oSIST prEN IEC 61308:2025

High-frequency dielectric heating installations - Test methods for the determination of power output

Hochfrequente dielektrische Erwärmungsanlagen - Prüfverfahren für die Bestimmung der Ausgangsleistung

Installations de chauffage diélectrique à haute fréquence - Méthodes d'essai pour la détermination de la puissance de sortie

Inštalacije za visokofrekvenčno dielektrično segrevanje - Preskusne metode za ugotavljanje izhodne moči

General Information

• Status: Not Published
• Public Enquiry End Date: 31-Jul-2025
• ICS: 25.180.10 - Electric furnaces
• Technical Committee: I09 - Imaginarni 09
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 18-Jun-2025
• Due Date: 05-Nov-2025
• Completion Date: 18-Jul-2025
• Ref Project: prEN IEC 61308:2025 - High-frequency dielectric heating installations - Test methods for the determination of power output

Relations

• Revises: SIST EN 61308:2006 - High-frequency dielectric heating installations - Test methods for the determination of power output
• Effective Date: 18-Feb-2025

Overview

The oSIST prEN IEC 61308:2025 standard, titled High-frequency dielectric heating installations - Test methods for the determination of power output, is developed by the CLC (European Committee for Electrotechnical Standardization) under the International Electrotechnical Commission (IEC). This standard specifies essential test methods to accurately determine the high-frequency power output of industrial dielectric heating equipment operating primarily between 100 kHz and 300 MHz. It is especially relevant to HF generators provided as separate units for industrial heating and material processing applications.

This standard provides a harmonized approach to testing, ensuring reliable measurement of power output, which is critical for performance validation, safety compliance, and equipment optimization in industrial electroheating processes.

Key Topics

• Scope of Application

  • Applicable to industrial HF dielectric heating equipment operating within ISM frequency bands: 6.78 MHz, 13.56 MHz, 27.12 MHz, and 40.68 MHz.
  • Not applicable to induction heating, household, commercial, laboratory, or medical HF equipment.

• Equipment Classification

  • Type A Equipment: HF generator separable from the applicator, connected typically via coaxial lines.
  • Type B Equipment: HF generator directly coupled to the applicator, such as built-in welders or heating chambers.

• Test Loads and Methods

  • Calorimetric Load: Substitutes normal load for power measurement above ~1 kW; uses water flow through a chamber with electrodes.
  • Lamp Load: Incandescent lamps arranged in series/parallel for power measurement up to ~1 kW.
  • Matched Resistive Load: For loads directly connected to HF output terminals.
  • Wet-Sand Load: Simulates load impedance using wet sand in the applicator, mainly for type B equipment.

• Testing Procedures

  • Methods to measure useful output power under continuous rated conditions.
  • Importance of impedance matching using equipment tuning circuits.
  • Specialized methods for plastic welding equipment involving specific welding electrodes.

• Safety and Measurement Precision

  • Ensures safe operation under high-frequency electromagnetic fields.
  • Guidance on minimizing heat losses during calorimetric testing to enhance accuracy.

• Supporting Documentation

  • Normative references including IEC 60519-6 (Safety in electroheating installations) and CISPR11 (Radio-frequency disturbance characteristics).
  • Detailed terms and definitions for standardized language and understanding.

Applications

This standard serves an important role in industries employing high-frequency dielectric heating for material processing, such as:

• Plastic Welding

  • Verification of output power for type B equipment integrated into welding presses.

• Industrial Heating

  • Accurate power determination for use in processes like drying, curing, or composite material bonding.

• Equipment Manufacturers

  • Assists in designing and tuning HF generators to meet performance standards.

• Certification Bodies

  • Provides a reliable framework for conformity assessment and quality control.

• Research and Development

  • Enables consistent testing conditions for innovation in dielectric heating technologies.

By standardizing test methods, oSIST prEN IEC 61308:2025 helps improve efficiency, reproducibility, and safety of dielectric heating systems widely used in manufacturing and processing industries.

Related Standards

• IEC 60519-6:2022 – Safety in installations for electroheating and electromagnetic processing (Particular requirements for high-frequency dielectric and microwave heating equipment).
• CISPR 11:2024 – Industrial, scientific and medical equipment - Radio-frequency disturbance characteristics - Limits and methods of measurement.
• IEC 60050-841:2004 – International Electrotechnical Vocabulary – Part 841: Industrial electroheat (noting this is under revision).
• IEC 60519-1:2020 – Safety in electroheating - General requirements.

These related standards collectively support the technical and safety framework surrounding high-frequency dielectric heating equipment and ensure harmonized industrial practice globally.

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Keywords: high-frequency dielectric heating, HF power output test, dielectric heating installations, IEC 61308, calorimetric load, lamp load, matched resistive load, wet-sand load, industrial electroheating standards, plastic welding power measurement, HF generator testing

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2025
Inštalacije za visokofrekvenčno dielektrično segrevanje - Preskusne metode za
ugotavljanje izhodne moči
High-frequency dielectric heating installations - Test methods for the determination of
power output
Hochfrequente dielektrische Erwärmungsanlagen - Prüfverfahren für die Bestimmung
der Ausgangsleistung
Installations de chauffage diélectrique à haute fréquence - Méthodes d'essai pour la
détermination de la puissance de sortie
Ta slovenski standard je istoveten z: prEN IEC 61308:2025
ICS:
25.180.10 Električne peči Electric furnaces
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

27/1207/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 61308 ED3
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2025-06-13 2025-09-05
SUPERSEDES DOCUMENTS:
27/1201/CD, 27/1204/CC
IEC TC 27 : INDUSTRIAL ELECTROHEATING AND ELECTROMAGNETIC PROCESSING
SECRETARIAT: SECRETARY:
Poland Mrs Mariola Nowecka
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):

ASPECTS CONCERNED:
Safety
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft for
Vote (CDV) is submitted for parallel voting.
The CENELEC members are invited to vote through the
CENELEC online voting system.
This document is still under study and subject to change. It should not be used for reference purposes.
Recipients of this document are invited to submit, with their comments, notification of any relevant patent rights of which they
are aware and to provide supporting documentation.
Recipients of this document are invited to submit, with their comments, notification of any relevant “In Some Countries”
clauses to be included should this proposal proceed. Recipients are reminded that the CDV stage is the final stage for
submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).

TITLE:
High-frequency dielectric heating installations - Test methods for the determination of power output

PROPOSED STABILITY DATE: 2030
NOTE FROM TC/SC OFFICERS:
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
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IEC 61308 ED3 © IEC 2025 2
1 CONTENTS
3 FOREWORD . 3
4 1 Scope . 5
5 2 Normative references . 5
6 3 Terms and definitions . 6
7 4 Test loads . 6
8 4.1 General . 6
9 4.2 Calorimetric load . 7
10 4.3 Lamp load . 7
11 4.4 Matched resistive load . 7
12 4.5 Wet-sand load . 7
13 5 Description of tests . 7
14 5.1 General . 7
15 5.2 Calorimetric load method . 7
16 5.3 Lamp-load temperature method . 10
17 5.4 Matched resistive load method . 12
18 5.5 Wet-sand load method . 12
19 5.6 Evaluation of the output power for high-frequency dielectric plastic welders . 13
20 5.7 Evaluation of the output power for type B equipment . 14
21 Annex A (informative) Recommended test circuit for the lamp-load method . 15
23 Figure 1 – Example of a calorimeter load . 9
24 Figure 2 – Example of a short tubular calorimeter load . 10
25 Figure 3 – Lamp-load circuit . 10
26 Figure 4 – Example of a lamp load . 11
27 Figure 5 – Detail of the lamp load . 12
28 Figure 6 – Plastic welding test electrode . 14
29 Figure A.1 – Recommended test circuit for the lamp-load method . 15
IEC 61308 ED3 © IEC 2025 3
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HIGH-FREQUENCY DIELECTRIC HEATING INSTALLATIONS –
TEST METHODS FOR THE DETERMINATION
OF POWER OUTPUT
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national
electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all
questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities,
IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS)
and Guides (hereafter referred to as "IEC Publication(s)"). Their preparation is entrusted to technical committees; any IEC
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the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between
the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus
of opinion on the relevant subjects since each technical committee has representation from all interested IEC National
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in
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6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of
its technical committees and IEC National Committees for any personal injury, property damage or other damage of any
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use of, or reliance upon, this IEC Publication or any other IEC Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable
for the correct application of this publication.
9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). IEC
takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the
date of publication of this document, IEC had not received notice of (a) patent(s), which may be required to implement this
document. However, implementers are cautioned that this may not represent the latest information, which may be obtained
from the patent database available at https://patents.iec.ch [and/or] www.iso.org/patents.IEC shall not be held responsible
for identifying any or all such patent rights.
This International Standard IEC 61308 has been prepared by IEC technical committee 27: Industrial
electroheating and electromagnetic processing. It is an International Standard.
This third edition replaces the cancelled second edition published in 2005 and constitutes a technical
revision.
The text of this International Standard is based on the following documents:
Draft Report on voting
27/XX/FDIS 27/XX/RVD
Full information on the voting for its approval can be found in the report on voting indicated in the above
table.
IEC 61308 ED3 © IEC 2025 4
The language used for the development of this International Standard is English

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in accordance
with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, [and the ISO/IEC Directives,
JTC 1 Supplement] available at www.iec.ch/members_experts/refdocs. The main document types
developed by IEC are described in greater detail at www.iec.ch/publications.
The committee has decided that the contents of this document will remain unchanged until the stability
date indicated on the IEC website under webstore.iec.ch in the data related to the specific document.
At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IEC 61308 ED3 © IEC 2025 5
HIGH-FREQUENCY DIELECTRIC HEATING INSTALLATIONS –
TEST METHODS FOR THE DETERMINATION
OF POWER OUTPUT
1 Scope
This International Standard specifies test methods for the determination of available high frequency
power output in equipment for industrial heating and processing of materials. It is in particular applicable
to HF generators made available to users as separate units.
This document is basically applicable to equipment operating in the frequency range 100 kHz to 300
MHz, as defined in IEC 60519-1:2020, with the following limitations.
– This document does not apply to induction heating, which it is possible to carry out in the lower part
of the specified frequency band.
– The ISM centre frequencies for dielectric heating and processing of industrial interest are
narrow bands about 6,78 MHz, 13,56 MHz, 27,12 MHz and 40,68 MHz.
– This document is not applicable to:
• appliances for household and similar use;
• commercial use;
• laboratory use;
• medical high frequency equipment.

NOTE 1 The following criteria are suitable for determination of the classification as industrial equipment:
– commercial equipment is typically designed and planned for series production of many identical units,
– industrial equipment is typically produced in small series or even as single units. The processed goods are consumed or
ready for final use at the end of the heating process.

NOTE 2 Heating a workload with dielectric parameters which change significantly in time and/or with temperature, the value of
the output power obtained with the actual charge may be different from that obtained with the test load specified in this standard.

NOTE 3 For equipment working in designated ISM bands it is required that the frequency remains within the ISM bands
according to CISPR11, but the resonant frequency of the circuit varies with the change of dielectric parameters of the load.
Therefore, the value of the mean output power in the work cycle can be much lower than the value obtained under the test
conditions. This value depends upon the response of the tuning system.
This standard relates to equipment normally operating under continuous rated conditions.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60050-841:2004, International Electrotechnical Vocabulary – Part 841: Industrial electroheat
NOTE Since chapter 841 in IEV is under revision, no references to the 2004 version are given in this standard. (CISPR 2024).

IEC 61308 ED3 © IEC 2025 6
IEC 60519-6:2022, Safety in installations for electroheating and electromagnetic processing –Part 6:
Particular requirements for high frequency dielectric and microwave heating and processing equipment
CISPR11:2024, Industrial, scientific and medical equipment - Radio-frequency disturbance
characteristics - Limits and methods of measurement

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp

Terms and definitions listed in different documents:
For the purposes of this document, the terms and definitions given in IEC60519-1 ED 6 and/or
IEC60519-6 ED 4 apply. In particular, the definition of test load in IEC60519-6 ED 4, 3.3.104 shall be
noted as well as of normal operation in IEC 60519-1 ED6, 3.2.6.
NOTE Some terms in this document have the same or similar definitions in IEC 60050 (IEV). If different, those in this standard
apply.
3.1
type A equipment
equipment with the high frequency converter or generator independent of, or separable from, the
applicator to which the high-frequency power is provided.
EXAMPLE 1 The separation is by a coaxial line feeder or alternative means.
3.2
type B equipment
equipment with the high frequency converter or
...