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We observe for each thickness the ampacity is best modelled using a power equation. We generate the following table of extrapolated points using the more conservative 1/8" model. We expect this to bound bus bars of smaller thickness (such as 1/32"). All areas are rounded up to the nearest tenth. Note that in the 60 A - 90 A region the area relationship is approximately linear, but this does not hold true for the entire dataset.

Recommendations

We recommend a hard lower bound on bus bar area of 17 sq. mm, corresponding to an ampacity of at around 70 A with a 30°C rise. This should give a moderate safety factor to ensure a temperature rise lower than 30°C at a 50 A load. Where practical from an engineering tradeoff standpoint, larger areas should be selected to provide further confidence and design margin during peak operating conditions.