BID_9789.1_Switch_Gear_Zip_Documents.docx

image4.emf

26 2416 Panelboards.pdf

Fields Road ES Electrical Equipment Replacement Panelboards ©2026 James Posey Associates, Inc. 8253-25 26 2416 - 1

SECTION 26 2416

PANELBOARDS

PART 1 - GENERAL

1.1 SECTION INCLUDES

A. Circuit breaker panelboards, lighting and appliance branch-circuit types.

B. Fusible branch circuit panelboards.

1.2 RELATED SECTIONS

A. Identification for electrical systems: Section 26 0553.

B. Overcurrent protective device studies: Section 26 0573.

C. Surge protective devices: Section 26 4313.

1.3 REFERENCES

A. ANSI/NECA 407: Recommended Practice for Installing and Maintaining Panelboards.

B. NEMA 250: Enclosures for Electrical Equipment (1000 Volts Maximum).

C. NEMA PB 1: Panelboards.

D. NEMA PB 1.1: Proper Installation, Operation, and Maintenance of Panelboards Rated 600 Volts or Less.

E. NETA ATS: Acceptance Testing Specifications for Electrical Power Distribution Equipment and

Systems.

F. UL 50: Enclosures for Electrical Equipment.

G. UL 67: Panelboards.

H. UL 1449: Surge Protective Devices.

1.4 DEFINITIONS

A. Circuit-breaker panelboards in this section:

1. Lighting and appliance panelboards: Maximum branch circuit breaker amperage:

a. 277/480-volt panelboards: 125 amperes

b. 120/208-volt panelboards: 100 amperes.

1.5 SUBMITTALS

A. Product data: For each type of panelboard, overcurrent protective device, surge protective device, accessory, and component indicated.

B. Bill of materials: Provide detailed list of components.

©2026 James Posey Associates, Inc. 8253-25 26 2416 - 2

C. Shop drawings: For each type of panelboard, include the following details:

1. Dimensioned plans, elevations, sections, and details. Show tabulations of installed devices, equipment features, and ratings in panel schedule format.

2. Detail enclosure types and details for types other than NEMA 250, Type 1.

3. Detail bus configuration, current, and voltage ratings.

4. Short-circuit current rating of panelboards and overcurrent protective devices.

5. Features, characteristics, ratings, and factory settings of individual protective devices and auxiliary components.

D. Operation and maintenance data: For panelboards and components to include in operation and maintenance manuals. In addition to items specified in Division 01 and Section 26 0101, include the following:

1. Manufacturer's written instructions for testing and adjusting overcurrent protective devices.

2. Copy of each printed panelboard schedule representing final version following installation.

1.6 QUALITY ASSURANCE

A. Do not submit equipment submittals prior to completing Short-Circuit and Coordination Study as indicated in Section 26 0573.

B. Source limitations: Obtain panelboards, overcurrent protective devices, components, and accessories through one source from a single manufacturer.

C. Electrical components, devices, and accessories: Listed and labeled as defined in NFPA 70, by a qualified testing agency accepted by the authority having jurisdiction, and marked for intended location and application; listed as a complete assembly.

1. UL label and local testing (where required): As specified in Section 26 0500, Common Work

Results for Electrical.

D. Comply with referenced standards and listings previously identified including NEMA PB 1, NFPA 70, and UL 67.

1.7 COORDINATION

A. Coordinate layout and installation of panelboards and components with other construction that penetrates walls or is supported by them, including electrical and other types of equipment, raceways, piping, encumbrances to workspace clearance requirements, and adjacent surfaces.

Maintain required workspace clearances and required clearances for equipment access doors and panels.

1.8 DELIVERY, STORAGE, AND HANDLING

A. Store equipment indoors in clean dry space with uniform temperature to prevent condensation.

Protect equipment from exposure to dirt, fumes, water, corrosive substances, and physical damage.

©2026 James Posey Associates, Inc. 8253-25 26 2416 - 3

1.9 PROJECT CONDITIONS

A. Product selection for restricted space:

1. Drawings indicate maximum dimensions for panelboards, including clearances between panelboards, and adjacent surfaces and other items. Comply with indicated maximum dimensions.

2. Contractor shall make all necessary field measurements to verify that equipment shall fit in allocated space in full compliance with minimum clearances specified in NFPA 70.

B. Interruption of existing electrical service: Do not interrupt electrical service to facilities occupied by

Owner or others unless permitted under the following conditions and then only after arranging to provide temporary electrical service according to requirements indicated:

1. Notify Owner no fewer than seven days in advance of proposed interruption of electrical service. Provide applicable details of proposed outage including sequence of work and methods of providing temporary electrical service.

2. Do not proceed with interruption of electrical service without written permission.

1.10 EXTRA MATERIALS

A. Furnish extra materials that match products installed and that are packaged with protective covering for storage and identified with labels describing contents.

1. Keys: Two spares for each type of panelboard cabinet lock.

2. Furnish spare breakers for panelboards as indicated in schedule on drawings.

3. Furnish spare fuses for fused switches: Equal to 10 percent of quantity installed for each size and type, but no fewer than three of each size and type.

PART 2 - PRODUCTS

2.1 ACCEPTABLE MANUFACTURERS

A. Circuit breaker panelboards: Subject to compliance with requirements, provide circuit breaker panelboards manufactured by Schneider Electric; Square D products or comparable product by one of the following:

1. ABB; General Electric products

2. Eaton Corporation

3. Schneider Electric; Square D products

4. Siemens Industry, Inc.

B. Fusible branch circuit panelboards: Subject to compliance with requirements, provide fusible branch circuit panelboards manufactured by Eaton Corporation; Bussmann products or comparable product by one of the following:

2. Eaton Corporation; Bussmann

3. Littelfuse, Inc.

4. Mersen

5. Schneider Electric; Square D products

6. Siemens Industry, Inc.

©2026 James Posey Associates, Inc. 8253-25 26 2416 - 4

2.2 PANELBOARDS, GENERAL

A. UL listing: UL 67, listed and labeled.

B. Integrated equipment short-circuit rating: Each panelboard, as a complete unit, shall have a short-circuit rating equal to or greater than the integrated equipment rating shown or scheduled on the drawings.

1. Rating shall be established by testing in accordance with UL 67, with the overcurrent devices mounted in the panelboard. Make short-circuit tests on the overcurrent devices and on the panelboard structure simultaneously, by connecting the fault to each overcurrent device with the panelboard connected to its rated voltage source. The source shall be capable of supplying specified panelboard short-circuit current or greater.

2. Testing of overcurrent devices only while individually mounted is not acceptable. Testing the bus structure by applying a fixed fault to the bus structure alone is not acceptable.

3. Mark each panelboard with its maximum short-circuit current rating at the supply voltage.

4. Series rating of panelboards with devices outside of the panelboard enclosure are not permitted.

C. Enclosures: Recess- or surface-mounted as indicated, NEMA PB 1, Type 1, UL 50, galvanized steel.

1. Size: Where multiple-width or multiple-section panelboards are indicated or required, each cabinet shall be the same width and height.

2. Provide enclosure type as indicated below or listed on drawings:

a. Indoor Dry and Clean Locations: NEMA 250, Type 1.

D. Directory card: Inside panelboard door, mounted in metal frame with transparent protective cover with information as indicated in Part 3, Identification.

E. Provisions for future devices: Mounting brackets, bus connections, filler plates, and necessary appurtenances required for future installation of devices.

F. Furnish each unit with a master nameplate, listing standard manufacturer information including voltage, ampacity, frequency, and short-circuit ratings; manufacturer's model and project designations.

2.3 CIRCUIT-BREAKER PANELBOARDS

A. Factory-assembled complete with bolt-on circuit breakers.

B. Cabinets and fronts: Minimum 20 inches wide, unless otherwise noted, wiring gutter space in accordance with UL 67, with minimum four-inch width on every side.

1. Cabinet front: Hinged trim with entire front hinged to cabinet box with piano hinge and screw fasteners for surface mounted cabinets. Door-in-door construction, one or more latches as required for size, with outer door covering the gutter.

2. Door: Required for sizes up to and including 600 amperes.

a. Lock: Flush, cylinder tumbler type, with catch and spring-loaded stainless steel door pull.

All panelboards shall be keyed alike. Provide two keys per lock. Provide extra keys as required in "Extra Materials" in Part 1 above.

b. Hinges: Steel, completely concealed.

©2026 James Posey Associates, Inc. 8253-25 26 2416 - 5

C. Circuit breakers: UL 489; voltage, continuous-current rating, and interrupting rating as indicated on the drawings or determined by the results of the Short-Circuit Analysis performed under Section 26 0573, whichever is greater.

1. Breakers shall be 1-, 2- or 3-pole, with an integral crossbar to ensure simultaneous opening of all poles in multipole circuit breakers.

2. Operating mechanism: Over center, trip-free, toggle-type with quick-make, quick-break action. Handles shall have on, off, and tripped positions.

3. Circuit breakers shall be able to be installed in the panelboard without requiring additional mounting hardware or disturbing adjacent units, bars, or branch circuit connections.

4. Where indicated on the drawings, provide shunt-trip main breakers, standard main breakers, or lugs.

5. Main and branch circuit breakers shall have device ampacity rating engraved on the front or side of each breaker handle. The breaker rating shall be clearly visible without removing panelboard cover.

6. Circuit breakers shall be rated for use with 75°C wire (conductor temperature rating).

7. Thermal-magnetic circuit breakers: Inverse time-current element for low-level overloads, and instantaneous magnetic trip element for short circuits. Adjustable magnetic trip setting for circuit-breaker frame sizes 250 amperes and larger.

8. Adjustable instantaneous-trip circuit breakers: Magnetic trip element with front mounted, field-adjustable trip setting.

9. Electronic trip circuit breakers: RMS sensing; field-replaceable rating plug or field replicable electronic trip; and the following field-adjustable settings:

a. Instantaneous trip.

b. Long- and short-time pickup levels.

c. Long- and short-time time adjustments.

10. Ground-fault circuit interrupter (GFCI) type circuit breakers: Single- and two-pole configurations with Class A ground-fault protection (6-mA trip).

11. Tandem breakers are not permitted.

D. Bussing assembly and temperature rise: Panelboard bus structure and main lugs or main circuit breaker shall have current ratings as shown on the panelboard schedule, established by heat rise tests conducted in accordance with UL 67.

1. Conductor dimensions shall not be accepted in lieu of actual heat tests.

2. Current-carrying parts of the bus structure shall be hard-drawn copper, 98 percent conductivity.

3. Provide a separate copper ground bus with screw terminals for branch wiring and feed-through lugs.

E. Additional connections: Where indicated on drawings, provide the following:

1. Feed-through lugs: Mechanical type, suitable for use with conductor material. Locate at opposite end of bus from incoming lugs or main device.

2. Sub-feed (double) lugs: Mechanical type suitable for use with conductor material. Locate at same end of bus as incoming lugs or main device.

F. Branch circuit panelboards: Panelboard shall be capable of accepting up to 100- ampere branch circuit breakers at 120/208 volts.

1. Branch circuit breakers serving exit lights and fire alarm shall be provided with handle-blocking devices which shall prevent accidental operation but not prevent tripping.

©2026 James Posey Associates, Inc. 8253-25 26 2416 - 6

2.4 FUSIBLE BRANCH CIRCUIT PANELBOARDS

A. Factory-assembled complete with branch fuse disconnect:

1. Emergency (life-safety) panelboard(s) shall be fusible branch circuit panelboards.

2. Main lug only, main fused switch, or main non-fused switch as indicated on the drawings, with main fused switch selectively coordinated with fusible branch switches.

3. Six spare single-pole 20-ampere fuses, unless otherwise noted.

4. UL Listed minimum interrupting rating of 200,000 rms symmetrical amperes at 600 volts AC.

B. Cabinets and fronts: Minimum 20 inches wide, wiring gutter space in accordance with UL 67.

1. Cabinet front: Door-in-door construction, one or more latches as required for size, with outer door covering the gutter.

2. Door: Lock, two keys per lock, steel hinges, and circuit directory card on inside of door.

C. Branch fuse disconnects: UL 248, UL 98, and NEMA FU 1; voltage, continuous-current rating, and interrupting rating as indicated on the drawings or determined by the results of the Short- Current Analysis performed under Section 26 0573, whichever is greater.

1. Incorporating overcurrent protection fuse and disconnecting means into a single integrated finger-safe component (1-pole, 2-pole or 3-pole) mechanically interlocked to prevent removal of the fuse while fuse terminals are energized.

2. Interchangeable from 15 amperes to 100 amperes without requiring additional space.

3. Time-delay UL Listed Class CF power fuses (equivalent to Class J).

4. Visible circuit ON/OFF indication positions and open fuse indication.

5. Permanently installed lockout means in the OFF position.

D. Bussing assembly and temperature rise: Panelboard bus structure and mains shall have current ratings as shown on the drawings:

1. Sufficient cross section to meet UL 67 temperature rise requirements.

2. Current-carrying parts of the bus structure shall be hard-drawn copper, 98 percent conductivity.

3. Provide a separate copper equipment ground bar and neutral bus bar.

2.5 SOURCE QUALITY CONTROL

A. With branch circuit breakers installed, short-circuit test panelboards as complete units, in accordance with requirements of UL 67.

PART 3 - EXECUTION

3.1 INSTALLATION

A. Securely attach panelboards to the wall where indicated on the drawings. Install in accordance with NEMA PB 1.1 and manufacturer's written installation instructions.

1. Mounting height:

a. 72 inches to top of panelboard.

b. Panelboards taller than 72 inches: Bottom edge no more than 4 inches above floor.

c. Top breaker maximum height: No more than 6 feet, 7 inches above the floor or working platform.

©2026 James Posey Associates, Inc. 8253-25 26 2416 - 7

B. Comply with applicable portions of NECA 407.

C. Frame and mount printed circuit directory indicating type and location of equipment on each circuit.

D. Wiring in gutters: Arrange conductors into groups, and bundle and wrap with wire ties.

E. Install filler plates in unused spaces.

3.2 CONNECTIONS

A. Connect panelboards and components to wiring and to ground as indicated.

B. Shared neutral conductors shall not be permitted, except where indicated.

C. Tighten electrical connectors and terminals according to manufacturer's published torque-tightening values. Where manufacturer's values are not indicated, use those specified in UL 486A and UL 486B.

3.3 IDENTIFICATION

A. Materials: Refer to Division 26 Section "Identification for Electrical Systems." Identify units, auxiliary devices, controls, and wiring. Identify equipment ratings.

B. Nameplates: Refer to Division 26 Section "Identification for Electrical Systems" for additional requirements. Provide identification nameplate for each panelboard and associated components located on front of assembly.

C. Identify field-installed wiring and components. Refer to Division 26 Section "Identification for

Electrical Systems" for additional requirements.

D. Identify available fault current and calculation date. Refer to Division 26 Section "Overcurrent Protective Device Studies" for additional requirements.

E. Provide printed directory for each panelboard. Handwritten directories are not acceptable.

Copying of panel schedules and descriptions on drawings is not acceptable. Circuit directory shall reflect final circuit installation. Include the following information:

1. Panelboard designation and room location.

2. Circuit breakers, size and number of poles.

3. Circuit or feeder description including destination room name(s) and number(s).

4. Clear description of type of load circuit serves.

5. Panelboard ratings: Main bus ampacity, main circuit breaker or main lug ampacity, AIC rating.

6. Incoming primary feeder size and source panelboard circuit designation.

F. Room names and numbers on the panelboard circuit directories shall match names and numbers used by the Owner. Note that room names and numbers on the drawings may not match the Owner's final room name and numbering scheme.

©2026 James Posey Associates, Inc. 8253-25 26 2416 - 8

3.4 FIELD QUALITY CONTROL

A. Make insulation-resistance tests of each panelboard bus, component, and connecting supply, feeder, and control circuit.

B. Make continuity tests of each circuit.

C. Perform each visual and mechanical inspection and electrical test stated in NETA Acceptance

Testing Specification for molded-case circuit breakers, with the exception of thermographic survey. Certify compliance with test parameters.

D. Correct malfunctioning units on-site, where possible, and retest to demonstrate compliance;

otherwise, replace with new units and retest.

3.5 CLEANING

A. Clean interior and exterior of panelboards.

B. Refinish painted surfaces damaged during construction to match the rest of the panelboard.

END OF SECTION

image5.emf

26 2413 Switchboards.pdf

Fields Road ES Electrical Equipment Replacement Switchboard ©2026 James Posey Associates, Inc. 8253-25 26 2413 - 1

SECTION 26 2413

SWITCHBOARD

A. Service entrance switchboard rated 600 volts and less, for interior installation, including:

1. Utility metering section

2. Main service disconnect, circuit breaker type

3. Distribution section, circuit breaker type

4. Surge protective device

A. Identification for electrical systems: Section 26 0553.

B. Overcurrent protective device studies: Section 26 0573.

C. Equipment foundations: Section 26 0528.

D. Surge protective devices: Section 26 4313.

A. NEMA 250, Enclosures for Electrical Equipment (1000 Volts Maximum).

B. NEMA AB 1, Molded Case Circuit Breakers and Molded Case Switches.

C. NEMA PB 2, Deadfront Distribution Switchboards.

D. NEMA PB 2.1, Proper Handling, Installation, Operation and Maintenance of Deadfront Distribution Switchboards Rated 600 V or Less.

E. UL 891, Dead-Front Switchboards.

1.4 SUBMITTALS

A. Product data: For switchboard including overcurrent protective devices, ground-fault protective devices, transient voltage suppression, and accessories. Include weights, dimensions, minimum clearances; and manufacturer’s technical data on features, performance, electrical characteristics, ratings, accessories, and finishes.

B. Shop drawings: For switchboard, include the following:

1. Dimensioned plans, elevations, sections, and details, including required clearances and service space around equipment. Show method of field assembly, location, and size of each field connection.

2. Single-line diagram representation of switchboard, bus configuration, current, and voltage ratings.

3. Short-circuit current rating of switchboard assembly and overcurrent protective devices.

4. Utility company metering provisions with indication of approval by utility company.

5. Scheduled of features, characteristics, ratings, and factory settings of individual protection devices.

©2026 James Posey Associates, Inc. 8253-25 26 2413 - 2

6. Wiring diagrams for power and control, differentiating between manufacturer-installed and field-installed wiring.

7. Include time-current coordination curves for each type and rating of overcurrent protective device included in switchboards.

C. For service entrance switchboards, submit to utility company, Pepco, for approval.

D. Coordination drawings: Floor plans, drawn to 1/4" = 1'-0" scale, on which the following items are shown and coordinated with each other based on input from installers of the items involved:

1. Dimensioned concrete base; outline of equipment; and required clearances; relationship between components and adjacent architectural, structural, and mechanical elements.

2. Underground conduit stub-up locations, where applicable.

3. Overhead conduit riser locations.

4. Grounding cable locations and terminations.

5. Identify equipment sections including front and rear orientation.

E. Field quality-control test reports: Results of field testing.

F. Operation and maintenance data: For switchboards to include in the maintenance manuals specified in Division 01. Include manufacturer’s detailed written instructions on adjusting overcurrent protective devices.

1.5 QUALITY ASSURANCE

A. Do not submit equipment submittals prior to completing Short-Circuit and Coordination Study as indicated in Section 26 0573.

B. Source limitations: Obtain switchboards, overcurrent protective devices, components, and accessories from single source from single manufacturer.

C. Electrical components, devices, and accessories: Listed and labeled as defined in NFPA 70, by a qualified testing agency accepted by the authority having jurisdiction, and marked for intended location and application; listed as a complete assembly.

1. UL label and local testing (where required): As specified in 26 0500, Common Work Results for Electrical.

D. Product selection for restricted space: Drawings indicate maximum dimensions for switchboards including clearances between switchboards and adjacent surfaces and other items. Comply with indicated maximum dimensions.

1.6 COORDINATION

A. Coordinate layout and installation of switchboard and components with other construction including conduit, piping, equipment, and adjacent surfaces. Maintain required clearances for workspace and equipment access doors and panels.

B. Coordinate size and location of concrete bases.

1.7 DELIVERY, STORAGE, AND HANDLING

A. Delivery in sections of lengths that can be moved past obstructions in delivery path.

©2026 James Posey Associates, Inc. 8253-25 26 2413 - 3

B. Store equipment indoors in clean dry space with uniform temperature to prevent condensation.

Protect equipment from exposure to dirt, fumes, water, corrosive substances, and physical damage.

1.8 PROJECT CONDITIONS

A. Product selection for restricted space:

1. Drawings indicate maximum dimensions for switchboards, including clearances between switchboards, and adjacent surfaces and other items. Comply with indicated maximum dimensions.

2. Contractor shall make all necessary field measurements to verify that equipment shall fit in allocated space in full compliance with minimum clearances specified in NFPA 70.

B. Interruption of existing electrical service: Do not interrupt electrical service to facilities occupied by owner or others unless permitted under the following conditions and then only after arranging to provide temporary electrical service according to requirements indicated:

1. Notify Owner no fewer than seven days in advance of proposed interruption of electrical service. Provide applicable details of proposed outage including sequence of work and methods of providing temporary electrical service.

2. Do not proceed with interruption of electrical service without written permission.

2.1 ACCEPTABLE MANUFACTURERS

A. Switchboards manufactured by Schneider Electric; Square D products are the basis for design of the project. The following listed manufacturers also provide units of acceptable quality. If units by any of these manufacturers should be proposed, verify that they meet requirements specified in Division 01 and the article “Product Options” in Section 26 0101, and submit shop drawings as specified in the article “Submittals” above.

2. Eaton Corporation

3. Schneider Electric; Square D products

4. Siemens Industry, Inc.

2.2 MAIN SWITCHBOARD

A. Service entrance switchboard, NEMA PB 2, UL listed, in a NEMA 250 Type 1 enclosure except as indicated otherwise.

B. Construction: Deadfront with front access.

1. Formed code-gauge steel, welded and bolted together to support cover plates, bussing, and component devices during shipment and installation.

2. Finish: Gray enamel over a rust-inhibiting phosphate primer.

3. Furnish each unit with a master nameplate, listing standard manufacturer information including voltage, ampacity, frequency, and short-circuit ratings; manufacturer’s model and project designations.

C. Sections: Each shall have an open bottom and individual removable top plate for installation and termination of conduit.

©2026 James Posey Associates, Inc. 8253-25 26 2413 - 4

1. Wireway front covers: Hinged to permit access to the branch breaker load side terminals without removing the covers.

D. Bussing: Plated copper and of sufficient cross-sectional area to meet UL 891 for temperature rise.

1. Through bus: Ampacity, and braced to have a short-circuit current rating of RMS symmetrical amperes, as shown on the drawings. The through bus shall have provisions for the addition of future sections. Bolt supports, connections and joints with grade 5 hex head bolts and belleville washers.

1. Potential and current transformers: ANSI C57.13.

E. Main circuit breaker section: Enclosed, molded-case type circuit breaker, totally front-accessible and front-connectable. Line side circuit-breaker connections shall be jaw type plug-on.

1. Circuit breaker: NEMA AB 1, handle lockable; frame size, trip rating, number of poles, and auxiliary devices as indicated; interrupting capacity rating to meet available fault current.

a. 200 amperes and larger: Trip units interchangeable within frame size.

b. 400 amperes and larger: Field-adjustable short-time and continuous current settings.

c. Lugs: Mechanical lugs and power-distribution connectors for number, size, and material of conductors indicated.

F. Ground fault protection system for main service disconnect:

1. Current sensor and relaying equipment: Split-core type current sensor shall enclose all phase conductors, and neutral conductors, if present, of the circuit to be monitored.

2. Monitor panel: Include a push-to-test button for the test circuit and a red, ground fault indicator light which indicates the circuit interrupter has opened due to a ground fault condition.

3. Test winding: Shall simulate the flow of ground fault current through the current sensor, in order to test the complete system, including sensor pickup, relaying equipment, and electric trip mechanism of the switch.

a. Ground fault relay: Solid-state construction, with adjustable pickup for ground fault currents from 200 amperes to 1200 amperes. Settings for individual relays shall be as shown on the drawings. Time delay provided by the field-adjustable ground fault relay circuitry shall have continuous settings from 0.03 to 0.6 seconds.

G. Circuit breaker distribution section:

1. Circuit breakers shall be suitable for mounting in the switchboard sections for which they are scheduled: Either group- or individually-mounted distributed sections.

a. Group-mounted circuit breakers through 600 amperes:

(1) Circuit breaker(s) shall be grouped-mounted plug-on with mechanical restraint on a common pan or rail assembly.

(2) The interior shall have three flat bus bars stacked and aligned vertically with glass reinforced polyester insulators laminated between phases. The molded polyester insulators shall support and provide phase isolation to the entire length of bus.

(3) Circuit breaker(s) equipped with line terminal jaws shall not require additional external mounting hardware. Circuit breaker(s) shall be held in mounted position by a self-contained bracket secured to the mounting pan by fasteners. Circuit breaker(s) of different frame sizes shall be capable of being mounted across from each other.

©2026 James Posey Associates, Inc. 8253-25 26 2413 - 5

(4) Line-side circuit breaker connections shall be jaw type.

(5) Unused spaces provided, unless otherwise specified, shall be fully equipped for future devices, including appropriate connectors and mounting hardware.

2. Thermal magnetic molded case circuit breakers: Molded case circuit breaker(s), with integral thermal and instantaneous magnetic trip in each pole. Ampere and fault current-interrupting ratings shall be as noted on the schedules.

H. Energy reduction maintenance switch (ERMS):

1. Switchboard shall contain an arc energy reduction maintenance switch (ERMS) for each circuit breaker rated 1200 amperes or larger including any provisional spaces indicated as “space and provision” and marked with 1200-ampere or greater frame size. The ERMS shall include the following features:

a. External override and circuitry which shall be connected to a breaker’s trip unit, and shall be adjustable between 2.5x – 10x trip unit sensor rating.

b. Operation: Enabled via a mode selector switch located adjacent the circuit breaker or electronic trip unit integral to circuit breaker.

(1) Mode selector switch: A separate local LED status indicator light shall demonstrate switch is in the “normal” or “maintenance” mode. The selector switch shall be lockable and accessibly mounted on the front enclosure cover above or adjacent to each breaker position served.

(2) Electronic trip unit: Confirmation of protection mode via LED indicator light.

c. An ERMS hazard warning label shall be provided indicating presence of the ERMS.

2. Provide trip unit settings for maintenance after performing arc flash study in accordance with the NFPA 70E. The arc flash study shall provide arc flash energy and hazard category with “normal” and “maintenance” device protection (trip unit) settings respectively including protective coordination curves.

2.3 SURGE PROTECTIVE DEVICES (SPD)

A. As part of the main service switchboard, provide service entrance SPD specified in Section 26 4313, Surge Protective Devices.

2.4 FACTORY TESTS

A. Each switchboard, as a complete unit, shall be given a single short-circuit current rating by the manufacturer. Rating shall be established by actual tests by the manufacturer, in accordance with UL specifications, and on equipment similar to the switchboard provided for this project.

3.1 EXAMINATION

A. Examine elements and surfaces where switchboard will be installed for compliance with installation tolerances, required clearances, and other conditions affecting performance.

B. Verify that equipment foundations are level and ready to receive equipment.

C. Verify field measurements are as indicated on architectural drawings and coordination drawings.

©2026 James Posey Associates, Inc. 8253-25 26 2413 - 6

D. Verify that required utilities are available, in proper location, and ready for use.

E. Beginning of installation indicates installer accepts conditions.

3.2 INSTALLATION

A. Provide equipment foundation (housekeeping pad).

B. Level switchboard in place before mounting and bolt to the foundation. Assemble sections as required by the manufacturer and in accordance with NEMA PB 2.1.

C. Frame and mount printed operating instructions, including control and key interlocking sequences and emergency procedures, on front of switchboards.

3.3 CONNECTIONS

A. Connect switchboards and components to wiring systems according to other sections of Division 26 and instructed by manufacturer’s recommendations.

B. Ground equipment according to Section 26 0526, Grounding and Bonding, and as instructed by manufacturer’s recommendations.

C. Tighten electrical connectors and terminals according to manufacturer’s published torque-tightening values. Where manufacturer’s values are not indicated, use those specified in UL 486A and UL 486B.

3.4 IDENTIFICATION

A. Materials: Refer to Division 26 Section "Identification for Electrical Systems." Identify units, auxiliary devices, controls, and wiring. Identify equipment ratings.

B. Nameplates: Refer to Division 26 Section "Identification for Electrical Systems" for additional requirements. Provide identification nameplate for each switchboard and each section, including associated components, located on front of assembly.

C. Identify field-installed wiring and components as specified in 26 0553, Identification for Electrical Systems.

D. Identify available fault current and calculation date. Refer to Division 26 Section "Overcurrent

Protective Device Studies" for additional requirements.

3.5 FIELD QUALITY CONTROL

A. Perform tests and inspections and prepare test reports.

1. Manufacturer’s field service: Engage a factory-authorized service representative to inspect components, assemblies, and equipment installations, including connections, and to assist in testing.

B. Tests and inspections:

1. Perform each visual and mechanical inspection and electrical test stated in NETA Standard for Acceptance Testing Specifications for Electrical Power Equipment and Systems. Certify compliance with test parameters.

©2026 James Posey Associates, Inc. 8253-25 26 2413 - 7

2. Inspect, test, and adjust the equipment.

a. Set field-adjustable switches and circuit-breaker trip ranges as indicated.

b. Test insulation resistance for each switchboard bus, components, and connecting supply, feeder, and control circuit.

c. Test continuity of each circuit.

d. Test ground-fault protection of service entrance equipment.

C. Correct malfunctioning units on-site, where possible, and retest to demonstrate compliance;

otherwise, replace with new units and retest.

D. Ensure that the equipment functions properly by actual operation prior to final acceptance.

3.6 ADJUSTING

A. Set field-adjustable, circuit breaker trip characteristics according to results in Section 26 0573, Overcurrent Protective Device Studies.

3.7 CLEANING

A. Clean interior and exterior of switchboards.

B. Refinish painted surfaces damaged during construction to match the rest of the switchboard.

3.8 OPERATING INSTRUCTIONS

A. As specified in Section 26 0500, Common Work Results for Electrical, provide operating instructions.

B. Provide at least 8 hours of additional instruction time for the equipment specified in this section, consisting of 2 periods of 4 consecutive hours, during a period of not less than 60 days.

Blank Page image6.emf

26 0573 Overcurrent Protective Device Studies.pdf

Fields Road ES Electrical Equipment Replacement Overcurrent Protective Device Studies ©2026 James Posey Associates, Inc. 8253-25 26 0573 - 1

SECTION 26 0573

OVERCURRENT PROTECTIVE DEVICE STUDIES

A. Electrical system fault-current and protective device study:

1. Fault-current analysis.

2. Coordination study and device settings.

3. Arc flash hazard analysis.

B. Description: Provide fault-current and protective device study for new switchboard, new panelboards, and associated feeders.

A. Sections in Division 26, including 26 2413 Switchboards and 26 2416 Panelboards.

A. Institute of Electrical and Electronics Engineers (IEEE):

1. IEEE 141 – Recommended Practice for Electric Power Distribution and Coordination of Industrial and Commercial Power Systems.

2. IEEE 241 – Recommended Practice for Electric Power Systems in Commercial Buildings.

3. IEEE 242 – Recommended Practice for Protection and Coordination of Industrial and

Commercial Power Systems.

4. IEEE 399 – Recommended Practice for Industrial and Commercial Power System Analysis.

5. IEEE 1015 – Recommended Practice for Applying Low-Voltage Circuit Breakers Used in

Industrial and Commercial Power Systems.

6. IEEE 1584 - Guide for Performing Arc flash Hazard Calculations.

B. American National Standards Institute (ANSI):

1. ANSI C57.12.00 – Standard General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers.

2. ANSI C37.13 – Standard for Low Voltage AC Power Circuit Breakers Used in Enclosures.

3. ANSI C37.010 – Standard Application Guide for AC High Voltage Circuit Breakers Rated on a

Symmetrical Current Basis.

4. ANSI C37.41 – Standard Design Tests for High Voltage Fuses, Distribution Enclosed Single-

Pole Air Switches, Fuse Disconnecting Switches and Accessories.

C. National Fire Protection Association (NFPA):

1. NFPA 70 – National Electrical Code, latest edition.

2. NFPA 70E – Standard for Electrical Safety in the Workplace.

D. Occupational Safety and Health Administration (OSHA):

1. OSHA 29 Code of Federal Regulations (CFR) Part 1910, Subpart S.

©2026 James Posey Associates, Inc. 8253-25 26 0573 - 2

A. Product data: For computer software to be used to perform studies.

B. Product certificates: For coordination-study and fault-current analysis computer software programs, certifying compliance with IEEE 399.

C. Qualifications: Submit evidence indicating individual and organization compliance with requirements indicated in “Quality Assurance” below.

D. Preliminary electrical system study: Submit for review before distribution equipment shop drawings have been submitted, and before equipment order has been released to the manufacturer.

1. If formal completion of the study may delay the project schedule, Owner may approve use of the preliminary draft for ordering equipment.

2. If approved for use in ordering equipment, preliminary draft shall include sufficient study data to ensure that the selection of device ratings and characteristics will be satisfactory.

E. Final electrical system study:

1. Submit final report for review and record.

2. Incorporate changes resulting from deficiencies and corrections of preliminary draft report.

F. Reports:

1. Electrical system study report: Submit reports required above including the following items:

a. General report information: Scope, definitions, descriptions, assumptions, and other information necessary to properly interpret results of the report.

b. Tabulated summary comparing protective device ratings and calculated available fault-current levels.

c. Fault-current analysis calculations.

d. Arc flash hazard calculations including details of the incident energy and flash protection boundary calculations.

e. Recommendations for system improvements.

f. System one-line diagram.

2. Submit final reports as electronic files in portable document format (.pdf) to Owner. Submit program base files in file format of computer software utilized to perform study.

A. Electrical system study shall be performed by one or more independent qualified organizations, and under the supervision and approval of a Registered Professional Engineer skilled in performing and interpreting the power system studies.

B. Qualifications of organization performing electrical system study: An entity experienced in the application of computer software used for studies, having performed successful studies of similar magnitude on electrical distribution systems using similar devices:

1. Registered Professional Engineer shall be a full-time employee of the equipment manufacturer or of an approved engineering firm.

2. Registered Professional Engineer shall have a minimum of five (5) years of experience in performing power system studies and registered in the state where the project is located.

©2026 James Posey Associates, Inc. 8253-25 26 0573 - 3

C. Qualifications of computer-based software: Widely available, complying with standards, guides, and codes as referenced above.

D. Comply with IEEE 399 for general study procedures.

E. Comply with IEEE 242 for short-circuit currents and coordination time intervals.

2.1 MANUFACTURERS

A. Computer software: Subject to compliance with requirements, utilize product by one of the following:

1. EDSA Micro Corporation

2. Operation Technology, Inc.

3. SKM Systems Analysis, Inc. (Basis of Design)

2.2 COMPUTER SOFTWARE REQUIREMENTS

A. Comply with IEEE 399.

B. Computer software program shall be capable of performing fault-current analysis of project electrical distribution system.

C. Computer software program shall be capable of plotting and diagramming time-current characteristic curves as part of its output. Computer software program shall report device settings and ratings of all overcurrent protective devices and shall demonstrate selective coordination by computer-generated, time-current coordination plots.

D. Computer software program shall be capable of performing arc fault hazard analysis using equations as established by IEEE 1584 and requirements presented in NFPA 70E, Annex D.

E. Software shall include a comprehensive equipment library of manufacturer-based and IEEE / ANSI based equipment to accurately model the electrical distribution system.

3.1 EXAMINATION

A. Examine project submittals for compliance with electrical distribution system requirements outlined on the drawings and in electrical specification sections.

3.2 SYSTEM DATA COLLECTION

A. The Contractor shall furnish all data required to perform the power system studies. The Engineer performing the fault analysis, protective device coordination, and arc flash hazard analysis studies shall furnish the Contractor with a listing of required data immediately after award of the contract. The Contractor shall expedite collection of the data to ensure completion of the studies as required for final approval of the distribution equipment shop drawings and/or prior to the release of the equipment for manufacturing.

B. If applicable, include fault contribution of existing motors and equipment in the study. The

Contractor shall obtain required existing equipment data, if necessary, to satisfy the study requirements.

©2026 James Posey Associates, Inc. 8253-25 26 0573 - 4

C. The Engineer performing the studies shall gather and tabulate input data necessary to support each study including the following:

1. Product data for each component of the electrical distribution system.

2. Utility available fault contribution and impedance values.

3. Drawings, one-line, and riser diagrams showing system configuration, equipment designations, feeder lengths, and other applicable system characteristics.

3.3 SYSTEM FAULT CURRENT ANALYSIS

A. Calculate the maximum available short-circuit momentary current and interrupting duties in amperes rms symmetrical for electrical power distribution system components. The calculation shall be performed for current immediately after initiation and for a three-phase bolted fault at each of the following locations:

1. Electric utility’s supply termination.

2. Switchboards.

3. New branch circuit panelboards.

B. Study the project’s electrical distribution system from normal and alternate power sources throughout electrical distribution system.

C. For grounded systems, provide line-to-ground fault current values for areas as defined above for the three-phase, bolted fault, short-circuit study.

D. Calculations to verify interrupting ratings of overcurrent protective devices shall comply with IEEE 141, IEEE 241 and IEEE 242.

E. Study report:

1. Input data: Gather and provide the following input data, in tabular or graphic form, used to perform fault calculations and other studies in this section.

a. Utility three-phase and line-to-ground available contribution with associated X/R ratios.

b. Short-circuit reactance of rotating machines with associated X/R ratios.

c. Cable type, construction, size, quantity per phase, length, impedance and conduit type.

d. Circuit breaker types and sizes.

2. Methods and assumptions: Indicate calculation methods and assumptions that may have been used to perform analysis.

3. Results: Show calculated X/R ratios and equipment interrupting rating (1/2-cycle) fault currents on electrical distribution system diagram. Provide the following in a table format:

a. Source fault impedance and generator contributions

b. X/R ratios

c. Asymmetry factors

d. Motor contributions

e. Short circuit KVA

f. Symmetrical and asymmetrical fault currents

4. Equipment evaluation and conclusions:

a. Verify interrupting ratings and withstand ratings are equal to or higher than calculated fault current levels.

b. Verify adequacy of phase conductors at maximum three-phase, bolted fault currents.

©2026 James Posey Associates, Inc. 8253-25 26 0573 - 5

5. Recommendations: List recommendations for equipment with inadequate ratings. Notify Engineer, in writing of existing equipment improperly rated for the calculated available fault current of the system.

3.4 AVAILABLE FAULT CURRENT LABELS

A. Provide a machine printed adhesive label on the enclosure for each switchboard and new panelboards. The label shall include the following information, at a minimum:

1. Available fault current

2. Calculation date

B. Labels will be based on calculated maximum available short-circuit momentary current and will be provided after the results of the analysis have been presented to the Owner and after any system changes, upgrades or modifications have been incorporated in the system.

C. Labels shall be in compliance with NFPA 70E and OSHA standards.

3.5 SYSTEM ARC FLASH HAZARD ANALYSIS

A. The arc flash hazard analysis shall be performed according to the IEEE 1584 equations that are presented in NFPA 70E, Annex D.

B. The flash protection boundary and the incident energy shall be calculated at all significant locations in the electrical distribution system (such as switchboards and new panelboards, where work could be performed on energized parts.

C. The arc flash hazard analysis shall include electrical equipment locations where work such as examination, adjustment, service, or maintenance could be performed on energized parts.

D. Safe working distances shall be based upon the calculated arc flash boundary considering incident energy of 1.2 cal/cm2.

E. When appropriate, the short circuit calculations and the clearing times of the phase overcurrent devices will be retrieved from the short-circuit and coordination study model. Ground overcurrent relays should not be taken into consideration when determining the clearing time when performing incident energy calculations.

F. The short-circuit calculations and the corresponding incident energy calculations for multiple system scenarios must be compared and the greatest incident energy must be uniquely reported for each equipment location. Calculations must be performed to represent the maximum and minimum contributions of fault current magnitude for all normal and emergency operating conditions. The minimum calculation will assume that the utility contribution is at a minimum and will assume a minimum motor contribution (all motors off).

1. Conversely, the maximum calculation will assume a maximum contribution from the utility and will assume the maximum number of motors to be operating. Calculations shall take into consideration the parallel operation of synchronous generators with the electric utility, where applicable.

G. The incident energy calculations must consider the accumulation of energy over time when performing arc flash calculations on buses with multiple sources. Iterative calculations must take into account the changing current contributions, as the sources are interrupted or decremented with time. Fault contribution from motors and generators should be decremented as follows:

1. Fault contribution from induction motors should not be considered beyond 3-5 cycles.

©2026 James Posey Associates, Inc. 8253-25 26 0573 - 6

2. Fault contribution from synchronous motors and generators should be decayed to match the actual decrement of each as closely as possible (e.g., contributions from permanent magnet generators will typically decay from 10 per unit to 3 per unit after 10 cycles).

H. For each equipment location with a separately enclosed main device (where there is adequate separation between the line side terminals of the main protective device and the work location), calculations for incident energy and flash protection boundary shall include both the line and load side of the main breaker.

I. When performing incident energy calculations on the line side of a main breaker (as required per above), the line side and load side contributions must be included in the fault calculation.

J. Mis-coordination should be checked amongst all devices within the branch containing the immediate protective device upstream of the calculation location and the calculation should utilize the fastest device to compute the incident energy for the corresponding location.

K. Arc flash calculations shall be based on actual overcurrent protective device clearing time.

Maximum clearing time will be capped at 2 seconds based on IEEE 1584. Where it is not physically possible to move outside of the flash protection boundary in less than 2 seconds during an arc flash event, a maximum clearing time based on the specific location shall be utilized.

L. Incident energy and flash protection boundary calculations:

1. Arcing fault magnitude

2. Device clearing time

3. Duration of arc

4. Arc flash boundary

5. Working distance

6. Incident energy

7. Hazard Risk Category

8. Recommendations for arc flash energy reduction

3.6 ARC FLASH WARNING LABELS

A. The Contractor and organization performing the Arc Flash Hazard Analysis shall provide a 3.5 in.

x 5 in. thermal transfer type label of high adhesion polyester for each work location analyzed.

B. Labels will be based on recommended overcurrent device settings and will be provided after the results of the analysis have been presented to the Owner and after any system changes, upgrades or modifications have been incorporated in the system.

C. The label shall include the following information, at a minimum:

1. Location designation

2. Nominal voltage

3. Flash protection boundary

4. Hazard risk category

5. Incident energy

6. Working distance

7. Engineering report number, revision number and issue date

D. Labels shall be machine printed, with no field markings.

E. Labels shall be in compliance with NFPA 70E and OSHA standards.

©2026 James Posey Associates, Inc. 8253-25 26 0573 - 7

F. Provide arc flash labels in the following manner based on recommended overcurrent device settings.

1. For each new 208-volt panelboard, one arc flash label shall be provided.

2. For switchboard, one arc flash label shall be provided.

3.7 ARC FLASH TRAINING

A. The equipment vendor shall train personnel of the potential arc flash hazards associated with…