1. What is Voltage Drop?

Voltage drop is the reduction in voltage in an electrical circuit between the source and load. It's important to calculate to ensure proper operation of electrical equipment according to UK government regulations.

2. How Does the Calculator Work?

The calculator uses the voltage drop formula:

Where:

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

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

3. Importance of Voltage Drop Calculation

Details: Calculating voltage drop is crucial for compliance with UK wiring regulations (BS 7671) and ensuring electrical equipment operates within specified voltage tolerances.

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 the UK?
A: For lighting circuits, 3% of supply voltage; for other uses, 5% of supply voltage (as per BS 7671).

Q2: Where can I find mV/A/m values for cables?
A: These are typically provided in cable manufacturer datasheets or the IET Wiring Regulations (BS 7671).

Q3: Does voltage drop affect energy efficiency?
A: Yes, voltage drop represents power lost in the cables, which reduces energy efficiency.

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

Q5: Is this calculator suitable for DC circuits?
A: The same principle applies, but DC calculations may use different parameters depending on the application.