Question 13043 of 731 · Texas Journeyman Electrician Exam
In the common voltage drop formula VD = 2KIL / CM, what K value is normally used for aluminum conductors?
Exactly one answer is correct.
You got of questions right. Here on the question pages nobody remembers which ones you got wrong. The trainer saves your progress and asks the mistakes again until they stick.
Or free: the 10 questions most people get wrong
Show solution
Correct answer to question 13043
- C: 21.2
Explanation
K represents the resistance of a one circular mil, one foot conductor at operating temperature: about 12.9 ohms for copper and 21.2 ohms for aluminum. Aluminum has a higher K because it is a poorer conductor than copper.
More questions: Electrical Calculations
- 13044A three-phase 208 volt circuit of 10 AWG copper (10,380 circular mils) supplies 25 A per phase at 120 feet one way. What is the percent voltage drop?
- 13045A 120 volt, 20 A load is 150 feet from the panel. What is the smallest copper conductor that keeps voltage drop at or below 3 %?
- 13046What is the allowable ampacity of 6 AWG THHN copper (90 °C column) with three current-carrying conductors in a raceway at an ambient temperature of 40 °C?
- 13047Six current-carrying 10 AWG THHN copper conductors share one raceway at 30 °C ambient. What is the adjusted ampacity from the 90 °C column?
- 13048Nine current-carrying 12 AWG THHN copper conductors are installed in one conduit at 30 °C ambient. What is the adjusted ampacity of each conductor based on the 90 °C column?
- 13049Eight current-carrying 12 AWG THHN copper conductors run through an area with a 45 °C ambient. What is the allowable ampacity using the 90 °C column?