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. 1. What electrical code is universally used in the United States? 2. Describe the following branch circuits and where each is used: a. Individual b. General purpose c. Appliance 3. Describe a split wired circuit. 4. How many circuits are required to accommodate kitchen appliances in an average size home? 5. When selecting the panelboard size, what considerations for the future should be taken into account? 6. How is the general lighting load for a building determined? 7. How is the minimum service entrance determined? 8. In selecting the service entrance size, what should be considered? 9. On a 120/240 V, single-phase, three-wire system, identify the following: a. Voltage between one grounded conductor and one ungrounded conductor b. Voltage between two ungrounded conductors 10. On a 208Y/120 V, three-phase, four-wire system, identify the following: a. Voltage between one grounded conductor and one ungrounded conductor b. Voltage between two ungrounded conductors 11. On a 240 ?/120 V, three-phase, four-wire system, identify the following: a. Voltage between one grounded conductor and one ungrounded conductor b. Voltage between two ungrounded conductors 12. On a 480Y/277 V, three-phase, four-wire system, identify the following: a. Voltage between one grounded conductor and one ungrounded conductor b. Voltage between two ungrounded conductors 13 Identify five types of equipment that may require volt ages higher than 120 V AC. 14. Identify three types of equipment that may require three-phase power. 15. Identify the type of cable permitted in single- and multifamily dwelling units but that cannot be used under ground, nor in buildings that are more than three stories above grade, nor in commercial garages, motion picture studios, theaters, places of assembly, elevator hoist ways, and other corrosive or hazardous locations. .16. Identify the type of cable permitted in direct-burial applications such as a feeder or branch circuit provided it’s protected by an overcurrent protection device (fuse or circuit breaker) before if leaves the panelboard. Design Exercises 17. Determine the ampacity of a No. 12 AWG copper conductor with THHN insulation that will be used in a 120 V, two-wire circuit in an environment with an average ambient air temperature of no greater than 86°F (30°C). Neglect temperature and bundling correction factors. 18. Determine the ampacity of a No. 14 AWG copper conductor with THHN insulation that will be used in a 120 V, two-wire circuit in an environment with an aver age ambient air temperature of no greater than 86°F (30°C). Neglect temperature and bundling correction factors. 19 Determine the ampacity of a No. 12 AWG copper conductor with THHN insulation that will be used in a 277 V, two-wire circuit in an environment with an average ambient air temperature of no greater than 86°F (30°C). Neglect temperature and bundling correction factors. 20. Determine the ampacity of a No. 4 AWG copper conductor with THHN insulation that will be used in a 120 V, two-wire circuit in an environment with an aver age ambient air temperature of no greater than 86°F (30°C). Neglect temperature and bundling correction factors. 21. Determine the ampacity of a No. 1/0 AWG copper conductor with underground feeder (UF) insulation that will be used in a 120 V, two-wire circuit in an environment with an average ambient air temperature of no greater than 86°F (30°C). Neglect temperature and bundling correction factors. 22. Determine the maximum one-way distance two conductors can carry a current of 20A on a 120 V, single phase circuit based on a maximum voltage drop of 3%. Base your analysis on the following conductor sizes: a. No. 14 AWG-copper b. No. 14 AWG-aluminum c. No. 12 AWG-copper d. No. 12 AWG-aluminum e. No. 8 AWG-copper f. No. 8 AWG-aluminum 23. Determine the maximum distance two conductors can carry a current of 20A on a 277 V, single-phase circuit based on a maximum voltage drop of 3%. Base your analysis on the following conductor sizes: a. No. 14 AWG-copper b. No. 14 AWG-aluminum c. No. 12 AWG-copper d. No. 12 AWG-aluminum e. No. 8 AWG-copper f. No. 8 AWG-aluminum 24. A set of conductors will feed power to a well station with pump having a load of 30 A. The building is 150 ft from the 120 V power source. Determine the required wire size for copper and aluminum conductors at a maximum voltage drop of 3%. 25. A set of conductors will feed power to an outbuilding with equipment having a total load of 12 000 VA. The building is 200 ft from the 120 V power source. Deter mine the required wire size for copper and aluminum conductors at a maximum voltage drop of 3%. 26. Determine the circuit rating for the following appliances or equipment on a 120/240 V circuit: a. Household range b. Trash compactor c. Household clothes washer d. Household clothes dryer (electric) e. Central air conditioner (5 ton) f. Eight luminaires with 4-32 W fluorescent lamps per luminaire (138 W including ballast) 27. Determine the circuit rating for the following appliances or equipment on a 277 V circuit: a. Eight luminaires with 4-32 W fluorescent lamps per luminaire (138 W including ballast) b. Sixteen luminaires with 4-32 W fluorescent lamps per luminaire (138 W including ballast) c. Twenty luminaires with 4-32 W fluorescent lamps per luminaire (138 W including ballast) 28. Design the electrical service entrance system for the residence in Sect. D. Base your analysis on: a. Water heater 3800 W b. Clothes dryer 4400 W c. Dishwasher 1000 W d. Range 11 700 W e. Air conditioner 9000 W 29. Design the electrical service entrance system for one of the apartments in Sect. A. Calculate the total load and service for the 38 ft _ 28 ft (11.6 m _ 8.55 m) apartment building. Base your analysis on: a. Air conditioner, 2000 W b. Electric range, 10 500 W c. Water heater, 3500 W d. Dishwasher, 1000 W e. No clothes dryer Prev: Design Example |