Select one: A. An AFCI is basically like a GFCI but it will protect the entire circuit from the breaker and back. Note 1 of Table 450.3(B) says that if 125% of the primary current does not correspond to a standard rating of an overcurrent protective device [Sec. If a vented dry-type transformer is installed in an equipment room with a door: A terminal bar for equipment grounding conductors (EGCs), system bonding jumpers, supply-side bonding jumpers, and grounding electrode conductors (GECs) must be installed and bonded inside the transformer enclosure [Sec. 800A. a. Hrone dans la guerre de 100 ans (100 years war). Reference 422.11(A). . National Firefighters Association (NFA) Underwriter's Laboratory (UL) National Fire Protection Association (NFPA) 1 ANS: PTS: Electrical Code REF: The National 9. A (n) ______ is a complete lighting unit consisting of a light. Occupational Safety and Health Administration, Outreach Training Program (10- and 30-hour Cards), OSHA Training Institute Education Centers, Severe Storm and Flood Recovery Assistance. Grounding triad Each conductor intentionally grounded must have . 450.9]. What else can you see that might impinge upon a safe and reliable installation? 102. Over areas, other than public streets, alleys, roads, and driveways, subject to truck traffic. Duplexes control outlets of energy, as well as switches and can be used in conjunction such as a garbage disposal, Enclosed Equipment, conductors, ect. This program shall comply with the following requirements: A written description of the program, including the specific procedures adopted by the employer, shall be available at the jobsite for inspection and copying by the Assistant Secretary of Labor and any affected employee; The employer shall designate one or more competent persons to implement the program; Each cord set, attachment cap, plug, and receptacle of cord sets, and any equipment connected by cord and plug, except cord sets and receptacles which are fixed and not exposed to damage, shall be visually inspected before each day's use for external defects, such as deformed or missing pins or insulation damage, and for indications of possible internal damage. Article 450 then takes you to the next logical step providing overcurrent protection and the proper connections. - Maximum Cord- and Plug-Connected Load to Receptacle, Table S-5. Article 90 explains that the NEC is not a design manual, and it assumes that anyone using the Code has a certain level of expertise. Ready accessibility to wiring in luminaires is required in all cases required when a building is considered public c.not required dat required if there is a junction bexaby ANS: PTS: REF: Definitions A load having the maximum level of current sustained for three hours or more is referred to as a load. Identify each wire with a proper terminal marking, as shown in the example, above the disconnect switch. The switch is, A: Given, You are right, and the other guy is wrong. 18. 450.13 contains accessibility requirements. . Knowing the NEC rules for transformers is only a start. So you cannot plug this appliance into a receptacle outlet that is fed from a 20 amp branch circuit, because their is a protective limit marked on the appliance. Reason, actually had a debate with a guy that was installing an 'appliance' that say maxium overcurrent rating of 15 amps. 1. contiguous. Ensure the room is vented either via door vents that cannot be blocked or (preferably) an exhaust vent to the outside. In this example, the receptacle is that outlet. Dry-type transformers having a secondary voltage of 1,000V or less are not required to be readily accessible. This can be outside the structure. b) Differentiate between Insulated-Neutral and Earthed-Neutral systems as applied to. 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. Use and identification of grounded and grounding conductors -, A nongrounding-type receptacle may be replaced with a ground-fault circuit-interrupter-type of receptacle that is marked "No Equipment Ground;" an equipment grounding conductor may not be connected from the ground-fault circuit-interrupter-type receptacle to any outlet supplied from the ground-fault circuit-interrupter receptacle; or. A surface, flush, or freestanding raceway designed to hold conductors and receptacles (in the field or the factory). 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. Exterior protected locations under canopies, roofs, porches, and similar sites are considered damp locations. A: The Digital OUT of the first IR Sensor is connected to Pin 11 of Arduino and the Digital OUT of the, A: The convolution theorem is used to convert a time signal into an s-domain signal when multiple, A: As stated by National Electric Code(NEC),the maximum cover of UF cable or the maximum burial depth, A: The circuit is shown below: Volume in boxes can be increased by using ____ rings, domed covers, extension rings, or similar items. A: The solution is provided in the following section: A: Cable Tester- The equipment grounding conductor shall be connected to its proper terminal; and. 240.6(A)], the next higher rating is permitted [Sec. Never set two transformers with their vents facing each other. According to Note 1 of Table 450.3(B), transformers having a primary current rating of 9A or more are permitted to use the next size up rule when 125% of the primary current doesnt correspond to the standard rating of a fuse or nonadjustable circuit breaker listed in Sec. 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 same panelboard or similar distribution equipment. Main panel, Branch Circuit Multi-wire E. There must be only one grounded neutral conductor, and there must be an equal voltage between it and each undergrounded conductor of the circuit. If you can move this dresser, and it has a cover plate its accessible. An ____ is the organization, office, or individual responsible for enforcing the requirements of a code. It may also include parts to protect the light source ballast or distribute the light. Location Dry A. LOCATED WITHIN A GROUNDED JUNCTION BOX B. Tests performed as required in paragraph (b)(3)(ii)(C) of this section shall be recorded. Box calculations for 4 AWG and larger conductors (under 600 volts) are performed based on the ____. These overcurrent devices may not be located where they will be exposed to physical damage or in the vicinity of easily ignitable material. A: Equipment Grounding Conductor (EGC) A conductive path that 's a component of a decent ground-fault, A: It's critical to ground-fault protection of equipment system functionality that the ground, A: A power cable is an electrical cable that is made up of one or more electrical conductors that are, A: Communication System : equipment grounding terminal bus Power conductors below communication conductors -- 762 mm (30 in. A contact device installed at an outlet for the connection of an attachment plug is a receptacle. D. THE DISCONNECTING MEANS IS READILY ACCESSIBLE. Evaluate the indefinite integrals in this exercise by using the given substitution to reduce the integral to standard form. The grounding contacts of receptacles and cord connectors shall be grounded by connection to the equipment grounding conductor of the circuit supplying the receptacle or cord connector. A major concern with transformers is preventing overheating. Noncurrent-carrying metal parts of fixed equipment, if required to be grounded by this subpart, shall be grounded by an equipment grounding conductor that is contained within the same raceway, cable, or cord, or runs with or encloses the circuit conductors. Dry-type transformers having a secondary voltage of 1,000V or less and not more than 50kVA can be installed above a suspended ceiling. The noncurrent-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are bonded to the generator frame. A nongrounding-type receptacle may be replaced with a grounding-type receptacle where supplied through a ground-fault circuit-interrupter; the replacement receptacle shall be marked "GFCI Protected" and "No Equipment Ground;" an equipment grounding conductor may not be connected to such grounding-type receptacles. Service Point A. However, equipment that is guarded by location and isolated from ground need not be grounded. "must" or "must note penalties for noncompliance" b. shall" or "shall not suggested but discretionary ANS: PTS: Electrical Code REF: The National 10. B. Example: A service disconnecting means must be readily accessible or near the entry point of the service conductor. What size primary-only protection overcurrent device and conductor is required for a 45kVA, 3-phase, 480V transformer that is fully loaded? It has no direct connection from circuit conductors. 240.4(B). 1). A wire, bus, screw, or similar suitable conductor is acceptable as a main bonding. The service disconnecting means shall plainly indicate whether it is in the open or closed position and shall be installed at a readily accessible location nearest the point of entrance of the service-entrance conductors. . The maximum number of conductors applies only if the box does not contain any ____. The grounding electrode to which the portable equipment system neutral impedance is connected shall be isolated from and separated in the ground by at least 6.1 m (20.0 ft) from any other system or equipment grounding electrode, and there shall be no direct connection between the grounding electrodes, such as buried pipe, fence, and so forth. T(v1,v2,v3)=(v1+v2,v2+v3,v3). Where flexible cords are permitted to be permanently connected, receptacles may be omitted. 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. Step back from the transformer installation task itself, and look at the context that is, see the forest and not just the tree you are working on. Holes must be bored so that the edge of the hole is at least ____. Service conductors installed as open conductors or multiconductor cable without an overall outer jacket shall have a clearance of not less than 914 mm (3.0 ft) from windows that are designed to be opened, doors, porches, balconies, ladders, stairs, fire escapes, and similar locations. 5. Overcurrent devices shall be readily accessible to each employee or authorized building management personnel. What might block airflow? 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. Decreased bending radius during operation, Which of the following is a term missing from the National Electrical Code but used by manufacturers of equipment that's suitable for use as service equipment? The supply systems for sensitive electronic equipment are _______ systems.A. If the door is an inswing type, ensure the opened door will not block the transformer vent. (If these areas are accessible to other than pedestrian traffic, then one of the other conditions applies). Branch Circuit Multi-wire D. Although the box contains a multi-wire branch circuit, only one ungrounded (hot) conductor is feeding this duplex receptacle. Cables running horizontally (or diagonally) are considered supported and secured when passing through a(n) ____. A. Between the three-phase line and the disconnect switch. Rigid metal conduit (RMC) is a raceway of ____. They cant be attached to any fire escape, downspout or plumbing equipment. The neutral conductor of a multiphase system in which one phase is used as a neutral conductor shall be grounded. Thus, you do not create a new branch circuit. The secondary conductors do not extend beyond the enclosure(s) of the The secondary conductor ampacity is not less than 1 10 of the rating of the overcurrent device protecting the primary of the transformer multiplied by the turns ratio. Problems due to aging during operationC. Just as any other overcurrent protective device . Equipment found damaged or defective shall not be used until repaired; The following tests shall be performed on all cord sets and receptacles which are not a part of the permanent wiring of the building or structure, and cord- and plug-connected equipment required to be grounded: All equipment grounding conductors shall be tested for continuity and shall be electrically continuous; Each receptacle and attachment cap or plug shall be tested for correct attachment of the equipment grounding conductor. A compartment or chamber having one or more attached air ducts and forming the distribution system is known as a plenum. Cables entering or exiting conduit used for support or protection against physical damage require fittings on the conduit ends to prevent ____. If someone props the door open (for example, because the room is hot and they need to work in there), and the inswing door blocks the vent of a transformer, that transformer is more likely to overheat. The following additional requirements apply to feeders only: Conductors tapped to a feeder may be protected by the feeder overcurrent device where that overcurrent device also protects the tap conductor. three-wire, single-phaseC. Prior to the 2017 NEC, "overcurrent devices" were required to be readily accessible. Frames of electric ranges, wall-mounted ovens, counter-mounted cooking units, clothes dryers, and metal outlet or junction boxes that are part of the circuit for these appliances shall be grounded. Exposed noncurrent-carrying metal parts of cord- and plug-connected equipment that may become energized shall be grounded under any of the following conditions: If in hazardous (classified) locations (see 1910.307); If operated at over 150 volts to ground, except for guarded motors and metal frames of electrically heated appliances if the appliance frames are permanently and effectively insulated from ground; If the equipment is of the following types: Refrigerators, freezers, and air conditioners; Clothes-washing, clothes-drying, and dishwashing machines, sump pumps, and electric aquarium equipment; Hand-held motor-operated tools, stationary and fixed motor-operated tools, and light industrial motor-operated tools; Motor-operated appliances of the following types: hedge clippers, lawn mowers, snow blowers, and wet scrubbers; Cord- and plug-connected appliances used in damp or wet locations, or by employees standing on the ground or on metal floors or working inside of metal tanks or boilers; Portable and mobile X-ray and associated equipment; Tools likely to be used in wet and conductive locations; and. Indicate your answer where indicated. 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. As shown in Figure 5, the electrical . Transformers having a secondary voltage not exceeding 1,000V, with primary overcurrent protection only, must have the primary overcurrent protective device sized per the percentages shown in Table 450.3(B) and the percentages mentioned in its applicable notes [Sec. Example: Conductors connected to switches and receptacles are accessible by a removable plate or device. There are a wide variety of supplementary fuses and fuse holders, which have small physical dimensions . Primary Overcurrent Protection = 54A 125% = 68A; use the next size up, 70A [Sec. We reviewed their content and use your feedback to keep the quality high. Accessible (Equipment) Accessible equipment is equipment not guarded by locked doors, elevators, or other. If a delta-connected high voltage system is used to supply the equipment, a system neutral shall be derived. three-wire, three-phaseD. "I have learned, in whatsoever STATE I am, therewi, http://www.usahardware.com/inet/shop/item/30550/icn/20-068163/bussman/bp_sru.htm. Installing a main bonding jumperB. Where the neutral is not grounded on the load side of the circuit, the current transformer may link all three phase conductors and the grounded circuit conductor (neutral); and. Metal cable trays, metal raceways, and metal enclosures for conductors shall be grounded, except that: Metal enclosures such as sleeves that are used to protect cable assemblies from physical damage need not be grounded; and. Ground-fault detection and relaying shall be provided to automatically deenergize any high voltage system component that has developed a ground fault. Grounded (grounding) is defined as being connected to ground or to a conductive body that extends to the a ground connection. Overcurrent protection shall not exceed _____. Branch Circuit Individual An individual branch circuit supplies only one piece of utilization equipment. Select one: You are using an out of date browser. A cable assembly's ____ conductor can be used as a switch loop (leg) in single-pole, three-way, and four-way switch installations, even though it is an ungrounded (hot) conductor. LOCATED ADJACENT TO THE EQUIPMENT WHERE ACCESS IS ACHIEVED BY THE USE OF PORTABLE MEANS, C.THE TOTAL LOAD OF THE ADJACENT CIRCUIT DOES NOT EXCEED LOCAL STANDARDS, D.THE DISCONNECTING MEANS IS READILY ACCESSIBLE. Listed equipment protected by a system of double insulation, or its equivalent, and distinctively marked as such. Overcurrent devices do not have to be readily accessible if ____. Where the ampacity of the ungrounded conductors doesn't correspond with the standard rating of overcurrent protection devices as listed in 240.6(A), you can use the next higher protection device if it doesn't exceed 800A [240.4(B)]. Wire connectors, pigtails, locknuts, bushings, raceway connectors, grounding screws, and equipment bonding jumpers are not factors when calculating ____. source such as a lamp or lamps, together with the parts designed to position the light source and to connect it to the power supply. Accessible (Readily Accessible) Ready accessibility to wiring in luminaires is not required. Branch circuits are divided into four categories: Appliance, General purpose, Individual, and Multi-wire. In most cases, access can be gained through the use of a ladder or scaffolding ect. Handles or levers of circuit breakers, and similar parts that may move suddenly in such a way that persons in the vicinity are likely to be injured by being struck by them, shall be guarded or isolated. The _______ is required to be connected to the grounded conductor of the sensitive electronic system on the line side of the separately derived system disconnecting means. Find the preimage of www for the linear transformation. This tab has been removed to allow separate feeds of each outlet. Not be located where they will be in the . Service Drop A. What is the angle pull for a raceway in the horizontal dimension where the trade size of the largest raceway is 3 and the sum of the other raceways in the same row on the same wall is 4?v. If the circuit\'s overcurrent device exceeds _____, the conductor ampacity shall have a rating not less than the rating of the overcurrent device. Micro-grid Branch Circuit Multi-wire A. Branch circuits are divided into four categories: Appliance, General purpose, Individual, and Multi-wire. Next we will jump to 240.24 Location in or on Premises. All this can be considered equipmentpretty much anything sold at home depot, Feeder B. The space above a suspended ceiling used for environmental air-handling purposes is an example of other space used for environmental air described in 300. The conductors are terminated at a through-the-roof raceway or approved support. One of the most common applications for "readily accessible" occurs in 240.24(A), in which the NEC states that overcurrent devices must be readily accessible and installed so that the center of the grip of the operating handle of the switch or circuit breaker, when in its highest position, is not more than 6 feet, 7 inches above the floor . Bonding Jumper (Main) An Equipment bonding jumper is the connection between two or more portions of the equipment grounding conductor. Aug 12, 2009. Cord connections. I dont like the 'new definition' of 'Branch circuit overcurrent device'. NEC Requirements for Conductor Material Types and Sizing Requirements, Electrical Troubleshooting Quiz July 19, 2022, NEC Requirements for Overvoltage Protection, EC&M Tech Talk Video Medium-Voltage Conductors and Cable, Monthly Quiz: Grounding and Bonding Connections. They can also be installed in panelboards or control boards that are in rooms or enclosures free from dampness, easily ignitable material and accessible only to qualified personnel. Lets show how this all works through an example problem. It comprises a, A: ANSWER (1) Arc-Fault Circuit Interrupter A device intended to provide protection from the effects of arc faults by recognizing characteristics unique to arcing and by deenergizing the circuit when an arc fault is detected. Over commercial areas subject to pedestrian traffic or to vehicular traffic other than truck traffic. The main bonding jumper is connection at the service between the grounded circuit conductor and the equipment grounding conductor. 110.25 [Sec. Then we have: VII. These overcurrent devices may not be located where they will be exposed to physical damage or in the vicinity of easily ignitable material. 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. The weight supported by any single conduit shall not exceed ____ pounds. 22. The service lateral is the underground conductors between the utility electric supply system and the service point. That plug-in breaker thing is a piece of utilization equipment. Branch Circuit The circuit conductors found between a circuits final overcurrent protective device (breaker) and the circuits outlet is called a branch circuit. This prevents the equipment from being readily accessible to people in general and is a good safety measure. Fuses and circuit breakers shall be so located or shielded that employees will not be burned or otherwise injured by their operation. A voltmeter will not register a voltage when connected to the same ungrounded (hot) phase. The record shall be made available on the jobsite for inspection by the Assistant Secretary and any affected employee. For each given ppp-series, identify ppp and determine whether the series converges. On three-phase, three-wire circuits, an overcurrent relay in the residual circuit of the current transformers may replace one of the phase relays. Therefore, So a telephone occupies a circuit for, A: A circuit breaker is a kind of electrical switch which is used to protect an electrical circuit from, A: A power station is to provide electricity to a huge number of people.

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