LED Cable Voltage Drop Calculator | 12V & 24V Guide

✅ Good (Under 3% drop)

• Bright, even lighting
• Correct colours
• Long LED lifespan
• No flickering

❌ Bad (Over 3% drop)

• Dim LEDs at far end
• Wrong colours (especially white)
• Overheating & failures
• Flickering issues

1. Mains Socket (240V AC)

↓

2. LED Driver / Power Supply

(Converts 240V AC → 12V or 24V DC)

↓

⚠️ CABLE RUN #1: Driver to Controller (or direct to LEDs if no controller)

3. Controller (Optional - for RGB/dimming)

(Controls brightness, colour, effects)

↓

⚠️ CABLE RUN #2: Controller to LEDs

4. Your LEDs

(LED strip, modules, neon flex, fairground lights)

⚠️ CABLE RUN #3 (if needed): Connecting multiple LED sections together

📍 WHERE IT GOES:

• Letter-to-letter: Connecting individual channel letters in signs (the clear wire is nearly invisible)
• Module-to-module: Linking 2-3 small LED module clusters together
• Very short strip connections: Emergency repairs or tiny sections only

⚠️ NOT FOR:

• ❌ Driver to controller (too thin for long runs!)
• ❌ Any run over 3 metres at 12V
• ❌ High-power installations (over 30W)

⭐ WHAT MAKES IT SPECIAL: This is our HIGHER-RATED clear cable with specialty double insulation. It handles more power than standard 0.2mm clear cable while staying nearly invisible. Perfect upgrade when 0.2mm isn't enough but you still need the clear look!

📍 WHERE IT GOES:

• Letter signs (visible wiring): When letters are spread further apart or drawing more power
• LED strip extensions: Connecting strip sections where cable visibility matters
• Short controller runs: When controller is close to LEDs but cable must be visible/clear
• Module chains: Linking higher-power modules (up to 6.5A total)

✅ ADVANTAGES OVER 0.2mm:

• ✅ More than DOUBLE the amperage rating (6.5A vs 3A)
• ✅ 19-strand tinned copper construction (better flexibility)
• ✅ Specialty double-insulated PVC coating
• ✅ Still maintains the "invisible" clear appearance
• ✅ Can handle longer runs with same voltage drop

💡 WHEN TO CHOOSE THIS: Use this instead of 0.2mm when you need clear/visible cable BUT have higher power (30-75W) or longer distances (3-8m). It's the sweet spot between invisible aesthetics and proper power handling!

⭐ KEY DIFFERENCE: This is standard double-insulated BLACK flat cable with HIGHER amperage (11A) - designed for hidden installations where you DON'T need clear cable. Use this for main power runs behind walls, in conduit, or anywhere aesthetics don't matter.

📍 WHERE IT GOES:

• Driver → Controller: Your main power feed cable for medium-distance runs (MOST COMMON USE)
• Controller → LEDs: Powering your LED strips or modules from the controller
• Direct connections: Driver straight to LEDs when no controller needed
• Behind-wall runs: Any hidden cable routing where you need good power capacity

✅ PERFECT FOR: Most standard commercial installations under 130W and 5-8 metre cable runs where cable will be HIDDEN.

📍 WHERE IT GOES:

• Long driver runs: When your driver is 10+ metres from your LEDs/controller
• High-power installations: Over 100W loads requiring thick cable
• Fairground lighting: Our standard for all festoon light strings
• Public spaces: The LSZH (Low Smoke) rating is required for events/venues

✅ SAFETY BONUS: LSZH means in case of fire, this cable produces minimal smoke and no toxic gases—essential for public events and enclosed spaces!

1️⃣ Is your cable visible or hidden?

Visible/Clear needed:

→ Very short (under 2m), low power → 0.2mm clear

→ Longer (2-8m) or medium power → 0.5mm Clear Twin (6.5A)

Hidden:

→ Standard runs (3-8m) → 0.5mm Flat Black (11A)

→ Long/high-power → 1.5mm LSZH

2️⃣ How much power (watts)?

Under 30W → 0.2mm clear (if visible) or 0.5mm flat (if hidden)

30-75W → 0.5mm Clear Twin (visible) or 0.5mm Flat (hidden)

75-130W → 0.5mm Flat Black (11A) mandatory

Over 130W → Always use 1.5mm LSZH

3️⃣ Which voltage?

12V → Need thicker cable OR shorter runs

24V → Can use thinner cable OR longer runs (recommended!)

✅ Solution 1: Upgrade Cable

Replace with the next thickness up. This is the most reliable fix.

→ Browse All Cables

✅ Solution 2: Relocate Driver

Move your power supply or controller closer to the LEDs to shorten the cable run.

✅ Solution 3: Upgrade to 24V

Swap your 12V LEDs and driver for 24V versions. This instantly halves your voltage drop!

→ Shop 24V Drivers

✅ Solution 4: Power Injection

Feed power from both ends of long LED strip runs instead of just one end.

❌ Confusing the Two 0.5mm Cables

We have TWO different 0.5mm cables with very different ratings! The Clear Twin (6.5A) is for visible connections. The Flat Black (11A) is for hidden high-power runs. Using the clear cable for a hidden driver run wastes its aesthetic benefit, and using the flat cable for visible letter connections looks terrible!

✅ Fix: Clear cable when aesthetics matter, flat black cable for hidden power runs.

❌ Using 0.2mm for Driver-to-Controller Runs

This is the #1 mistake we see! 0.2mm cable is ONLY for very short LED-to-LED connections under 3 metres. Never use it for your main power feeds.

✅ Fix: Use 0.5mm Clear Twin (6.5A), 0.5mm Flat Black (11A), or 1.5mm for all driver and controller connections.

❌ Choosing 12V When 24V Would Work

12V systems draw double the current of 24V for the same power, meaning you need thicker cables or shorter runs. Always choose 24V when possible!

✅ Fix: Specify 24V LEDs and 24V drivers for all new projects.

❌ Not Measuring Actual Cable Runs

Cable has to go around corners, through conduit, and along walls—not in a straight line! Your actual cable length is always longer than you think.

✅ Fix: Always add 20% to your measured length for cable routing.