Delmar's Standard Textbook Of Electricity
7th Edition
ISBN: 9781337900348
Author: Stephen L. Herman
Publisher: Cengage Learning
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 10, Problem 7PP
A bank of electric heaters has a power rating of 25 kW. The heaters are connected to 480 volts. The heaters will operate for more than three hours at a time. The conductors supplying the heaters are to be aluminum with type THWN-2 insulation. The heaters are located in an area with an ambient temperature of
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
We are running 3 wires and a ground in a RMC to a control panel with a 60 amp circuit breaker disconnect in the control panel. The conduit is run along the ceiling where the ambient air temperature is 100 degrees. The control panel feeds our secondary cooling pump. What size are the ungrounded conductors? All conductors have typeTHHN insulation.
A
#6 AWG
B
600 Kcmil
C
#8 AWG
D
#2 AWG
What size RMC do we need?
A
3"
B
3/4"
C
1"
D
1 1/2"
Most residential general lighting circuits are wired with 14-AWG copper conductors and are protected by 15-amp circuit breakers. However, there are many electricians who install 12-AWG copper conductors and protect them with 20-amp circuit breakers. How will you know which conductor size and which circuit breaker size will be used for the general lighting branch circuits in the house you are wiring?
Six 1/0 aluminum conductors are to be run in a conduit. Each conductor has type THWN insulation's, and the ambient air temperature is 30 degrees celcius. What is the ampacity of each conductor?
Chapter 10 Solutions
Delmar's Standard Textbook Of Electricity
Ch. 10 - What is the maximum temperature rating of Type...Ch. 10 - 2. Name two types of conductor insulation designed...Ch. 10 - A 10 AWG copper conductor with Type THW insulation...Ch. 10 - 4. Six 1/0 aluminum conductors are to be run in a...Ch. 10 - Name five conditions that must be met for running...Ch. 10 - What is the largest solid (nonstranded) conductor...Ch. 10 - Can Type TW cable be used in an area that has an...Ch. 10 - How is the grounded conductor in a flat...Ch. 10 - What three colors are ungrounded conductors not...Ch. 10 - Twenty-five 12 AWG copper conductors are run in...
Ch. 10 - A single-hase load is located 2800 ft from its...Ch. 10 - It is decided to use parallel 0000 conductors to...Ch. 10 - A three-phase motor operates on 480 V and is...Ch. 10 - You have been hired by a company to connect an...Ch. 10 - 2. You are a journeyman electrician in an...Ch. 10 - You are an electrician working in an industrial...Ch. 10 - Using the above example, determine the wire size...Ch. 10 - 1. A 2 AWG copper conductor is 450 ft long. What...Ch. 10 - 2. An 8 AWG conductor is 500 ft long and has a...Ch. 10 - 3. Three 500-kcmil copper conductors with Type RHH...Ch. 10 - 4. Eight 10 AWG aluminum conductors with Type THWN...Ch. 10 - 5. A three-phase motor is connected to 480 V and...Ch. 10 - 6. A 50-hp DC motor is connected to 250 volts. The...Ch. 10 - 7. A bank of electric heaters has a power rating...Ch. 10 - A 15-hp squirrel-cage induction motor is connected...Ch. 10 - Determine the resistance of a 16 AWG copper...Ch. 10 - Determine the ohms-per-mil-foot of an aluminum...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, electrical-engineering and related others by exploring similar questions and additional content below.Similar questions
- Explain the method of carrying out insulation resistance test on an electrical installationarrow_forwardh.1. In an alternating-current system, the maximum size for a copper grounding electrode conductor isA. 250 kcmil.B. 3/0.C. 500 kcmil.D. 4/0. h.2. The figure shows a fault condition in an ungrounded electrical system. Which of the following will occurbecause of the fault in this system?A. Only the overcurrent protector at Point A will trip open.B. The ground fault will heavily damage the service.C. Nothing will happen until a second ground fault occurs.D. The overcurrent protection will trip, shutting off all the line side power.arrow_forwarda. If both elements of the water heater in this residence are energized at the same time, how much current will they draw? (Assume the elements are rated at 240 volts.) b. What size and Type THHN wire is required for the load of both elements? Show calculations.arrow_forward
- Is it permissible to use standard 60C insulated conductors to connect all counter-mounted cooking units? ___________________________________________________ Why? ________________________________________________________________arrow_forwardLoad in Figure 1 needs to be connected to Mains Switch Board (MSB) using multicore PVC cable. As a maintenance engineer, you need to proposed cable size for the load, Determine the following issues. 1) Calculate current demand for the circuit. 1) Detemine suitable MCCB (Model and nominal current rating) should be used to protect the load against over-current. im Propose suitable cable size for the load in Figure 1. iv) Calculate voltage drop of the proposed cable WITHOUT consider the cable reactance and voltage drop correction due to higher cable operating temperature v) Calculate voltage drop of the proposed cable BY consider the cable reactance and voltage drop correction due to higher cable operatıng temperature vi) If the multicore PVC eable is change into 3 single core PVC cables, what the suitable cable size. All other multicore cables not available. (25 + variable x) m (A) 30 m (B) (15 + variable b) m (C) Multicore PVC cable MCCB 95 kW. (400 + variable y) V. 0.85 p.f. Load MSB…arrow_forwardAssume a bank of heating strips is rated at 22 KW and is connected to 240 volts. The heat strips operate for 4 hours at a time and are located in an area with an ambient temperature of 86 degrees F. The termination temperature rating of the heat disconnect lugs are unknown. Copper conductors with type THWN-2 insulation are to be used because of the environment of the installation to connect the heaters. What size conductors should be used?arrow_forward
- 1. A14/2 type copper used for a general lighting branch circuit. Ampacity:______________ Maximum Fuse or Circuit Breakers Sizes:________________ 2.Three 8 AWG copper conductors with THHN insulation Installed in garage in electrical metallic tubing (EMT). The ambient temperature in the garage can reach as high as 110'F. All termination points for this circuit are rated 60'C. Ampacity:______________ Maximum Fuse or Circuit Breakers Sizes:________________ 3.Four 4 AWG copper conductor with THWN insulation imstalled in EMT in a basement. All termination points are rated at 60'C. Ampacity:______________ Maximum Fuse or Circuit Breakers Sizes:________________ 4. An 8/3 Type UF copper cable installed underground from a house to a detached garage to feed a 120/240-volt subpanel. All termination points are rated at 60'C.…arrow_forwardIf the cable in Figure ran for the whole of its length, grouped with others of the same size in a high ambient temperature, and was totally surrounded with thermal insulation, The correction factors considered will be----------- Fuseboard High ambient temperature Cable Grouping of cables Thermal insulation Load BS 3036 fuse O a. Cg O b. All Ca,Cg.Ci and Cf O c. Ci O d. Caarrow_forwardYou are an electrician working in an industrial plant. The company is constructing a maintenance shop located 225 feet from the main plant electrical system. You are to install a 400-ampere three-phase wire system in the new maintenance shop. The service is supplied by the existing plant service. The voltage is 480 volts and the voltage drop is to be kept at 3% or below at full load. The conductors are to be aluminum. What size conductors should be installed for the new service? Express your answer to the nearest standard wire size. (Note: Determine the wire size by calculating length, resistance, and voltage drop as opposed to using the National Electrical Code.)arrow_forward
- QUESTION 3 We are running 3 wires and a ground in a RMC to a control panel with a 60 amp circuit breaker disconnect in the control panel. The conduit is run along the ceiling where the ambient air temperature is 100 degrees. The control panel feeds our secondary cooling pump. What size are the ungrounded conductors? All conductors have typeTHHN insulation.arrow_forwardYou are a journeyman electrician in an industrial plant. You have been assigned the task of connecting a 25-kW electric heater to a 240-V, single-phase panel. The heater is located in an area with an ambient temperature of 90°F. The conductors are to be copper with Type TW insulation. The heater is expected to operate for more than three hours at a time. What size conductors would you use to connect this heater? Is this correct? I=P/EI=25000 W/ 240 VI= 104.17 amps x 125%I= 130.21 amp/ .96I= 135.63 amp2/0 AWG conductor will be neededarrow_forwardSeven 8 AWG copper conductors are run in conduit. Each conductor has type THHN insulation. The conduit is located in an area with an ambient temperature of 138oF. What is the ampacity of each conductors?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
EBK ELECTRICAL WIRING RESIDENTIALElectrical EngineeringISBN:9781337516549Author:SimmonsPublisher:CENGAGE LEARNING - CONSIGNMENT
Electricity for Refrigeration, Heating, and Air C...Mechanical EngineeringISBN:9781337399128Author:Russell E. SmithPublisher:Cengage Learning
EBK ELECTRICAL WIRING RESIDENTIAL
Electrical Engineering
ISBN:9781337516549
Author:Simmons
Publisher:CENGAGE LEARNING - CONSIGNMENT
Electricity for Refrigeration, Heating, and Air C...
Mechanical Engineering
ISBN:9781337399128
Author:Russell E. Smith
Publisher:Cengage Learning
What is an electric furnace and how does it work?; Author: Fire & Ice Heating and Air Conditioning Inc;https://www.youtube.com/watch?v=wjAWecPGi0M;License: Standard Youtube License