📡 Measurement of radio-frequency disturbances of ISM equipment — PN-EN IEC 55011

Electronics and EMC PN-EN 55011

Overview

A NOTE AT THE OUTSET — HERE TOO THE DESIGNATION HAS CHANGED, AND IN 2026. PN-EN 55011:2016-05 was WITHDRAWN on 17-06-2026 and replaced by PN-EN IEC 55011:2026-06, implementing EN IEC 55011:2025 and CISPR 11:2024 as identical. The IEC element was added to the new designation. Together with the parent standard, the withdrawal covered all three of its amendments: A1:2017-06, A11:2020-07 and A2:2021-08. An accreditation scope with the line "PN-EN 55011:2016-05" (even with the full set of amendments) has therefore cited a withdrawn document since June 2026. This is the second such case among the standards described in this database — the first is Test Cab, where the same change took place on 09-09-2026.

AN EMISSION STANDARD, SO THE VALUES GIVEN ARE LIMITS. With PN-EN 50130-4, described in this database, it is the other way round: there the number is a TEST level that the equipment must withstand. Here the number is a limit that the equipment must not exceed. A reader comparing two lines of their accreditation scope — one with an immunity standard, the other with an emission standard — faces two opposite meanings of the same word.

SCOPE, QUOTED FROM THE TEXT OF CISPR 11:2024 (clause 1): "This document applies to industrial, scientific and medical electrical equipment operating in the frequency range 0 Hz to 400 GHz and to domestic and similar appliances designed to generate and/or use locally radio-frequency energy. This document covers emission requirements related to radio-frequency (RF) disturbances in the frequency range of 9 kHz to 400 GHz." TWO DIFFERENT RANGES IN ONE SENTENCE, AND THEY ARE EASY TO CONFUSE: the equipment covered by the standard operates from 0 Hz, but the emission requirements cover the band from 9 kHz. For ISM RF applications within the meaning of the ITU Radio Regulations, the emission requirements extend to 18 GHz, not 400 GHz. The 2024 edition adds to the scope things that the 2009 edition did not have: industrial, scientific and medical robots (with examples — welding, spraying, handling, machining, assembly, medical, educational and experimental) and ISM equipment with a transmit-receive function. At the same time, it stipulates that the emission requirements do NOT apply to the intended transmissions of a radio transmitter — but do apply to composite emissions, for example those resulting from intermodulation between the radio and non-radio parts of the equipment. Equipment covered by other CISPR emission standards is excluded from the scope.

THE CLASSIFICATION DECIDES WHICH TABLE APPLIES — AND IT IS DONE BEFORE THE MEASUREMENT. The standard divides equipment twice and independently: DIVISION INTO GROUPS. Group 2 is equipment in which radio-frequency energy is intentionally generated or only used — in the form of electromagnetic radiation, inductive or capacitive coupling — FOR THE TREATMENT OF MATERIAL or for inspection and analysis. Group 1 is all other equipment covered by the standard. A NOTE OF PRACTICAL IMPORTANCE: the definition of group 1 CHANGED between editions. In the 2003 edition it was defined positively — as equipment in which conductively coupled RF energy is generated or used and is necessary for the internal functioning of the equipment itself. In the 2009 edition it is defined negatively: "group 1 contains all equipment in the scope of this standard which is not classified as group 2 equipment". Anyone who carries over the definition from an old study may assign equipment to a group differently from the way the standard in force would. DIVISION INTO CLASSES. Class A is equipment suitable for use in all establishments OTHER than domestic ones and other than those directly connected to a low-voltage power supply network which supplies buildings used for domestic purposes. Class B is equipment suitable for use in domestic establishments and in establishments directly connected to such a network. Class A equipment meets the class A limits, class B equipment — the class B limits. AN OBLIGATION THAT IS NOT A MEASUREMENT: the standard places on the manufacturer or supplier the obligation to INFORM THE USER of the class and group of the equipment — by marking or in the documentation — and to explain in the documentation what both of these mean. For arc welding equipment containing arc striking or stabilising devices (and also for such stand-alone devices), the standard requires the user to be informed that this is class A equipment.

WHERE THE MEASUREMENT IS MADE — AND WHY THIS IS NOT THE SAME DECISION FOR BOTH CLASSES. The standard provides two routes of assessment: on a standardised test site or IN SITU, that is, at the place where the equipment is installed. The 2003 edition puts it directly: class A equipment may be measured on a test site or in situ, at the manufacturer's choice, whereas class B equipment SHALL BE measured on a standardised test site. The reason for allowing in situ measurement is the size, complexity or operating conditions of equipment that cannot be brought to a test site. The 2024 edition keeps both routes and separates them by frequency range: the requirements for a standardised test site allow ISM RF applications operating up to 18 GHz to be tested, and the requirements for in situ assessment cover the band up to 1 GHz.

THE DIVISION OF RESPONSIBILITY BETWEEN CISPR AND THE ITU, WHICH THE STANDARD EXPLAINS IN THE INTRODUCTION: CISPR deals with limiting disturbances through the ASSESSMENT of equipment — on a standardised test site, or at the place of operation when it cannot be done otherwise; the ITU deals with limiting disturbances during the normal OPERATION of equipment at its place of use. The standard points out that for many types of ISM applications the manufacturer, installer or customer should expect additional national regulations — concerning licences and the protection of local radio services — especially when operating outside the designated ISM bands and above 18 GHz.

WHAT WE DO NOT GIVE IN THIS ENTRY AND WHY. WE DO NOT GIVE ANY LIMIT VALUE. The 2024 edition contains at least 21 tables of limits, divided by group, class, type of port (AC power, DC power, wired network), place of measurement (test site or in situ) and band — and electro-discharge machining equipment and arc welding equipment have separate tables. The extract of the text that we read covers the introduction, the scope and the normative references; it does not contain the tables. Giving a single number "for PN-EN IEC 55011" here would therefore be not so much incomplete as misleading: without indicating the group, class, port and place of measurement, such a number has no addressee. NOR DO WE GIVE the definitions of the groups and classes in the wording of the 2024 edition — those quoted above come from the 2003 and 2009 editions and are marked as such in this entry. The definition of class A is literally the same in both of these editions; the definition of group 1 has already changed once, so we do not assume that it has not changed again since 2009.

Method principle

The equipment is first assigned to a group (1 or 2) and a class (A or B), which indicates the appropriate tables of limits. Then the disturbance voltages at the power and wired network ports and the radiated disturbances are measured — on a standardised test site or, for equipment that cannot be brought to one, at the place of installation. The measured values are compared with the limits appropriate to the established group, class, port and band.

Applications

• Industrial, scientific and medical equipment generating or locally using radio-frequency energy
• Induction and dielectric heaters, high-frequency welders — typical group 2 equipment
• Electro-discharge machining (EDM) and arc welding equipment — they have their own tables of limits in the standard
• Laboratory and analytical apparatus using RF energy for the inspection and analysis of material
• Medical equipment generating RF energy (diathermy, electrosurgery)
• ISM RF lighting and ultraviolet irradiators operating in ISM bands designated by the ITU
• Industrial, scientific and medical robots — explicitly included in the scope in the 2024 edition
• Domestic and similar appliances, if designed to generate or locally use RF energy

Key parameters

Standard

Standard number

PN-EN IEC 55011:2026-06 (wersja angielska; wprowadza EN IEC 55011:2025 [IDT], CISPR 11:2024 [IDT])

Title (PL)

Urządzenia przemysłowe, naukowe i medyczne — Charakterystyki zaburzeń o częstotliwości radiowej — Poziomy dopuszczalne i metody pomiaru

Title (EN)

Industrial, scientific and medical equipment — Radio-frequency disturbance characteristics — Limits and methods of measurement

Step-by-step procedure

1. Assignment to a group

   It is decided whether the equipment intentionally generates or uses RF energy for the treatment of material or for inspection and analysis (group 2) or not (group 1). This decision is made BEFORE the measurement and indicates the tables of limits. NOTE TO THE WHOLE PROCEDURE: we reconstruct the order and content of the steps from CLAUSE 1 of the 2024 edition and from the definitions of groups and classes in the 2009 and 2003 editions — we did not have the clauses of the 2024 edition on classification and measurements, so we cannot state whether the edition in force conducts the test exactly like this.

2. Assignment to a class

   It is established whether the equipment is intended for domestic establishments and for those directly connected to a low-voltage network supplying buildings used for domestic purposes (class B), or for others (class A).

3. Choice of the place of assessment

   Class B equipment is tested on a standardised test site. For class A the manufacturer may choose a test site or in situ assessment — the latter is used when size, complexity or operating conditions make testing on a test site impossible.

4. Establishing the operating modes of the equipment under test

   The operating conditions are chosen so that they correspond to normal use and produce the greatest disturbances; for group 2 the standard gives separate requirements concerning operating conditions and peak and weighted measurements.

5. Measurement of conducted disturbances

   The disturbance voltage is measured at the power port (AC and, where applicable, DC) and at the wired network ports, in the bands and with the detectors appropriate to the table indicated by the group and class.

6. Measurement of radiated disturbances

   The radiated field is measured up to the highest frequency required for the given equipment — the standard gives it in a separate table depending on the highest internal frequency of the equipment.

7. Comparison with the limits

   The measured values are compared with the limits from the table appropriate to the established group, class, port and place of measurement. An exceeded limit means failure to meet the requirements of that class — it does not automatically mean that the equipment belongs to class A.

8. Information for the user

   Irrespective of the measurement result, the manufacturer or supplier is to inform the user of the class and group of the equipment — by marking or in the documentation — and explain in the documentation the meaning of both terms. For arc welding equipment with arc striking or stabilising devices, the standard requires class A to be indicated.

9. Recording the result together with the classification

   The report gives the group, the class, the place of measurement, the ports tested and the detectors used. A result without these four things does not make it possible to reconstruct the table against which it was compared.

Required equipment and apparatus

Health and safety (OHS)

• Group 2 equipment generates high-power RF energy — the clearances and guards provided for by the manufacturer apply, also during the measurement
• In situ assessment is carried out on equipment operating at the place of installation — the measuring station then enters the operating area of the plant, with its own hazards
• The electromagnetic field near induction and dielectric heaters may exceed the values permissible for humans — separate regulations on protection against electromagnetic fields apply, independent of this standard
• Arc welding and electro-discharge machining equipment combine electrical hazards with thermal and optical ones
• The artificial mains network and coupling devices remain at mains voltage throughout the measurement of conducted disturbances

Frequently asked questions