Cable Size Calculator
Calculate the correct cable cross-section for your lighting circuits based on voltage, current, and distance per IEC/UAE standards.
Parameters
Cable Comparison
| Cable (mm²) | Max Amp | V Drop | Drop % | Status |
|---|---|---|---|---|
| 0.5mm² | 3A | 4.50V | 18.8% | |
| 0.75mm² | 6A | 3.06V | 12.8% | |
| 1mm² | 10A | 2.26V | 9.4% | |
| 1.5mm² | 14A | 1.51V | 6.3% | |
| 2.5mm² | 20A | 0.93V | 3.9% | |
| 4mm² | 27A | 0.58V | 2.4% | |
| 6mm² | 34A | 0.39V | 1.6% | |
| 10mm² | 46A | 0.23V | 1.0% | |
| 16mm² | 62A | 0.14V | 0.6% | |
| 25mm² | 80A | 0.09V | 0.4% | |
| 35mm² | 99A | 0.07V | 0.3% | |
| 50mm² | 119A | 0.05V | 0.2% |
Frequently Asked Questions
How do I calculate cable size for LED lighting?
Determine the total current (load watts / voltage), the one-way cable distance, and your maximum acceptable voltage drop (typically 3-5%). Use the formula: Required CSA = (2 x length x current x resistivity) / (max voltage drop). Our calculator automates this for copper cables per IEC standards.
What is the maximum voltage drop for lighting circuits?
IEC and UAE regulations typically allow 3-5% total voltage drop from the distribution board to the furthest fixture. For low-voltage LED systems (12/24V), even 2V drop can cause visible dimming, so stricter limits of 2-3% are recommended.
Why is voltage drop important for LED installations?
LEDs are sensitive to voltage. A drop of just 5% on a 24V system (1.2V) can cause noticeable brightness differences between near and far fixtures. Proper cable sizing ensures uniform brightness, prevents flicker, and maintains driver efficiency.
What cable size for 24V LED strip?
For a 5m run of 14.4W/m LED strip at 24V: Current = 72W/24V = 3A. Using 2.5mm² cable gives a voltage drop of about 0.22V (0.9%) — well within limits. For longer runs (10m+), consider 4mm² or parallel feeding from both ends.