower voltages. Concrete encased conduit shall be of polyvinyl. Then if you use 600 V insulation for all low-voltage cables, they can occupy the same space in a manhole/handhole. We generally split out separate manholes/handholes for the 15 kV (or any medium-voltage) cables. The problem come when you enter a manhole or handhole, since the high voltage must be isolated from the lower voltages. It is permissible to run a 12 kV circuit in one conduit, a 480 V circuit in another conduit and a 24 V dc circuit in a third conduit within a common duct bank. It does not apply to running different voltage system in different conduits within the same duct bank. KCC was also responsible for providing all Quality Control and Quality Assurance Testing services with an independent testing laboratory for the project to document that all work met the specified quality standards for the project.That NEC article refers to running different voltage systems within the same conduit or cable.Therefore, KCC prepared a site-specific Health & Safety Plan (HASP) and provided full-time Health & Safety oversight during the entire project to assure compliance with the HASP, and to ensure that the workers were provided with the appropriate PPE and monitoring. Since the site was previously used as a petrochemical production facility, there were several underground areas where contaminated soil and groundwater could have been encountered during the trenching and excavation operations.In order to protect the newly installed light towers, transformers, and fire hydrants from potential collisions and damage from the marine terminal truck traffic, KCC installed approximately 240, concrete-filled, steel pipe bollards that were set into reinforced concrete footings and painted Safety Yellow.KCC installed the HML’s on 48” diameter, reinforced concrete, Drilled Shafts that were constructed to depths of 25 feet below the ground surface. The HML’s were distributed throughout the new marine terminal and were designed to withstand 115 mph wind loading. In order to provide appropriate illumination for the nighttime operation of the completed marine terminal, an important feature of the new electrical infrastructure was the installation of 17 new, 100-foot-tall High Mast Light (HML) Towers and associated lighting controls.KCC designed and constructed the PDC Foundation System using custom fabricated Helical Piles that supported reinforced concrete pile caps, all of which had to be very accurately planned and installed using templates in order to accommodate multiple groups of duct banks that tied into the floor of the Substation.KCC prepared a lifting plan in advance and used a 110 Ton hydraulic crane and special rigging to hoist, set and assemble the 49,000-pound PDC modules on the previously prepared PDC foundations. Installation of a new high voltage electrical service to provide power to the new marine terminal was coordinated with Atlantic City Electric (ACE), the local utility, which provided 12 KV power to a new 14’ wide x 66’ long Substation/Power Distribution Center (PDC) that was prefabricated at an off-site facility and transported to the site by truck in two modules.The electrical work also included the furnishing, installation, termination, testing and commissioning of all high voltage, medium voltage cables and switchgear that provided power to the marine terminal and the recently constructed wharf on the Delaware River. The medium voltage power was distributed through 9 new Medium Voltage pad-mounted transformers, mini-power centers, and panelboards.Contract PMT-016 required the installation of an additional 40,000 LF of 2”, 4” & 5” Schedule 40 PVC conduits in concrete-encased duct banks, along with 31 precast concrete electrical and communications manholes and handholes that weighed up to 16 tons each. Contract PMT-016 extended and completed the medium voltage electrical distribution infrastructure work that KCC had just constructed in their previous contract PMT-013 at the mew marine terminal site. ![]()
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