SIST EN 50647:2017

SLOVENSKI STANDARD
01-september-2017
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Basic standard for the evaluation of workers' exposure to electric and magnetic fields
from equipment and installations for the production, transmission and distribution of
electricity
Basisnorm für die Evaluierung der beruflichen Exposition gegenüber elektrischen und
magnetischen Feldern ausgehend von Komponenten und Anlagen zur Erzeugung,
Übertragung und Verteilung elektrischer Energie
Norme fondamentale pour l’évaluation de l’exposition des travailleurs aux champs
électriques et magnétiques produits par les équipements et installations de production,
transport et distribution d’électricité
Ta slovenski standard je istoveten z: EN 50647:2017
ICS:
13.100 Varnost pri delu. Industrijska Occupational safety.
higiena Industrial hygiene
17.220.01 Elektrika. Magnetizem. Electricity. Magnetism.
Splošni vidiki General aspects
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 50647
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2017
ICS 17.220.20; 17.240
English Version
Basic standard for the evaluation of workers' exposure to electric
and magnetic fields from equipment and installations for the
production, transmission and distribution of electricity
Norme fondamentale pour l'évaluation de l'exposition des Basisnorm für die Evaluierung der beruflichen Exposition
travailleurs aux champs électriques et magnétiques produits gegenüber elektrischen und magnetischen Feldern
par les équipements et installations de production, transport ausgehend von Komponenten und Anlagen zur Erzeugung,
et distribution d'électricité Übertragung und Verteilung elektrischer Energie
This European Standard was approved by CENELEC on 2017-04-10. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,
Switzerland, Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 50647:2017 E
Contents Page
European foreword . 4
3.1 Terms and definitions . 6
3.2 Physical quantities and units . 8
3.3 Abbreviations . 8
6.1 General . 11
6.2 Exposure assessment regarding external fields . 11
6.2.1 General . 11
6.2.2 Harmonics of magnetic field. 12
6.2.3 Harmonics of electric field . 12
6.3 Numerical calculation of induced electric fields inside the human body . 13
8.1 General . 13
8.2 Simplified criteria for compliance with action levels . 15
8.2.1 General . 15
8.2.2 Magnetic fields . 15
8.2.3 Electric fields . 16
8.3 Assessment using measurements or calculations . 17
8.3.1 General . 17
8.3.2 Magnetic fields . 17
8.3.3 Electric fields . 18
9.1 General . 19
9.2 Simplified criteria for compliance with exposure limit values . 19
9.2.1 General . 19
9.2.2 Magnetic fields . 20
9.2.3 Electric fields . 21
9.3 Assessment using dosimetry and considerations for non-uniform fields . 21
13.1 Workers at particular risk . 23
13.2 Other requirements . 23
Annex A (informative) Assessment of harmonics in magnetic fields . 24
A.1 Introduction . 24
A.2 Assessment Method using TEI . 24
A.3 Assessment using the weighted peak function . 26
A.4 Simplified assessment procedure for public grids . 28
Annex B (normative) 50 Hz magnetic field sources in the environment of equipment and installations
for production, transmission and distribution of electricity . 29
B.1 General . 29
B.2 Currents in single conductors . 29
B.3 Currents in circuits . 31
B.4 Assessing magnetic fields exposures . 31
B.5 Check list for assessing compliance for magnetic fields . 33
Annex C (informative) Examples of application of the different assessment criteria . 34
C.1 Assessment for air-cored reactors: Simplified calculation of the magnetic field under a

vertical air-cored self-inductance . 34
C.2 Assessment for insulated cables: Calculation of compliance distances for typical XLPE

cables. 36
C.3 Assessment for exposure to electric fields considering different coupling conditions . 38
Annex D (informative) Method for deriving Exposure-Limit-Equivalent-Fields (LEFs) . 41
D.1 Introduction . 41
D.2 Method . 41
D.3 Selection of the reference model: . 42
D.4 Reference organs and data . 42
D.5 Uncertainty assessment . 43
D.6 Deriving the Exposure-Limit-Equivalent-Field (LEF) . 44
Annex E (informative) Considerations about DC magnetic fields in electrical companies . 45
E.1 Introduction . 45
E.2 Exposure of workers to DC magnetic field in electrical companies . 45
E.3 Attention points . 45
Annex F (informative) contact currents . 46
F.1 Introduction . 46
F.2 Influence of electric fields . 46
F.2.1 General . 46
F.2.2 Person isolated (at floating potential), capacitive coupling to ground . 46
F.2.3 Person at earth potential, isolated object . 47
F.2.4 Spark discharges . 48
F.3 Influence of magnetic fields . 48
F.3.1 General . 48
F.3.2 Working adjacent to live circuits . 48
F.4 Summary . 49
Annex G (informative) Exposure during transient and fault conditions . 50
G.1 Introduction . 50
G.2 Faults . 50
G.2.1 Overview . 50
G.2.2 Short-circuit currents during faults . 50
G.2.3 Prevention and protection against faults. 50
G.2.4 Magnetic field exposures during faults. 51
G.3 Switching transients . 51
G.4 Lightning strikes . 51
G.5 Inrush currents . 51
G.6 Compliance of short-duration events with the Directive. 52
Bibliography . 53
European foreword
This document [EN 50647:2017] has been prepared by CLC/TC 106X “Electromagnetic fields in the human
environment”.
The following dates are fixed:
• latest date by which this document has to be (dop) 2018-04-10
implemented at national level by publication of
an identical national standard or by
endorsement
• latest date by which the national standards (dow) 2020-04-10
conflicting with this document have to
be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a mandate given to CENELEC by the European Commission and
the European Free Trade Association.
1 Scope
This European Standard provides a general procedure to assess workers’ exposure to electric and magnetic
fields (EMF) in work places associated with the production, transmission and distribution of electric energy,
and to demonstrate compliance with exposure limit values and action levels as stated in the Council and
European Parliament “EMF” Directive 2013/35/EU [11].
NOTE 1 The Council and European Parliament Directive 2013/35/EU will be transposed into national legislation in all
the EU member countries. It is important that users of this standard consult the national legislation related to this
transposition in order to identify the national regulations and requirements. These national regulations and requirements
may have additional requirements that are not covered by this standard
It has the role of a specific workplace standard. It takes into account the non-binding application guide for
implementing the EMF Directive [10] and it defines the assessment procedures and compliance criteria
applicable to the electric industry.
The frequency range of this standard covers from DC to 20 kHz, which is sufficient to include the power
frequency used for electric power supply systems throughout Europe (50 Hz) and the various harmonics and
inter-harmonics occurring in the supply system. In this extremely low frequency range, electric and magnetic
fields are independent and, therefore, they both have to be addressed in the exposure assessment.
NOTE 2 Electrical companies also use radio frequency transmissions to operate and maintain their networks and
power plants. Similarly, other exposures to EMF may occur during maintenance operations, for instance, due to the use
of hand-held electrical tools. All these EMF sources are outside the scope of this standard.
NOTE 3 Regarding EMF in the low frequency range, the scientific basis of the EMF directive is the ICNIRP health
guidelines published in 2010 [13]. Reference is made to this scientific basis when necessary for justifying or clarifying
some of the technical statements of the present document.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
EN 61786-1, Measurement of DC magnetic, AC magnetic and AC electric fields from 1 Hz to 100 kHz with
regard to exposure of human beings - Part 1: Requirements for measuring instruments (IEC 61786-1)
EN 50527-1, Procedure for the assessment of the exposure to electromagnetic fields of workers bearing
active implantable medical devices - Part 1: General
EN 50527-2-1, Procedure for the assessment of the exposure to electromagnetic fields of workers bearing
active implantable medical devices - Part 2-1: Specific assessment for workers with cardiac pacemakers
IEC 61786-2, Measurement of DC magnetic, AC magnetic and AC electric fields from 1 Hz to 100 kHz with
regard to exposure of human beings - Part 2: Basic standard for measurements
3 Terms, definitions, physical quantities, units and abbreviations
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
action level
AL
operational level established for the purpose of simplifying the process of demonstrating compliance with the
relevant exposure limit value or, where appropriate, to take relevant protection or prevention measures
Note 1 to entry: “Reference levels” as defined in the European Recommendation 1999/519/EC [3] for limiting the
exposure of the public and in ICNIRP Health Guidelines [13] are based on the same approach as Action Levels and the
two terms are defined to achieve the same objective.
Note 2 to entry: For electric fields, “Low ALs” and “High ALs” are levels which relate to the specific protection or
prevention measures specified in the EMF Directive [11].
Note 3 to entry: The Low AL for external electric field is based both on limiting the internal electric field below ELVs and
on limiting spark discharges in the working environment. Below the High AL, the internal electric field does not exceed
ELVs and annoying spark discharges are prevented, provided that the relevant protection measures are taken.
Note 4 to entry: For magnetic fields, “Low ALs” are levels which relate to the sensory effects ELVs and “High ALs” to
the health effects ELVs.
Note 5 to entry: Compliance with the ALs will ensure compliance with the relevant ELVs. If the assessed exposure
values are higher than the ALs, it does not necessarily follow that the ELVs have been exceeded, but a more detailed
analysis is necessary to demonstrate compliance with the ELVs.
Note 6 to entry: ALs may not provide adequate protection to workers at particular risks, for whom a particular risk
assessment shall be performed.
3.1.2
compliance distance
distance from a source of field that ensures respect of the relevant exposure limit values or action levels
Note 1 to entry: Working at distances smaller than compliance distances requires a specific assessment.
3.1.3
contact current
current between a person in established contact with a conductive object, resulting from the inductive or
capacitive coupling between the field and the person and/or object, and expressed in amperes (A)
Note 1 to entry: The EMF directive [11] specifies limits for the steady-state value of the contact current.
3.1.4
electric field
constituent of an electromagnetic field which is characterized by the electric field strength E together with the
electric flux density D
Note 1 to entry: In French, the term “champ électrique ” is also used for the quantity electric field strength.
[SOURCE: IEV, ref 121-11-67]
3.1.5
exposure index
EI
assessed exposure divided by the relevant action level or exposure limit value
3.1.6
exposure-limit-equivalent field
LEF
magnitude of uniform external electric or magnetic field that exposes the person to the sensory or health
effects ELV
Note 1 to entry: The numerical values of LEFs are derived from dosimetry.
3.1.7
exposure limit value
ELV
limit which is based directly on established health effects and biological considerations
Note 1 to entry: In the frequency range covered by the present standard, ELVs are expressed in terms of induced
electric fields except between 0 Hz and 1 Hz where the ELV is given in terms of external magnetic field.
Note 2 to entry: “Basic restrictions” as defined in the European Recommendation 1999/519/EC [3] for limiting the
exposure of the public and in ICNIRP Health Guidelines [13] are based on the same approach as Exposure Limit Values
and the two terms are defined to achieve the same objective.
3.1.8
exposure limit values for sensory effects (sensory effects ELVs)
ELVs above which workers might be subject to transiently disturbed sensory perceptions, i.e. retinal
phosphenes and minor changes in brain functions
Note 1 to entry: The sensory effects relate only to the central nervous system of the head. Exceeding sensory effects
ELVs is allowed under controlled conditions for informed workers.
3.1.9
exposure limit values for health effects (health effects ELVs)
ELVs above which workers might be might be subject to adverse health effects, such as stimulation of nerve
and muscle tissue
Note 1 to entry: Compliance with health effects ELVs will ensure that workers exposed to electric and magnetic fields
are protected against all established adverse health effects.
Note 2 to entry: The threshold for muscle excitation is far higher than for nerve excitation, and therefore the directive
[11], consistently with its scientific basis [13], considers limits to prevent only nerve excitation, as they are conservative
with regard to muscle excitation. As a result, the health effects relate to the peripheral nervous system, i.e. the whole
body.
3.1.10
induced electric field
electric field inside a human body resulting directly from an exposure to an external source of electric or
magnetic field
3.1.11
magnetic field
constituent of an electromagnetic field which is characterized by the magnetic field strength H together with
the magnetic flux density B
Note 1 to entry: In French, the term “champ magnétique” is also used for the quantity magnetic field strength.
Note 2 to entry: In this document, the term magnetic field is used for magnetic flux density.
[SOURCE: IEV ref 121-11-69]
3.1.12
total exposure index
TEI
sum of all exposure indexes (e.g. at different frequencies, or from different sources) of either electric or
magnetic field
Note 1 to entry: If the total exposure index is less than one, the exposure is compliant.
Note 2 to entry: Using the arithmetic sum makes the TEI a conservative assessment of exposure.
3.1.13
unperturbed field
field at a point that would exist in the absence of persons or in the absence of movable objects which are not
necessary for the work progress
Note 1 to entry: All limits expressed in terms of fields external to the human body refer to the unperturbed field.
[SOURCE: EN 61786-1:2014, 3.3.1]
3.2 Physical quantities and units
For the purposes of this document, the physical quantities and units given in Table 1 apply.
Table 1 — Physical quantities and units
Quantity Symbol Unit Comments
Electric field strength E V/m
Magnetic flux density B T µT is more usually used at 50 Hz
Contact current I A
c
3.3 Abbreviations
AL action level
CNS central nervous system
DC direct current
EI exposure index
ELV exposure limit value
GIS gas insulated substation
HV high voltage
LEF exposure limit equivalent field
PNS peripheral nervous system
TEI total exposure index
WPR worker at particular risk
rms root mean square
4 Assessment procedure
According to Article 4 of EU Directive 2013/35/EU [11] “.the employer shall assess all risks for workers
arising from electromagnetic fields at the workplace and, if necessary, measure or calculate the levels of
electromagnetic fields to which workers are exposed.In workplaces open to the public it is not necessary
for the exposure assessment to be carried out if an evaluation has already been undertaken in accordance
with the provisions on the limitation of exposure of the general public to electromagnetic fields, if the
restrictions specified in those provisions are respected for workers and if the health and safety risks are
excluded. Where equipment intended for the public use is used as intended and complies with Union law on
products that establishes stricter safety levels than those provided for by this Directive, and no other
equipment is used, these conditions are deemed to be met.”
Electrical equipment for the production, transmission and distribution of electricity is highly standardized and
a few general assessments may cover many sites which have similar equipment and work positions.
Therefore, a systematic and thorough assessment of every site containing electrical equipment is not
necessary. For a given site, the risk assessment should be limited to any specific equipment or work
positions not covered by the general assessments.
The exposure assessment shall be updated if any modification to the installation, the working environment or
the work practice significantly affects the EMF exposure conditions.
In electrical companies, many workplaces are exposed simultaneously to electric and magnetic fields. The
internal electric fields induced simultaneously by external electric and magnetic fields are vectors, which
most often are neither collinear in space nor coincident in phase. ICNIRP’s position [13] is that situations
where these field vectors are collinear and in phase “are judged to be very infrequent taking into account the
great difference in the distribution of the electrically and magnetically induced electric fields“.
Therefore, when assessing compliance with the Directive according to the present standard, exposure to low
frequency electric and magnetic fields shall be considered separately and not additively.
This clause gives a general procedure for the exposure assessment of a work place, which is presented in
Figure 1 as a flowchart. It shows all the possible methods to demonstrate compliance with the EMF directive
[11]. The different steps of this flowchart are developed in Clauses 5, 7, 8, 9, 10 and 13.
Compliance can be demonstrated using any of the possible methods. For example, in some cases it might
be more simple and efficient to demonstrate compliance using measurements (e.g. subclause 8.3) rather
than identifying all the electrical equipment and checking whether it meets the criteria for simplified
assessment (e.g. subclause 8.2).
Figure 1 — General flowchart of the compliance assessment procedure
5 Collection of technical data
For assessing compliance, it is necessary to characterize the workplace in terms of EMF sources and of
work positions in relation to them, and of the work practices involved. In terms of the scope of this standard,
relevant field sources are energized electrical conductors and electrical equipment for producing and
distributing electricity.
A simple identification is sufficient for the equipment covered by simplified procedures and general
assessments (see Clause 7 and 8.2).
For the specific electrical equipment which may need a particular assessment, the following technical data
may be useful to characterize the workplaces being assessed:
— type of equipment;
— rated characteristics (e.g. voltage, current);
— whether the equipment is insulated or not;
— whether any screens or shields are present;
— extent of any harmonics;
— distance of the energized parts of the equipment to workers;
— etc.
6 Methods for assessing exposure of workers
6.1 General
When assessing exposure in a particular area, it is normally sufficient to identify only the main EMF sources
that affect that area. If the workers are very close to - or in contact with - one EMF source, any other sources
located further away can generally be neglected (examples: HV live-line working, GIS inspection, etc.).
For working environments where different sources are at comparable distances to the workers (examples:
low voltage environments, where the three phases are close to each other), the simultaneous contribution of
all such sources should be considered.
The worst case exposure of workers shall be determined. As the exposure may vary as a function of the
operating conditions, it may be necessary to extrapolate the exposure to worst case exposure conditions.
Magnetic fields are generated by currents in electric equipment, such as lines, cables, coils and windings.
The current may vary significantly over time and thus so will the magnetic field. This means that
extrapolations of measured or calculated values will often be relevant when considering magnetic fields.
Electric fields are generated by non-shielded electric equipment, such as overhead lines or busbars in
substations. The voltage does not vary significantly over time and neither does the electric field at a given
point, provided it remains unperturbed i.e. not affected by any moving object. Therefore, extrapolations of
measured or calculated values are not normally relevant when considering power frequency electric fields,
except under special circumstances such as a change in maximum operating voltage.
Waveforms of electric and magnetic fields at 50 Hz are not always purely sinusoidal but may contain
significant harmonic components, which have to be taken into account in the exposure assessment when
relevant. See 6.2.2 and 6.2.3.
6.2 Exposure assessment regarding external fields
6.2.1 General
External fields may be assessed by measurements and/or calculations.
Field meters shall be compliant with EN 61786-1.
This standard does not specify any specific measurement protocol, because of the diversity of the exposure
situations experienced by workers. The measurement protocol shall be compliant with IEC 61786-2.
For small distances to a magnetic field source, where the magnetic field is highly non uniform, the size of the
measuring probe may introduce an averaging bias and therefore may underestimate the actual field.
Therefore the size of the probe shall be appropriate to the spatial variation of the field. Guidance is given in
the measurement standard IEC 61786-2.
Magnetic field measurements should not be performed for assessing compliance for distances to field
sources smaller than the measuring probe.
Measurements and calculations of electric fields are much more complex than for magnetic fields, as the
electric field is perturbed by all conducting objects, even poorly conducting objects, and particularly by
metallic structures. This is known as the “peak effect” and it results in strong local enhancements of the
electric field. The strongly non-uniform field resulting from the peak effect is not representative of the
exposure of a worker. That is why, in order to measure the unperturbed field, IEC 61786-2 recommends:
— a minimum distance of 2 m between the operator and the E field probe;
— to remove movable objects if possible;
— a minimum distance of 1 m to permanent objects if possible.
To overcome this effect, it is recommended to remove any movable object not necessary for the work in
progress that might disturb the measurements during electric fields measurements.
Similarly, the peak effect also affects E-fields measurements close to fixed metallic structures, and a
minimum distance to such structures should be respected in order to perform reliable and reproducible
measurements. IEC 61786-2 recommends a minimum distance of 1 m when possible. However, a
measuring distance of 1 m is not applicable to many work situations which involve contact to metallic
structures, such as workers climbing in lattice steel electrical towers. In this case, a minimum distance of
20 cm shall be maintained between conducting objects and the measurement probe to reduce the peak
effect measurement bias.
6.2.2 Harmonics of magnetic field
For transmission and distribution systems it is acceptable to perform a simplified assessment of harmonics,
except around supplies for industry operating high power converters and rectifiers. Annex A proposes
different approaches for assessing harmonics.
For simplified assessment of harmonics, the total exposure index is allocated partly to the exposure index for
50 Hz and partly to the sum of exposure indexes of harmonics. A total exposure index, including the
fundamental and all harmonics, below 1 demonstrates compliance. Criteria for the 50 Hz exposure index,
depending on the nominal voltage, are given in order to demonstrate that the total exposure index remains
lower than 1. Alternative values may be used if based on specific assessment of harmonics.
— Criterion for voltage range ≥ 60 kV
Based on available field measurements and current measurements, the harmonics of magnetic field at
voltage levels higher than 60 kV can be neglected because the maximum harmonic content of currents in
transmission and distribution systems is limited during normal operations.
NOTE Circumstances where significant harmonics can occur, such as resulting from saturation of transformers
during energizing or during geomagnetic storms, are too rare to need considering further.
— Criterion for voltage range 1 kV to 60 kV
Based on available field measurements and current measurements from medium voltage distribution and
transmission systems, the harmonics up to the 50th might be relevant, but the exposure is compliant if the
exposure index for 50 Hz is below 0,8 (see Annex A). The same criterion can be applied for broadband
measurements.
— Criterion for low voltages (<1kV)
Based on available field measurements and current measurements from low voltage distribution systems,
the harmonics up to the 50th might be relevant, but the exposure is compliant if the exposure index for 50 Hz
is below 0,7 (see Annex A). The same criterion can be applied for broadband measurements.
For power plants, assessment of harmonics may be limited to the excitation unit.
6.2.3 Harmonics of electric field
The harmonics of electric field at any voltage level can be neglected because the maximum harmonic
content of voltage in transmission and distribution systems, which is limited by voltage quality requirements,
usually increases the total exposure index only within the range of the expected uncertainty of assessment.
6.3 Numerical calculation of induced electric fields inside the human body
Numerical computations of induced electric fields inside the human body can be performed using different
numerical methods, such as Finite Elements Method, Finite Integration Technique, Finite Difference Time
Domain, and Scalar Potential Finite Difference. (See [7] and [8]).
Sophisticated models for calculating induced currents in the body have been used and are the subject of a
number of scientific publications. These models use numerical 3D electromagnetic field computation codes
and detailed models of the internal structure with specific electrical characteristics of each tissue within the
body. Such scientific models can be used to assess compliance to ELVs.
7 Assessment against exposure limits for the public
At many workplaces, EMF levels will remain below the reference levels or basic restrictions for the public,
such as those established in the Council Recommendation 1999/519/EC [3]. For such workplaces, when
compliance to these values has already been demonstrated, no further assessment is needed.
The Application Guide [10] of the EMF Directive [11] gives a non-exhaustive list of workplaces where it
should not be necessary to carry out a specific assessment as there is expected to be no risk from EMFs.
The corresponding sources (Table 2) are not expected to give rise to exposures in excess of the reference
levels of the Council Recommendation [3] under any conditions of normal operations.
Table 2 — Equipment or work places deemed to comply with reference levels for public exposure, i.e.
100 µT or 5 kV/m at 50 Hz (from Table 3.2 of the application guide [10])
Type of equipment or workplace Type of exposure
Overhead bare conductors of any voltage Magnetic fields
Electrical installations or electrical circuits within an installation, with a phase
current rating of 100 A or less for the individual circuit (includes wiring, switchgear, Magnetic fields
transformers, etc.)
Any underground or insulated cable circuit, rated at any voltage Electric fields
Any overhead bare circuit in substations above the work place rated at a voltage up
Electric fields
to 110 kV
Any overhead bare circuit in substations with a grounded shield, rated at any
Electric fields
voltage
Any overhead line above the work place rated at a voltage up to 150 kV Electric fields
Any overhead lines at any voltage over-sailing the workplace building where the
Electric fields
workplace is indoors
8 Assessment against Action Levels
8.1 General
Action Levels may not provide sufficient protection for workers at particular risk, as defined in the EMF
directive [11], and a separate assessment is required for those categories of workers (see 13.1).
The rms values for Low and High ALs are given in Figure 2 (magnetic field) and Figure 3 (electric field). At
50 Hz the corresponding values are given in Table 3.
Figure 2 — Low and High Action Levels for magnetic fields in the frequency range from 1 to 20 kHz

Figure 3 — Low and High Action Levels for electric fields in the frequency range from 1 to 20 kHz
Table 3 — Action Levels at 50 Hz
AL for limbs exposure
Low AL High AL
to a localized field
Electric field 10 kV/m 20 kV/m -
Magnetic field 1 000 µT 6 000 µT 18 000 µT
Contact current 1 mA
For magnetic fields up to 400 Hz, the Low and High ALs refer to different biophysical effects and different
organs of the human body. In practice, the Low ALs are related to sensory effects on the central nervous
system and are only applicable to the head. The High ALs are related to health effects on the peripheral
nervous system and therefore apply to the whole body.
Therefore, when the magnetic field is non uniform over the body, compliance with the Low ALs at the
position of the head may not necessarily imply compliance with the High ALs over the remainder of the body.
On the other hand, when the magnetic field can be considered as uniform over the body, compliance with
the Low AL always ensures compliance with the High AL.
Regarding electric fields, the Low and High AL are based upon the same biophysical effects, and therefore
compliance with the Low AL for electric fields always ensures compliance with the High AL.
8.2 Simplified criteria for compliance with action levels
8.2.1 General
This section gives non-exhaustive lists of electrical equipment and operating conditions under which the
equipment is deemed to be compliant with the ALs. For other equipment or different operating conditions
further assessment is needed (see 8.3).
Some electrical equipment is compliant with the ALs provided that a compliance distance to the magnetic
field source is respected. A workplace containing only this kind of equipment is deemed to be compliant with
the EMF Directive [11] regardless the number of instances of such equipment. Such workplaces will require
no further assessment. There may be additional requirements for the employer (see Clause 13).
8.2.2 Magnetic fields
For electrical circuits, this compliance distance depends directly on the current flowing in the circuit. A
rationale for the compliance distance applicable to electrical circuits is given in Annex B (Table B.1).
The list of equipment given in Table 4 is compliant with the Low AL for 50 Hz magnetic fields without further
assessment.
Table 4 — Equipment or work places deemed to comply with the Low AL for 50 Hz magnetic field
(live-line situations not considered)
Type of electrical equipment Remark
Overhead bare conductors of any voltage Provided that electrical safety distances are
respected
Justification for 250 A is given in Annex B
Any electricity installation or circuit in the workplace
with a phase-current rating of 250 A or less (includes
For currents exceeding 250 A, a compliance
wiring, switchgear, transformers, etc.)
distance can be calculated using Formula (2) or
Table B.1 of Annex B
Exceptions listed below in Table 5
Excluding the connections to these equipment and
Any iron-cored transformer (with metallic enclosure) or
motor or generator
the end-windings of high-power turbogenerators
IPB (Isolated Phase Busbars) and GIS/GIC/GIL (Gas Excluding parts outside the regions where the
Insulated Substations/Cables/Lines) of any rating metal enclosures of the different phases are
bonded together
Other situations may exceed the ALs for magnetic field and require further assessment for demonstrating
compliance with the ELVs of the EMF Directive [11]. Based either on measurements or computation, a
possible method is to determine the distance which guarantees that the magnetic field strength falls below
the ALs (subclause 8.3 assessment) or below the exposure-limit-equivalent-field (subclause 9.2
assessment). Some examples are given in Table 5:
EN 5064
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