In the 2014 NEC, the definition of readily accessible in Article 100 was revised to make it clear that something is not readily accessible if a tool is needed to gain access to it. All conductors of a multiwire branch circuit must originate from ____. 4. A load having the maximum level of current sustained for three hours or more is referred to as a ____ load. Selecting the next higher standard size overcurrent protective device is NOT allowed. overcurrent devices do not have to be readily accessible if. LOCATED ADJACENT TO THE EQUIPMENT WHERE ACCESS IS ACHIEVED BY THE USE OF PORTABLE MEANS. A transformer must have a disconnect within sight of the transformer unless the disconnect location is field marked on the transformer, and the disconnect is capable of being locked in the open position per Sec. Reference 422.11(A). T(v1,v2,v3)=(v1+v2,v2+v3,v3). Branch Circuit Multi-wire A. 225.40 Wiring and Protection, Access to Overcurrent Protective Devices. Article 450 then takes you to the next logical step providing overcurrent protection and the proper connections. https://www.facebook.com/ElectricalConstructionMaintenanceMagazine, https://www.linkedin.com/company/electrical-construction-maintenance/. The overhead conductors between the utility electric supply and the service point. Start your trial now! Communications conductors alone -- no requirement. Cable tester is a device which is used to test a cable. LOCATED WITHIN A GROUNDED JUNCTION BOX, B. neutral disconnect link, 18. The service point is the point of connection between the facilities of the serving utility and the premises wiring. Receptacle A. Applying solder to the connectionD. The definition of that word begins with, "A point on the premises wiring system. This Note does not require the next size up protection; it permits the next size up. Main panel, Branch Circuit Multi-wire C. The one grounded Neutral conductor of a multi-wire circuit must be connected to the neutral or grounded conductor of the system Main panel, Branch Circuit Multi-wire D. All conductors of a multi -wire branch circuit must originate from the same panel board or similar distribution equipment. f(x)=4x+53. A major concern with transformers is preventing overheating. Primary Conductor = 6 AWG conductor rated 65A at 75C [Sec. However, a current-limiting device without a disconnecting means is permitted on the supply side of the service disconnecting means. To catch up on Lorenzo Mari's series on Overcurrent Protection, please visit: National Electrical Code Basics: Overcurrent Protection Part 1 . luminaire. A separately derived system is a premises wiring system whose power is derived from a source of electric energy or equipment other than a service. Above finished grade or sidewalks, or from any platform or projection from which they might be reached. four-wire, single-phase. Tests performed as required in paragraph (b)(3)(ii)(C) of this section shall be recorded. #10. steve66 said: According to the definition of a branch circuit, it starts at the final overcurrent protection device. Next we will jump to 240.24 Location in or on Premises. Clearance from ground. Different customers power, A: AWG or American Wire Gauge is the US standard measure for the diameter of electrical conductors. What can installation records be used to determine while servicing equipment?A. A wire, bus, screw, or similar suitable conductor is acceptable as a main bonding. Check The Knowledge Multi-Wire A ____ branch circuit supplies two or more receptacles or outlets for lighting and appliances? Branch Circuits. Overcurrent protection for transformers not over 1,000V. But these and similar recommendations are the kinds of best practices that improve the performance, reliability, and safety of a transformer over its lifetime. Over commercial areas subject to pedestrian traffic or to vehicular traffic other than truck traffic. The area above a roof surface subject to pedestrian or vehicular traffic shall have a vertical clearance from the roof surface in accordance with the clearance requirements of paragraph (c)(2) of this section. Service Drop A. Systems supplying portable or mobile high voltage equipment, other than substations installed on a temporary basis, shall comply with the following: The system shall have its neutral grounded through an impedance. Exception: Overcurrent devices don not have to be readily accessible if located adjacent to the equipment where access is achieved by the use of portable means. Receptacle outlets shall comply with the following provisions: A single receptacle installed on an individual branch circuit shall have an ampere rating of not less than that of the branch circuit; Where connected to a branch circuit supplying two or more receptacles or outlets, a receptacle may not supply a total cord- and plug-connected load in excess of the maximum specified in Table S-4; and. A compartment or chamber having one or more attached air ducts and forming the distribution system is known as a plenum. True What are the steps for plotting points on microstation uisng offset, station, side and elevation? Identify and describe the step-by-step process used to install cable in the NCT Colledge buildings? Install the service disconnecting means at a readily accessible location. Verified questions. B. You are using an out of date browser. We will hit the highlights here, the first being that the overcurrent devices have to be readily accessible and shall be installed so that the center of the grip of the operating handle is not more than 6 feet 7 inches in its highest position from the floor or working platform. B. ); Power conductors alone or above communication conductors: Communication conductors below power conductors -- same as power conductors; and. Over commercial areas subject to truck traffic. In this example, the receptacle is that outlet. A circuit breaker with a slash rating, such as 120/240 V or 480Y/277 V, may only be installed in a circuit where the nominal voltage of any conductor to ground does not exceed the lower of the two values of the circuit breaker's voltage rating and the nominal voltage between any two conductors does not exceed the higher value of the circuit breaker's voltage rating. The equivalent of ____ is the maximum allowed between pull points. If the door is an inswing type, ensure the opened door will not block the transformer vent. Notice the language is accessible to qualified personnel. This in no way inhibits making transformers inaccessible to unqualified personnel. 19. 240.6(A). If the system is a high-impedance grounded neutral system in which a grounding impedance, usually a resistor, limits the ground-fault current to a low value for 3-phase ac systems of 480 volts to 1000 volts provided all of the following conditions are met: Ground detectors are installed on the system; and. In this example, a 70A breaker and 6 AWG conductor will meet Code requirements. Courtesy ofwww.MikeHolt.com. Grounded (grounding) is defined as being connected to ground or to a conductive body that extends to the a ground connection. For fire pumps, conductors may be protected for short circuit only; and. four-wire, three-phaseB. Example: A service disconnecting means must be readily accessible or near the entry point of the service conductor. A luminaire that weighs more than ____ pounds shall be supported independently of the outlet box, unless the outlet box is listed and marked for the maximum weight to be supported. Overcurrent devices do not have to be readily accessible if located within anded jacobs k. the connecting means is readily accessible the total of the conceitdees of wood local andards Located at the equipmenl where excess is achieved by the we of poetic ANS: PTS: REF: Definitions 3. Much of what weve discussed here isnt explicitly required by the NEC. See 210. 2). However, equipment that is guarded by location and isolated from ground need not be grounded. A two-pole circuit breaker may not be used for protecting a 3-phase, corner-grounded delta circuit unless the circuit breaker is marked 1 -- 3 to indicate such suitability. For example, most of the general tips for setting it in place are not found in the NEC. Both the equipment grounding conductor and the grounding electrode conductor shall be connected to the grounded circuit conductor on the supply side of the service disconnecting means or on the supply side of the system disconnecting means or overcurrent devices if the system is separately derived. C. A single conduit is not permitted as sole support for an FS-type or weatherproof junction box. Formal interpretations of the NEC are govered by regional construction authorities. They cant be attached to any fire escape, downspout or plumbing equipment. The conductors from the service point to the service disconnecting means are known as service conductors. Service Equipment ?Overcurrent Protection: 230.91 Location ." Accessible (Equipment) Accessible equipment is equipment not guarded by locked doors, elevators, or other. Overcurrent protection shall not exceed _____. continuous Using an approved polyvinyl chloride conduitC. If that is right, then the in-line fuse (whether or not rated as a branch circuit OCPD) does not establish the beginning of a branch circuit, and the wires upstream (i.e., up to the receptacle, and from the receptacle back to the panel) have not been re-designated as a feeder. The definition of that word begins with, "A point on the premises wiring system. Also, suggest that card access to the room be granted only to people who fit OSHAs definition of a qualified worker per the equipment inside the room. Branch Circuit The circuit conductors found between a circuits final overcurrent protective device (breaker) and the circuits outlet is called a branch circuit. The NEC assumes you have already selected a transformer suitable for the load characteristics. Always install transformers per the manufacturers instructions and ensure transformer ventilating openings are not blocked by walls or other obstructions [Sec. Not Readily Accessible Capable of being reached quickly for operation, renewal, or inspections without climbing over or having to remove obstacles. A voltmeter will not register a voltage when connected to the same ungrounded (hot) phase. The Code does not completely address this issue. A receptacle outlet shall be installed wherever flexible cords with attachment plugs are used. These circuits exclude the connection of luminaires (lights) unless they are part of the appliance being connected. Stumped by the Code? n the Duplicate Busbar System, continuity of service is possible even if the Main, A: All the exposed noncurrent carrying metal parts of an information technology system shall be bonded, A: Correct option is B that is ELECTRIC GROUND CONDUCTORS must be capable of withstanding the higher, A: Jumpers allow the computer to shut down the electrical circuit, allowing electricity to flow to, A: Question. Texas Electrical Code 2020 > 2 Wiring and Protection > 225 Outside Branch Circuits and Feeders . The main bonding jumper is connection at the service between the grounded circuit conductor and the equipment grounding conductor. One conductor of a single-phase, two-wire system shall be grounded; The neutral conductor of a single-phase, three-wire system shall be grounded; The common conductor of a multiphase system having one wire common to all phases shall be grounded; One phase conductor of a multiphase system where one phase is grounded shall be grounded; and. Luminaire A luminaire is a complete lighting unit consisting of a light source such as a lamp or lamps, together with the parts designed to position the light source and connect it to the power supply. Many inline fuses are not suitable for use as a branch circuit OCPD. Every electric circuit must have overcurrent protection, whether a high-voltage transmission line carries many amperes or a low-voltage lighting circuit passes a few amperes.Some devices must protect conductors and equipment from overloads and short . The noncurrent-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are bonded to the generator frame. Overcurrent devices shall be readily accessible to each employee or authorized building management personnel.
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