EN 55011 / CISPR 11
EN 55011 (CISPR 11) is the primary international EMC emissions standard for industrial, scientific and medical (ISM) radio-frequency equipment. This article covers its scope, Class A/B distinctions, measurement procedures, and Compatible Electronics' accredited testing services. Part of the Compatible Electronics Learning Center.
What is EN 55011 / CISPR 11?
EN 55011 is the European harmonized edition of CISPR 11, published by the International Special Committee on Radio Interference (CISPR). It specifies the electromagnetic disturbance limits and measurement methods for industrial, scientific, and medical (ISM) radio-frequency equipment — equipment that intentionally generates and uses RF energy for industrial, scientific, medical, domestic, or similar purposes, other than for communications.
The standard covers both conducted emissions (measured at the mains port, 150 kHz–30 MHz) and radiated emissions (measured in the frequency range 30 MHz and above). It is the mandatory standard for CE Marking of ISM equipment under the EMC Directive, and it is referenced by the FCC and Industry Canada for ISM equipment operating in North America. Compatible Electronics is NVLAP-accredited for testing to EN 55011 / CISPR 11 and provides dedicated CISPR 11 ISM equipment testing services.
ISM Equipment — What it Covers
ISM equipment encompasses a wide range of products, including:
- Industrial heating and welding equipment (induction heaters, dielectric heaters, arc welders)
- Medical RF equipment (electrosurgical units, diathermy equipment, MRI systems)
- Scientific RF equipment (plasma generators, particle accelerators, RF spectroscopy)
- Domestic microwave ovens and other intentional RF heating appliances
- Ultrasonic equipment (cleaning baths, welders, machining tools)
Note that EN 55011 applies to intentional ISM radiators. Digital products and IT equipment that incidentally generate RF but are not ISM devices fall under CISPR 32 (EN 55032) or other product family standards, not CISPR 11.
Class A vs. Class B Equipment
A
Class A Equipment
ISM equipment not intended for use in a domestic environment and not directly connected to the public low-voltage supply. Class A includes industrial, commercial, and business premises equipment. Limits are less stringent than Class B because the electromagnetic environment and the sensitivity of nearby receivers differ from those in residential settings. A Class A declaration must appear in the instruction manual and as a warning label.
B
Class B Equipment
ISM equipment intended for use in the domestic environment, including equipment connected to the public low-voltage supply. Class B limits are 10 dB or more below Class A limits in key frequency ranges, reflecting the need to protect broadcast reception and other consumer services in residential buildings. Class B compliance is required for any ISM equipment marketed to the general public.
Measurement Procedures
CISPR 11 specifies measurement procedures derived from CISPR 16 (the basic CISPR measurement standard). Key test parameters include:
- Conducted emissions: Measured using a CISPR-compliant LISN (Line Impedance Stabilisation Network) at the mains port. Quasi-peak and average detectors; limits apply from 150 kHz to 30 MHz.
- Radiated emissions: Measured at 10 m or 30 m distance on an OATS or in an accredited semi-anechoic chamber. Quasi-peak detector; limits apply from 30 MHz to 1 GHz (with higher frequency extensions for equipment generating energy above 1 GHz).
- Conducted disturbances on signal/control ports: For equipment with ports other than the mains supply, additional conducted emission measurements may apply.
| Standard Version | Locations Accredited |
|---|
| EN 55011 (2007) + A2 (2007) | Lake Forest/Silverado, Brea |
| EN 55011 (2009) + A1 (2010) | Lake Forest/Silverado, Newbury Park |
| IEC/CISPR 11 Ed. 5.1 (2010) | Lake Forest/Silverado, Newbury Park |
| IEC/CISPR 11 ED. 7.0 (2024-02) | Lake Forest/Silverado |
| AS CISPR 11 (2017) | Lake Forest/Silverado, Brea, Newbury Park |
| AS/NZS CISPR 11 (2011) | Lake Forest/Silverado, Brea |
Ready to Test Your Product?
Compatible Electronics is an NVLAP-accredited EMC and safety testing laboratory (Lab Code 200527-0) with three Southern California locations. Contact us for a test quote.
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