1. What is Voltage Drop?

Voltage drop is the reduction in voltage in an electrical circuit between the source and load. It occurs due to the resistance in conductors (wires/cables) and can affect equipment performance.

2. How Does the Calculator Work?

The calculator uses the voltage drop equation:

Where:

• \( Drop \) — Voltage drop in volts
• \( L \) — Length of cable in feet
• \( I \) — Current in amperes
• \( R \) — Resistance per 1000 feet in ohms

Explanation: The equation calculates the voltage lost due to the resistance of the cable over its length when carrying current. The factor of 2 accounts for the round-trip path (both hot and neutral wires).

3. Importance of Voltage Drop Calculation

Details: Excessive voltage drop can cause equipment to malfunction, reduce efficiency, and potentially damage electrical devices. National Electrical Code recommends limiting voltage drop to 3% for branch circuits and 5% for feeders.

4. Using the Calculator

Tips: Enter cable length in feet, current in amps, and cable resistance in ohms per 1000 feet. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is voltage drop important?
A: Excessive voltage drop can lead to equipment malfunction, reduced efficiency, and potential safety hazards.

Q2: What's an acceptable voltage drop?
A: Generally, less than 3% for branch circuits and 5% for feeder circuits is recommended by the NEC.

Q3: How can I reduce voltage drop?
A: Use shorter cable runs, larger wire gauge (lower resistance), or reduce the current load.

Q4: Does this calculator work for DC circuits?
A: Yes, the same formula applies to DC circuits. For AC circuits, additional factors like power factor may need consideration.

Q5: Where can I find resistance values for cables?
A: Cable manufacturers provide resistance per 1000 feet values in their specifications. NEC tables also list common values.