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Proposed Specifications for Single Phase and Three Phase Fiberglass
ND Roto Cab Sectionalizing Cabinets
MATERIALS
RESIN - To be polyester thermosetting and tested for flammability under ASTM D635 with rating to be self-extinguishing and with extent of burning not to be over 12mm nor average time burning to be over eighty seconds on test.
FIBERGLASS - used will be a combination of chopped glass with a minimum of one layer throughout of 18 ounce or 510 gram woven roving so as to form a continuous filament from top to bottom and from one side to the other for maximum strength. The overall laminate thickness shall be 3/16” throughout the base and cover.
GELCOAT – The exterior surface shall be coated with an Isophthalic base gel coat or surface coat that will provide maximum protection from UV light and weathering. Test data results from DSET Laboratories using the EMMAQUA Test Method with the results of the equivalent of two standard ultra-violet light years showing no change in Fiber Show or Fiber Bloom and no worse than a “Good” rating on General Appearance and Color Change.
An alternate test for UV resistance can be the ASTM-G-70 test method with a maximum of change of 2.3 Macadam Units after one thousand hours of exposure in a Model 65WR Atlas Weatherometer.
PHYSICALS
The base section of the sectionalizing enclosures shall be molded in one piece. The ground sleeve section of the enclosure shall be designed in a manner to resist sidewall deflection. The cover will be attached using two shoulder bolts fastened with two ½” stainless steel nuts on the inside of the cabinet base. The single-phase cabinet will incorporate one nylon-coated lanyard. The three-phase cabinet will incorporate two nylon-coated lanyards. The lanyard(s) will be riveted to the lid and the base. The lanyard(s) will restrain the lid’s back flange from touching the ground sleeve’s upper base section in an open position. The stainless steel locking system includes a stainless steel bit and latch with a captive 1/2” stainless penta-head bolt. The lock system can accept up to a Ø3/8” shank pad-lock. The enclosures will be meeting all of the requirements specified by the RUS as specified by the ANSI C 57 12.28 standards for enclosure security. All hardware will be produced from 304 series stainless steel with the exception of the mounting plates and lifting eyes. The mounting plates will be hot-dipped galvanized steel in the single-phase cabinets with an optional stainless steel plate. The three-phase cabinets will be hot-dipped galvanized with an option of aluminum or stainless steel. The lifting eyes shall be zinc plated and have two located in the back and two in the front to allow for lifting. The base flange will be a minimum of 3 1/2” to provide a stable base when installed. Each mounting plate in the single-phase cabinet will come standard with parking stands and a bolting pattern to allow for 2, 3, or 4 point 200 amp junction in either 15 or 25 kV from various manufacturers. Other mounting plates will have a bolting pattern to allow for 2, 3, or 4 point 600 amp junctions in either 15, 25, or 35 kV ratings in addition to 200 amp junctions. Each plate in the single-phase cabinet will have provisions for ground points. The three-phase cabinets will come standard with hot-dipped galvanized mounting plates with an optional aluminum junction bar mounting system and sliding parking stands. The aluminum junction bar system will allow for stand-offs or a feed-through to be installed on the parking stands either above or below. The aluminum junction bar will have a bolting pattern to allow for 2, 3, or 4 point 200 and 600 amp junctions in either 15, 25, or 35 kV for most manufacturers. The three-phase cabinet’s junction bar will have two ½”-13 UNC tapped holes for grounding provisions.
Proposed Specifications for Single Phase and Three Phase Fiberglass
ND Hinged Sectionalizing Cabinets
MATERIALS
RESIN - To be polyester thermosetting and tested for flammability under ASTM D635 with rating to be self-extinguishing and with extent of burning not to be over 12mm nor average time burning to be over eighty seconds on test.
FIBERGLASS - used will be a combination of chopped glass with a minimum of one layer throughout of 18 ounce or 510 gram woven roving so as to form a continuous filament from top to bottom and from one side to the other for maximum strength. The overall laminate thickness shall be ¼” throughout the base. It shall be ¼” around the perimeter of the cover. And finally, it shall be 3/16” throughout the remaining area of the cover.
GELCOAT – The exterior surface shall be coated with an Isophthalic base gel coat or surface coat that will provide maximum protection from UV light and weathering. Test data results from DSET Laboratories using the EMMAQUA Test Method with the results of the equivalent of two standard ultra-violet light years showing no change in Fiber Show or Fiber Bloom and no worse than a “Good” rating on General Appearance and Color Change.
An alternate test for UV resistance can be the ASTM-G-70 test method with a maximum of change of 2.3 Macadam Units after one thousand hours of exposure in a Model 65WR Atlas Weatherometer.
PHYSICALS
The base section of the Primary sectionalizing enclosures shall be molded in one piece as to form a unitized body construction between the equipment mounting board and the ground sleeve section of the base. The ground sleeve section of the enclosure shall be reinforced in a manner to resist sidewall deflection. The cover will be attached using a continuous hinge. The locking system shall incorporate the means for a penta-head, hasp, and padlock. The enclosures will be meeting all of the requirements specified by the RUS as specified by the ANSI C 57 12.28 standards for enclosure security. All hardware will be produced from 304 series stainless steel with the exception of the mounting plates and lifting eyes. The mounting plates will be a standard of hot dipped galvanized with stainless steel plates being an option. The lifting eyes shall be zinc plated and have two located in the back and two in the front to allow for a four-point lift. The base flange will be a minimum of 3 ½” to provide a stable base when installed. The three phase enclosures shall have a positive lock prop arm on one side and a non-locking prop arm on the opposite side. The single phase shall have one positive lock prop arm. The mounting plates shall be fastened individually and must be removable. Each mounting plate will come standard with parking stands and a bolting pattern to allow for 2, 3, or 4 point 200 amp junction in either 15 or 25 kV from various manufacturers. Other mounting plates will have a pre-drilled bolting pattern to allow for 2, 3, or 4 point 600 amp junctions in either 15, 25, or 35 kV ratings in addition to 200 amp junctions. Each plate will also have provisions for ground points.
Dielectric Strength
Electrical underground distribution begins with primary cables from the high-line poles going underground. Back-hoes, trench diggers, and boring machines are the means to bury the cable. These primary cables travel great distances to a variety of pad-mounted electrical equipment. Nordic sectionalizing cabinets are one of those electrical components that help sectionalize the underground electrical distribution. Nordic sectionalizing cabinets provide safe housing for load or dead-break junctions in a high dielectric strength fiberglass cabinet. They also provide a spacious interior for cable looping.
A variety of Nordic’s single and three-phase cabinets are designed with mounting plates to accommodate a wide range of manufacturer’s 2, 3 and 4 point; 15, 25, or 35kV; 200 amp load-break or 600 amp dead-break junctions. These cabinets, with their built-in ground sleeves, provide the necessary depth for a lineperson to pull an elbow from an electrical junction. In case of an elbow failure, the looped cable is available for repair. Some cabinets are also designed to accommodate 200 amp taps on 600 amp dead-break junctions.
Safety is always a concern when working with electricity. The Nordic fiberglass sectionalizing cabinets are very low conductors of electrical current. In fact, the dielectric strength of these cabinets is superior.
Dielectric Strength Definition: A measure of the voltage required to puncture a material, expressed in volts per mil of thickness. The voltage figure used is the average root-mean-square voltage gradient between two electrodes at which electrical breakdown occurs under prescribed conditions of test. It is expressed as volts at which an insulator breaks down, divided by the thickness in mils (0.001 in) 1. Based on that information, a 1/4” Nordic Fiberglass thick part insulates up to approximately 86,250 volts².
1Definition Copyright ©1989 Technomic Publishing Company, Inc. All rights reserved.
² Modern Plastic Encyclopedia, Mid-October 1990 issue volume 67, Number 11 page 508.
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