It is further specified the machine-room lighting switch be located at the point of entry. As they review the plans and the construction site, they may have conflicting interpretations or requirements. In such cases, it's economically justifiable to specify a traction type elevator. Such vehicles include, but are not . Where voltages exceed 600, a sign reading DANGER HIGH VOLTAGE is required. Therefore, elevator equipment rooms must maintain a temperature between 50F and 90F. Another important electrical system design consideration for supplying power to multiple elevators is NEC 620.62. The condition is that all conductors must be insulated for the maximum voltage applied to any conductor within the cables or raceway system, and all live parts of the equipment must be insulated from ground for this maximum voltage. (To design and install an elevator for a Class I, Division 1 location would be quite an undertaking.). 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. The idea is quite simple. The action you just performed triggered the security solution. You need at least one 120VAC GFCI-protected receptacle at each location. 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. NFPA 72 requires the control circuit between the Fire Alarm System and the shunt trip be monitored for integrity. The disconnecting means must disconnect the elevator from the emergency, standby and normal power systems. 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. They are to be part of listed equipment, a driving machine or a driving-machine brake. 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. from components that are not otherwise guarded. (All intentionally grounded elements must be held at equal potential.) Specifically, Section 725.43 provides that overcurrent protection for conductors 14 AWG and larger is to be provided in accordance with the conductor ampacity without applying ampacity adjustment and correction factors. 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. 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. Modern electronic elevator controls can be sensitive to temperature shifts. Fireman telephone jacks and telephone cabling are typically sufficient for each of these locations. 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. Article 620 follows this pattern by opening, in Section I, General, with a statement of scope and definitions applicable to the topic under consideration. By subscribing, you agree to our User Agreement and Privacy Policy & Cookie Statement. Building codes were deemed necessary to protect the public against shoddy builders and outmoded construction techniques. Per the 2017 NEC, if the elevator is designated as an emergency system load, the disconnect must be protected by a surge protective device (SPD). Feeder and branch-circuit conductors are required to have specified ampacities: Feeder conductors of less ampacity are permitted for group installations and quite common in elevator work. It does specify wiring methods allowed, though, in 620. Liquid-tight flexible nonmetallic conduit, Flexible cords and cables, or conductors grouped together and taped or corded, are permitted without raceway, where they are part of listed equipment, a driving machine or a driving-machine brake, Flexible metal conduit, liquid-tight flexible metal or nonmetallic conduit, 3/8 in. 68 | WWW.ELEVATORWORLD.COM | June 2012 Continuing Education . 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. ) > word/_rels/document.xml.rels ( N0HC;qRN/W$#{1EM]ZY|vj5h),-g!`./V/KKFY4D#la&V#=$Q7|l/d#hS 7+IDZ!J 6KucD^s`+>=(3E The traveling cable, of necessity, is exempted. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data. We resume with a look at wiring methods, overcurrent protection, grounding and other NEC provisions as they relate to these installations. 1993 NEC 15-20 Amp 120 volt Receptacle Requirements: Wet bar sinks, all bathrooms, roof tops, elevator machines rooms, elevator car tops, elevator pits. 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. For example, wiring that is under exclusive utility control and has to do with the generation and distribution of electrical power is not NEC regulated. The disconnecting means is to be located adjacent to or an integral part of the motor controller. First, you'll need to install lighting in the elevator equipment room (Photo 1) and shaft pit (Photo 2). (A) tells us that the lighting and receptacle (s) for the pit must be on separate circuits. This clear working space must be 30 in. (C) Duplex Receptacle. Guarding: Where possible, install temporary guarding to protect from inadvertent contact. The vast majority of equipment serving the elevator is located within this room (i.e., elevator controller). NEC Article 0: Elevator art by David Herres Continued. 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. The electrical system designer calculates the maximum available fault current at the elevator controller. The disconnecting means is also to be a listed device. Notice the definition mentions the full range of operating times. In these installations, it is best to design the elevator controller so the elevator controller SCCR is adequate for the available fault current. The panel further clarified that the marked SCCR value must be adequate for the available fault current to ensure a safe installation. Additionally, duty on elevator and dumbwaiter motors is rated as intermittent, whereas duty on escalator and moving-walk motors is considered continuous. Mobile, AL 36606 USA The basic wiring methods are rigid-metal, rigid nonmetallic or intermediate-metal conduit; electrical metallic or rigid nonmetallic tubing; wireways; or Type MC, MI or AC cable, unless otherwise permitted. To address this issue, Code Making Panel (CMP) 12 of the National Electrical Code acted on several proposed changes to Article 620 during the revision cycle for the 2017 NEC that deal with the proper installation of elevator controllers. Corporate Office Jul 15, 2021. This accomplishes two functions. Society of Mechanical Engineers. Good documentation is of key importance to recalling what decisions were made and why. The light switch in the pit must be mounted 42 in. NEC Article 620 Part V, Traveling Cables, is driven by two major issues. Flexible metal, liquid-tight flexible metal or liquid-tight flexible nonmetallic conduit 3/8 in. You are seeing this message for one of three reasons: You have reached your limit of free content. (ASME has a separate document, A18.1-2008 Safety Standard for Platform Lifts and Stairway Lifts). This is because the material may contribute fuel to a fire that has originated elsewhere. Through numerous editions, the NEC has, to a great extent, mitigated the hazards accompanying widespread use of electricity, particularly with respect to elevator technology. A separate branch circuit shall supply the hoistway pit lighting and receptacle (s). If a smoke detector goes into alarm, it signals the elevator to go into Fire Recall Function, at which point the controller directs the elevator cab to travel to its pre-programmed designated landing, open its doors, and remain stopped there until the alarm clears. It is important for design engineers to communicate this with the architect and owner during the design phase, as it will impact space needs elsewhere in the facility to accommodate electrical equipment. On existing or listed equipment, conductors are permitted to be grouped together and taped or corded without being installed in a raceway. Installing electrical equipment where its SCCR is less than the available short-circuit current creates serious safety hazards. For example, an inadequately supported ceiling fan could fall and cause injury or property damage. And so the needs can be very different. So, we see that for elevator work, greater fill is allowed. The same figure applies to nonmetallic wireways. 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. 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. The lighting is not to be connected to a GFCI, because the elevator car is not a place that should experience nuisance tripping. First, the ATS signals the elevators that it's about to switch over to emergency power preferably 30 sec or more prior to switching, which allows the elevator controller to bring each elevator cab to the nearest landing and stop, thus protecting the motors and electrical system. Limit switches placed throughout the height of the shaft communicate with the controller and stop the cab at each landing. The main concern is to ensure that workers may escape to safety in the awful circumstance of an arc-fault event. In order to aid enforcement, the panel additionally required marking the available fault current at the elevator controller. It begins by considering metal and nonmetallic wireways. In addition, the shunt-trip voltage must also be monitored by the Fire Alarm System. The circuit(s) for the lighting and receptacles must be dedicated to the elevator area only. Get more of Elevator World. Of particular importance is the location of the disconnecting means so it can be found by an individual who may not be familiar with the installation. NEC Article 620 Part IV, Installation of Conductors, contains key mandates for elevator wiring. A few years later, in 1880, Werner von Siemens built the first electric elevator, setting the stage for a new industry that would change the world by making the practical use of tall buildings possible. Part X, Emergency and Standby Power Systems, is simple and straightforward. This switch will ensure that the elevator won't descend into the elevator pit and allow maintenance people to work safely in the area beneath the cab. Cloudflare Ray ID: 7a2fbe9ebd7e2fe8 Similar provisions are attached to elevator-car heating and air-conditioning disconnecting means, and to other utilization equipment. This lighting and receptacle circuit is separate from the circuit serving the motor. There are options available to achieve this depending upon the customers needs. %PDF-1.5 % With the elevator car at the bottom landing, it is the length of cable as measured from the point of suspension in the hoistway to the bottom of the loop. They are permitted to be run without raceway when used inside the hoistway, on the elevator car, hoistway wall, counterweight, or controllers and machinery located inside the hoistway, provided they are in their original sheaths. : inspecting; troubleshooting; observing; etc.) 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. Fuses: Verify that the correct size, type and capacity are installed. It states an elevator is permitted to be run by an emergency or standby power system. Second, it must be configured so as to eliminate any chance of tangling or chafing against the inner surface of the hoistway or items mounted on it. Something went wrong. This, however, can result in a dramatic increase in cost, space availability (lack thereof), and reduced efficiency. 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. For platform lifts and stairway chairlifts, the duty is intermittent. Get more of Elevator World. By subscribing, you agree to our User Agreement and Privacy Policy & Cookie Statement. Any other utilization equipment associated with the elevator Pits shall be maintained in a clean and dry condition. endstream endobj 954 0 obj <.
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