Harmonic current emissions

What this standard covers and how we test it

EN 61000-3-2 limits the harmonic current an appliance draws from the mains so that many small loads together do not distort the supply. Which limit applies depends entirely on the classification: Class A for most equipment, Class B for portable tools, Class C for lighting and Class D for equipment with a special input current waveform below 600 W.

What is measured:

• Harmonic current up to the 40th order in steady state
• Transient harmonics and the observation period for fluctuating loads
• Class determination, including the Class D power threshold
• Test supply impedance and the reference impedance network used

Class D is where projects get surprised: a 300 W product with a switching supply can land in Class D purely because of its current waveform, and then fail limits that Class A would have met easily. We check the waveform shape first, before booking the full run.

We normally test EN 61000-3-2 together with EU 2014/30/EU (EMC): one sample set, one set of test dates, and a single report pack that the declaration of conformity can reference.