Exposed runs of Type AC cable installed on the underside of joists must be supported at ____. Note: Please do not handwritten. In this example, a 70A breaker and 6 AWG conductor will meet Code requirements. Broken fiberD. Which of the following would help avoid the choke effect in grounding electrode conductors?A. LOCATED WITHIN A GROUNDED JUNCTION BOX, B. Article 450 of the National Electrical Code (NEC) opens by saying, This article covers the installation of all transformers. Then it lists eight exceptions. Most supplemental overcurrent protective devices have very low interrupting ratings. A compartment or chamber having one or more attached air ducts and forming the distribution system is known as a plenum. Bonding Connected to establish electrical continuity and conductivity. Overcurrent Protection Device Overcurrent Protection (Breaker) A branch-circuit overcurrent protection is a device capable of protecting feeders, branch circuits, service equipment between its rated current and its interrupting rating. These overcurrent devices may not be located where they will be exposed to physical damage or in the vicinity of easily ignitable material. The in-line fuse holder is not an outlet, because it is not part of the premises wiring system. Micro-grid 450.3(B)]. Electric Metal Tubing (EMT) provides protection from ____. 4. Overcurrent protection simply means a fuse, breaker, or fusible link is used to protect the equipment . An ____ is the organization, office, or individual responsible for enforcing the requirements of a code. Meaning that if you had to get a ladder to reset this breaker, its considered accessible equipment as long as its not blocked. These circuits exclude the connection of luminaires (lights) unless they are part of the appliance being connected. A group of conductors that fit into one conduit may not fit into another type because the ____ of different types of conduit vary. Overcurrent devices do not have to be readily accessible if located within anded jacobs k. the. 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. conducting. All required tests shall be performed before first use; before equipment is returned to service following any repairs; before equipment is used after any incident which can be reasonably suspected to have caused damage (for example, when a cord set is run over); and at intervals not to exceed 3 months, except that cord sets and receptacles which are fixed and not exposed to damage shall be tested at intervals not exceeding 6 months; The employer shall not make available or permit the use by employees of any equipment which has not met the requirements of paragraph (b)(3)(ii)(C) of this section; and. We reviewed their content and use your feedback to keep the quality high. Occupational Safety and Health Administration, Outreach Training Program (10- and 30-hour Cards), OSHA Training Institute Education Centers, Severe Storm and Flood Recovery Assistance. Part I contains the general requirements (such as guarding, marking, and accessibility), and Part II contains requirements for specific types of transformers. Main Equipment B. Conductive Path C. Grounded Neutral D. Bonding Jumper E. Bonding Conductor F. Grounding Electrode Conductor G. Grounding Electrode: The path installed with all the parts of the path A G. Guarded is defined as covered, shielded, fenced, enclosed, or otherwise protected by barriers, rails, screens, mats, or a platform removing the approach of contact by people or persons. An appliance branch circuit supplies energy to one or more outlets for the purpose of ____. Receptacle A. Service Equipment A. See 210. 240.6(A)], the next higher rating is permitted [Sec. True Over residential property and driveways. Bonding means that everything is connected or conductivity of the electron through wires. Installations built before August 13, 2007, Installations built on or after August 13, 2007, Circuit breakers used as switches in 120-volt and 277-volt, fluorescent lighting circuits shall be listed and marked "SWD. Which agency is responsible for the maintenance and publication of the NEC ? Notwithstanding the provisions of paragraph (g)(6)(iv) of this section, exposed noncurrent-carrying metal parts of the following types of fixed equipment need not be grounded: Enclosures for switches or circuit breakers used for other than service equipment and accessible to qualified persons only; Electrically heated appliances that are permanently and effectively insulated from ground; Distribution apparatus, such as transformer and capacitor cases, mounted on wooden poles, at a height exceeding 2.44 m (8.0 ft) above ground or grade level; and. 450.14] (Fig. The frame of a vehicle need not be grounded and may serve as the grounding electrode for a system supplied by a generator located on the vehicle under the following conditions: The frame of the generator is bonded to the vehicle frame; The generator supplies only equipment located on the vehicle and cord- and plug-connected equipment through receptacles mounted on the vehicle; The noncurrent-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are bonded to the generator frame; and. Raceway fill calculations are a prerequisite in ____ needed for particular circuits. The neutral conductor of a multiphase system in which one phase is used as a neutral conductor shall be grounded. Exposed noncurrent-carrying metal parts of portable and mobile equipment shall be connected by an equipment grounding conductor to the point at which the system neutral impedance is grounded. In the conduit layout shown in picture attached, determine how many wires are contained in each conduit between each piece of equipment. What else can you see that might impinge upon a safe and reliable installation? Enclosures are guarded against employee contact. b) Differentiate between Insulated-Neutral and Earthed-Neutral systems as applied to. They are fire-alarm circuits having a maximum current of 0.030 amperes; AC circuits of less than 50 volts shall be grounded if they are installed as overhead conductors outside of buildings or if they are supplied by transformers and the transformer primary supply system is ungrounded or exceeds 150 volts to ground; AC systems of 50 volts to 1000 volts shall be grounded under any of the following conditions, unless exempted by paragraph (g)(1)(v) of this section: If the system can be so grounded that the maximum voltage to ground on the ungrounded conductors does not exceed 150 volts; If the system is nominally rated three-phase, four-wire wye connected in which the neutral is used as a circuit conductor; If the system is nominally rated three-phase, four-wire delta connected in which the midpoint of one phase is used as a circuit conductor; or. Branch Circuits. A. The secondary conductors do not extend beyond the enclosure(s) of the Enclosure for a motor starter, Equipment is a general term, including fittings, devices, appliances, luminaires, apparatus, machinery, and ect. Where a feeder overcurrent device is not readily accessible, branch-circuit overcurrent devices shall be installed on the load side, shall be mounted . A wire, bus, screw, or similar suitable conductor is acceptable as a main bonding. 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. Plenum (Space) B. This Note does not require the next size up protection; it permits the next size up. ." A fixed or portable optional standby systems, A: Choose the correct option Volume in boxes can be increased by using ____ rings, domed covers, extension rings, or similar items. If I understand the situation correctly (no guarantee of that! According to that same definition, the branch circuit ends at an outlet. Mark the new location the same way the old location was marked; if the old location was not marked, clearly mark the new location using a permanent and acceptable means. If fuses are used for overcurrent protection, a fuse shall be connected in series with each ungrounded conductor; Each protective device shall be capable of detecting and interrupting all values of current that can occur at its location in excess of its trip setting or melting point; The operating time of the protective device, the available short-circuit current, and the conductor used shall be coordinated to prevent damaging or dangerous temperatures in conductors or conductor insulation under short-circuit conditions; and. Where connected to a branch circuit supplying two or more receptacles or outlets, receptacle ratings shall conform to the values listed in Table S-5; or, where larger than 50 amperes, the receptacle rating may not be less than the branch-circuit rating. Cables running horizontally (or diagonally) are considered supported and secured when passing through a(n) ____. A fuse is an electrical gadget used to shield the circuit from overcurrent. 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. What size primary-only protection overcurrent device and conductor is required for a 45kVA, 3-phase, 480V transformer that is fully loaded? Neutral Conductor or Point A. Electrical Engineering questions and answers, FLAC NEC Whi MULTIPLE CHOICE 1 Wiring components are considered accessible if(t) access can be gained without damaging the structure or finish of the building or if (2) they are ae Sledstry of the wiring here salatile in the ANS: PTS: 1 REF: Definitions 2. 5. National Firefighters Association (NFA) Underwriter's Laboratory (UL) National Fire Protection Association (NFPA) 1 ANS: PTS: Electrical Code REF: The National 9. Proper transformer selection is an important part of preventing transformers from overheating. A reduction in clearance above only the overhanging portion of the roof to not less than 457 mm (18 in.) Metal enclosures for conductors added to existing installations of open wire, knob-and-tube wiring, and nonmetallic-sheathed cable need not be grounded if all of the following conditions are met: Runs are less than 7.62 meters (25.0 ft); Enclosures are free from probable contact with ground, grounded metal, metal laths, or other conductive materials; and. Related Code Sections. Thus, you do not create a new branch circuit. A voltmeter will not register a voltage when connected to the same ungrounded (hot) phase. Over areas, other than public streets, alleys, roads, and driveways, subject to vehicular traffic other than truck traffic. k=13k51. But you can reduce or eliminate power quality problems by correcting grounding and bonding errors at the transformer or somewhere else (e.g., at the utilization equipment). 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. Verified Answer for the question: [Solved] Overcurrent devices do not have to be readily accessible if ____. Multi-Outlet Assembly A. A conductor used as an equipment grounding conductor shall be identifiable and distinguishable from all other conductors. Above finished grade or sidewalks, or from any platform or projection from which they might be reached. Overcurrent devices shall be readily accessible and shall be 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 2.0 m (6 ft 7 in.) Table S-4. Special Permission AHJ Special permission is the written consent of the authority having Jurisdiction or the AHJ who enforce the NEC and grant variances in the code (building department). All 3-wire dc systems shall have their neutral conductor grounded; Two-wire dc systems operating at over 50 volts through 300 volts between conductors shall be grounded unless: They supply only industrial equipment in limited areas and are equipped with a ground detector; They are rectifier-derived from an ac system complying with paragraphs (g)(1)(iii), (g)(1)(iv), and (g)(1)(v) of this section; or. 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. This can be outside the structure. A fitting is an accessory, such as a locknut or bushing, whose function is primarily mechanical, rather than electrical in nature. 240.6(A)]. 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. 450.3(B)]. 70 for switch controlled, Concealed Concealed means rendered inaccessible by the structure of finish of a building Conductors in concealed raceways, even though they become accessible by withdrawing them, are still considered concealed. - Maximum Cord- and Plug-Connected Load to Receptacle, Table S-5. There was general agreement that climbing over or under something would render equipment accessible but not readily accessible. For an ungrounded service-supplied system, the equipment grounding conductor shall be connected to the grounding electrode conductor at the service equipment. Reason, actually had a debate with a guy that was installing an 'appliance' that say maxium overcurrent rating of 15 amps. 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. D. THE DISCONNECTING MEANS IS READILY ACCESSIBLE. Readily accessible We recently had a spirited discussion on the job about the term "readily accessible" and what that really means in the NEC. All conductors of a multiwire branch circuit must originate from ____. Note 1 to paragraph (b)(3)(ii)(A) of this section: A cord connector on an extension cord set is considered to be a receptacle outlet if the cord set is used for temporary electric power. First week only $4.99! It comprises a, A: ANSWER (1) LOCATED ADJACENT TO THE EQUIPMENT WHERE ACCESS IS ACHIEVED BY THE USE OF PORTABLE MEANS. Notwithstanding the provisions of paragraph (g)(6)(vi) of this section, the following equipment need not be grounded: Tools likely to be used in wet and conductive locations if supplied through an isolating transformer with an ungrounded secondary of not over 50 volts; and. 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. Metal enclosures for service equipment shall be grounded. Using bonding bushes on the ends of the raceway, Four 4 AWG copper conductors with THHN insulation installed in EMT in a basement. Mandatory rules in the NEC contain the language 450.13]. T(v1,v2,v3)=(v1+v2,v2+v3,v3). Rigid metal conduit (RMC) is a raceway of ____. Holes must be bored so that the edge of the hole is at least ____. 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. 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. The equipment grounding conductor shall be connected to its proper terminal; and. 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. Branch Circuit Multi-wire D. Although the box contains a multi-wire branch circuit, only one ungrounded (hot) conductor is feeding this duplex receptacle. For an ungrounded separately derived system, the equipment grounding conductor shall be connected to the grounding electrode conductor at, or ahead of, the system disconnecting means or overcurrent devices. Post author: Post published: June 10, 2022; Post category: printable afl fixture 2022; A circuit breaker with a straight voltage rating, such as 240 V or 480 V, may only be installed in a circuit in which the nominal voltage between any two conductors does not exceed the circuit breaker's voltage rating. Above finished grade or sidewalks, or from any platform or projection from which they might be reached. This prevents the equipment from being readily accessible to people in general and is a good safety measure. Many inline fuses are not suitable for use as a branch circuit OCPD. If the transformer will be set where forklifts might be present, ensure someone installs the correct protection (such as a bollard set into the floor). Identify and describe the step-by-step process used to install cable in the NCT Colledge buildings? 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. A. Cable tester detects the, A: Materials that allow current to flow through them are called conductors. The branch circuit wiring method shall include or provide an equipment grounding conductor to which the grounding contacts of the receptacle or cord connector shall be connected. Each service disconnecting means shall simultaneously disconnect all ungrounded conductors. The article 100 definition of a branch circuit ends at an outlet. located adjacent to the equipment where access is achieved by the use of portable means. Additionally, pole-mounted distribution apparatus at a height exceeding 2.44 m (8.0 ft) above ground or grade level need not be grounded. IMO, if you stick a fuse within a cord, and plug that cord into a receptacle outlet, you are outside the premises wiring system. Adding an air intake vent and then adding a fan in the exhaust ducting will make the room more tolerable for both the transformer(s) and the electricians working in that room. A motor disconnecting means must be located in sight from the motor location as required by 430. 15A for 14 AWG copper, 20A for 12 AWG copper, and 30A for 10 AWG copper. Festoon Lighting C. Messenger wire(s), together with insulators is used to support conductors in all span exceeding 40 ft (12 m) in length. Overhead conductors for festoon lighting shall not be smaller than 12 AWG unless supported by messenger wires. There are a wide variety of supplementary fuses and fuse holders, which have small physical . The following requirements apply to temporary wiring installations that are used during construction-like activities, including certain maintenance, remodeling, or repair activities, involving buildings, structures or equipment. 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. Home > 2022 > June > 10 > Uncategorized > overcurrent devices do not have to be readily accessible if. Over residential property and driveways. Broken connectors in a cable linkB. Except for motor running overload protection, overcurrent devices may not interrupt the continuity of the grounded conductor unless all conductors of the circuit are opened simultaneously. 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. 102. 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. Overcurrent devices shall be readily accessible, except for busways (368.17(C)), supplementary overcurrent protection (240.10), overcurrent devices per 225.40 and 230.92, and overcurrent devices located adjacent to the equipment they feed if accessible by portable means - e.g., a ladder. All 125-volt, single-phase, 15- and 20-ampere receptacles installed in bathrooms or on rooftops shall have ground-fault circuit-interrupter protection for personnel. 28(7x2)5dx,u=7x2\int 28(7 x-2)^{-5} d x, \quad u=7 x-2 The. Verified questions. For a better experience, please enable JavaScript in your browser before proceeding. A major concern with transformers is preventing overheating. ); Power conductors alone or above communication conductors: Communication conductors below power conductors -- same as power conductors; and. For fire pumps, conductors may be protected for short circuit only; and. Power conductors below communication conductors -- 762 mm (30 in. Box calculations for 4 AWG and larger conductors (under 600 volts) are performed based on the ____. tribale maximize ANS: PTS: REF: Definitions 5 A contact device installed at an outlet for the connection of an attachment plug is an) rumpor und Sutlet canale ANS: PTS: REF: Definitions 6. What can installation records be used to determine while servicing equipment?A. The conductors are terminated at a through-the-roof raceway or approved support. 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. Service Equipment ?Overcurrent Protection: 230.91 Location Start your trial now! . 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. When any element of this branch circuit is replaced, the entire branch circuit shall use an equipment grounding conductor that complies with all other provisions of paragraph (g) of this section. 250.12]. What might block airflow? ", The continuous ampere rating of a fuse may not exceed three times the ampacity of the conductors. Over commercial areas subject to pedestrian traffic or to vehicular traffic other than truck traffic. 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. It can apply to industrial motor as well that run facilities, Device A unit of an electrical system that carries or controls electrical energy as its principal function is known as a device.

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