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1 COMPLETE REVISION October 2010 Electrical PIP ELSSG01 Design and Fabrication of Low-Voltage Metal-Enclosed AC Power Circuit Breaker Switchgear

2 PURPOSE AND USE OF PROCESS INDUSTRY PRACTICES In an effort to minimize the cost of process industry facilities, this Practice has been prepared from the technical requirements in the existing standards of major industrial users, contractors, or standards organizations. By harmonizing these technical requirements into a single set of Practices, administrative, application, and engineering costs to both the purchaser and the manufacturer should be reduced. While this Practice is expected to incorporate the majority of requirements of most users, individual applications may involve requirements that will be appended to and take precedence over this Practice. Determinations concerning fitness for purpose and particular matters or application of the Practice to particular project or engineering situations should not be made solely on information contained in these materials. The use of trade names from time to time should not be viewed as an expression of preference but rather recognized as normal usage in the trade. Other brands having the same specifications are equally correct and may be substituted for those named. All Practices or guidelines are intended to be consistent with applicable laws and regulations including OSHA requirements. To the extent these Practices or guidelines should conflict with OSHA or other applicable laws or regulations, such laws or regulations must be followed. Consult an appropriate professional before applying or acting on any material contained in or suggested by the Practice. This Practice is subject to revision at any time. (PIP), Construction Industry Institute, The University of Texas at Austin, 3925 West Braker Lane (R4500), Austin, Texas PIP Member Companies and Subscribers may copy this Practice for their internal use. Changes or modifications of any kind are not permitted within any PIP Practice without the express written authorization of PIP. Authorized Users may attach addenda or overlays to clearly indicate modifications or exceptions to specific sections of PIP Practices. Authorized Users may provide their clients, suppliers and contractors with copies of the Practice solely for Authorized Users purposes. These purposes include but are not limited to the procurement process (e.g., as attachments to requests for quotation/ purchase orders or requests for proposals/contracts) and preparation and issue of design engineering deliverables for use on a specific project by Authorized User s client. PIP s copyright notices must be clearly indicated and unequivocally incorporated in documents where an Authorized User desires to provide any third party with copies of the Practice. PRINTING HISTORY September 1997 Issued October 2004 Complete Revision October 2010 Complete Revision Not printed with State funds

3 COMPLETE REVISION October 2010 Electrical Table of Contents PIP ELSSG01 Design and Fabrication of Low-Voltage Metal-Enclosed AC Power Circuit Breaker Switchgear 1. Introduction Purpose Scope References Industry Codes and Standards Definitions Requirements Service Conditions Switchgear Assembly Additional Requirements for Arc- Resistant Switchgear Power Circuit Breakers Bus Work Voltage Transformers Control Power Transformers Current Transformers Control Devices, Indicating Lights and Metering Protective Relaying Breaker Interlocking and Transfer Schemes Space Heaters Wiring and Terminations Bus Ducts and Cable Bus Nameplates Finish Secondary System Grounding Accessories Shipping Inspection and Testing Documentation Conflict Resolution Page 1 of 25

4 PIP ELSSG01 COMPLETE REVISION Design and Fabrication of Low-Voltage Metal-Enclosed AC Power Circuit Breaker Switchgear October Introduction 1.1 Purpose This Practice provides requirements for design, fabrication, and testing of metal-enclosed, low-voltage AC power circuit breaker switchgear assemblies. 1.2 Scope 2. References This Practice describes the requirements for metal-enclosed power switchgear assemblies employed in three-phase AC electrical systems having a voltage not greater than 1000 volts and located in a nonclassified area. Applicable parts of the following Practices and industry codes and standards shall be considered an integral part of this Practice. The edition in effect on the date of contract award shall be used, except as otherwise noted. Short titles are used herein where appropriate. 2.1 (PIP) PIP ELSBD01 - Design and Fabrication of Metal-Enclosed Nonsegregated-Phase Bus Duct Assemblies PIP ELSBD01D - Data Sheet for Design and Fabrication of Metal-Enclosed Nonsegregated-Phase Bus Duct Assemblies PIP ELSGS01 - Design and Fabrication of High-Resistance Grounding System (600 Volts or below) PIP ELSGS01D - Data Sheet for Design and Fabrication of High-Resistance Grounding System (600 Volts or below) PIP ELSSG01D - Data Sheet for Design and Fabrication of Low-Voltage Metal- Enclosed AC Power Circuit Breaker Switchgear PIP ELSSG12 - Design and Fabrication of Outdoor Enclosures for Motor Controllers and Switchgear 2.2 Industry Codes and Standards American National Standards Institute, Inc. (ANSI) ANSI C Low-Voltage Power Circuit Breakers and AC Power Circuit Protectors Preferred Ratings, Related Requirements, and Application Recommendations ANSI C Trip Devices for AC and General Purpose DC Low-Voltage Power Circuit Breakers ANSI C Switchgear - Low-Voltage AC Power Circuit Breakers Used in Enclosures - Test Procedures ANSI Z American National Standard for Product Safety Signs and Labels American Society for Testing Materials (ASTM) ASTM D Standard Practice for Specifying Code by the Munsell System Page 2 of 25

5 COMPLETE REVISION PIP ELSSG01 October 2010 Design and Fabrication of Low-Voltage Metal-Enclosed AC Power Circuit Breaker Switchgear 3. Definitions International Code Council (ICC) IBC - International Building Code Institute of Electrical and Electronic Engineers (IEEE) IEEE C Standard for Low-Voltage AC Power Circuit Breakers Used in Enclosures IEEE C Standard for Metal-Enclosed Low-Voltage Power Circuit-Breaker Switchgear IEEE C IEEE Guide for Testing Metal-Enclosed Switchgear Rated Up to 38 kv for Internal Arcing Faults IEEE C Standard for Control Switchboards Underwriters Laboratories (UL) UL Standard for Safety Metal-Enclosed Low-Voltage Power Circuit Breaker Switchgear arc resistant accessibility Type 1: Equipment with arc-resistant designs or features at the freely accessible front of the equipment only arc resistant accessibility Type 1B: Equipment with arc-resistant designs or features at the freely accessible front of the equipment only, and the additional requirements of ANSI C Annex A, for equipment if normal operation of the equipment involves opening the door or cover of compartments specifically identified as Low Voltage Control or Instrumentation compartments arc resistant accessibility Type 1C: Equipment with arc-resistant designs or features at the freely accessible front of the equipment only, and the additional requirements of ANSI C Annex A, which are intended to reduce the collateral damage to adjacent compartments and equipment, and should not be interpreted to indicate any additional degree of protection for personnel arc resistant accessibility Type 2: Equipment with arc-resistant designs or features at the freely accessible exterior (i.e., front, back, and sides) of the equipment only Arc resistant accessibility Type 2B: Equipment with arc-resistant designs or features at the freely accessible exterior (i.e., front, back, and sides) of the equipment only, and the additional requirements of ANSI C Annex A, for equipment if normal operation of the equipment involves opening the door or cover of compartments specifically identified as Low Voltage Control or Instrumentation compartments arc resistant accessibility Type 2C: Equipment with arc-resistant designs or features at the freely accessible exterior (i.e., front, back, and sides) of the equipment only, and the additional requirements of ANSI C Annex A, which are intended to reduce the collateral damage to adjacent compartments and equipment, and should not be interpreted to indicate any additional degree of protection for personnel arc resistant equipment: Equipment designed to withstand the effects of an internal arcing fault, in accordance with the test requirements of ANSI C Page 3 of 25

6 PIP ELSSG01 COMPLETE REVISION Design and Fabrication of Low-Voltage Metal-Enclosed AC Power Circuit Breaker Switchgear October 2010 internal arcing fault: An unintentional discharge of electrical energy in air within the confines of an electrical equipment enclosure owner: The party who owns the facility wherein the low voltage metal-enclosed switchgear will be used purchaser: The party who awards the contract to the supplier. The purchaser may be the owner or the owner s authorized agent. purchaser s inspector: The purchaser s authorized representative with authority to act in the interest of, and on behalf of, the purchaser in all quality assurance matters supplier: The party responsible for furnishing the low-voltage metal-enclosed AC power circuit breaker switchgear 4. Requirements 4.1 Service Conditions Unless otherwise specified on the purchaser s PIP ELSSG01D Data Sheet, equipment shall be designed to perform satisfactorily under the following ambient conditions: a. Ambient conditions within the limits of -30 C (-18 F) and 40 C (104 F) b. Altitude of installation does not exceed 1000 m (3300 feet) c. Humidity within the limits of 0-95% non-condensing Seismic requirements shall be as specified on the purchaser s PIP ELSSG01D Data Sheet. If specified on the purchaser s PIP ELSSG01D Data Sheet, the manufacturer shall provide a certificate of compliance and anchoring recommendations for all equipment. 4.2 Switchgear Assembly The switchgear assembly shall consist of metal-enclosed freestanding selfventilated vertical steel structures containing power buses, a ground bus, lowvoltage power circuit breakers, and auxiliary control devices in accordance with the attached purchaser s PIP ELSSG01D Data Sheet and one-line diagram(s) The switchgear shall be designed such that the breakers can be tripped and closed and the breaker position can be viewed with the doors closed. Refer to section for breaker operation All enclosures shall be fabricated from freestanding steel frames, steel panels, and doors to provide a strong and rigid structure. The design shall allow the switchgear to be rolled across a floor on pipes or other means without causing the structure to deform or otherwise be damaged Enclosure panel and doors shall be 14-gage minimum thickness Unless otherwise specified on the purchaser s PIP ELSSG01D Data Sheet, enclosures shall be NEMA Enclosures for outdoor service shall be in accordance with PIP ELSSG12. Page 4 of 25

7 COMPLETE REVISION PIP ELSSG01 October 2010 Design and Fabrication of Low-Voltage Metal-Enclosed AC Power Circuit Breaker Switchgear Maximum number of feeder circuit breakers in each vertical section shall be as indicated in the purchaser s PIP ELSSG01D Data Sheet All bolted doors and removable panels shall be secured with captive slotted fasteners or machine screws or machine bolts engaging captive nuts or tapped holes in structural members. All fasteners shall employ vibration-resistant devices. Self-tapping sheet metal screws shall not be permitted Unless otherwise specified on the purchaser s PIP ELSSG01D Data Sheet, rear access to cable compartments shall be by removable panels. Any removable panels weighing more than 50 pounds (23 kg) shall have two lifting handles When rear access doors are specified on the purchaser s PIP ELSSG01D Data Sheet, they shall be either full height or split, hinged, and bolted. All rear access doors shall have provisions for padlocking All doors shall have hinges. The hinges may be either continuous or separate. If separate hinges are used, a minimum of three hinges shall be provided on fullheight doors Provisions shall be made for the addition of vertical sections with future breakers at open ends of the line-up. This shall include removable plates or side sheets furnished on the end of vertical sections Breaker compartment doors shall have door handle latches and shall remain closed when racking the breaker to any of three positions: disconnected, test or connected. Breaker compartment doors shall not have ventilation louvers Breaker compartments shall be furnished with a mechanism which will move the breaker between the connected, test and disconnected positions. The mechanism shall be designed so that the breakers will be self-aligning and will be held rigidly in the operating position without the necessity of locking bars or bolts From the disconnect position the breaker shall be easily removable from the compartment without further disassembly or the use of special tools other than a breaker lift device Provisions shall be made for padlocking breakers in the test and disconnected positions. Padlocking shall not interfere with removal or operation of the breaker or its mechanism In double-ended switchgear, each main and tie breaker shall be in separate vertical sections. Comment: This does not preclude metering, auxiliary equipment, or a feeder breaker being in the same vertical section with the main breaker or tie breaker The purchaser shall be notified of any breaker-derating factors caused by ambient conditions and the cumulative circuit loads in the vertical sections with multiple breakers in accordance with IEEE C , Section When specified on the purchaser s PIP ELSSG01D Data Sheet, an interlock shall be provided to prevent opening of the breaker compartment door unless the breaker is in the disconnect position. This interlock shall have an override mechanism for authorized entry. Page 5 of 25

8 PIP ELSSG01 COMPLETE REVISION Design and Fabrication of Low-Voltage Metal-Enclosed AC Power Circuit Breaker Switchgear October Interlocks shall prevent moving the breaker to or from the operating position unless its main contacts are in the open position. As a further safety precaution, the operating springs shall be discharged automatically when a breaker is rolled fully into the compartment or is moved into the disconnect position Spaces shall be provided for future use as specified on the one-line diagram. Spaces shall be of three types: equipped, unequipped, and blank. Spaces shall be configured as follows: a. Equipped spaces shall be capable of being modified to add future circuit breakers of the same ampere rating without shutdown of the switchgear. b. Equipped spaces shall be furnished with all hardware, wiring, doors, and miscellaneous equipment including current transformers and monitoring devices required to permit completion of the unit by the addition of only a circuit breaker. c. Unequipped spaces shall be provided with doors but without other equipment for future use except the power stabs. Unequipped spaces shall not be used for mounting control switches and other auxiliary equipment. d. Power stabs (both line and load side) shall be provided with covers to prevent accidental contact with live parts when door is opened. e. Blank spaces shall be completely empty cubicles with doors but without power stabs or other equipment Unless otherwise specified on the purchaser s PIP ELSSG01D Data Sheet, shutters shall be provided to automatically isolate the primary line and load disconnects as the breaker is removed from the connected position. Shutters shall be nonmetallic. The line and load shutters shall operate by movement of the circuit breaker truck or racking mechanism. The shutters shall also be capable of being operated by hand with the breaker removed from the cell If uninsulated buses are specified on the purchaser s PIP ELSSG01D Data Sheet, removable vertical barriers shall be provided in the rear cable compartments to prevent accidental contact of personnel with all energized buses. The barriers shall not cover load connections Sheet steel barriers shall be provided between power and control compartments Unless otherwise specified on the purchaser s PIP ELSSG01D Data Sheet, full height and depth barriers shall be provided between adjacent vertical sections in the rear load terminal compartments If specified on the purchaser s PIP ELSSG01D Data Sheet, sheet steel barriers shall be provided between breaker compartments in vertical sections Unless otherwise specified on the purchaser s PIP ELSSG01D Data Sheet, enclosure vent openings shall be provided with stainless steel screens having a maximum opening size of 1/16 inch (1.6 mm) Breaker control power shall be as specified on the purchaser s PIP ELSSG01D Data Sheet Indicator lights shall have replaceable cluster-type LED lamps and colored lens. Page 6 of 25

9 COMPLETE REVISION PIP ELSSG01 October 2010 Design and Fabrication of Low-Voltage Metal-Enclosed AC Power Circuit Breaker Switchgear Switchgear shall be provided with removable lifting eyes or angles for handling during installation If specified on the purchaser s PIP ELSSG01D Data Sheet, a remote racking device to electrically rack the breaker shall be provided and shall include a minimum of 25 feet (7.6 m) of heavy duty umbilical cord. Means shall be provided to shut off the remote racking device when breaker is in the connected position If specified on the purchaser s PIP ELSSG01D Data Sheet, thermography windows shall be provided. Location of windows shall be as specified on the purchaser s PIP ELSSG01D Data Sheet If specified on the purchaser s PIP ELSSG01D Data Sheet, the switchgear assembly shall be UL labeled. 4.3 Additional Requirements for Arc-Resistant Switchgear If specified on the purchaser s PIP ELSSG01D Data Sheet, the switchgear shall be arc-resistant design as described below Switchgear shall be tested in accordance with IEEE C Unless otherwise specified on the purchaser s PIP ELSSG01D Data Sheet, Switchgear shall be arc-resistant construction Type 2 (switchgear with arcresistant construction at front, rear, and sides) A written certificate of successful type testing, including all the parameters used in the testing, shall be submitted to the purchaser. Testing shall be based on prospective current of the highest rated circuit breaker without insertion of any current limiting device in the test circuit Switchgear shall be designed for closed door racking. Arc-resistant integrity shall be maintained during closed door racking Instrument compartment door(s) shall be designed and tested to allow the compartment door to be opened without affecting the arc-resistant rating of the switchgear The front and rear compartment doors shall be designed to withstand the effects of an internal arcing fault Instrument compartment shall have steel hinged doors that are in accordance with IEEE C testing requirements The design of openings shall pass the requirements of IEEE C , with respect to the emission of arc/flash products Openings intended to close on initiation of a fault to preserve arc-resistant construction shall be provided with the necessary guards on top and sides to prevent dropping of any foreign material that can prevent openings from closing Design and construction of the switchgear shall prevent effects of any fault in the circuit breaker and bus compartments from entering the instrument compartment All opening cover plates provided to preserve arc-resistant construction shall be accessible for inspection. Page 7 of 25

10 PIP ELSSG01 COMPLETE REVISION Design and Fabrication of Low-Voltage Metal-Enclosed AC Power Circuit Breaker Switchgear October Means to manually trip the breaker without requiring opening the door and compromising the integrity of arc-resistant construction shall be provided Provisions for closed door manual racking of the circuit breaker while maintaining the integrity of arc-resistant construction shall be provided A single-handle latch system with position labeling and provision for padlocking shall be provided on each door such that arc-resistant integrity is maintained when the latch is in closed position. Additional tie down bolts are acceptable on the doors to maintain arc resistant construction Personnel shall be protected from arc products and noise expelled from the switchgear enclosure. Unless otherwise specified on the purchaser s PIP ELSSG01D Data Sheet, a plenum system shall be provided as described below: a. Plenum system shall exhaust arc products from the switchgear room. b. Exhaust outlet shall be weatherproof and directed to an area that minimizes personnel exposure. c. Plenum minimum volume shall be tested and certified in accordance with IEEE C d. Plenum shall be separate from other plenum systems. If a combined plenum system is desired, manufacturer(s) shall analyze and certify the combined plenum system design. 4.4 Power Circuit Breakers Low-voltage power circuit breakers shall be air break type and shall be designed, rated, manufactured, and tested in accordance with IEEE C37.13, ANSI C37.16, ANSI C37.17, and ANSI C Breakers shall be of the stored-energy type with standard draw-out construction for both power and control circuits. Breakers shall be three-pole and complete with necessary operating mechanisms Breakers shall be operated electrically or manually as specified on the purchaser s PIP ELSSG01D Data Sheet. Electrically operated breakers shall also be capable of manual operation Circuit breakers shall have continuous current ratings as specified on the purchaser s PIP ELSSG01D Data Sheet or one line diagram(s). Ratings stated are those when installed and working under the specified service conditions. Ratings shall not be dependent upon the use of cooling fans Circuit breaker shall have a maximum interrupting time of 5 cycles, excluding sensing mechanism time Closing and tripping circuits shall be individually protected within each breaker compartment by fuses. When specified on the purchaser s PIP ELSSG01D Data Sheet other control and indication circuits (such as breaker trip indication) shall be individually protected within each breaker compartment by fuses. Page 8 of 25