-
- Electrical system distribution throughout the building shall be based upon either the 480Y/277V or 208YV/120V volt three phase configuration.
- Protection: Surge Protection Devices shall be located on main service distribution equipment. Surge Protection shall be provided on distribution electrical equipment and panels serving the MDF and IDF rooms and all panels serving technology receptacles.
- Grounding: Continuous equipment grounding conductors shall be installed in all circuits bonded to all ground lugs, bussing, switches, receptacles, equipment frames, etc., per the City of Chicago Building Code. The main facility grounding field electrode system to ground shall be 5 ohms or less.
- Capacity: Electrical systems main service equipment shall be designed with a 15 percent spare amperage capacity and 30 percent spare space capacity. Branch circuit panelboards shall be designed up to 70 percent of capacity and be provided with a minimum of 6 spare overcurrent protection devices. and (4)-3 pole spaces distribution boards shall be provided with four (4)-3 pole spaces.
- GFCI: Provide ground fault outlets (GFCI) for all receptacles located as required by Code to include all outlets within 6’ of a wet area.
- Provide an exterior, weatherproof GFCI duplex receptacle outside each main exterior door.
- Provide a maximum of 5 technology receptacles per circuit. Technology receptacles/circuits are those that serve voice, data, computer, and other IT equipment throughout the school, with the exception of the MDF room.
-
- Electrical distribution equipment shall be in dedicated electrical or mechanical rooms and shall be readily accessible.
- Main electrical service (switchboards) distribution equipment shall be in a dedicated electrical room with fire ratings as required by the City of Chicago Building Code. Main electrical room shall have access to the exterior of the building.
- Branch circuit distribution panel boards and Automatic Transfer Switches (ATS) shall be in dedicated electrical closets.
- Locating electrical or control equipment in instructional spaces or corridor walls is not acceptable.
- Service Entrance: Coordinate service entrance requirements with local utility service companies for electrical.
-
- Dry type transformers shall be the most energy efficient type transformer. Locate in a dry area indoors. Coordinate location with architectural to achieve required fire rating of room.
- Noise level requirement shall be as established in other sections in this standard.
-
- Dedicated distribution equipment shall be provided for all mechanical equipment and renewable energy equipment. Electrical branch circuits to 5 horsepower, 3-phase, and larger motors for air-handling units, exhaust fans, pumps, chillers, and condensing units shall be provided with phase loss protection. Phase loss protection equipment shall be integral to starters or variable frequency drives serving the equipment.
- 480 volt, 3 phase - motors 1/2 HP and larger
- HVAC equipment
- Pumps
- Large appliances
- In 208-volt systems all three phase motors will be 208 volt listed motors.
- 120-volt, single phase - small equipment
- Motors less than 1/2 HP
- Lighting
- Receptacles
- Miscellaneous Equipment
- Electrical power connections will be made to all mechanical equipment electrically held or secured doors, elevators, air conditioning equipment, air compressors, air dryers, exhaust fans, kitchen equipment, laundry equipment, water heaters, electric water coolers, pumps, unit heaters, baseboard heaters, security equipment, computer equipment and all electrically operated building equipment.
- Equipment bracing and short circuit withstand ratings will exceed the available fault current as calculated using ANSI/IEEE Standard 242-1986
- Voltage drop for feeders between the service entrance equipment and the branch circuit distribution equipment shall conform to the requirements of ASHRAE standard 90.1 most recent version.
- Feeder conductors shall be designed for a maximum voltage drop of 2% at full-connected load.
- Branch circuit conductors shall be designed for a maximum voltage drop of 3% at full-connected load.
- Branch circuits shall generally be loaded to 60% of the branch circuit overcurrent device rating.
- Feeders supplying the branch circuit panel board for voice and data systems (technology) circuits shall contain three phase conductors, sized in accordance with Code requirements and shall have surge protection devices.
- Branch circuits for IT system receptacles in the MDF room shall contain an isolated ground wire. Neutral conductors for shared neutral multiwire circuits shall be minimum No. 10 AWG. All branch circuit panel boards supplying MDF room circuits shall be supplied from a separate feeder overcurrent protective device (OCPD) in the main switchboard, or from a separate distribution panel supplied by its own feeder) in the main switchboard.
- Feeders supplying the branch circuit panel board for IT system receptacles in the MDF room shall contain three phase conductors, sized in accordance with Code requirements, a 200% neutral conductor(s), and an isolated ground conductor. The isolated ground conductor system shall be kept separate from the receptacle or branch circuit to the main switchboard ground bus or separately derived system. The isolated ground conductor and equipment ground system shall be connected only at the main switchboard or separately derived system, and shall have surge suppression.
- If isolated ground circuits are required by Audio/Visual equipment, provide isolated ground distribution for those circuits similar to those listed above for MDF rooms.
- Solar-ready
- Install metallic conduit from roof to the electrical room.
- Electric Vehicle Charging Infrastructure:
- Install listed raceway capable of accommodating a 208-volt dedicated branch circuit.
- The raceway shall not be less than trade size 1 (nominal 1-inch inside diameter).
- The raceway shall originate at the main service or subpanel and shall terminate into a listed cabinet, box or enclosure in close proximity to the proposed location of the EV space.
- When multiple charging spaces are required, raceway(s) is/are required to be provided at the time of construction.
-
- Electrical power monitoring shall be accomplished through the building automation system.
- Refer to BAS section 6.3.6 of Chapter 6 (Mechanical) for metering requirements. Meters to be furnished by Div 23, installed by Div 26 and wired to the BAS system by Div 23.
- Meter any individual energy end uses that represent 10% or more of the total annual consumption of the building.
- Meter separately renewable energy systems and electric vehicle charging stations.