In a simplified single-phase resistive voltage-drop model, assume unity power factor and negligible reactance. A design permits 7.56 volts of drop at 42 amperes. What maximum total outgoing-and-return conductor resistance satisfies that limit?

Texas Journeyman exam practice question · Feeder Calculations

In a simplified single-phase resistive voltage-drop model, assume unity power factor and negligible reactance. A design permits 7.56 volts of drop at 42 amperes. What maximum total outgoing-and-return conductor resistance satisfies that limit?

0.18 ohm
B0.12 ohm
C0.32 ohm
D5.56 ohms

Where to look it up

Explicit exercise assumptions; not a universal code requirement.

Why A is correct

For this specified model, R = voltage drop / current = 7.56 / 42 = 0.18 ohm. This is the total loop resistance, so do not apply a second length factor. The 7.56-volt limit is supplied by the problem, not established here as a code limit.

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In a simplified single-phase resistive voltage-drop model, assume unity power factor and negligible reactance. A design permits 7.56 volts of drop at 42 amperes. What maximum total outgoing-and-return conductor resistance satisfies that limit?

In a simplified single-phase resistive voltage-drop model, assume unity power factor and negligible reactance. A design permits 7.56 volts of drop at 42 amperes. What maximum total outgoing-and-return conductor resistance satisfies that limit?

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