An example would be the elevator, as well as all wiring in a utility-owned administration building. In an elevator machine room, where space may be limited in the first place, the working-space mandate must be factored in very early in the design process lest an unthinkable amount of rework be necessary. Accordingly, the supply wires are protected only for short circuit, and the overload protection is provided closer to the motor. If it kills the son of the owner, the son of that builder shall be put to death.. (A) tells us that the lighting and receptacle (s) for the pit must be on separate circuits. In such cases, it's economically justifiable to specify a traction type elevator. The electrical conductors and equipment for non-mine elevators that extend below grade are under NEC jurisdiction. 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 they need to move and flex, traveling cables are not required to be in a raceway. Flexible cords and cables, or conductors grouped together and taped or corded, are permitted to be installed without a raceway. 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. A further requirement concerns elevator-car air-conditioning and heating. After reading this article, you should have learned: Which locations require sepa-rate, dedicated branch circuits Which branch circuits are not to be provided with ground fault circuit interrupter (GFCI) pro-tection Which locations must have one or more duplex receptacles Where overcurrent protection for hoistway, pit and machine-room lighting must be located How unsupported lengths of traveling cables are measured. Flexible cords and cables part of listed equipment operating at 30 V (42 VDC) or less, similarly supported and protected, jacketed and flame retardant, are permitted. Elevator power disconnect (with utility feed marking) located in the machine room or other permitted location. Installing electrical equipment where its SCCR is less than the available short-circuit current creates serious safety hazards. Many NEC articles address voltage limitations, and Article 620 is no exception. The conduit alone can't act as the grounding means. Part II of Article 620 concerns conductors used in elevator work, and several important requirements are covered. Similarly, the integrity of the traveling cable is emphasized. Flexible metal, liquid-tight flexible metal or liquid-tight flexible nonmetallic conduit 3/8 in. The simplest option is to use a shunt trip circuit breaker in either the feeder supplying the elevator or the elevator disconnect. This room is to be secured against unauthorized access (kept locked). NEC Article 620 contains numerous other disconnect provisions, which must be carefully scrutinized prior to design work so the installation is compliant. The branch circuit supplying these units is to be similarly dedicated, with the associated overcurrent device located in the machine room or similar location. Receptacle for pumps located in the pit shall be a single non-GFCI and shall be located 6 inches above the lowest landing. All elevator hoistways must be equipped with a sump pit located at the rear of the elevator pit. 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. So, we see that for elevator work, greater fill is allowed. All Rights Reserved | Contact Us | Privacy Policy. 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. Pit light with guard (ten foot candles min. z, /|f\Z?6!Y_o]A PK ! Mobile, AL 36606 USA 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. The Americans with Disabilities Act Accessibility Guidelines for Buildings and Facilities (ADAAG) now require the cab to have a special phone accessible by individuals with disabilities. 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. For circuit breakers, time-current curves must be consulted as well as the circuit breaker manufacturers selective coordination tables. 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. Hydraulic elevators comprise a hydraulic reservoir, pump, cylinder, and controller. On existing or listed equipment, conductors are permitted to be grouped together and taped or corded without being installed in a raceway. 2023 Endeavor Business Media, LLC. 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. 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. These 29 CFR 1910.146 (c) (8) requirements are: Article 620s Definitions section includes two terms that describe spaces not attached to the outside of a hoistway. The traveling cable, of necessity, is exempted. 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. And so the needs can be very different. 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. U.S. Latham, NY Shopping Miscellaneous Retail Stores, NEC Wheelchair lifts EazyLift Elevators, . NEC Article 0: Elevator art by David Herres Continued. 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. For platform lifts and stairway chairlifts, the duty is intermittent. It is worth noting that these NEC terms, used throughout Article 620, have been chosen to correlate with A17.1-2007 usage. Furthermore, at least one 125-V, single-phase, 15- or 20-amp duplex receptacle is to be provided in each machine room or similar location. C.1.4 ELEVATOR PIT REQUIREMENTS 1. But the lights don't have to be in the pit itself. ASME A17.1 . 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. from the exposed components, and the incident energy calculated at 18 in. 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. This is the area within the hoistway beneath the car, and there are occasions when elevator technicians have to work in this area for maintenance and troubleshooting. 354 Morgan Ave. One. The lighting is not to be connected to a GFCI, because the elevator car is not a place that should experience nuisance tripping. The elevator equipment room that serves a hydraulic elevator is almost always located on the lowest floor adjacent to the elevator shaft. All of these options and special wiring can be challenging depending upon the location of the shunt trip circuit breaker as well as who has responsibility for providing these additional options. Follow the manufacturers instructions and precautions. Hint: Duct Tape to the Rescue, NEC: Air Conditioning and Refrigerating Equipment Part 5. This clear working space must be 30 in. They are to be part of listed equipment, a driving machine or a driving-machine brake. You must locate this key switch at the main lobby or at the building fire command center. The most complex of these is the elevator. 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. Car air-conditioning and heating units 3. This will normally require you to vent the room with a fire/smoke damper and include smoke detector signals in the control logic. Cylinders in hydraulic elevators usually aren't suitable for buildings taller than five stories. NEC articles generally adhere to a template, which greatly aids in navigating and quickly locating mandates as needed for project design or, on an installation level, in the field. 2.2.6.1 This switch shall be so located as to be acces-sible from the pit access door. Guarding: Where possible, install temporary guarding to protect from inadvertent contact. In these installations, it is best to design the elevator controller so the elevator controller SCCR is adequate for the available fault current. Elevator cab lights require emergency back-up power. In driving through commercialized suburban areas, you frequently see paralleled conductors for large retail grocers (where there is a heavy refrigeration load). from components that are not otherwise guarded. Utility-owned electrical structures not directly concerned with electrical generation, transmission and distribution are NEC regulated. Marking the available short-circuit (fault) current on the controller by the equipment installer. A single dedicated receptacle supplying a permanently installed sump pump does not have to be a GFCI type. Reinforcing NEC 110.3(B) and NEC 110.10 to require the elevator controller marked SCCR to be equal to or greater than the calculated and 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. An exception provides that liquid-tight flexible metal conduit or liquid-tight flexible nonmetallic conduit 3/8 in. 23.254.250.15 This lighting and receptacle circuit is separate from the circuit serving the motor. The code exempts some fairly broad areas where compliance is not expected. NFPA 72 requires the control circuit between the Fire Alarm System and the shunt trip be monitored for integrity. Years may lapse between the design and installation stages of a project. charlie b. Many of these are for portable lighting.). Flexible cords and cables (same conditions as within hoistways). The 12 definitions provided in NEC 2011, Section 620.2 are the place to start for guidance in this area, and the sections that follow lay out implementation guidelines that are very relevant in todays environment. Design practices that are acceptable in some jurisdictions may not be in others. 3. NEC 2011 Article 620.21(2)(b) states that hard-service cords and junior hard-service cords that conform to the requirements of Article 400 (Table 400.4) are permitted as flexible connections between the fixed wiring on the car and devices on the car doors or gates. However, when I've put in elevators, NEC seems to always take a back seat to ANSI, which seems . Section 725.45 concerns the location of overcurrent devices and provides for feeder and branch-circuit taps, transformer primary side overcurrent device location and overcurrent device location at the input side of electronic power sources. The electrical system designer calculates the maximum available fault current at the elevator controller. The circuit(s) for the lighting and receptacles must be dedicated to the elevator area only. Get more of Elevator World. Here again, the lighting is not to be connected to a GFCI, whereas such protection is required for the receptacle(s). z!0: - [Content_Types].xml ( n0EUb*>-RxV=QUAl"93dFk%Y?l}MGDV For current-limiting fuses, the information to achieve selective coordination has been available for many years in fuse amp ratio tabular form. Finally, typical installations and compliance with all these requirements will be discussed. Always verify all conditions and requirements with the state and the AHJ where the installation is taking place. Apr 24, 2013. correct me if I'm wrong, but I believe it's damp. In Part One of this series (ELEVATOR WORLD, April 2012), we began an examination of National Electrical Code (NEC) 2011 mandates for elevators and related equipment installations. +1-251-479-4514 | [emailprotected], Trkiye Office Additionally, ampacities of the individual conductors and flame-retardant properties of the overall cable are important factors. wide or the width of the equipment, whichever is greater. When you consider that an elevator is an enclosed room with one or more doors that people voluntarily enter so they may travel hundreds of feet up or down, several observations are in order. 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. The sump pump/drain shall have the capacity to remove a minimum of 11.4 m. 3 /h (3,000 gal/h) per elevator. The two documents are in harmony and should be used in conjunction. Elevators with driving machines located on the car or counterweight, or in the hoistway are permitted outside the specified spaces. The various items to consider and check when designing for elevator installations have many potential pitfalls. 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. The branch circuit is to be protected by an overcurrent device located in the machine room, control room/machinery space or control space. After such an event, it is important that the affected worker is able to escape the area and get to help. Additional branch circuits are to supply other utilization equipment not covered above. 1. Hydraulic elevator installations are typically supplied from the main switchboard and have an elevator fused switch or circuit breaker in the machine room that serves as the elevator disconnect. If the disconnecting means is an integral part of the motor controller, it is to be operable without requiring opening of the enclosure. The main impetus for the creation of the NEC in the closing years of the 19th century was the collective anguish experienced by insurance underwriters who were losing vast amounts of money due to liability and physical damage claims resulting from Edisons electrification of, first, Lower Manhattan and then the world. My reasoning comes from 620.24 (A) and (C). The fire loading resulting from an accumulation of abandoned low-voltage cabling may be considerable, and has to be understood and dealt with. Hazards created by water, snow or condensation in the work area can cause slips, falls and accidental contact. 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. In a time when increasing value is placed on even small amounts of real estate, elevator design must strive to configure, efficiently control and drive elements to whatever degree possible, and that is the thinking behind some alternate locations for these structures. Personal protective equipment (PPE): Use appropriate PPE to protect body parts within the range of 3-16 in. A section on branch circuits for car lighting, receptacles, ventilation, heating and air-conditioning contains a number of important provisions. For instance, one method to reduce the available fault current is to add an isolation transformer ahead of the elevator controller. Section 620.62, Selective Coordination, is central to multi-elevator installations and must be closely observed. Both electric and nonelectric elevators are to comply with Article 250, the code article that covers grounding and bonding in general. 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 cover shall be secured and level with the pit floor. The fan should be on a dedicated circuit. Since 1953, Elevator World, Inc. has been the premier publisher for the global vertical transportation industry.
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