Wire Gauge Chart

Querschnitt und Belastbarkeit nach AWG

AWG (American Wire Gauge) ist die in den USA übliche Bezeichnung für Leiterdurchmesser. Die Belastbarkeit gilt für Kupfer bei 60 °C Umgebungstemperatur.

Berechnen Sie den nötigen Querschnitt aus Länge, Strom und zulässigem Spannungsfall mit dem Kabelquerschnitt-Rechner.

Worked Example and Common Errors

To understand how the AWG wire gauge chart functions in practice, consider a standard residential circuit scenario. You are installing a 15-ampere branch circuit for lighting and outlets, and you must select the appropriate copper conductor size based on the 60 °C column of the chart. The chart indicates that 14 AWG copper wire has an ampacity of 15 amperes at this temperature rating. This means 14 AWG is the minimum acceptable size for this specific load. If you were to upgrade to a 20-ampere circuit breaker, the chart shows that 14 AWG is no longer sufficient because its maximum current-carrying capacity is exceeded. In this case, you must move to the next larger gauge, which is 12 AWG. The 12 AWG copper conductor is rated for 20 amperes at 60 °C, making it the correct choice for protecting the wiring from overheating under full load conditions. This selection process ensures that the insulation surrounding the copper does not degrade due to excessive heat generated by electrical resistance.

The two most frequent mistakes made when using this chart involve confusing gauge numbers with physical dimensions and ignoring temperature ratings. First, many users incorrectly assume that a higher AWG number corresponds to a thicker wire. In reality, the American Wire Gauge system is inverse; as the number increases, the diameter decreases. For example, 18 AWG is significantly thinner than 10 AWG. A common error is selecting 18 AWG for a high-current application because the user mistakenly believes the higher number indicates greater capacity. This leads to severe undersizing, where the thin wire cannot handle the current, resulting in dangerous voltage drops or fire hazards. Always verify that the selected gauge number is lower (or equal) to the required capacity, meaning the physical wire is thicker.

The second critical error is applying the wrong temperature column. The chart provides distinct ampacity values for different insulation types, typically categorized by their maximum operating temperatures, such as 60 °C, 75 °C, and 90 °C. Users often default to the highest available rating without checking the actual insulation type of the wire they purchased. Using the 90 °C column for a wire rated only for 60 °C creates a false sense of security. Even if the wire can technically withstand higher temperatures internally, the connected terminals and devices may be limited to 60 °C. Therefore, the entire circuit must be evaluated based on the lowest temperature rating of any component in the chain. Ignoring this constraint can lead to improper sizing and potential code violations, regardless of what the raw chart data suggests for higher-rated insulations.

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