1. What is Voltage Drop?

Voltage drop is the reduction in voltage in an electrical circuit between the source and load. In UK electrical installations, it's important to calculate voltage drop to ensure proper operation of electrical equipment.

2. How Does the Calculator Work?

The calculator uses the UK voltage drop formula:

Where:

• \( V_{drop} \) — Voltage drop (V)
• \( I \) — Current (A)
• \( L \) — Length of cable (m)
• \( \rho \) — Resistivity of copper (1.68 × 10^-8 Ω·m)
• \( A \) — Cross-sectional area of conductor (m²)

Explanation: The formula accounts for the resistance in both the live and neutral conductors (hence the ×2 factor) in single-phase AC circuits.

3. Importance of Voltage Drop Calculation

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

4. Using the Calculator

Tips: Enter current in amperes, cable length in meters, and conductor cross-sectional area in square meters. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the maximum allowed voltage drop in UK installations?
A: For lighting circuits, 3% of supply voltage (6.9V for 230V). For other circuits, 5% (11.5V for 230V).

Q2: Why is copper resistivity used in the formula?
A: The calculator assumes copper conductors, which is standard in UK electrical installations.

Q3: Does this formula work for three-phase systems?
A: No, this is for single-phase systems. Three-phase calculations use a different formula.

Q4: How does temperature affect voltage drop?
A: Higher temperatures increase conductor resistance, which increases voltage drop. The calculator uses standard temperature values.

Q5: Where can I find cable cross-sectional areas?
A: Standard UK cable sizes are 1mm², 1.5mm², 2.5mm², 4mm², 6mm², 10mm², etc. Convert to m² (1mm² = 1×10^-6m²).