Cable Sizing Calculator

Calculate the correct cable size for your electrical installation

Per SS 436 40 00 / IEC 60364-5-52

Load power in watts

One-way distance, not round trip

Electrical Parameters

1.0 for resistive loads, ~0.85 for motors

Cable Selection

Installation Method

Select how the cable will be installed per SS 436 40 00

Correction Factors

Reference: 25°C for cables in air

Number of cables in same conduit/tray

Typically 3% for lighting, 5% for other loads

About Cable Sizing

Cable sizing is crucial for safe electrical installations. The correct cable cross-section ensures the cable can handle the current without overheating, while keeping voltage drop within acceptable limits.

Installation Methods

  • A1/A2Cables in conduit in insulated wall - worst cooling, lowest capacity
  • B1/B2Cables in conduit on wall or in cavities - better cooling
  • CCables directly on wall - most common, good cooling
  • DCables in ground - constant temperature, special considerations
  • E/F/GCables in free air - best cooling, highest capacity

Correction Factors

Cable current capacity is affected by ambient temperature and grouping with other cables. At higher temperatures or when cables are grouped together, the allowed current must be reduced.

Voltage Drop

Voltage drop should typically not exceed 3% for lighting and 5% for other loads. For long cable runs, voltage drop may become the sizing factor instead of current capacity.

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