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Product Specifications for Phase-Over-Phase GOABS®

1. General
a) This specification covers the design, manufacture, and shipment of phase-over-phase, One-way, Two-way, and Three-way, gang-operated disconnecting switches, both air-break and load-break, for transmission switching applications
b) All switches furnished shall conform to all applicable IEEE, NEMA, and ANSI standards
c) The switch manufacturer shall furnish all parts required to install a complete operating switch, including switch frames, operating mechanism, and equipment mounting hardware; insulators, if required, will be specified separately
d) The pole structure, dead-end assemblies, guying and grounding materials, and miscellaneous pole line hardware will be provided by Others
e) This equipment will be field assembled and installed by Others   

Applicable Standards and Specifications 


The following standards shall form a part of this specification unless otherwise stated: 

ANSI C29.9 Wet-Process Porcelain Insulators
ANSI C37.32 Schedules of Preferred Ratings,  Manufacturing Specifications, and Application Guide for High Voltage Air Switches
ANSI C37.34 Test Code for High-Voltage Air Switches
ASTM 123 Zinc Coating (Hot Dip) on Iron and Steel Hardware
NEMA SG6 Power Switching Equipment


All switches furnished shall be in accordance with the latest versions of the appropriate specifications. 


Materials and Workmanship

a) The equipment shall be new and of standard commercial, first-grade quality as to materials, workmanship, and design, in accordance with the best engineering practice, and shall be such as has been proven to be suitable for the intended purpose. 
b) All welding shall be done by welders experienced in the process to be used and in a manner evidencing good workmanship.   

Environmental Conditions   

a)  Temperature - Equipment supplied shall be adequate for an operating range of -30 degrees C to +55 degrees C
b)   Humidity - Equipment supplied shall be operated under humidity of up to 95% at a temperature of 40 degrees C
c)  Environment - Equipment supplied shall provide reliable performance in environments with high exposure to salt, minerals, chemicals, or windborne particulate
d)  Ice - Equipment supplied shall operate adequate with a build-up of 3/4” clear ice

Ratings and Type   

a) Type - Switches shall be group operated side-break switches, mounted upright, phase-over-phase  

Ratings - Switches shall meet or exceed the following ratings:

Rated Voltage   15 kV through 161 kV
Rated Maximum Voltage 15.5 kV through 169 kV
Rated Frequency  60 Hz
Rated Continuous Current  600 Amp through 2,000 Amp
Rated Momentary Current 40 kA through 100 kA
Rated Withstand Voltage (BIL) 110 kV through 750 kV

Switch Design and Construction

a)  Jaw Contacts  
i)  All jaw contacts shall be silver to copper and designed so that wiping action is provided with a minimum of roughening or wear on the silver surfaces
ii)  The design of the jaw contacts shall be such that the resultant magnetic forces during short circuit will tend to hold the blade in the closed position and maintain contact pressure  
iii) Switch contacts shall be the high pressure line contact type with a minimum of 100 lbs pressure on each silver contact  
iv) Contact pressure shall be maintained by separate back-up spring members independent of the main current path.  Contact members shall be independently adjustable for proper contact deflection  
v) Wear of contacts shall not result in diminished contact performance due to reduction of contact pressure  
vi) The number and size of contact fingers shall be sufficient to ensure adequate transfer of rated current from the blade to the jaw  
vii) All contacts shall be self-aligning and self-adjusting and designed to ensure firm positive contact   

Switch Blade  

i) Each switch blade shall form one solid piece and shall be so assembled that no part of the blade can move relative to another  
ii) Ends of switch blades shall be completely closed except for drain holes  
iii) For rotating-blade switches, rotation and vertical movement of the blade shall be affected by a single and simple linkage between the rotating stack and the blade   


  Terminal Pads  

i) Terminal pads on each end of the switch shall be located at the same height above the insulator  
ii) Terminal pads shall have flat, machined surfaces  
iii) Terminal pads shall be NEMA standard 2-hole for 600 ampere switches and NEMA standard 4-hole for switches rated 1200 to 2000 amperes


Switch Assembly  

i) Switches of the same rating and design shall have interchangeable parts  
ii) The switch shall be so designed that when installed, its operation will not be prevented by accumulated water, sleet, ice, snow, dirt, or other atmospheric contamination.  
iii) Metal live parts shall be non-rusting and corrosion resistant.  All current carrying parts shall be non-ferrous.  
iv) Live parts shall be designed to eliminate sharp points, edges, and other corona producing surfaces.  Where this is impractical, adequate shields for corona suppression shall be provided  
v) Live parts shall be designed to use at least three of the four mounting holes in the insulator or insulator adapter.  
vi) Bolts, screws, and pins shall be provided with lockwashers, keys, or equivalent locking facilities  
vii) No part of the switch blade or jaw assembly, except arcing horns, shall project lengthwise beyond the terminal pads   


Switch Mechanism

i) The mechanism shall be so designed that all three blades per phase are in positive continuous control throughout the entire operating cycle  
ii)  Each rotating insulator stack shall have double roller or double ball bearings in the base bearing assembly.  Bearing housings shall be weatherproof.  Open type bearing assemblies must be rustproof and non-corroding, and they shall be designed to completely drain water and moisture accumulation.  
iii) All roller or ball bearings shall be greaseless or maintenance free type  
iv) Rotating insulator stacks with 5” bolt circles (115 kV and greater) shall have leveling provisions at the base of each stack; rotating insulator stacks with 3” bolt circles (69 kV and below) may employ shims for alignment  
v) All operating pipes shall be sufficiently rigid to maintain positive control under the most adverse conditions, including a heavily iced switch and operating mechanism.  
vi) It shall be impossible, after proper and final adjustment has been made, for any part of the mechanism to be displaced sufficiently, at any point in the travel, to allow improper functioning of the switch when the switch is opened or closed at any operating speed  
vii) All ferrous parts, except springs, shall be hot-dip galvanized in accordance with ASTM A153, latest revision   


Operating Mechanism

i) The operating mechanism shall be positively toggled when the switch is closed to ensure correct, complete switch operation and to provide operating personnel with visual confirmation
ii) All vertical operating shafts shall be supported on ball or roller thrust bearings.  Guides shall be provided on the vertical shaft at regular intervals to ensure proper operation.
iii) Switches rated 161 kV and below shall be furnished with a horizontal swing handle.  Geared mechanisms shall be acceptable, if required, to ensure proper operation.
iv) Provision shall be made for padlocking the mechanism in the open or closed position.
v) A flexible copper braid shunt shall be provided on the operating mechanism for ground connections by Others




Switches requiring load interruption capability shall utilize a vacuum interrupter to interrupt current and to provide a confined arc when switching load, line charging or transformer magnetizing currents


The interrupter unit shall be designed to ensure high speed interruption regardless of the operational speed of the switch


When not being operated, the interrupter unit shall be out of the current path so that it is not subject to fault currents

iv) When the interrupter employs a dielectric to enhance the interrupting rating of the enclosed vacuum bottle, accidental loss or disposal of the dielectric shall not pose a risk to the health of utility personnel or the environment; SF6 is not acceptable as a dielectric

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