In driving through commercialized suburban areas, you frequently see paralleled conductors for large retail grocers (where there is a heavy refrigeration load). The traveling cable or raceway is also permitted to include shielded conductors and/or one or more coaxial cables. The traveling cable, moreover, may be run without raceway from inside the hoistway to elevator-controller enclosures and to the elevator car and machine room and similar locations outside the hoistway for a distance not exceeding 6 ft. Flexible cords and cables, or conductors grouped together and taped or corded, are permitted to be installed without a raceway. This is important as the tradition of using only time-current curves for the analysis of overcurrent device operation is usually not sufficient since the time-current curves traditionally stop at 0.01 second (not time zero). If the entire feeder/branch circuit assembly were to be protected in the conventional manner, the motor would cut out long before reaching operating speed. You are a subscriber that needs to Sign In. Modern electronic elevator controls can be sensitive to temperature shifts. Flexible cords and cables (same conditions as within hoistways). Here are 23 ways that both chapters and the national office can meet todays major challenge of making members feel valued, IAEIs Online Training allows you to learn at your own pace or live with an expert instructor, from the comfort of your laptop or PC. Weight (passengers, freight, car and attendant machinery) may be fairly substantial, and speed is significant. Also located in this room might be, but not limited to: exhaust fan, cooling unit (depending on local requirements and/or requirements set forth by the individual elevator supplier), lighting, voice and/or data drop serving the elevator cab emergency phone, elevator controller primary fused disconnect, elevator feeder shunt-trip circuit (i.e., shunt-trip circuit breaker), elevator cab lighting fused switch, and convenience receptacle(s). In many cases, the overcurrent protective devices that are suitable for this level of protection are current-limiting fuses rather than a traditional circuit breaker. Convenience receptacles and lighting for maintenance purposes are required at the base of the pit and, in some instances (elevator manufacturer dependent), at the top of the elevator shaft. Dont troubleshoot unless you can keep your shoe/boot soles dry. Such design innovations require sophisticated wiring strategies. With the new elevator controller requirements, more attention will be focused on the elevator system. (ASME has a separate document, A18.1-2008 Safety Standard for Platform Lifts and Stairway Lifts). The action you just performed triggered the security solution. Accordingly, the supply wires are protected only for short circuit, and the overload protection is provided closer to the motor. This is typically accomplished via a shunt trip device. You may go up to 600 V for power circuits supplying door-operator controllers and door motors, branch circuits and feeders to motor controllers, driving-machine motors, machine brakes and motor-generator sets. The vast majority of equipment serving the elevator is located within this room (i.e., elevator controller). Louisiana State Uniform Construction Code Council adopts the 2014 NEC, Basic three-phase power measurements explained, Safety After the Storm Operating Portable Generators. This is especially true in an elevator shaft where measures have to be taken to ensure that a hazardous situation is not created. 2. Nevertheless, the primary NEC focus is on elevators, and the intention is to mitigate the hazards associated with the use of electricity. Motors for traction elevators were traditionally DC or synchronous, but new installations use AC motors and VFDs for speed control. NEC Article 620 covers elevators, dumbwaiters, escalators, moving walks, platform lifts and stairway chairlifts. Installing electrical equipment where its SCCR is less than the available short-circuit current creates serious safety hazards. Metal grating shall be installed over the hole that sits flush with the pit floor. As recommended in NFPA 70E, the National Elevator Industry, Inc. (NEII) commissioned an arc-flash hazard analysis (in compliance with IEEE Standard 1584-2002 for procedures for calculating the incident energy of the arc flash) by an independent consultant to determine at what level an arc-flash hazard exists to employees who work on energized elevator equipment. Sign up for our free e-newsletter. Section 620.62, Selective Coordination, is central to multi-elevator installations and must be closely observed. A raceway that comes loose on the inside of a hoistway could catch on a moving car, causing immense damage and hazard to users. However, this can vary depending on building conditions and exterior grade. A clean and dry elevator pit and machine/control room provided (ASME A17.1 Rule 2.1.2) Machine/control room meets manufacturer's requirement of preserving ambient temperature control and humidity (ASME A17.1 Rule 2.7.9) Elevator floor covering installed with appropriate smoke and flame spread (ASME A17.1 Rule 2.14.2) Traveling cables are to be approved for hazardous locations and must comply with the appropriate sections for each hazardous-location class that covers use of flexible cords. ,l7CLHmcX9*F -{Q|^"XL`b1y]$,y *R/2Rn{\xG L*vMP.uKW,)68]Y}+ FYS1B=Q0S>Hc Cloudflare Ray ID: 7a2fbe9ebd7e2fe8 After reading this article, you should have learned about: The meanings of definitions for control room and control space versus machine room The purpose and specifications for working spaces Insulation types and minimum sizes of conductors Requirements for feeder and branch-circuit conductors Feeder demand factors for ele-vators. Main feeders that supply elevator power must be kept outside the hoistway unless one of the following applies: Feeders for elevators are permitted within an existing hoistway (provided they are not spliced within the hoistway) by special permission of the AHJ. Supports for cables or raceways in a hoistway or in an escalator or moving-walk wellway or platform lift and stairway chairlift runway must be securely fastened to the guide rail, escalator or moving-walk truss, or to the hoistway, wellway or runway construction. In all cases, the working space must permit at least a 90 opening of equipment doors or hinged panels. 974 0 obj <>/Filter/FlateDecode/ID[<64E135C225F1064D91BC8119D14516A9>]/Index[953 36]/Info 952 0 R/Length 105/Prev 204101/Root 954 0 R/Size 989/Type/XRef/W[1 3 1]>>stream In addition, requirements for selective coordination and shunt tripping should be complied with as needed for the installation. q!^mDtsnEX3_ shvqu+X9@w3gSj`g Years may lapse between the design and installation stages of a project. The proposals resulted in adding new requirements in the 2017 NEC for: This article will also discuss other Code requirements that include selective coordination for elevators that are supplied by emergency, legally required standby or critical operation power systems or multiple elevators supplied from a single feeder, and shunt tripping of elevators where the elevator equipment room and/or shaft has a fire suppression sprinkler system. +91 8025357028, 2022 Elevator World, LLC. They must be in enclosures with doors or removable panels that can be locked in the closed position. Many of these are for portable lighting.). All rights reserved. The fan should be on a dedicated circuit. 6 feet, and shall meet the requirements of NEC 70 620.21(A)(1)(d). Part IX, Grounding, states that metal raceways, Type MC cable, Type MI cable or Type AC cable attached to elevator cars are to be bonded to metal parts of the car bonded to the equipment grounding conductor. Traditional wiring methods and materials come into play, as always, but it is necessary to rethink their deployment. Section 620.43, Location of and Protection for Cables, provides that traveling cable supports are to be located so as to reduce the possibility of damage due to the cables coming in contact with the hoistway construction or equipment in the hoistway to a minimum. Proper selective coordination in a multi-elevator installation on the same feeder ensures if one elevator develops a fault, the other units will not be shut down. See Section 3 of the. It is worth noting that these NEC terms, used throughout Article 620, have been chosen to correlate with A17.1-2007 usage. As for height, the working space must extend from the grade, floor or platform to 6-1/2 ft. or the height of the equipment, whichever is greater. Because of this, there is often a communications gap between the electrical system designer, whose design typically stops at the required elevator disconnecting means, and the architect who designs the elevator system. Finally, typical installations and compliance with all these requirements will be discussed. proved for elevator locations - car, hoistway, pit and a-chine roo equireents in Article odify the articles in Chap - ter For eaple, it is stated that the cross-sectional area (e) Pit Maintenance. These must also be insulated for the maximum voltage applied to any conductor within the cable or raceway system. For current-limiting fuses, the information to achieve selective coordination has been available for many years in fuse amp ratio tabular form. Limit switches placed throughout the height of the shaft communicate with the controller and stop the cab at each landing. Conductors supplying a single motor are to have an ampacity not less than the percentage of motor nameplate current determined from Section 430.22(A) and (E). Hydraulic elevators comprise a hydraulic reservoir, pump, cylinder, and controller. Your elevator supplier will take care of all the wiring and related code requirements for the elevator cab and the various controls. Additional branch circuits are to supply other utilization equipment not covered above. For example, an inadequately supported ceiling fan could fall and cause injury or property damage. The locking capability is important so during maintenance, the equipment will not be inadvertently energized. Cables used in Class 2 power-limited circuits are permitted between risers and signal equipment and operating devices, provided they are supported and protected from physical damage and are of the jacketed and flame-retardant type. For instance, one method to reduce the available fault current is to add an isolation transformer ahead of the elevator controller. They are differentiated from other similar structures by the fact that they are not attached to the outside perimeter or surface of the walls, ceiling or floor of the hoistway. ranged from 0.06 cal/cm2 to 0.95 cal/cm2, which indicates that the arc-flash hazard to employees is primarily to the hands and arms. First, the traveling cable must be composed of very fine-stranded conductors so it can flex with a minimum of internal stresses, ensuring long service life and reliability. endstream endobj 954 0 obj <. Such vehicles include, but are not . For elevators that regenerate power back into a power source unable to absorb the regenerative power under overhauling elevator load conditions, a means to absorb this power is to be provided. Suspending the cables from the supports by a means that automatically tightens around the cable when tension is increased for unsupported lengths up to 200 ft. An NEC Informational Note defines unsupported lengths. Regardless of the number of elevators, only one smoke detector is required at each floor lobby, but it must be located within 21 ft of every elevator door. Conductors supplying a single motor controller are to have an ampacity not less than the motor controller nameplate current rating plus all other connected loads. 988 0 obj <>stream By subscribing, you agree to our User Agreement and Privacy Policy & Cookie Statement. The floor specified as the designated landing, which must be approved by the Fire Marshal, is usually the floor on grade level so passengers can quickly exit to the outside. Additionally, duty on elevator and dumbwaiter motors is rated as intermittent, whereas duty on escalator and moving-walk motors is considered continuous. The next section, 620.36, concerns different systems in one raceway or traveling cable. As we have seen, a limited number of these are approved for elevator locations car, hoistway, pit and machine room. The many codes and guidelines that regulate the electrical design of an elevator can seem overwhelming, and dealing with the electrical inspector, elevator inspector, and Fire Marshal can be even more intimidating. Selective coordination is defined by the NEC as: Localization of an overcurrent condition to restrict outages to the circuit or equipment affected, accomplished by the selection and installation of overcurrent protective devices and their ratings or settings for the full range of available overcurrents, from overload to the maximum available fault current, and for the full range of overcurrent protective device opening times associated with those overcurrents.. When you're designing an electrical system for a building, don't let elevator requirements bring you down. Traditionally, the electrical system design engineer has given little attention to the elevator controller. PK ! Motor controllers are permitted outside the spaces specified above. Another important electrical system design consideration for supplying power to multiple elevators is NEC 620.62. Please check your entries and try again. You can email the site owner to let them know you were blocked. Related Code Sections 802.1.8 Indirect/Special Waste, Elevator Pit Drain or Sump Pump A separate branch circuit shall supply the hoistway pit lighting and receptacle (s). As they review the plans and the construction site, they may have conflicting interpretations or requirements. Pits shall be maintained in a clean and dry condition. IAEI News Magazine. 2.2.6.1 This switch shall be so located as to be acces-sible from the pit access door. Notice the definition mentions the full range of operating times. This will normally require you to vent the room with a fire/smoke damper and include smoke detector signals in the control logic. It is important for the design engineer to coordinate with the architect to determine the elevator manufacturer basis of design to determine if and when additional power and lighting is required. The disconnecting means is to be located adjacent to or an integral part of the motor controller.