PART 4 ELECTRICAL STANDARDS

PART 4 ELECTRICAL STANDARDS

1.0 INTRODUCTION AND SCOPE: These standards reflect the general requirements and recommendations of elevator contractors, with respect to the power distribution system to achieve acceptable elevator performance. Additional requirements will be found on the Power Supply Confirmation Data Form. 1.1 Design Responsibility and System Boundary Point: The requirements and recommendations of these standards represent design and installation responsibility for the contractor(s) who design and install the building or site electrical distribution system. Because of design requirements and electrical contractor(s) responsibility for coordination with other building loads, it is necessary to define and agree upon the boundaries of responsibility between electrical contractor, and elevator installer. The defined boundary of responsibility for the elevator installer is at the mainline input power terminals to the elevator equipment. The electrical contractor is responsible for all electrical power system design up to the elevator equipment, including the appropriate location of the point of common coupling for other building loads that might be influenced by harmonic distortion. See AC Line Distortion Tutorial in NEII 1, Part 4 for recommendations on point of common coupling. 2.0 VOLTAGE: Nominal System Voltage. 208, 240, 480, 600-3 Phase, 3 live phases plus a ground, Main Elevator Feeders. 125-1 Phase (See 11.0, Additional Power). 3.0 VOLTAGE VARIATION: The actual continuous service voltage supplied to the elevator equipment (measured at per car Mainline Disconnecting Means) should be at the nominal system voltage. Under all load conditions short duration voltage variations must be limited to the maximum and minimum values found on the appropriate Power Supply Confirmation Data Form, inclusive of voltage drop. Continuous operation of equipment at or near the maximum or minimum values may result in reduction of equipment life. 4.0 VOLTAGE BALANCE: Maximum deviation from the average voltage, divided by the average voltage times 100. Phase to Phase 5% Phase to Neutral 5% 5.0 NOMINAL FREQUENCY: Confirmed at site. 60 Hz 50 Hz 6.0 FREQUENCY TOLERANCE: ± 2% with a maximum Slew Rate (the rate of change of frequency with respect to time) of 5 Hz/s. For static DC control 1 Hz/s maximum (continuous) 3.5 Hz/s maximum (10 cycles maximum transient). 7.0 HARMONIC DISTORTION: Solid-state power converters used in elevator control panels generate line current harmonics and line voltage distortion. See AC Line Distortion Tutorial in NEII-1, Part 4. Equipment that is sensitive to these distortions should be properly isolated from the elevator feeders. 8.0 CONDUCTORS: Ampacity of conductors is determined by the electrical contractor per NFPA 70 and/or local code requirements, based on information provided on the Power Supply Confirmation Data Form. 9.0 CONDUCTOR BRACING: Recommend conductor bracing to avoid unwanted noise being emitted from raceway. 10.0 MAIN LINE DISCONNECTING MEANS: Size and locate the fused Main Line Disconnect switch or circuit breaker in accordance with NFPA 70. Fuses are to be current limiting class RK1 or equivalent. Circuit breakers are to have current limiting characteristics equivalent to RK1 fuses. 11.0 ADDITIONAL POWER: Requirements for additional supplies will vary with the type of equipment. These are typically single phase, 125 Vac (nominal) 15A or 20A circuits. The additional supplies are used for: 11.1 Machinery Spaces, Machine Rooms, Control Spaces and Control Rooms: Lighting per ASME A17.1/CSA B44, Section 2.7 and 125 V duplex receptacle. 11.2 Secondary Level Rooms: Lighting per ASME A17.1/CSA B44, Section 2.7 and 125 V duplex receptacle. Page 4-2 30-Oct-13

11.3 Elevator Pit: Adequate illumination with switch near entrance and 125 V duplex receptacle (ASME A17.1/CSA B44, Section 2.2.5). 11.4 Car: Separate 125 V feed with disconnecting means in machinery space, machine room, control space or control room to each elevator. The car lighting branch circuit is not required to be provided with ground-fault circuit-interrupter (GFCI) protection for personnel. 11.5 Other: Elevator contractor should identify any other additional circuits or requirements for their equipment (e.g. intercom systems, console panels, car receptacles, etc.). 11.6 Receptacles: 125 V receptacles must be provided with ground fault circuit interrupter protection, where required by NFPA 70, Article 620 Note: A single receptacle supplying a permanently installed sump pump (in pits) does not require GFCI protection. It is recommended that the sump pump receptacle not be provided with GFCI protection. 12.0 ADDITIONAL WIRING: 12.1 Guidelines for Initiating Devices for Phase I Emergency Recall Operation: Installed in compliance with NFPA 72. See ASME A17.1/CSA B44, Section 2.27.3.2. 12.1.1 Elevator control circuits must functionally interface with fire alarm initiating devices as required by ASME A17.1/CSA B44, 2.27.3.2. As a life-safety system, the integrity of the signalization from the fire alarm system is very important. The wiring practices of the interface circuits between the fire alarm system and the elevator control circuits is governed by NFPA 72. 12.1.2 NFPA 72 requires that the field installed wiring between the fire alarm control unit and the elevator control circuit interface be monitored for signal integrity. The design for monitoring is the responsibility of the fire alarm system contractor. 12.1.3 Furthermore, to maintain the signal integrity on the elevator side of the interface, relays or modules must be placed in a secure location per NFPA 72, so that the wiring from the interface relay or module is unlikely to be subjected to external faults. 12.1.4 NFPA requires such interface relays or modules to be physically located within three feet of the controlled circuit. Practically, this means that the field installed wiring is either by direct entry in dedicated conduit to the elevator controller, or within the confines of the elevator machine room, control room, or control space (e.g. within wiring duct). See diagram 12.1 for an illustration of incorrect and correct interface wiring practices. 12.2 Communications: Communication lines, one per car, to be brought into the machine room by others, for hookup by the elevator contractor. 13.0 ALTERNATE POWER REQUIREMENTS: 13.1 Alternate power may be either standby or emergency. The requirements specified for standby power and emergency power shall conform to NFPA 70 and local code. For example, display of car position at fire command station. 13.2 Elevator contractors require that the standby (emergency) power system be sized to provide the required operation of the elevators. 13.3 The maximum electrical demand on the standby (emergency) power system depends upon the number of elevators to be simultaneously started. The required per car starting/acceleration power is provided by the elevator contractor on the Power Supply Confirmation Data Forms. 13.4 The duration of the accelerating load on the standby (emergency) power system varies depending on elevator contract speed. It is important to note that the accelerating load on the power system can persist for periods of several seconds each time the elevator(s) runs. 13.5 The standby (emergency) power system must be capable of absorbing the regenerative power from the elevators, in compliance with NFPA 70, Article 620, to prevent overspeed during regeneration. The maximum per car regenerative power is provided by the elevator contractor on the Power Supply Confirmation Data Forms. 13.6 For standby (emergency) power operation of one car out of a group, avoid reducing the size of the standby (emergency) power feeders and the protective device. Static power converters usually have isolation or autotransformers. Each car's transformer may remain connected to the line. On energizing, the transformers have large peak magnetizing in-rush currents lasting for several cycles of the ac line. A reduced size circuit breaker will likely trip. 14.0 ADDITIONAL DISCONNECTING MEANS: When sprinklers are provided in an elevator machinery space, machine room, control space, or control room, or hoistway see ASME A17.1/CSA B44, Section 2.8.2.3 for requirements. 15.0 POWER DISTRIBUTION SYSTEM: 15.1 NFPA 70 requires all main feeder and branch circuit full load, starting and accelerating currents of the elevator(s) electrical system must be completely coordinated with the time-current characteristic of the elevator(s) branch circuit protection device(s). Also, the short circuit component of elevator(s) main, feeder and branch circuit device(s) must be coordinated. In particular, the time-current characteristics thermal, thermal magnetic or magnetic branch circuit protection 30-Oct-13 Page 4-3

devices that service main, feeder and branch circuits must be analyzed for compliance with selective coordination. The omission of selective coordination will result in a total or partial elevator system blackout. 15.2 In addition to selective coordination of main, feeder and branch circuit protection devices, electronically controlled circuit protection devices should be rms current sensing to avoid nuisance tripping. Electronically controlled circuit protection devices which are not rms current sensing may trip under normal operating conditions as a result of measuring peak or harmonic currents of variable voltage and/or variable frequency elevator drives. The application of electronic circuit protection devices with solid-state elevator drive systems should be verified with the device manufacturer. 15.3 When variable frequency drives are used to control ac motors and a ground fault or earth leakage device is provided, it should be specified as "Product For Inverter Use" or be designed so that its sensitivity is reduced at high frequencies. 16.0 REFERENCES: 16.1 The following Codes and Standards are referenced: 16.1.1 Safety Code for Elevators and Escalators, ASME A17.1/CSA B44. 16.1.2 National Electrical Code, NFPA 70. 16.1.3 National Code, NFPA 72. 16.2 Power Supply Confirmation Data Forms: An information bulletin that states the characteristics of the equipment's electrical load demand upon the power supply system. It is intended as a "Universal Approach" which all elevator contractors can use to obtain required information prior to manufacture and to establish the conditions expected as part of the elevator, escalator or moving walk installation. Page 4-4 30-Oct-13

DIAGRAM 12.1(a) Elevator Control Enclosure Initiating Devices INCORRECT METHOD Unsupervised wiring is subject to faults or external disturbance. Signal integrity not assured. 30-Oct-13 Page 4-5

DIAGRAM 12.1(b) Initiating Devices Shortest Practical Distance Elevator Control Enclosure MAIN Elevator Control Room, Control Space, Machinery Room, Machinery Space, Hoistway All Other Levels Relays and/or s are located outside of restricted spaces such as the hoistway or pit. Initiating Devices Control Panel Shortest Practical Distance Annunciator(s) Elevator Control Enclosure MAIN Control Panel Elevator Control Room, Control Space, Machinery Room, Machinery Space, Hoistway All Other Levels Annunciator(s) Correct Methods Installed wiring is supervised and monitored between the fire alarm system and the fire alarm interface. Signals to elevator control circuits are secure due to close proximity to elevator control enclosure. Signal Integrity is assured. Page 4-6 NEII-1 2000-2011, National Elevator Industry Inc., Salem, NY. NEII and NEII logo Registered, U.S. Patent and Trademark Office. 18-Nov-11