Conventions concerning electric circuits (IEC 60375:2018)

This International Standard specifies the rules for signs and reference directions and
reference polarities for electric currents and voltages in electric networks.
In Clauses 3 to 10, the time dependence is arbitrary. It is assumed that the wavelength of the
highest frequency involved is larger than the largest distance between two points of the
network; processes are considered to be quasi-static. Clause 11 specifies the rules and
recommendations for complex notation.

Vereinbarungen über elektrische Stromkreise

Conventions concernant les circuits électriques (IEC 60375:2018)

IEC 60375:2018 spécifie les règles relatives aux signes, sens de référence et polarités de référence des courants électriques et des tensions dans les réseaux électriques.

Konvencije o električnih tokokrogih (IEC 60375:2018)

Ta mednarodni standard določa pravila za znake in referenčne smeri ter referenčne polarnosti za električne tokove in napetosti v električnih omrežjih.
Uporaba časovne odvisnosti pri točkah 3–10 je poljubna. Ta standard predvideva, da je valovna dolžina največje frekvence večja od največje razdalje med dvema točkama omrežja; procesi veljajo kot navidezno statični. Točka 11 določa pravila in priporočila za kompleksne zapise.

General Information

Status
Published
Publication Date
06-Sep-2018
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
22-Aug-2018
Due Date
27-Oct-2018
Completion Date
07-Sep-2018

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SLOVENSKI STANDARD
SIST EN IEC 60375:2018
01-oktober-2018
1DGRPHãþD
SIST EN 60375:2004
.RQYHQFLMHRHOHNWULþQLKWRNRNURJLK ,(&
Conventions concerning electric circuits (IEC 60375:2018)
Conventions concernant les circuits électriques (IEC 60375:2018)
Ta slovenski standard je istoveten z: EN IEC 60375:2018
ICS:
17.220.01 Elektrika. Magnetizem. Electricity. Magnetism.
Splošni vidiki General aspects
SIST EN IEC 60375:2018 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN IEC 60375:2018
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SIST EN IEC 60375:2018
EUROPEAN STANDARD EN IEC 60375
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2018
ICS 01.060; 01.080.40 Supersedes EN 60375:2003
English Version
Conventions concerning electric circuits
(IEC 60375:2018)
Conventions concernant les circuits électriques Vereinbarungen für Stromkreise
(IEC 60375:2018) (IEC 60375:2018)

This European Standard was approved by CENELEC on 2018-06-12. 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: Rue de la Science 23, B-1040 Brussels

© 2018 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN IEC 60375:2018 E
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SIST EN IEC 60375:2018
EN IEC 60375:2018
European foreword

The text of document 25/620/FDIS, future edition 3 of IEC 60375, prepared by IEC/TC 25 "Quantities

and units, and their letter symbols" was submitted to the IEC-CENELEC parallel vote and approved by

CENELEC as EN IEC 60375:2018.
The following dates are fixed:
(dop) 2019-03-12
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2021-06-12
standards conflicting with the
document have to be withdrawn
This document supersedes EN 60375:2003.

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.

Endorsement notice

The text of the International Standard IEC 60375:2018 was approved by CENELEC as a European

Standard without any modification.
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SIST EN IEC 60375:2018
EN IEC 60375:2018
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the relevant

EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:

www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60617-DB - Graphical symbols for diagrams - -
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SIST EN IEC 60375:2018
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SIST EN IEC 60375:2018
IEC 60375
Edition 3.0 2018-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Conventions concerning electric circuits
Conventions concernant les circuits électriques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 01.060; 01.080.40 ISBN 978-2-8322-5597-1

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
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SIST EN IEC 60375:2018
– 2 – IEC 60375:2018 © IEC 2018
CONTENTS

FOREWORD ........................................................................................................................... 5

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms and definitions ...................................................................................................... 7

4 Orientation of geometrical objects ................................................................................. 15

4.1 Orientation of a curve ........................................................................................... 15

4.2 Orientation of a surface......................................................................................... 15

4.3 Arrows perpendicular to the plane of the figure ..................................................... 15

5 Conventions concerning currents ................................................................................... 15

5.1 Physical direction of current .................................................................................. 15

5.2 Reference direction of current ............................................................................... 16

5.3 Indication of the reference direction for currents ................................................... 16

5.3.1 Indication of the reference direction for currents for a branch ........................ 16

5.3.2 Indication of the reference direction for mesh currents ................................... 16

5.4 Kirchhoff law for nodes ......................................................................................... 17

6 Conventions concerning voltages .................................................................................. 17

6.1 Physical polarity of voltage ................................................................................... 17

6.2 Reference polarity for a pair of nodes ................................................................... 18

6.3 Indication of the reference polarity ........................................................................ 18

6.3.1 First method .................................................................................................. 18

6.3.2 Second method.............................................................................................. 18

6.3.3 Third method ................................................................................................. 19

6.4 Kirchhoff law for meshes ....................................................................................... 19

7 Conventions concerning power ...................................................................................... 20

7.1 Physical direction of power ................................................................................... 20

7.2 Reference direction of power ................................................................................ 20

7.3 Indication of the reference direction of power ........................................................ 20

7.4 Combined conventions .......................................................................................... 20

7.4.1 General ......................................................................................................... 20

7.4.2 Motor convention ........................................................................................... 21

7.4.3 Generator convention .................................................................................... 21

8 Conventions concerning two-port networks .................................................................... 21

9 Conventions concerning sources ................................................................................... 22

9.1 Conventions concerning voltage sources .............................................................. 22

9.1.1 Independent voltage sources ......................................................................... 22

9.1.2 Controlled voltage sources ............................................................................ 22

9.2 Conventions concerning current sources ............................................................... 23

9.2.1 Independent current sources ......................................................................... 23

9.2.2 Controlled current sources ............................................................................. 23

10 Conventions concerning passive elements..................................................................... 24

10.1 General conventions ............................................................................................. 24

10.2 Resistive elements ................................................................................................ 24

10.2.1 Resistive two-terminal elements .................................................................... 24

10.2.2 Resistive n-terminal elements ........................................................................ 25

10.3 Capacitive elements .............................................................................................. 26

10.3.1 Capacitive two-terminal elements .................................................................. 26

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10.3.2 Capacitive n-terminal elements ...................................................................... 27

10.4 Inductive elements ................................................................................................ 29

10.4.1 Inductive two-terminal elements ..................................................................... 29

10.4.2 Inductive n-port elements ............................................................................... 30

11 Complex notation ........................................................................................................... 32

11.1 General ................................................................................................................. 32

11.2 Conventions concerning complex representation of sinusoidal quantities .............. 32

11.3 Reference direction of a complex current .............................................................. 32

11.4 Reference polarity for a complex voltage .............................................................. 33

11.5 Complex representation of Ohm's law ................................................................... 34

11.6 Conventions concerning the graphical representation of phasors .......................... 35

11.7 Conventions concerning phase differences ........................................................... 35

11.8 Conventions concerning power ............................................................................. 36

11.8.1 Time-dependent electric power ...................................................................... 36

11.8.2 Complex power .............................................................................................. 36

Bibliography .......................................................................................................................... 37

Figure 1 – Orientation of a curve ........................................................................................... 15

Figure 2 – Orientation of a surface ........................................................................................ 15

Figure 3 – Indication of the reference direction for a current by an arrow .............................. 16

Figure 4 – Indication of the reference direction using the node names .................................. 16

Figure 5 – Indication of the reference direction for mesh currents ......................................... 17

Figure 6 – Examples of the Kirchhoff law for nodes ............................................................... 17

Figure 7 – Indication of the reference polarity by means of plus and minus signs .................. 18

Figure 8 – Simplified indication of the reference polarity by means of plus signs ................... 18

Figure 9 – Indication of the reference polarity by an arrow .................................................... 18

Figure 10 – Indication of the reference polarity using the node names .................................. 19

Figure 11 – Simplified indication of the reference polarity using the node names .................. 19

Figure 12 – Examples of the Kirchhoff law for meshes .......................................................... 20

Figure 13 – Indication of the reference direction of power ..................................................... 20

Figure 14 – Examples of motor conventions .......................................................................... 21

Figure 15 – Examples of generator conventions .................................................................... 21

Figure 16 – A reference convention for a two-port network.................................................... 22

Figure 17 – Graphical representation of an independent voltage source ............................... 22

Figure 18 – Graphical representation of a voltage source controlled by a voltage:

u =αu .............................................................................................................................. 22

s c

Figure 19 – Graphical representation of a voltage source controlled by a current:

u =β i ............................................................................................................................... 23

s c

Figure 20 – Graphical representation of an independent current source ................................ 23

Figure 21 – Graphical representation of a current source controlled by a voltage:

i =γ u ................................................................................................................................ 24

s c

Figure 22 – Graphical representation of a current source controlled by a current:

i =δ i ................................................................................................................................. 24

s c

Figure 23 – Examples of graphical representations of a two-terminal resistive element ......... 25

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Figure 24 – Examples of the graphical representation of a four-terminal resistive

element................................................................................................................................. 25

Figure 25 – Examples of the graphical representation of a two-terminal capacitive

element................................................................................................................................. 26

Figure 26 – Examples of the graphical representation of a four-terminal capacitive

element................................................................................................................................. 27

Figure 27 – Examples of the graphical representation of a two-terminal inductive

element................................................................................................................................. 29

Figure 28 – Examples of the graphical representation of a three-port inductive element ........ 30

Figure 29 – Examples of the Kirchhoff law for nodes in complex notation .............................. 33

Figure 30 – Examples of the Kirchhoff law for meshes in complex notation ........................... 34

Figure 31 – Examples of graphical representation of reference directions and polarities

in Ohm's law for a complex two-terminal element .................................................................. 35

Figure 32 – Graphical representation of a phasor in the complex plane ................................. 35

Figure 33 – Graphical representation of phase difference in the complex plane .................... 35

Figure 34 – Examples of the reference directions for time-dependent electric power ............. 36

Figure 35 – Examples of the reference directions for the complex power .............................. 36

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SIST EN IEC 60375:2018
IEC 60375:2018 © IEC 2018 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CONVENTIONS CONCERNING ELECTRIC CIRCUITS
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 National Committee interested

in the subject dealt with may participate in this preparatory work. International, governmental and non-

governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely

with 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 Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC

Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any

misinterpretation by any end user.

4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications

transparently to the maximum extent possible in their national and regional publications. Any divergence

between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

the latter.

5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

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 nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, 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) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 60375 has been prepared by IEC technical committee 25:

Quantities and units, and their letter symbols.

This third edition cancels and replaces the second edition issued in 2003. This edition

constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:

a) the clause on conventions concerning magnetic circuits has been removed; accordingly

the title of the document has been abbreviated to read “Conventions concerning electric

circuits”;
b) text and figures have been revised and homogenised;
c) Clause 3 has been structured into subclauses;

d) Clause 4 – Orientation of geometrical objects – has been inserted, and thus the clause

numbering has been altered.
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SIST EN IEC 60375:2018
– 6 – IEC 60375:2018 © IEC 2018
The text of this standard is based on the following documents:
FDIS Report on voting
25/620/FDIS 25/622/RVD

Full information on the voting for the approval of this standard can be found in the report on

voting indicated in the above table.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

The committee has decided that the contents of this publication will remain unchanged until

the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data

related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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SIST EN IEC 60375:2018
IEC 60375:2018 © IEC 2018 – 7 –
CONVENTIONS CONCERNING ELECTRIC CIRCUITS
1 Scope

This International Standard specifies the rules for signs and reference directions and

reference polarities for electric currents and voltages in electric networks.

In Clauses 3 to 10, the time dependence is arbitrary. It is assumed that the wavelength of the

highest frequency involved is larger than the largest distance between two points of the

network; processes are considered to be quasi-static. Clause 11 specifies the rules and

recommendations for complex notation.
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 60617, Graphical symbols for diagrams
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
orientation

property of a curve described by the position vector r(u) which is associated with

increasing or decreasing values of the parameter u
[SOURCE: IEC 60050-102:2007, 102-04-19]
3.2
orientation

for a surface having a tangent plane at any point, property determined by the

choice, continuously from point to point, of one of the two normal unit vectors at each point

[SOURCE: IEC 60050-102:2007, 102-04-36, modified – Note 1 to entry omitted.]
3.3
electric charge

additive scalar quantity, associated with elementary particles and with macroscopic matter

that characterizes their electromagnetic interactions
_____________

IEC 60617 is a database containing symbols referenced in the form (IEC 60617-Sxxxxx) where Sxxxxx is the

identity number of the symbol.
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SIST EN IEC 60375:2018
– 8 – IEC 60375:2018 © IEC 2018

Note 1 to entry: The (electric) charge of a capacitor is defined in IEC 60050-131:2002, 131-12-11 differently by

q= i(τ )dτ ; where it is used in this document, it is marked with this source in square brackets.

[SOURCE: IEC 60050-121:1998, 121-11-01, modified – Note 1 to entry has been replaced

and Note 2 to entry has been omitted.]
3.4
positive electric charge

electric charge which is of the same sign as that attributed by convention to a proton

[SOURCE: IEC 60050-113:2011, 113-02-12]
3.5
quasi-infinitesimal

for a system of elementary entities distributed in space, qualifies the length, the area, or the

volume of an element of space, all the geometrical dimensions of which are small compared

with those of the system under consideration but sufficiently large for the element of space to

contain a large number of elementary entities; qualifies also an extensive quantity when

summed for all elementary entities within such an element of space
[SOURCE: IEC 60050-121:1998, 121-11-06, modified – Notes to entry omitted.]
3.6
electric current
current
conduction current

scalar quantity equal to the flux of the electric current density J through a given oriented

surface S:
I= J⋅e dA
where e dA is the vector surface element
[SOURCE: IEC 60050-121:1998, 121-11-13, modified – Notes to entry omitted.]
3.7
integral quantity

line, surface or volume integral of a quantity associated with an electromagnetic field

[SOURCE: IEC 60050-131:2002, 131-11-01, modified – Notes to entry omitted.]
3.8
circuit theory

study of electric and magnetic systems in which the electric and magnetic phenomena are

described in terms of integral quantities
[SOURCE: IEC 60050-131:2002, 131-11-02, modified – Note to entry omitted.]
3.9
circuit element

in electromagnetism, mathematical model of a device characterized by one or more relations

between integral quantities
[SOURCE: IEC 60050-131:2002, 131-11-03]
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SIST EN IEC 60375:2018
IEC 60375:2018 © IEC 2018 – 9 –
3.10
electric circuit element

circuit element for which only relations between electric integral quantities are considered

[SOURCE: IEC 60050-131:2002, 131-11-04]
3.11
circuit
set of interconnected circuit elements
[SOURCE: IEC 60050-131:2002, 131-11-06]
3.12
electric circuit
circuit consisting of electric circuit elements only

[SOURCE: IEC 60050-131:2002, 131-11-07, modified – Synonym "electric network" and notes

to entry omitted.]
3.13
terminal

point of interconnection of an electric circuit element, an electric circuit or a network with

other electric circuit elements, electric circuits or networks
[SOURCE: IEC 60050-131:2002, 131-11-11, modified – Notes to entry omitted.]
3.14
n-terminal

qualifies an electric circuit element, an electric circuit or a network having n terminals with n

generally greater than two
[SOURCE: IEC 60050-131:2002, 131-11-12]
3.15
n-terminal circuit element
electric circuit element having n terminals with n generally greater than two
[SOURCE: IEC 60050-131:2002, 131-11-13, modified – Note to entry omitted.]
3.16
n-terminal circuit
electric circuit having n terminals with n generally greater than two
[SOURCE: IEC 60050-131:2002, 131-11-14, modified – Note to entry omitted.]
3.17
two-terminal circuit
electric circuit having two terminals
[SOURCE: IEC 60050-131:2002, 131-11-15]
3.18
two-terminal element
electric circuit element having two terminals
[SOURCE: IEC 60050-131:2002, 131-11-16]
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3.19
phasor

representation of a sinusoidal integral quantity by a complex quantity whose argument is

equal to the initial phase and whose modulus is equal to the root-mean-square value

[SOURCE: IEC 60050-131:2002, 131-11-26, modified – Notes to entry omitted.]
3.20
direction of electric current

by convention, the direction of the net flow of positive electric charge transferred from one

terminal to another terminal
[SOURCE: IEC 60050-131:2002, 131-11-29, modified – Note to entry omitted.]
3.21
passive

qualifies a circuit element or a circuit for which the time integral of the instantaneous power

cannot be negative over any time interval beginning at an instant before the first supply of

electric energy
[SOURCE: IEC 60050-131:2002, 131-11-34, modified – Notes to entry omitted.]
3.22
complex power
under sinusoidal conditions, product of t
...

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