As stated in Section 7 of the Elevator Industry Field Employees Safety Handbook: Unless it is not feasible, (i.e. 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.. endstream endobj 954 0 obj <. You are seeing this message for one of three reasons: You have reached your limit of free content. Hard-service cords and junior hard-service cords are permitted as flexible connections between the fixed wiring on the car and devices on the car doors or gates. NEC Article 620 Part VI, Disconnecting Means and Control, is rather exacting. Marking the elevator controller short-circuit current rating (SCCR) by the elevator controller manufacturer. or larger, not exceeding 6 ft. in length, are permitted between control panels and machine motors, machine brakes, motor-generator sets, disconnecting means and pumping motors and valves. wide or the width of the equipment, whichever is greater. For instance, a typical elevator controller may traditionally have SCCR ratings from 5 to 10 kA. This is especially true in an elevator shaft where measures have to be taken to ensure that a hazardous situation is not created. The vast majority of equipment serving the elevator is located within this room (i.e., elevator controller). Additional requirements concern escape routes. However, it is likely that for many elevator controllers, this may not be high enough for the available fault current where they will eventually be installed. 23.254.250.15 From the website: Mohawk Lifts offers car lifts and auto lifts for purchase, including 2 post lifts, 4 post lifts, storage lifts, heavy duty mobile column lifts, parallelogram lifts, and other specialty items. If the equipment must remain energized to perform work, effective insulation and safe electrical working practices should be observed. Part VII, Overcurrent Protection, divides this topic into four categories for elevators and similar equipment, depending upon the nature of the specific equipment: For operating devices and control and signaling circuits, protection against overcurrent is in accordance with the requirements of Sections 725.43 and 725.45. ASME A17.1 . Mainline disconnect: DO NOT OPEN THE MAINLINE DISCONNECT SWITCH COVER unless employees are authorized, properly trained and appropriate measures are taken commensurate with the higher risk of arc-flash hazards. NFPA 72 requires the control circuit between the Fire Alarm System and the shunt trip be monitored for integrity. NEC Article 620 contains numerous other disconnect provisions, which must be carefully scrutinized prior to design work so the installation is compliant. The traveling cable or raceway is also permitted to include shielded conductors and/or one or more coaxial cables. The conduit alone can't act as the grounding means. Depending on your local codes, you can do this by installing heat or smoke detectors within 24 in. Upon loss of power, the rescuvator controls the cab, lowers it to the designated floor, and opens its doors. +90 (216) 348 4876, India Office Design practices that are acceptable in some jurisdictions may not be in others. Additionally, duty on elevator and dumbwaiter motors is rated as intermittent, whereas duty on escalator and moving-walk motors is considered continuous. We shall now take a look at the principle requirements of Article 620, with particular emphasis on wiring requirements for elevator shafts, machine rooms and cars. 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. They must be in enclosures with doors or removable panels that can be locked in the closed position. Elisha Otis safety elevator, introduced in 1853, prevented the fall of the car if the cable broke. . Finally, in 1897, the first National Electrical Code (NEC) appeared. These are the individual branch circuits required for car lighting, receptacles, auxiliary lighting and ventilation on each elevator car; individual branch circuits for machine-room and similar location lighting and receptacle; and branch circuits for hoistway pit lighting and receptacle(s). 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. 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. Flexible cords and cables in lengths not to exceed 6 ft. of a flame-retardant type and located to be protected from physical damage are permitted in machine rooms without being installed in a raceway. The article stands apart from the rest of the code in the sense it exempts these categories of circuits from the general requirements for wiring in most occupancies, found in Chapter 3. NEC Article 620 covers elevators, dumbwaiters, escalators, moving walks, platform lifts and stairway chairlifts. Fluid pressure in the cylinder raises and lowers the elevator cab. 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 The basic idea is that there must be a separate, dedicated circuit for car lights, receptacles and ventilation on each car. 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. IAEI News Magazine. from the exposed components, and the incident energy calculated at 18 in. NEC 620.62 requires the elevator disconnecting means (fused switch or circuit breaker) to selectively coordinate with all supply-side overcurrent devices. ), advise the building owner to correct the condition. The disconnecting means must disconnect the elevator from the emergency, standby and normal power systems. The proposals resulted in adding new requirements in the 2017 NEC for: Marking the elevator controller short-circuit current rating (SCCR) by the elevator control-ler manufacturer. 2023 Endeavor Business Media, LLC. Cloudflare Ray ID: 7a2fbe9ebd7e2fe8 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. charlie b. NEC Article 0: Elevator art by David Herres Continued. 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. Car lighting, receptacles and ventilation 2. Through numerous editions, the NEC has, to a great extent, mitigated the hazards accompanying widespread use of electricity, particularly with respect to elevator technology. 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. Sign up for our free e-newsletter. Since 1953, Elevator World, Inc. has been the premier publisher for the global vertical transportation industry. If the building has emergency power available, use it to supply the cab lights. Personal protective equipment (PPE): Use appropriate PPE to protect body parts within the range of 3-16 in. And as the designer, you can become the fulcrum on which all of these requirements and authorities exert their leverage, but an understanding of elevator basics can help you handle the pressure. [emailprotected] As we have seen, a limited number of these are approved for elevator locations car, hoistway, pit and machine room. You must run a separate insulated grounding conductor with the feeder conductors from the electrical source to the elevator controller. The idea is quite simple. [emailprotected] These may include: The author would like to recognize Jonathan Kennedy for his assistance in creating this article. It is also worth mentioning that the stated purpose of the NEC is the practical safeguarding of persons and property from hazards arising from the use of electricity. See Section 3 of the. The hazards are external to the equipment enclosure since equipment SCCR testing and evaluation criteria for product standards are most often performed with the enclosure doors closed and latched, and the fault occurring external to the enclosure. But the lights don't have to be in the pit itself. NEC has a further note that the term wheelchair lift has been changed to platform lift.. (e) Pit Maintenance. The pump sends hydraulic fluid from the reservoir to the cylinder, buried deep below the elevator shaft. 988 0 obj <>stream It provides that where more than one driving-machine disconnecting means is supplied by a single feeder, the overcurrent protective devices in each disconnecting means are to be selectively coordinated with any other supply side overcurrent protective devices. Hydraulic elevators are typically more cost effective and used for buildings up to 5-6 stories. It need not be exactly centered on the equipment, and working spaces of adjacent pieces of equipment may overlap. 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. The architect has a choice of either traction or hydraulic elevators. The party responsible for procuring the elevator control panel must state the minimum acceptable SCCR or the maximum available fault current where the controller will be installed. Described below are several work practices that may be used to reduce arc-flash hazards when working on energized equipment: David Herres holds a New Hampshire Master Electricians license and has worked as an electrician in the northern part of that state for many years. GET YOUR CEUS TODAY, 1998-2021. Traditionally, the electrical system design engineer has given little attention to the elevator controller. Traction elevators are typically faster and more energy efficient than hydraulic elevators, and are often used for high-rise buildings. You need to Subscribe to continuing reading. An example would be the elevator, as well as all wiring in a utility-owned administration building. These are: remote machine room and control room (for elevator and dumbwaiter), and remote machinery space and control space (for elevator and dumbwaiter). In contrast to the lighting, these receptacles must be connected to GFCI devices. 0 The elevator pit discharge system is not required to include an oil separator, except as required by section 1003.4. 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. +1-251-479-4514 | [emailprotected], Trkiye Office Flexible cords and cables, or conductors grouped together and taped or corded, are permitted to be installed without a raceway. Motor controllers are permitted outside the spaces specified above. Many people use portable generators until power is restored. ^W i word/document.xml=nr]6Id=,_$j9-"Y.iGU\h_}. Dan Neeser is a Senior Field Application Engineer with Eatons Bussmann Division. This may include wiring for signals, communication with the car, lighting, heating, air-conditioning and ventilation of the car or hoistway for fire-detecting systems and pit sump pumps. The next section, 620.36, concerns different systems in one raceway or 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. Every building is different. Moreover, it is necessary to consider future worker safety for an indefinite period. The two documents are in harmony and should be used in conjunction. The two main types of elevators are hydraulic and traction. (Cross-sectional areas of conductors are given in Chapter 9, Tables 5 through 8. 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. In such cases, it's economically justifiable to specify a traction type elevator. Below is a summary of these new 2017 NEC sections: In order to comply with these requirements a chain of events must occur. In the event of a breakdown, that phone must automatically call a location staffed 24 hours a day. You can email the site owner to let them know you were blocked. The new ADAAG guidelines now require that emergency power be available to elevators that have four or more stories of travel above or below the accessible floor [4.1.3(9)(1)]. 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. The basic rule for conductor fill of a metal wireway, as given in Article 376, is that the sum of the cross-sectional areas of all contained conductors at a cross section of a wireway is not to exceed 20% of the interior cross-sectional area of the wireway. The circuit(s) for the lighting and receptacles must be dedicated to the elevator area only. 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. Thus, the need for door interlock functionality is recognized. 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. The Code provides guidance through regulations to establish requirements. With these new NEC requirements, there is now the potential that an elevator controller SCCR may be required thats higher than what elevator manufacturers have historically furnished. The code exempts some fairly broad areas where compliance is not expected. 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. 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. The conductors must be in their original sheaths or grouped together and taped or corded. 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. Similar provisions are attached to elevator-car heating and air-conditioning disconnecting means, and to other utilization equipment. %%EOF Hard-service cords are permitted only as flexible connections for the top-of-car operating device or the car-top work light. All elevator hoistways must be equipped with a sump pit located at the rear of the elevator pit. First, it is now clear that elevator controllers must be marked by the manufacturer with their SCCR. 2.2.6.1 This switch shall be so located as to be acces-sible from the pit access door. z!0: - [Content_Types].xml ( n0EUb*>-RxV=QUAl"93dFk%Y?l}MGDV