Calculate Cable Size Guide

If your 5A fridge runs through a hot attic (0.87) and is bundled with 4 other cables (0.80): ( 5 / (0.87 \times 0.80) = 5 / 0.696 = 7.2A )

Step 3: Apply the Voltage Drop Formula The basic DC / single-phase AC formula is: calculate cable size

| Condition | Derating Factor | | :--- | :--- | | Ambient 30-40°C (normal) | 1.00 | | Ambient 40-50°C (hot attic) | 0.87 | | 3-6 cables bundled | 0.80 | | 7-9 cables bundled | 0.70 | If your 5A fridge runs through a hot attic (0

Now calculate cable size for , not 5A. Quick Reference: Common Cable Sizes & Current Ratings (Copper, 30°C) Use this as a starting point only—always verify with local codes. Calculating the correct cable size is straightforward once

But don't worry. Calculating the correct cable size is straightforward once you understand the four key factors:

You need at least 7.3 mm² . The nearest standard size is 10 mm² (since 6 mm² would be too small). Step 4: Adjust for Temperature and Grouping The formula above assumes ideal conditions. If cables run through hot attics or are bundled together, use these derating factors (from NEC/CEC tables):