SOLUTION MANUAL FOR Electrical Wiring Industrial 18th Edition Stephen L. Herman, Derrick Atkins Chapter 1-20
The Answers are Provided on Pages 51 to 148.
[This is Updated Document with Correct Answers] Updated Date 8/26/2026 CHAPTER 1 REVIEW All answers should be written in complete sentences, and calculations should be shown in detail. 1.
In a set of construction drawings, where would an electrician find information about the location and placement of a building?
2.
From information on the composite site plan, where is the lowest area on the site and what is the elevation?
3.
What device is generally used to measure length on a plot or building plan?
4.
What would be the elevation, at the pole, of the bottom of a trench being dug to install telephone service using rigid nonmetallic conduit?
5.
Which of the methods for measuring ground resistance is used to measure resistance over a wide area?
6.
What is the difference, in SI units, between the lowest and the highest contours?
To answer the following questions, examine the composite site plan, the north and west elevations, the site plan symbols, and the NEC. 7.
What is the elevation of the manhole rim where the benchmark is established?
8.
What is the elevation of the first floor of the industrial building?
9.
What is the vertical distance from the manhole rim to the first floor of the industrial building? (Measure in decimal feet.)
10.
What is the vertical distance from the manhole rim to the first floor of the industrial building, measured in feet and inches accurate to 1⁄16 inch?
11.
Where is the preferred area for location of the construction trailer? Why did you choose that area?
12.
It was determined that the rigid nonmetallic conduit for the telephone service could be installed in a trench with a bottom elevation of 743.65 ft. If the conduit is allowed to rise a distance of 1 ft, how deep is the trench at the building?
13.
Refer to plan E1 on page 2 of the plans. What is the height of the boiler room floor?
14.
A cable containing two insulated conductors and a bare grounding wire is installed to a lighting standard mounted on a base similar to the one shown in Figure 1-22. Assume you are the electrician in charge. What instruction
would you give to a first-year apprentice who will make up the grounding connection?
15.
Why is it necessary to have a good grounding system for the building?
16.
What are the three most common methods of determining ground resistance?
17.
Explain the difference between a soft metric conversion and a hard metric conversion.
CHAPTER 2 REVIEW All answers should be written in complete sentences, and calculations should be shown in detail. 1.
What is the available fault current on the secondary of a three-phase, 225-kVA, 480//208/120-volt transformer with an impedance of 1.8%?
2.
What is the maximum standard size fuse permitted for a single-phase 25-kVA transformer with an impedance of 4%, installed in any location, with a primary voltage of 4160 V?
3.
Explain the operation of ground detectors and identify the situation that would require their use.
4.
Explain the reasoning for installation of the two meters.
5.
Two current coils are installed. What is their function and why was it not necessary to install three coils?
6.
If the secondary is ungrounded (such as that shown in Figure 2-11), what connections would likely be made to the grounding bus?
7.
If the secondary is grounded, what connection(s), in addition to those listed in problem 6, would be made to the grounding bus?
8.
What type of three-phase connection requires only two transformers?
9.
An installation requires a capacity of 86 kVA. The utility company intends to set two transformers as an open delta to supply this installation. What is the minimum kVA capacity of each transformer?
10.
Why do most three-phase transformer connections have at least one side (primary or secondary) connected in delta?
11.
What type of three-phase connection requires overcurrent protection in only two of the three phases?
12.
List some of the protective relays found with large transformers.
13.
What material should be available before opening manholes on large transformers?
14.
Why is it important to inventory tools and equipment before and after working inside a transformer?
15.
What are the two major types of three-phase connections?
16.
In what type of three-phase connection are the line current and phase current the same?
17.
In what type of three-phase connection are the line voltage and phase voltage the same?
18.
What type of testing equipment should be used to determine if the insulation value of the windings of a transformer have degraded?
19.
The primary winding of a 250-kVA transformer is connected to 7200 volts, and the secondary has a voltage rating of 240 volts. The transformer nameplate lists an impedance of 7%. The transformer is protected by timedelay fuses. What are the maximum current ratings for the fuses that are permitted to be used to protect the primary and secondary windings of this transformer?
20.
The primary winding of a 750-VA transformer is connected to 240 volts. The