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Busbar; Why is the current carrying capacity higher than bare copper bars after painting the surface ?

• 2023-11-23

Standard DIN43671-1975 provides the current carrying capacity of Painted and Bare Busbars.

For example, the specification of the copper bar is 100*10, the current carrying capacity of the painted copper bar is 1810A, and the current carrying capacity of the bare copper bar is 1490A, which is 17.6% lower than that of the painted copper bar.

   According to Newton's formula, for a specific specification of copper bus, when the resistance, surface heat dissipation area and temperature rise are unchanged, the current carrying capacity of the copper bar is proportional to the comprehensive heat dissipation coefficient, and the high coefficient is the high current carrying capacity. The emissivity of thermal radiation heat dissipation of painted copper bars is higher than that of bare copper bars, so the comprehensive heat dissipation coefficient is large, and the current carrying capacity is also higher than that of bare copper bars.

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