---
title: "DC Cable Voltage Drop Calculator: CCTV, Gate and Fence Cable Size | Qyvea"
url: https://qyvea.co.ke/dc-cable-voltage-drop-calculator-kenya
description: "Free voltage drop calculator for 12 V and 24 V cables: enter current, length and cable size to see the volt drop and the minimum cable size for CCTV, gate motors and alarms."
updated: 2026-10-17
---

> Markdown copy of https://qyvea.co.ke/dc-cable-voltage-drop-calculator-kenya for AI assistants. Prices and stock change; check the live page.

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Free tool · Calculator

# DC Cable Voltage Drop Calculator

Check that your cable is thick enough so cameras, locks and gate motors get the voltage they need.

Supply voltage (V)

Current (amps)

One-way cable length (metres)

Cable size (mm2 per conductor)

Enter your numbers above.

## How it is calculated

Voltage drop = 2 x length x current x 0.0175 / cross-section (mm2) for copper, where 0.0175 is copper resistivity in ohm mm2 per metre and the factor 2 counts the go and return conductors. Keep drop under 5% (3% for sensitive loads). Use pure copper cable, not copper-clad aluminium.

Results are estimates for planning. Real systems depend on site conditions; Qyvea surveys and quotes before installation.

## Tips from our installers

- Low-voltage runs lose far more than mains runs: doubling the length doubles the drop.
- For long runs, power the device locally or use a higher voltage.
- Gate motors and locks draw peak current when they start: size for the peak.

## Frequently asked questions

What drop is acceptable?

About 5% or less is a common guideline for low-voltage loads.

Why do cheap cables fail?

Many are copper-clad aluminium, which has higher resistance than the label suggests.

Does this apply to AC mains?

The same formula applies with different limits; use proper electrical design for mains.

## Related

- [Electrical supplies in the store](https://qyvea.co.ke/products?cat=electrical)
- [Electrical installation](https://qyvea.co.ke/electrical-installation)
- [Automatic gates](https://qyvea.co.ke/automatic-gates)
- [All Qyvea calculators](https://qyvea.co.ke/calculators-kenya)

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---
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