Standard Specification for Type PSE Deadfront ... - Eaton Canada

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SECTION SB-2A-210 PSE TYPICAL SPECIFICATION APRIL 1999 PAGE 2 9. Insulators The interrupter switch and fuse mounting insulators shall have the following material characteristics and restrictions: a) Operating experience of at least 15 years under similar conditions. b) Ablative action to ensure non-tracking properties. c) Adequate leakage distance established by test per IEC Publication 507, First Edition, 1975. d) Adequate strength for short-circuit stress established by test. e) Conformance with applicable ANSI standards. f) Homogeneity of the cycloaliphatic epoxy resin throughout each insulator to provide maximum resistance to power arcs. Ablation due to high temperature from power arcs shall continuously expose more material of the same composition and properties so that no change in mechanical or electrical characteristics takes place because of arc-induced ablation. Furthermore, any surface damage to insulators during installation or maintenance of the padmounted gear shall expose material of the same composition and properties so that insulators with minor surface damage need not be replaced. g) Each insulator shall be x-rayed to assure it is essentially void free. An alternate testing method may be used only by approval of the engineer. 10. High Voltage Bus: Bus and interconnections shall consist of bare aluminum bar of 56% IACS conductivity with an oxide-inhibiting agent at all bus joints. Bus and interconnections shall withstand the stresses associated with short circuits up through the maximum rating of the padmounted gear, including proper allowance for transient conditions. Bolted aluminum-to-aluminum connections shall be made with a suitable number of non-corrosive bolts and with two Belleville spring washers per bolt, one under the bolt head and one under the nut. Bolts shall be tightened to an appropriate torque to assure good electrical connection. 11. Ground Connection Pads: A ground connection pad shall be provided in each termination compartment of the padmounted gear. The ground connection pad shall be constructed of 1/4" thick, galvanized or stainless steel and have a NEMA 2hole pattern for ground connections. The pad shall be welded to the enclosure and shall have a short-circuit rating equal to that of the integrated assembly. A full width copper grounding rod shall be provided in each cable terminating compartment. B. Construction 1. Enclosure: The padmounted enclosure shall be of unitized construction (not structural frame and bolted sheet) to maximize strength, minimize weight, and inhibit internal corrosion. The basic materials shall be 11 gauge hot rolled, pickled and oiled steel sheet. All structural joints and butt joints shall be welded, and the external seams shall be ground flush and smooth. A welding process shall be employed that eliminates alkaline residues and minimizes distortion and spatter. To guard against unauthorized or inadvertent entry, enclosure construction shall not utilize any externally accessible hardware. The base shall consist of continuous 90-degree flanges, turned inward and welded at the corners, for bolting to the concrete pad. The door openings shall have 90-degree flanges, facing outward, that shall provide strength and rigidity as well as deep overlapping between doors and door openings to guard against water entry. In consideration of tamper resistance, the enclosure shall conform to or exceed the requirements of ANSI C57.12.28. A heavy coat of insulating "no-drip" compound shall be applied to the inside surface of the roof to reduce condensation of moisture thereon. Lifting tabs shall be removable. Sockets for the lifting tab bolts shall be blind-tapped. A protective material shall be placed between the lifting tabs and the enclosure to prevent the tabs from scratching the enclosure finish. This material shall be non-hygroscopic to prevent moisture from being absorbed. Optional: A steel (specify compartmented or noncompartmented) base spacer shall be provided to increase the elevation of live parts in the padmounted gear above the mounting pad by (specify 6, 12, 18, 24) inches. 2. Barrier Assembly: Insulating interphase and end barriers shall be provided in each switch and fuse compartment. This barrier system shall be constructed of fiberglass reinforced polyester (NEMA rated GPO-3). 3. Doors: Doors shall be constructed of 11 gauge hot rolled, pickled and oiled steel sheet. Door edge flanges shall overlap with door opening flanges and shall be formed to create a mechanical maze that shall guard against water entry or discourage tampering or insertion of foreign objects. Doors shall have a minimum of three stainless steel hinges and hinge pins. The hinge pins shall be secured in place to guard against tampering. One active and one passive door shall be provided and in consideration of controlled access and tamper resistance, each active door shall be equipped with a positive-action three-point auto-latch mechanism and padlock hasp. Each active door shall be provided with a stainless steel door handle. The door handles shall be padlockable and shall incorporate a hood to protect the padlock shackle from tampering and access to the operating bolt. Each handle shall be provided with a recessed penta (hex optional) head bolt for additional security. Each passive door shall be independently secured to the enclosure and shall not require a tool for opening. Doors providing access to fuses shall have provisions to store spare expulsion type fuse units or refills. Each door shall be provided with a zinc plated, galvanized or stainless steel door holder located above the door opening. These holders shall be hidden from view when the door is closed, and it shall not be possible for the
holders to swing inside the enclosure. 4. Finish Full coverage at joints and blind areas shall be achieved by processing enclosures independently of components such as doors and roofs before assembly into the unitized structures. All exterior seams shall be sanded or ground smooth for neat appearances. To remove oils and dirt, and to form a chemically and anodically neutral conversion coating to improve the finishto-metal bond, and to retard underfilm propagation of corrosion, all surfaces shall undergo a chemical cleaning and phosphatizing process before any protective coatings are applied. The finishing system shall be applied without sags or runs for a pleasing appearance. After the enclosure is completely assembled and the components (switches, bus, etc.) are installed, the finish shall be inspected for scuffs and scratches. Blemishes shall be carefully touched up by hand to restore the protective integrity of the finish. Unless otherwise specified, the color shall be Munsell No. 7GY3.29/1.5, dark green. To insure that the finishing system is capable of resisting corrosion, the manufacturer shall provide on request, certification that representative test panels, protected by the manufacturer's finish system, have passed the following tests: a) Salt spray (relates to coastal environments and/or presence of snow-melting salts or fertilizers). Scribe to bare metal and test for 2000 hours in a 5% salt spray per ASTM B-117. Loss of adhesion from bare metal should not extend more than 1/8" from the scribe. Underfilm corrosion should not extend more than 1/16" from the scribe. b) Crosshatch adhesion (relates to adhesion after scratching of the finish). Scribe to bare metal a cross hatch pattern of 100 1/16" wide squares. Apply Scotch 710 tape and rapidly remove. There should be 100% adhesion to the bare metal and between layers. c) Humidity (relates to environments with high humidity). Test of 1000 hours subject to 100% humidity at 45-50 degrees C per ASTM D-2247. There should be no blisters. d) Impact (relates to transit and handling damage and abuse by the public). Impact the test panel with a 160 in-lb. falling dart per ASTM D-2794. There should be no cracking or chipping of the paint on the impact side of the test panels. e) Oil resistance (relates to probable contact with mineral oil). Immerse two test panels in mineral oil for 3 days, one at room temperature and one at 100 degrees C (212 degrees F). There should be no apparent changes, such as color shifts, blisters, loss of hardness or streaking. f) Ultraviolet Accelerated Weathering Test (relates to exposure to sunlight and rainfall, loss of gloss, color fading and chalking). Continuous exposure to ultraviolet light for 500 hours per ASTM G-53 with a cycle of 4 hours ultraviolet followed by 4 hours of condensation. Loss of gloss shall not exceed 50% of original per ASTM D523. g) Water Resistance (relates to rainfall or dew). Immerse a test panel in distilled water for 3 days at room SECTION SB-2A-210 PSE TYPICAL SPECIFICATION APRIL 1999 PAGE 3 temperature. There should be no apparent changes, such as blistering, color shift, loss of hardness or streaking. h) Adhesion Fed. Spec 141A, Method 6301.1 (relates to adhesion after scratching the finish). Immerse test panel in distilled water for 24 hours. Make two parallel scratches 1" apart. Apply Scotch 710 tape and rapidly remove. There should be 100% adhesion to the bare metal and between layers. i) Abrasion Test - Taber Abrader (relates to wear encountered during installation). Prepare a panel coated with the component of the finish intended to provide abrasion resistance. Test using a CS-10 wheel, 1000 gram weight, 3000 cycles, per Fed. Spec. 141, Method 6192. This provides a comparative test between samples. To guard against corrosion, all hardware (including door fittings, fasteners, etc.), all operatingmechanism parts, and other parts subject to abrasive action from mechanical motion shall be of either nonferrous materials, or galvanized or zinc chromate plated ferrous materials. Cadmium-plated ferrous parts shall not be used. C. Construction 1. Interrupter Switches: Interrupter switches shall have a three-time duty-cycle fault-closing rating equal to or exceeding the short circuit rating of the integrated padmounted gear assembly. These ratings define the ability to close the interrupter switch either alone (unfused) or in combination with the appropriate power fuses three times against a three-phase fault with asymmetrical current in at least one phase equal to the rated value, with the switch remaining operable and able to carry and interrupt rated current. Tests substantiating these ratings shall be performed at maximum design voltage with current applied for at least 10 cycles. Certified test abstracts establishing such ratings shall be furnished upon request. Interrupter switches shall utilize a quick-make, quick-break mechanism installed by the switch manufacturer. The quick-make, quick-break mechanism shall be integrally mounted on the switch frame, and shall swiftly and positively open and close the interrupter switch independent of the speed of the switch operating handle. Interrupter switches shall be operated by means of an externally accessible switch-operating hub. The switchoperating hub shall be located within a recessed stainless steel pocket mounted on the side of the padmounted enclosure. The switch-operating hub pocket shall include a padlockable stainless steel access cover that shall incorporate a hood to protect the padlock shackle from tampering. Labels or targets to indicate switch positions shall be provided in the switch operating hub pocket. Each interrupter switch shall be completely assembled and adjusted by the switch manufacturer on a rigid mounting frame. The frame shall be of heavy gauge steel construction. Interrupter switch shall be provided with contact blades and interrupters for circuit closing, including fault closing, continuous current carrying, and circuit interrupting. Spring loaded auxiliary blades shall not be permitted. Circuit interruption shall be accomplished by use of an interrupter which is positively and inherently sequenced with the blade position. It shall not be possible for the blade and interrupter to get out of sequence.
Page 1: Standard Specification for Type PSE

Standard Specification for Type PSE Deadfront ... - Eaton Canada

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