Each of these performs a different function, and the wiring mandates vary accordingly. It is noted that the article covers the installation of electrical equipment and wiring for elevators, dumbwaiters, escalators, moving walks, platform lifts and stairway chairlifts. Metal grating shall be installed over the hole that sits flush with the pit floor. The elevator controller manufacturer must determine the required elevator controller SCCR as stated in the elevator controller specification and provide an elevator controller SCCR that is equal to or greater than the available fault current thats indicated in the design documents where there are multiple elevator controllers at different locations. !>x=yy Bvv8?~e PK ! NEC 2011 also addresses branch circuits for machine room or control room/machinery space or control-space lighting and receptacles. Below is a summary of these new 2017 NEC sections: In order to comply with these requirements a chain of events must occur. We resume with a look at wiring methods, overcurrent protection, grounding and other NEC provisions as they relate to these installations. The lighting switch shall be located so as to be readily accessible from the pit access door. Machine room-less elevator installations incorporate the elevator controller and often the primary disconnecting means in a convenient package that is located within the elevator shaft. Flexible cords and cables, or conductors grouped together and taped or corded, are permitted to be installed without a raceway. Here again, the lighting is not to be connected to a GFCI, whereas such protection is required for the receptacle(s). Be sure to provide a horn/strobe alarm in large equipment rooms because they can be noisy, isolated places. The branch circuit supplying these units is to be similarly dedicated, with the associated overcurrent device located in the machine room or similar location. Building codes were deemed necessary to protect the public against shoddy builders and outmoded construction techniques. The next section, 620.36, concerns different systems in one raceway or traveling cable. Both electric and nonelectric elevators are to comply with Article 250, the code article that covers grounding and bonding in general. 2.2.2.6 . This may be countered by providing good machine-room ventilation. To achieve flexibility and endurance, traveling cable is more finely stranded and, where possible, separated into discrete conductors. For example, an inadequately supported ceiling fan could fall and cause injury or property damage. 2023 Endeavor Business Media, LLC. A traditional elevator installation (which includes a machine room) requires access inside the elevator shaft. In these installations, it is best to design the elevator controller so the elevator controller SCCR is adequate for the available fault current. Modern electronic elevator controls can be sensitive to temperature shifts. It is worth mentioning that when 600 V is talked about as a limit in the NEC, it is generally meant that the familiar 600-V nominal-voltage system is considered to lie within the permitted zone, making it a common usage. +90 (216) 348 4876, India Office The idea is quite simple. Motors for traction elevators were traditionally DC or synchronous, but new installations use AC motors and VFDs for speed control. The lighting is not to be connected to a GFCI, because the elevator car is not a place that should experience nuisance tripping. Therefore, there will be two signals to the elevator control panel related to smoke detectors: one from the designated floor smoke detector and another combined signal from the smoke detectors at the other lobby landings and in the equipment room. The main concern is to ensure that workers may escape to safety in the awful circumstance of an arc-fault event. Though I understand how someone might argue two. hb``` ea``j~p2nfH 'xXg00,/(_ Iq8PDdg-~ s$!XI;Fn0vu `h`R 1y 0B.":9.@, e`xI;=7O3fvbb8:SC;%O*20] It is stated that traveling cables are to be suspended at the car and hoistway ends, or counterweight end where applicable, so as to reduce the strain on the individual copper conductors to a minimum. ), a duplex 15A 120-volt receptacle in pit with ground- fault circuit protection and a 15A 120-volt Non GFCI receptacle for the sump pump. CLAIMED . For instance, one method to reduce the available fault current is to add an isolation transformer ahead of the elevator controller. Something went wrong. Power for the elevator controller must first enter a lockable safety disconnect device, located adjacent to the door of the equipment room. NEC specifies Hoistway wiring, and doesn't seem to distinguish between hoistway and pit. Notwithstanding, if sprinklers are installed in hoistways, machine rooms or the like, the disconnecting means is permitted to automatically open the power supply to the affected elevator(s) prior to the application of water. Another important electrical system design consideration for supplying power to multiple elevators is NEC 620.62. N _rels/.rels ( j0@QN/c[ILj]aGzsFu]U ^[x 1xpf#I)Y*Di")c$qU~31jH[{=E~ 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 equipment must remain energized to perform work, effective insulation and safe electrical working practices should be observed. Such cable groups are to be supported at intervals not over 3 ft. and located so as to be protected from physical damage. +1-251-479-4514 | [emailprotected], Trkiye Office The code is not concerned with the efficiency or sophistication of equipment that it covers, except insofar as safety (in terms of human injury and property damage) is concerned. You are a subscriber that needs to Sign In. If elevators are supplied by the emergency, legally required standby or critical operation power systems, then selective coordination is required per the 2017 NEC in 700.32, 701.27 or 708.54. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data. GFCIs in elevator pits During an inspection of the elevators in a commercial building, the state inspector failed us for using a GFCI-type circuit breaker to protect a receptacle in the elevator pit. Where multiple driving machines are connected to a single elevator, there is to be one disconnecting means to disconnect the motor(s) and control-valve-operating magnets. It is important, where mandated, that there be no more than a single disconnecting means, so if emergency action is required, first responders will not be able to power down the equipment from one location. 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. This website is using a security service to protect itself from online attacks. Nevertheless, the primary NEC focus is on elevators, and the intention is to mitigate the hazards associated with the use of electricity. Where necessary, it is mandated that suitable guards be provided to protect the cables against damage. 2.2.6.1 This switch shall be so located as to be acces-sible from the pit access door. Other terms defined in NEC Article 620 are Control System, Motion Controller, Motor Controller, Operation Controller, Operating Device and Signal Device. Many undertake trips in these devices two or more times daily in full confidence that they will survive an uneventful experience with a minute chance of disaster or even inconvenience. Elevator power disconnect (with utility feed marking) located in the machine room or other permitted location David Herres David Herres holds a New Hampshire Master Electrician's license and has worked as an electrician in the northern part of that state for many years. Later in the 19th century, Thomas Edison and his associates built an electrical distribution system in Lower Manhattan. of the sprinkler heads. The two primary hazards are fire and electric shock or arc flash, although there are others. You need to Subscribe to continuing reading. or larger is permitted to be installed in lengths in excess of 6 ft. Where motor-generators, machine motors or pumping-unit motors and valves are located adjacent to or underneath control equipment and provided with extra-length terminal leads not exceeding 6 ft. in length, such leads are permitted to be extended to connect directly to controller terminal studs without regard to carrying-capacity requirements. I've never run into this before. The feeder OCPD needs to remain closed so the remaining elevators have power and continue to function. Since 1953, Elevator World, Inc. has been the premier publisher for the global vertical transportation industry. Section 620.85, GFCI Protection for Personnel, provides that 125-V, single-phase, 15- and 20-amp receptacles installed in pits, hoistways, machinery spaces, machine rooms, escalators and moving walks, and on elevator car tops are to be GFCIs. APPENDIX A 2.2. Hydraulic reservoir characteristic of a hydraulic-piston-operated elevator. f?3-]T2j),l0/%b (Cross-sectional areas of conductors are given in Chapter 9, Tables 5 through 8. Limit switches placed throughout the height of the shaft communicate with the controller and stop the cab at each landing. [emailprotected] For all of this to come together in the real world, there had to be some assurance that these new technologies could be used safely on a wide scale. Other codes and standards interact with the NEC, and it is necessary to see how they all work together in order to create safe and compliant elevator designs/installations. It begins by considering metal and nonmetallic wireways. Finally, in 1897, the first National Electrical Code (NEC) appeared. (A) tells us that the lighting and receptacle (s) for the pit must be on separate circuits. You must locate this key switch at the main lobby or at the building fire command center. 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. High-rise buildings pose additional concerns. The drain or sump pump discharge shall be into the sanitary or storm drainage system through an indirect waste connection. GFI Receptacles: GFI receptacles shall be required in all elevator machine rooms, machinery spaces and elevator pit areas. If you specify a rescuvator, you must also specify a disconnect switch with an auxiliary contact that opens when the disconnect arm moves to the open position, but stays closed when the OCPD trips. 953 0 obj <> endobj After such an event, it is important that the affected worker is able to escape the area and get to help. It is mandatory, as in the car, that these items have a separate, dedicated branch circuit, and the required lighting is not to be supplied through a GFCI. The light switch in the pit must be mounted 42 in. If your specifications require a vent at the top of the shaft for venting smoke, you must provide a key switch with a pilot light to control that vent. This, however, can result in a dramatic increase in cost, space availability (lack thereof), and reduced efficiency. 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. 68 | WWW.ELEVATORWORLD.COM | June 2012 Continuing Education . See Section 3 of the. With heavy use on a hot day, the oil can overheat, causing elevator shutdown. These conductors may be covered with suitable shielding for telephone, audio, video or higher-frequency communications circuits. Traveling cables are to be supported by one of these means: Looping the cables around supports for unsupported lengths less than 100 ft. Hoistway door interlock wiring from the riser must be flame retardant and have insulation suitable for a temperature not less than 200C (392F), much higher than that required for most raceway or cable applications. Hard-service cords are permitted only as flexible connections for the top-of-car operating device or the car-top work light. Car lighting, receptacles and ventilation 2. All rights reserved. For some manufacturers, such as Eaton, testing has been completed to determine the selective coordination ability of current-limiting BussmannTM series fuses with upstream Eaton circuit breakers. Marking the available short-circuit (fault) current on the controller by the equipment installer. +91 8025357028, 2022 Elevator World, LLC. If the smoke detector at the designated landing goes into alarm, the elevator will stop at a predetermined alternate floor, which is usually the floor above the designated floor. Choose topics from a full list of courses covering electrical topics that cover what you need to know from the NEC and other electrical codes and standards. NEC Article 0: Elevator art by David Herres Continued. z!0: - [Content_Types].xml ( n0EUb*>-RxV=QUAl"93dFk%Y?l}MGDV However, this can vary depending on building conditions and exterior grade. By subscribing, you agree to our User Agreement and Privacy Policy & Cookie Statement. 988 0 obj <>stream Elevator cab lights require emergency back-up power. In this case, it may be best if the elevator controller manufacturer does not include the elevator disconnecting means (often offered as a circuit breaker) but instead have the installer provide a separate fused disconnect to comply with NEC 620.51(A) and also achieve a high SCCR for the elevator controller when fuses are provided as specified by the elevator controller and marked on the elevator controller nameplate. Apr 24, 2013. correct me if I'm wrong, but I believe it's damp. above the seal plate, adjacent to the ladder. The sum of the cross-sectional area of the individual conductors in raceways is not to exceed 40% of the interior cross-sectional area of the raceway, except as permitted for wireways. It is important to note, that these selective coordination tables can indicate a lack of selective coordination at a given fault current for circuit breakers that do not show overlap on the time-current curves of the circuit breakers. Working spaces for electrical equipment that may have to be examined, adjusted, serviced or maintained is required in all occupancies in an earlier NEC section, 110.26(A). Traditionally, the electrical system design engineer has given little attention to the elevator controller. You can email the site owner to let them know you were blocked. 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. The pump sends hydraulic fluid from the reservoir to the cylinder, buried deep below the elevator shaft. The electrical energy does not traverse the human body, but proximity to the explosion means severe injury is possible from the intense heat and concussive shockwave. Indeed, most elevator accidents involve maintenance workers, yet even theirs is not an excessively dangerous profession. Louisiana State Uniform Construction Code Council adopts the 2014 NEC, Basic three-phase power measurements explained, Safety After the Storm Operating Portable Generators. In addition, requirements for selective coordination and shunt tripping should be complied with as needed for the installation. Granle is a licensed professional engineer with Sebesta Blomberg & Associates, Rochester, Minn. https://www.facebook.com/ElectricalConstructionMaintenanceMagazine, https://www.linkedin.com/company/electrical-construction-maintenance/, ABCs Construction Backlog Indicator Down to Start 2023, The Most Popular Code Quizzes of the Week from 2021, The 10 Most Popular Photo Galleries of 2021, Whats Wrong Here? This strategy works to improve the flexibility of the traveling cable, but it is contrary to a general NEC rule concerning the paralleling of conductors, which is generally done in very large sizes to avoid unwieldy wire pulls and terminations. Cylinders in hydraulic elevators usually aren't suitable for buildings taller than five stories. Cross-sectional areas of wireways are found by multiplying the two interior dimensions.) The branch circuit is to be protected by an overcurrent device located in the machine room, control room/machinery space or control space. In order to aid enforcement, the panel additionally required marking the available fault current at the elevator controller. 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. from components that are not otherwise guarded. To safeguard the passengers and electrical equipment, ASME A17.12.8.2.3.2 requires the power source to the elevator control panel to shut down prior to the discharge of water from a sprinkler head. +90 (216) 348 4876, India Office Hydraulic reservoir characteristic of a hydraulic-piston-operated elevator. In elevators provided with Firefighters' Emergency Operation, a drain or sump pump shall be provided. NEC 620.62 requires the elevator disconnecting means (fused switch or circuit breaker) to selectively coordinate with all supply-side overcurrent devices. Three wiring categories within hoistways are allowed in addition, each with exceptions. Traction elevators raise and lower the elevator cab with cables, a pulley system, and counter weights powered by a motor at the main drive wheel. Hydraulic elevators comprise a hydraulic reservoir, pump, cylinder, and controller. 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. ASME A17.1, Section 2.2.5, National Electrical Code, Rule 620-85 4. Car air-conditioning and heating units 3. In hoistways not longer than 6 ft., these additional wiring methods are permitted: A sump or oil-recovery pump located in the pit is permitted to be cord connected. The NEC rule specifies that the minimum size for paralleled conductors is 1/0 AWG, which is much too big for an elevator traveling cable. 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. Motor controllers are permitted outside the spaces specified above. These must also be insulated for the maximum voltage applied to any conductor within the cable or raceway system. A traction elevator's equipment room is typically located at the top of the building, directly over or adjacent to the shaft. Based on the analysis, the arc-flash boundaries at the elevator/escalator controllers ranged from 3-16 in. 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. Traction elevators are typically installed in a bank of elevators where fused switches, or circuit breakers in a panelboard are located in the machine room serving the bank of elevators. Selective coordination is also required for multiple elevators per NEC 620.62. The basic idea is that there must be a separate, dedicated circuit for car lights, receptacles and ventilation on each car. The locking capability is important so during maintenance, the equipment will not be inadvertently energized. He participates in IEEE (Senior Member) with Industrial and Commercial Power Systems, NEMA (member of the Codes & Standards Committee), NFPA (committee member for NEC CMP-13 and NFPA 79), UL (508/60947 and 508A) and IAEI activities. Thus, the need for door interlock functionality is recognized. Provide continuous, non -slip, horizontal rungs every 12" for the full height of the pit ladder. While the definitions are straightforward, their deployment in real-life building projects involves enormous legal and moral implications, given the fact that we are carrying large numbers of people hundreds of feet above the earths surface on a daily basis. Bonding of elevator rails to a lightning-protection system grounding conductor is permitted, but the conductor itself is not to be located in the hoistway. 6 Stop Switch in Pits There shall be installed in the pit of each elevator an ASME A17.1 CODE enclosed stop switch or switches meeting the requirements The following material is reprinted with permission from the American of 2.26.2.7 and 2.2.6.1 through 2.2.6.3. If it kills the son of the owner, the son of that builder shall be put to death.. Part III, Wiring, looks at the types of wiring that may be installed in hoistways, cars, machine rooms and related spaces. 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. It does specify wiring methods allowed, though, in 620. If power is not being supplied to the elevator controller (e.g., open mainline fuses, etc. This may be countered by providing good machine-room ventilation. Examples of PPE that may be appropriate are non-conductive eye protection, clean leather or fire-resistant gloves, and natural-fiber or fire-resistant-rated long-sleeved shirts and pants, or fire-resistant-rated long-sleeved coveralls. Marking the elevator controller short-circuit current rating (SCCR) by the elevator controller manufacturer. However, space is frequently limited within the shaft and as such many ancillary components (shunt trip circuit breakers, fused disconnects) may need to be located outside of the elevator shaft. ^W i word/document.xml=nr]6Id=,_$j9-"Y.iGU\h_}. The electrical system designer calculates the maximum available fault current at the elevator controller. You'll need to run telephone cables to the equipment room control panel, but the elevator supplier will take care of getting the cables to the elevator cab. Every building is different. A little more narrowly focused (yet of great consequence) is the ubiquitous NEC, which, in the National Fire Protection Association (NFPA)s venerable Handbook edition, devotes 18 double-column pages to electrical design and installation requirements for elevators, escalators and related equipment.
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