Spannungsfall je 20 m Leitungslänge
Kupfer, Leitungslänge 20 m, Bezugsstrom 10 A je mm² Querschnitt (höchstens 100 A). Die Werte zeigen, warum lange Leitungen einen größeren Querschnitt brauchen.
| Querschnitt | 230 V (einphasig) | 400 V (Drehstrom) |
|---|---|---|
| 1.5 mm² | 3.11 % | 1.55 % |
| 2.5 mm² | 3.11 % | 1.55 % |
| 4.0 mm² | 3.11 % | 1.55 % |
| 6.0 mm² | 3.11 % | 1.55 % |
| 10.0 mm² | 3.11 % | 1.55 % |
| 16.0 mm² | 1.94 % | 0.97 % |
| 25.0 mm² | 1.24 % | 0.62 % |
| 35.0 mm² | 0.89 % | 0.44 % |
| 50.0 mm² | 0.62 % | 0.31 % |
Ihre eigenen Werte setzt der Spannungsfall-Rechner ein.
Worked Example and Common Errors
To understand how this table functions, consider a practical scenario involving a 3 kW electric heater connected to a 230 V single-phase supply. The circuit uses 2.5 mm² copper cable with a length of 20 metres. According to the table, the voltage drop for this specific configuration is 6.4%. To calculate the actual voltage loss at the appliance, multiply the supply voltage by the percentage value: 230 V multiplied by 0.064 equals 14.72 V. This means the voltage arriving at the heater is approximately 215.28 V. While this might seem acceptable for resistive heating elements, it highlights why monitoring these values is critical for sensitive electronics or motors that require stable power to operate correctly without overheating or failing to start.
The most frequent mistake users make is ignoring the difference between single-phase and three-phase systems. The table provides distinct values for 230 V single-phase and 400 V three-phase circuits because the current flow and resulting voltage drop differ significantly even if the power load appears similar. Using the single-phase column for a three-phase installation will yield an incorrect result, potentially leading to undersized cables or unexpected performance issues. Always verify your system type before selecting a row from the table. Another common error involves assuming the table applies to any distance. These figures are strictly calculated for a cable run of exactly 20 metres. If your installation requires a longer run, you must scale the percentage linearly. For instance, a 40-metre run would double the voltage drop percentage shown in the table, while a 10-metre run would halve it. Failing to adjust for length can lead to significant inaccuracies in your electrical planning.
- Always confirm whether your circuit is single-phase or three-phase before reading the table.
- Adjust the percentage proportionally if your cable length differs from the standard 20 metres.
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