Lesson 6: Practical Guidelines for OCPD Ampere Rating Sizing /
Quiz yourself by thinking what should be in
each of the black spaces below before clicking
on it to display the answer.
Help!
|
|
||||
|---|---|---|---|---|---|
| In addition to determining the proper OCPD ampere rating for an application, what criteria is/are important when selecting overcurrent devices? Select one: a. Interrupting rating b. Short-circuit current ratings c. Voltage rating d. All of the abov | show 🗑
|
||||
| show | d. 20
🗑
|
||||
| show | True
🗑
|
||||
| show | Tue
🗑
|
||||
| show | c. Both I. and II.
🗑
|
||||
| Which NEC section provides the separate overload device rating or trip setting requirement for continuous-duty motors more than one horsepower? | show 🗑
|
||||
| show | Horsepower
🗑
|
||||
| 9.Separate motor and branch-circuit overload protection is sized based upon the ? a. Full load current based on motor horsepower in NEC Tables 430.247 to 430.250 b. maximum locked-rotor current c. motor nameplate full-load current d. start-up curr | show 🗑
|
||||
| 10.It is necessary to select a separate overload protective device for a 25-horsepower continuous-duty motor with 32 amperes nameplate current rating and a marked 1.15 service factor. Table 430.250 shows 34 amperes for such a motor. What is the maximum tr | show 🗑
|
||||
| show | c. 62.5 A Correct
Note: Motor ampacity from Table 430.248: 50 A
Minimum conductor ampacity calculated = 50 × 1.25 = 62.5 A using Conductor Ampacity Selection Guide 6, 7, 8.
The correct answer is: 62.5 A
🗑
|
||||
| show | b. 115%
🗑
|
||||
| show | d.80 A or 90 A
🗑
|
||||
| 14.Using 430.52 and Table 430.248, what is the maximum size dual-element fuse short-circuit and ground-fault protective device allowed for a 10-horsepower, 230-volt, single-phase motor, assuming the motor starts with this size? a. 50 A b. 70 A c. 8 | show 🗑
|
||||
| 15.Using Table 430.52, what is the maximum instantaneous trip circuit breaker setting allowed for the motor installation using a 460-volt, 25-horsepower, 3-phase motor marked with a 115% service factor and a nameplate current of 32 amperes based upon 430. | show 🗑
|
||||
| show | True
🗑
|
||||
| show |
a.primary
🗑
|
||||
| 18.Size the maximum primary and secondary overcurrent devices for a 100-kilovolt-amperes, 3-phase transformer, a 480-volt primary, and a 208/120 volts secondary (Only consider the transformer and not conductor protection or panelboard protection). a. | show 🗑
|
||||
| 19.The purpose of overcurrent protection of capacitors is for ? a. delay sequence protection b. ground-fault protection c. overload protection d. short-circuit protection | show 🗑
|
||||
| show | c. 135%
The correct answer is: 460.8
🗑
|
||||
| show | 125%
The correct answer is: 430.24
🗑
|
Review the information in the table. When you are ready to quiz yourself you can hide individual columns or the entire table. Then you can click on the empty cells to reveal the answer. Try to recall what will be displayed before clicking the empty cell.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Created by:
Shawnt321