1. What is Voltage Drop?

Voltage drop is the reduction in voltage in an electrical circuit between the source and load. In South Africa, proper voltage drop calculation is essential for electrical installations to comply with SANS 10142-1 wiring regulations.

2. How Does the Calculator Work?

The calculator uses the voltage drop formula:

Where:

• \( mV/A/m \) — Millivolts per ampere per meter (cable characteristic)
• \( I \) — Current in amperes
• \( L \) — Length of cable in meters

Explanation: The formula calculates the voltage drop based on cable properties, current flow, and cable length.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation ensures electrical devices receive adequate voltage to operate correctly and prevents excessive power loss in cables.

4. Using the Calculator

Tips: Enter the mV/A/m value from cable specifications, the expected current in amps, and the cable length in meters. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the maximum allowed voltage drop in South Africa?
A: According to SANS 10142-1, the maximum voltage drop from origin to any point in the installation should not exceed 5% for lighting circuits and 3% for other circuits.

Q2: Where can I find mV/A/m values?
A: These values are typically provided in cable manufacturer specifications or electrical standards tables.

Q3: Does voltage drop affect energy efficiency?
A: Yes, excessive voltage drop results in power loss as heat in the cables, reducing energy efficiency.

Q4: How does cable size affect voltage drop?
A: Larger cable sizes have lower mV/A/m values, resulting in less voltage drop for the same current and distance.

Q5: Should I consider ambient temperature?
A: Yes, cable resistance (and thus voltage drop) changes with temperature. The calculator provides a baseline value at standard temperature.