1. What is a Voltage Drop Calculator (NZ)?

Definition: This calculator estimates the voltage drop in electrical circuits according to New Zealand standards.

Purpose: It helps electricians and engineers ensure proper voltage levels throughout electrical installations.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( VD \) — Voltage drop (volts)
• \( \rho \) — Resistivity of conductor material (ohm-m)
• \( L \) — Length of cable (meters)
• \( I \) — Current flowing through cable (amps)
• \( A \) — Cross-sectional area of conductor (m²)

Explanation: The formula calculates voltage drop for both the active and return paths (hence the factor of 2).

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop calculation ensures electrical appliances receive adequate voltage and comply with NZ electrical regulations (typically <5% drop).

4. Using the Calculator

Tips:

• Default resistivity (1.72×10⁻⁸ ohm-m) is for copper at 20°C
• For aluminum conductors, use 2.82×10⁻⁸ ohm-m
• Enter cable length as one-way distance (calculator accounts for return path)
• All values must be > 0

5. Frequently Asked Questions (FAQ)

Q1: Why is voltage drop important?
A: Excessive voltage drop can cause equipment malfunction, reduced efficiency, and potential safety hazards.

Q2: What's the maximum allowed voltage drop in NZ?
A: NZ Electrical Code recommends ≤5% voltage drop for most circuits (≤3% for lighting).

Q3: How does temperature affect the calculation?
A: Higher temperatures increase resistivity. For precise calculations at different temperatures, adjust ρ accordingly.

Q4: What's the difference between single-phase and three-phase voltage drop?
A: This calculator handles single-phase. Three-phase calculations use a different formula (√3 instead of 2).

Q5: How do I convert mm² to m² for conductor area?
A: Divide mm² by 1,000,000 (e.g., 2.5mm² = 2.5×10⁻⁶ m²).