Calculate Cable Size [best] -

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):

A 2000W water heater on 230V. ( I = 2000 / 230 = 8.7 \text Amps ) Step 2: Determine the Round-Trip Cable Length Many forget this. If your device is 20 meters from the source, the actual electrical path is 40 meters (go and return). calculate cable size

But don't worry. Calculating the correct cable size is straightforward once you understand the four key factors: You need at least 7

Step 3: Apply the Voltage Drop Formula The basic DC / single-phase AC formula is: If cables run through hot attics or are

| 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 |