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 and can affect equipment performance.

2. How Does the Calculator Work?

The calculator uses the voltage drop equation:

Where:

• \( V_{drop} \) — Voltage drop (Volts)
• \( I \) — Current (Amps)
• \( L \) — One-way length of wire (Feet)
• \( CM \) — Circular mils of conductor
• \( K \) — Resistivity constant (12.9 for copper, 21.2 for aluminum)

Explanation: The equation calculates voltage drop based on current, wire length, wire size (in circular mils), and material resistivity.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation ensures electrical devices receive adequate voltage to operate correctly and helps prevent energy waste and overheating.

4. Using the Calculator

Tips: Enter current in amps, length in feet, wire size in circular mils, and select conductor material. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is an acceptable voltage drop?
A: Generally, less than 3% for branch circuits and 5% for feeder and branch circuits combined is recommended.

Q2: How do I find the circular mils for my wire?
A: Refer to wire gauge tables - common values: 14 AWG = 4110 CM, 12 AWG = 6530 CM, 10 AWG = 10380 CM.

Q3: Why multiply length by 2 in the equation?
A: The factor of 2 accounts for the round-trip path of current (out to load and back to source).

Q4: Does this work for both AC and DC circuits?
A: Yes, for simple DC circuits and single-phase AC circuits with unity power factor.

Q5: When should I be concerned about voltage drop?
A: For long wire runs, high current applications, or sensitive equipment where voltage fluctuations could cause problems.