IEC/EN 61204-3 EMC Testing for DC Output Power Supplies & SMPS

IEC/EN 61204-3 DC Power Supply EMC Testing

Compatible Electronics provides comprehensive IEC/EN 61204-3 EMC testing for low-voltage DC output power supply units. NVLAP accredited for IEC/EN 61204-3 (2001) at Brea and Newbury Park — covering SMPS, linear regulated supplies, DC-DC converters, and DIN-rail industrial power supplies.

NVLAP AccreditedILAC MRA RecognizedBrea & Newbury ParkEmissions + Immunity

What is IEC/EN 61204-3?

IEC 61204-3 specifies EMC requirements for low-voltage power supply units with DC output — devices that convert AC mains or battery voltage to regulated low-voltage DC. Part 3 of the IEC 61204 series covers both emissions and immunity for standalone DC power supplies used in measurement, control, laboratory, and industrial applications.

EN 61204-3 is the European adoption and is harmonized under the EMC Directive 2014/30/EU. Many modern DC power supplies may also comply via generic standards (EN 61000-6-3/6-4) or EN 55032 — also accredited at Compatible Electronics — and we can advise on the most appropriate standard for your product.

Accredited Standards

Primary Standard

IEC/EN 61204-3 (2001)

Accredited at Brea and Newbury Park
Emissions and immunity for low-voltage DC output PSUs
AC-DC and DC-DC converter power supplies covered

Related Standards

EN 55032, EN 61000-6-3/6-4

EN 55032 (2015)+A11(2020) — all three locations (for ITE power supplies)
EN 61000-6-3 and EN 61000-6-4 generic emissions — all three locations
IEC 61000-3-2 / IEC 61000-3-3 — power quality at all three locations

Products Covered

Industrial & Commercial

Industrial Power Supplies

SMPS — DIN-rail and panel mount configurations
Linear regulated bench power supplies
DC-DC converters (isolated and non-isolated)
DIN-rail 24 VDC industrial automation power supplies
Control system and PLC power supplies

Specialized

Specialized DC Sources

Industrial battery chargers
Redundant power supply modules
DC output UPS systems
PoE injectors and midspans
Medical-grade power supplies (combined with IEC 60601)

EMC Testing

Emissions

Conducted & Radiated

Radiated: 30 MHz – 1 GHz; Class A or Class B limits
AC input conducted: 150 kHz – 30 MHz via LISN
DC output conducted emissions where applicable
IEC 61000-3-2 harmonic current (Class A or D for most SMPS)
IEC 61000-3-3 voltage flicker for supplies ≤16 A

Immunity

IEC 61000-4 Series

IEC 61000-4-2 ESD — contact and air discharge
IEC 61000-4-3 Radiated RF — 3 V/m or 10 V/m
IEC 61000-4-4 EFT/Burst — AC input and DC output ports
IEC 61000-4-5 Surge — ±1 kV or ±2 kV on AC input
IEC 61000-4-6 Conducted RF — mains and DC output
IEC 61000-4-11 Voltage dips on AC input

Performance

DC Output Stability Criteria

Output voltage within regulation tolerance during tests
Ripple and noise within spec during test stimulus
No damage to PSU or connected load equipment
Recovery time after EFT/Burst and surge within specification
Criterion A (normal operation) for industrial applications

Real-World Testing Examples

24 VDC DIN-Rail Industrial PSU — IEC/EN 61204-3 + CE Marking

An industrial power supply manufacturer needed CE marking for a 240W 10A DIN-rail 24 VDC SMPS for PLC and automation system installations. Compatible Electronics performed IEC/EN 61204-3 (2001) testing at Brea — conducted emissions on the AC mains (switching frequency at 130 kHz and harmonics clearly visible), radiated emissions to 1 GHz, and the full immunity suite. EFT/Burst at ±2 kV on AC input and ±1 kV on DC output, conducted RF at 10 Vrms (industrial environment) were the most demanding tests. DC output voltage deviation remained within ±1% regulation spec throughout. EN 61000-3-2 Class A harmonic current measurements completed the CE marking power quality package.

48V PoE Midspan — EN 61204-3 + EN 55032 + FCC Part 15

A network infrastructure manufacturer needed CE marking and FCC compliance for a 480W 30-port PoE midspan injector for IP cameras and VoIP phones in commercial buildings. The product was assessed under both IEC/EN 61204-3 (as a DC output power supply) and EN 55032 (as an ITE product with Ethernet interfaces). Compatible Electronics performed combined emissions at Newbury Park — EN 61204-3 on AC input and DC output ports, EN 55032 Class B from Ethernet ports, and FCC Part 15B via ANSI C63.4. All 30 ports were loaded during measurement. CE marking and FCC compliance were delivered from one session.

Medical-Grade 12V PSU — IEC/EN 61204-3 + IEC 60601-1-2

A medical equipment manufacturer needed a 12V 5A DC power supply module qualified for use inside Class II medical devices. Compatible Electronics structured an integrated test plan at Newbury Park: IEC/EN 61204-3 (2001) emissions and immunity for the standalone module, and IEC 60601-1-2 Ed. 4 immunity augmentation at professional healthcare facility levels for the integrated device. The combined NVLAP accredited reports supported both the power supply's standalone CE marking Declaration of Conformity and the medical device's IEC 60601-1-2 Ed. 4 technical documentation for FDA and EU MDR submissions.