2017 Master Electrician Exam Questions and Study Guide- Ray Holder. AC Systems, Level I - 3rd Ed. How many 14 AWG THWN conductors are permitted in a Type V500 surface metallic raceway? What is the minimum size THHN copper conductor (of at least equal ampacity) required to fulfill this replacement? Calculate to the nearest ampere. For commercial cooking related equipment, branch-circuits and ocpd are sized according to what? Determine the minimum standard size circuit breaker required for each of the 27 kW, 3-phase noncontinuous loads. 2017 Master Electrician Exam Questions and Study Guide- Ray Holder. and ground fault protection by the use of OCPD's such as fuses or circuit breakers. What NEC article has demand factors for household cooking appliances? The multiwire branch circuits are supplied by a 4-wire, 3-phase, wye-connected system. Three 1/0 AWG XHHW-2 aluminum conductors are installed in a rigid metal conduit, Type RMC, in an ambient temperature of 105F. The following conductors are the same AWG size and are made up of the same copper conductor material, but have different types of insulation. Single insulated 2 AWG THW copper conductors installed in a raceway in an ambient air temperature of 30C will have a lower ampacity than when installed as open conductors in free air at the same ambient temperature of 30C. and how many laundry circuits? THWN aluminum at 92F ambient 0.94. similar to P/E=I for the standard formula without taking into account reactive loads and the 3 phases. PP61. it has more recently been found in ___, utility distribution and transmission field. Each conductor of a 3-conductor (3/C) armored cable (Type AC) assembly using 10 AWG insulated copper conductors with 75C insulation has an ampacity of ? The following conductors are installed in rigid metal conduit in an ambient temperature of 40C. More than 3 current carrying conductors in the raceway or cable. in an elevated ambient temperature and a raceway OR CABLE longer than 24 inches uses what formula? PP81, required ampacity = load/correction factor. The ampere trip rating of overloads is based on the. clothes dryer at 5kVA or nameplate, whichever is bigger. Which annex in the NEC is used for conductors all of the same size in conduit and tubing? Capacitors shall be enclosed in vaults or outdoor fenced enclosures in compliance with the applicable provisions of Article 110 when they contain more than ? Does the 75% residential rule for 4 or more fastened in place appliances include space heaters, dryers, ranges, or air conditioning equipment? the final step in a residential calc is to add what? Mike Holt's Understanding the National Electrical Code, Vol. , and 240.4(D)(5) limits the overcurrent protection to ? Chapter 1 - Legislation & Codes for Power Engineering, Chapter 2 - Code Calculation (ASMSE Section I), Criminal Procedure and Investigations Act (CPIA) 1996. What is the ampacity of a 1 AWG THW copper conductor installed in a raceway located in an ambient temperature of 110F? Premises wiring primarily includes exterior wiring and does not include interior wiring. The common point on a 4-wire, three-phase, 120/208V wye-connected system is defined by the Code as the ________., Neutral point. 2017 Master Electrician Exam Questions and Study Guide- Ray Holder. 2017 Master Electrician Exam Questions and Study Guide- Ray Holder. (Note: The term "basic rule," as used here, indicates that exceptions or other conditions do not apply.). The ampacities listed in Table 310.16 are based upon an ambient air temperature of ? Annex D has this in the NEC as a reference. 7 Identify the correct copper conductor size needed for each insulation type. c. EVJT 25% of the largest motor is added to this calculation. , and 240.4(D)(7) limits the overcurrent protection to 30 amperes. Your email address is only used to allow you to reset your password. AC Theory, Level I - 3rd Ed. Unit load for dwelling units = 3 VA per ft.2. The following conductors are installed in rigid metal conduit in an ambient temperature of 40C. What table is used for conductors of different sizes in conduit, tubing, or raceways? listed hospital grade Answer: 230A Explanation: The lugs on both ends are rated for 90C but the XHHW insulation is only rated for 75C in a wet location. A 14 AWG XHHW-2 copper conductor is connected to a circuit breaker with termination temperature limitation marked (not to exceed) 60C. CB's are rated for continuous operation only at 400 amps or more. . A device box is mounted and firmly fastened on a wood stud with two nails located inside the box and less than 1/4 inch from the back or ends of the box. The rating of disconnecting means for a bank of capacitors shall not be less than ? PP124. 450.43(C) Using Type THWN copper for the service conductors, determine the proper conductor size for a new 175-ampere dwelling unit with a single-phase service. Using Table 310.16, what is the minimum size THHN copper conductor(s) required? demand load is the given demand at any given instance of a system or appliance. Chapter 1: Introduction to the Fire Officer - Fire Officer NFPA 1021 - Jones & Bartlett (Third Edition). NJATC workbook answer keys are found online at TriciaJoy.com and WPraceTech.com as of 2015. 8 AWG PFAH nickel-coated copper is expected to continue for three hours or more. Each dryer shall be calculated at a minimum of _______________. Considering all various conductor insulation types, the minimum size AWG copper conductor permitted to serve the load is ? Remember when you divide, you will get a larger number. This position is based on the fact that most, if not all, testing authorities do not allow programmable calculators to be used during testing. to send you a reset link. When sizing OCPD for motors, if adjustable, what should they be set at? fixed electric space heating is what type of load? Deflection of nonmetallic cable tray can be adversely affected by ? Section 110.12(A) requires unused openings, other than those intended for the operation of equipment, those intended for mounting purposes, or those permitted as part of the design for listed equipment, to be ? Job Info 1, lvl 2 lesson 1 Flashcards | Chegg.com Job Info 1, lvl 2 lesson 1. A calculated branch-circuit load is 173 amperes. specifies the requirements for fiberglass cable trays and associated fittings designed for use in accordance with the requirements of the NEC. The load for each small-appliance branch circuit required in a dwelling unit is calculated at ? QuickPass 2020 Journeyman Electrician Exam Study Guide Combo 15% Discount! Note: Over 100 amps is 75 Celsius rated. 4/0 AWG FEP copper 346 A is often used to determine the temperature rating of the entire circuit. Think home versus a store and time of occupancy. Transformers, Level I - 2nd Ed. input would be a larger number than the output watts. number of circuits= [linear ft. x 180VA]\circuit VA. this formula is used for simultaneous loads in a commercial buildings such as a bank or office building. the lowest possible adjustable setting is used for these to afford maximum protection. The calculated load for a 3-phase, 240-volt load is 196 amperes. . Training Bulletins, Memos & Index Files (74 Questions), Chapter 12.3 : The Synapse and The Neurotransmitter. OUTPUT WATTS/ INPUT WATTS=EFFICIENCY. . Privacy Policy and Bring your club to Amazon Book Clubs, start a new book club and invite your friends to join, or find a club thats right for you for free. Match the individual dwelling unit appliance loads for the correct service or feeder volt-ampere loads. All motors must have a disconnecting means, and the ampere rating is not less than what % of FLC as given in table 430.248-250? remember if they are not all the same size we use note 2 column C of T220.55. The correct answer is: 550.16(A)(1). Three 10 AWG FEP copper conductors are installed in a metal raceway in an area with an ambient temperature of 60C. Total service or feeder demand for these three appliances after appliance demand factor is applied. receptacles. . When the rating of a cooking appliance falls under both column A an B, you must do what? Determine the ampacity of the copper circuit conductors. What happens if you have all ranges of the same size and over 12KW through 27KW? Why would the minimum size service for a residence be 100amps? The following conductors are installed open in free air, with an ambient temperature of 30C. 20% of the cross section of the wireway or gutter shall not be exceeded where splices or taps are not made. What is the exception for the 125% rating for a load that runs for more than 3 hours that allows a 100% rating of the OCP? Browse over 1 million classes created by top students, professors, publishers, and experts. Under what conditions do we round down for a branch circuit if the standard OCPD (over current protective device) does not correspond to a size fuse or breaker? Two 8 AWG XHHW-2 copper conductors are connected to a two-pole circuit breaker with termination temperature limitation marked (not to exceed) 60/75C. 4 AWG Z aluminum 94 A Question: What is the maximum ampacity of a 3-phase feeder consisting of 3 - 4/0 and 1 No. PP68. Determine the ampacity of each of the 12 AWG conductors. Determine the ampacity of the circuit conductors. What size water heater is considered non-continuous loads? . If the equipment is not marked, it is 60 Celsius rated for 100 amps and less. The demand factors in table_______ shall be permitted when sizing feeders and service entrance conductors for electric clothes dryers in residences. 2017 Master Electrician Exam Questions and Study Guide- Ray Holder. . The 90C rating is for dry locations only. In general, dry-type transformers rated over 112 1/2 kilovolt-amperes installed outdoors shall not be located within ? All of the conductors are current-carrying conductors. Good job NJATC. To find amps when KVA is known you use what formula? yes these get counted for raceway or conduit fill calculations. Calculate to the nearest ampere. Read the installation information for this situation and determine whether the installation is acceptable or a violation of Section 314.20. Knowing how to find the number of branch circuits for lighting, how do you propose the formula would look to find the number of branch circuits for resistive heating? in motors with higher current draws they use the nameplate, typically. The correct answer is: solid fixed barrier of a material compatible with the cable traybarrier of a material compatible with the cable tray, The total difference between the minimum winter and maximum summer temperatures a cable tray system may be subject to must be considered to account for thermal expansion and contraction. 220.51, use 100% (Exception does not apply). A conductor's ampacity is directly related to the type of insulation used on the conductor. Formulas used to determine the power factor are Power factor = watts/VA. also R/Z and various other formulas are correct. Table 310.16 lists the ampacity of a 12 AWG TW copper conductor at ? Table 220.56 is used for this in commercial feeder and service calculations for cooking equipment. A 3-conductor 8 AWG copper Type MC cable is installed in an area with an ambient temperature of 96F. Three 8 AWG THW copper conductors are installed in the same raceway for use as equipment grounding conductors. An EMT raceway contains two 3-phase, 480-volt branch circuits. conductors ______inches or longer that are looped and unbroken are counted as what? Using an ampere load of 165 amperes, determine the minimum-size 120/240-volt, single-phase, 3-wire service.
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