What is the approximate line-to-ground arcing fault value on a 480/277-volt system where the line-line-line fault current has been calculated to be 30,000 amperes?
A)11,400
B)22,200
C)26,700
D)30,000

Question

Quizplus · Accepted Answer

The line-to-ground arcing fault value on a 480/277-volt system can be approximated by taking the line-line-line fault current and multiplying it by the square root of 3 (approximately 1.732). However, this calculation is typically used to go from line-to-ground to line-to-line fault current. For a line-to-ground fault, the current tends to be lower due to the higher impedance path. Given the options and the nature of the question, which seems to imply a reduction from the line-line-line fault current, the closest approximation without performing the exact calculation (which would typically result in a lower value than the line-line-line fault current due to system impedances) is 11,400 amperes, acknowledging that this is a simplification and actual calculations would depend on specific system impedances and configurations.

What Is the Approximate Line-To-Ground Arcing Fault Value on a 480/277-Volt