Question 13045 of 749 · Maryland Journeyperson Electrician Exam
A 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 %?
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 13045
- A: 6 AWG
Explanation
Allowed drop is 3.6 V, so CM = 2 x 12.9 x 20 x 150 / 3.6 = 21,500 circular mils. 8 AWG has only 16,510 circular mils, so 6 AWG (26,240) is the minimum; 12 AWG would be sized for ampacity alone.
More questions: Electrical Calculations
- 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?
- 13050What is the ampacity of 4 AWG THWN copper (75 °C insulation) with three current-carrying conductors at an ambient of 45 °C?
- 13051Four current-carrying 3/0 AWG THWN-2 copper conductors are installed in a raceway where the ambient is 50 °C. What is the derated ampacity from the 90 °C column?