Electrical – At what load is the leakage current quantified for a power supply

leakage-currentpower supply

In this document it says "According to IEC 60601-1, the leakage current limits are provided in Table 1."

If the leakage current is due to Y capacitor, the load R and the the parasitic capacitance of the PSU transformer will form an RC divider.

But then the leakage current depends on the load. If the load is big the stray voltage will be big and the leakage current will be small. If the load is small(low impedance setting), then the voltage will be small but the current will be higher comparing to high load impedance.

For which load the leakage current is measured and presented in datasheets?

Best Answer

The leakage currents referred to are those that flow from either of the DC output terminals to earth. The load between the two DC output wires is irrelevant.

See my answer here for details about an SMPS's transformer's inter-winding leakage capacitance and how this manifests itself in unwanted output noise AND how the output noise is removed by a Y capacitor BUT this then produces a common-mode AC power voltage (of low energy) on both output terminals.