Voltage Drop Cable Formula Calculator

Voltage Drop Formula:

\[ \text{Voltage Drop} = 2 \times I \times L \times R / 1000 \quad \text{(single phase)} \]

Voltage Drop (V):

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1. What is Voltage Drop?

Voltage drop refers to the reduction in voltage in an electrical circuit between the source and load. It occurs due to the resistance of conductors and can affect the performance of electrical equipment.

2. How Does the Calculator Work?

The calculator uses the voltage drop formula for single-phase circuits:

\[ \text{Voltage Drop} = 2 \times I \times L \times R / 1000 \]

Where:

\( I \) — Current in amperes (A)
\( L \) — Length of conductor in feet (ft)
\( R \) — Resistance in ohms per 1000 feet (ohms/1000ft)

Explanation: The factor of 2 accounts for the round trip of current in a single-phase circuit. The division by 1000 converts the resistance from ohms per 1000 feet to ohms per foot.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation ensures electrical equipment operates efficiently and safely. Excessive voltage drop can lead to equipment malfunction, reduced performance, and potential safety hazards.

4. Using the Calculator

Tips: Enter current in amperes, length in feet, and resistance in ohms per 1000 feet. All values must be positive numbers. Use standard resistance values based on wire gauge and material.

5. Frequently Asked Questions (FAQ)

Q1: What is an acceptable voltage drop?
A: Generally, voltage drop should not exceed 3% for branch circuits and 5% for feeder and branch circuits combined, as per electrical codes.

Q2: How does wire size affect voltage drop?
A: Larger wire sizes have lower resistance, resulting in less voltage drop for the same current and distance.

Q3: Is this formula different for three-phase systems?
A: Yes, for three-phase systems, the formula is: Voltage Drop = √3 × I × L × R / 1000

Q4: What factors influence conductor resistance?
A: Resistance depends on wire material (copper/aluminum), cross-sectional area, temperature, and frequency (for AC circuits).

Q5: When is voltage drop calculation critical?
A: Critical for long cable runs, high current applications, sensitive electronic equipment, and when designing electrical installations to meet code requirements.