The maximum voltage to ground in a 277/480-volt, 3-phase, 4-wire system is ___.

The maximum voltage to ground in a 277/480-volt, 3-phase, 4-wire system is ___.

• A. 208 volts
• B. 240 volts
• C. 277 volts
• D. 120 volts

Answer: (C)

In a 277/480-volt, 3-phase, 4-wire system, the maximum voltage to ground is determined by the phase-to-ground voltage. This system uses a wye (or star) configuration where the line voltage (480 volts) is the voltage measured between any two of the three phases. The phase-to-ground voltage, which is the voltage measured from any one phase conductor to the neutral conductor, is found by dividing the line voltage by the square root of three (approximately 1.732). For this system, the calculation would be as follows: 1. The line-to-line voltage is 480 volts. 2. To find the line-to-neutral (or phase) voltage, use the formula: \[ V_{phase} = \frac{V_{line-to-line}}{\sqrt{3}} = \frac{480V}{1.732} \approx 277V. \] This calculated value of approximately 277 volts represents the maximum voltage to ground in this 277/480-volt system. Thus, selecting 277 volts as the answer accurately reflects the design and voltage relationships within a 3-phase wye-connected electrical system.

In a 277/480-volt, 3-phase, 4-wire system, the maximum voltage to ground is determined by the phase-to-ground voltage. This system uses a wye (or star) configuration where the line voltage (480 volts) is the voltage measured between any two of the three phases. The phase-to-ground voltage, which is the voltage measured from any one phase conductor to the neutral conductor, is found by dividing the line voltage by the square root of three (approximately 1.732).

For this system, the calculation would be as follows:

1. The line-to-line voltage is 480 volts.

2. To find the line-to-neutral (or phase) voltage, use the formula:

[

V_{phase} = \frac{V_{line-to-line}}{\sqrt{3}} = \frac{480V}{1.732} \approx 277V.

]

This calculated value of approximately 277 volts represents the maximum voltage to ground in this 277/480-volt system. Thus, selecting 277 volts as the answer accurately reflects the design and voltage relationships within a 3-phase wye-connected electrical system.