Calculate maximum cable length

Electricity
100 calculations
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📝 How it works:
Calculate the maximum cable length for a given voltage drop. For safe electrical installations.

Fill in the fields below and click "Calculate".

Maximum cable length with specified voltage drop

In electrical installations, the cable length must be dimensioned so that the permissible voltage drop is not exceeded. Our calculator provides support for:

  • Cable planning: Determine the maximum distance to the consumer
  • Cable cross-section optimization: Economy vs. safety
  • PV systems: Correctly dimensioning DC cables
  • Outdoor lighting: Long cable runs to garden lights
  • Campsite connections: CEE sockets with sufficient voltage

Factors influencing the maximum cable length:

  • Cable cross-section (1.5 mm², 2.5 mm², 4 mm², etc.)
  • Current rating (consumer load in amperes)
  • Allowable voltage drop (usually 3% or 5%)
  • Conductor material (copper: 0.0178 Ω-mm²/m, aluminum: 0.0278)
  • Operating temperature (resistance increases with temperature)

Example calculation: 230V, 16A load, 2.5 mm² copper cable, 3% voltage drop permitted (6.9V). Maximum cable length: approx. 30 meters. For greater distances, a thicker cross-section must be selected. Two-core cable (phase + neutral) means double the cable length in the calculation.

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