Electrical Level 4 Module 1 Exam Questions
And Answers
Name one reason the current-carrying conductor size would be
adjusted. -
correct answer ✅There are more than three current-carrying
conductors in a raceway per NEC Section 310.15(B)(3)
Voltage drop rule of thumb (A) -
correct answer ✅VD for feeders should not exceed 3% to the
farthest outlet and 5% for the combo of feeders and branch circuits
to the farthest outlet.
Voltage Drop rule of thumb (B) -
correct answer ✅When combined, the max VD allowed for the
branch circuit is usually 3%, then VD allowed for feeder can be no
more than 2%.
What are the formulas to calculate VD for single-phase circuits with
resistive loads? -
correct answer ✅VD = 2xLxRxI/1,000 and VD = 2xLxKxI/CM
CM -
correct answer ✅Area of the conductor in circular mils
, Electrical Level 4 Module 1 Exam Questions
And Answers
Continuous duty load -
correct answer ✅A load that operates without interruption for
more than 3 hours straight
What is the adjusted ampacity for each of six No. 4/0 THHN copper
current-carrying conductors in a single conduit? -
correct answer ✅See NEC Table 310.15(B)(16) for ampacity and
NEC Table 310.15(B)(3)(a) for adjusted ampacity by 80%
1.732 -
correct answer ✅The square root of 3
VD = square root 3xLxRxI/1,000 -
correct answer ✅Formula for VD of a three-phase feeder with a
noncontinuous load
I= VA/V x square root of 3 or I = VA/V x 1.732 -
correct answer ✅Formula for balanced three-phase circuit feeder
ampacity
And Answers
Name one reason the current-carrying conductor size would be
adjusted. -
correct answer ✅There are more than three current-carrying
conductors in a raceway per NEC Section 310.15(B)(3)
Voltage drop rule of thumb (A) -
correct answer ✅VD for feeders should not exceed 3% to the
farthest outlet and 5% for the combo of feeders and branch circuits
to the farthest outlet.
Voltage Drop rule of thumb (B) -
correct answer ✅When combined, the max VD allowed for the
branch circuit is usually 3%, then VD allowed for feeder can be no
more than 2%.
What are the formulas to calculate VD for single-phase circuits with
resistive loads? -
correct answer ✅VD = 2xLxRxI/1,000 and VD = 2xLxKxI/CM
CM -
correct answer ✅Area of the conductor in circular mils
, Electrical Level 4 Module 1 Exam Questions
And Answers
Continuous duty load -
correct answer ✅A load that operates without interruption for
more than 3 hours straight
What is the adjusted ampacity for each of six No. 4/0 THHN copper
current-carrying conductors in a single conduit? -
correct answer ✅See NEC Table 310.15(B)(16) for ampacity and
NEC Table 310.15(B)(3)(a) for adjusted ampacity by 80%
1.732 -
correct answer ✅The square root of 3
VD = square root 3xLxRxI/1,000 -
correct answer ✅Formula for VD of a three-phase feeder with a
noncontinuous load
I= VA/V x square root of 3 or I = VA/V x 1.732 -
correct answer ✅Formula for balanced three-phase circuit feeder
ampacity
