Calculate Cable Size [exclusive] · No Login

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).

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):

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

[ \textMin. Cross Section (mm²) = \frac2 \times \rho \times I \times LV_d ]

Let’s break it down. Electricity flowing through a cable generates heat. The smaller the cable, the more resistance and heat it produces. The goal is to choose a cable large enough to carry the required current without exceeding its temperature rating. A 2000W water heater on 230V

Choosing the wrong cable size isn't just an inconvenience—it’s a fire hazard. Undersized cables overheat, melt insulation, and can cause voltage drops that damage your equipment.

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. You need at least 7

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 )