IEEE 1185-2019 pdf download

IEEE 1185-2019 pdf download.IEEE Recommended Practice for Cable lnstallation in Generating Stations and lndustrial Facilities.
4.3.2 Conduits, wire ways, and ducts
Conduits, wire ways, and ducts are common terms for enclosed raceways. Wire ways, which are usually rectangular, are sheet metal troughs with hinged or removable covers for routing and protecting electrical wires and cables. Conduits and ducts are tubular conveyances for protecting and routing electrical wires and cables. The term “duct” is typically used for underground raceways while the term “conduit” is normally used inside a building. More detailed guidelines are as follows:
a) NEC, Chapter 9, Table I shows conduit cross-sectional fill limits of 53%, 31%, and 40% for one, two, and three or more cables respectively. These fill limits are applicable for power, control, instrument, specialty, and fiber optic cables, and have been used for both conduits and ducts. Even though these fill limits are widely accepted and have been used for years, exceptions exist for instances where the conduit/duct path is short, straight, or where the cable can be pushed through the conduit or duct by hand. For more information regarding the design of conduit and ducts see IEEE Std 422 [B63j.
b) For wire ways, the sum of the cross-sectional areas of all conductors/cables in the wire way should not he greater than 20% of the interior cross-sectional area of the wire way per NEC, Article 376.22(A).
c) The percent fill of a conduit or duct is the sum of the conductor/cable areas divided by the useable conduit or duct area times 100%; thus % fill – conductor/cable area ÷ internal conduit area x 100%.
4.3.3 Troughs, gutters, and sleeves
Gutters are metal or plastic enclosures used to route and protect conductors or cables in meter centers, load distribution centers, switchboards, motor control centers, and other similar cabinets or panels. These items are used as a part of a complete assembly of electrical equipment to supplement wiring space by enclosing conductors and cables that are used as feeders or branch circuit conductors. Gutters are not designed or certified to enclose bus bars, switches, over current devices, or other equipment. Section 12—I 900 of the Canadian Electric Code [B32j limits the length that gutters are allowed to extend beyond the equipment that they support to a maximum of 2.0 m (6.6 ft). In addition, the CEC requires gutters to be supported throughout their entire length at intervals not more than 1.5 m (5 ft). NEC, Article 366.30 requires that metal auxiliary gutters be supported and secured throughout their entire length at intervals not exceeding I .5 rn (5 if). For nonmetallic gutters the interval is not to exceed 900 mm (3 if) and at each end or joint, and in no case the distance between supports exceed 3 m (10 if).
There is no maximum established fill limit for troughs or sleeves because these raceway types are normally straight and short in length, and the cables are either placed into them or pushed through them. For gutters, NEC, Article 366.22 (A) states that “the sum of the cross sectional areas of all contained conductors and cables at any cross section of a gutter shall not exceed 20 percent of the interior cross-sectional area of gutter.”
4.3.4 Duct banks
Many of the same considerations for Installing cables in conduit apply to installing cables in underground duct bank systems. However, there are unique installation considerations for underground duct banks that need to be considered. \Vhen done prior to plant startup, other cables in the same location are usually deenergized. However, after plant startup and during retrofit work, vaults, duct banks, hand holes, and manholes often contain other cables that are energized and cannot always be de-energized during the new work activity. Work under these conditions requires an added level of caution and extra safety measures to be considered and included in the planning prior to performing this type of work. These pulls often have the same problems as conduit pulls, plus the added difficulty of having to work in an enclosed or confined space at one or both ends, with other nearby energized cables. When the size of the manhole opening does not allow the setup of the pulling rig or the cable reel at the duct opening, extra rigging is required to guide both the pulling rope and the cable from outside the manhole into the duct or conduit. The minimum bending radius and maximum sidewall pressure requirements, for the cables being installed in these raceway types should not he violated. For information regarding the design of duct bank systems see IEEE Std 422 [B63].a