IEC 60584-3:2021

IEC 60584-3 ®
Edition 3.0 2021-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Thermocouples –
Part 3: Extension and compensating cables – Tolerances and identification
system
Couples thermoélectriques –
Partie 3: Câbles d'extension et de compensation – Tolérances et système
d'identification
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IEC 60584-3 ®
Edition 3.0 2021-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Thermocouples –
Part 3: Extension and compensating cables – Tolerances and identification

system
Couples thermoélectriques –
Partie 3: Câbles d'extension et de compensation – Tolérances et système

d'identification
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.200.20 ISBN 978-2-8322-9392-8

– 2 – IEC 60584-3:2021 © IEC 2021
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 General . 6
5 Tolerance values . 6
6 Colour coding . 7
6.1 Negative conductor . 7
6.2 Positive conductor . 7
6.3 Outer sheath . 7
6.4 Connectors . 7
7 Dimensions. 7
8 Requirements . 9
8.1 Materials . 9
8.1.1 Insulating materials . 9
8.1.2 Conductor materials. 9
8.2 Electromagnetic shielding . 9
8.3 Capacitance and inductance . 9
8.4 Resistance of positive or negative conductor and loop resistance of a cable . 9
8.5 Insulation resistance . 10
8.6 Dielectric strength . 10
9 Identification and shipping form . 10
9.1 Additional identification . 10
9.2 The shipping form and further information . 10
Annex A (informative) Examples for forms and sizes other than wires and stranded
wires . 11

Table 1 – Tolerance classes for extension and compensating cables . 6
Table 2 – Colour code of positive conductor insulation for extension and compensating
cables . 7
Table 3 – Nominal diameters of typical single strand (solid) wires . 8
Table 4 – Constructions and typical nominal cross-sectional area of multi-stranded
wires . 8
Table A.1 – Rods . 11
Table A.2 – Flat wires . 11
Table A.3 – Strips . 11

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
THERMOCOUPLES –
Part 3: Extension and compensating cables –
Tolerances and identification system

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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tional co-operation on all questions concerning standardization in the electrical and electronic fields. To this
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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6) All users should ensure that they have the latest edition of this publication.
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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 60584-3 has been prepared by subcommittee 65B: Measurement
and control devices, of IEC Technical Committee 65: Industrial-process measurement, control
and automation.
This third edition cancels and replaces the second edition issued in 2007. This edition consti-
tutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) revision of tolerance values to take recent technological advancement into account,
b) addition of new colour coding for the thermocouple Type C and A in response to the newly
revised IEC 60584‑1 Edition 3: 2013,
c) creation of an annex to provide examples of sizes for the rod, flat wire and strip of the
compensating and extending conductors for thermocouples.

– 4 – IEC 60584-3:2021 © IEC 2021
The text of this International Standard is based on the following documents:
FDIS Report on voting
65B/1189/FDIS 65B/1191/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
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, availa-
ble at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts of the IEC 60584 series, under the general title Thermocouples, can be
found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://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.
THERMOCOUPLES –
Part 3: Extension and compensating cables –
Tolerances and identification system

1 Scope
It is necessary for thermocouple temperature measurement that the electro-motive force (ab-
breviated as e.m.f. hereafter) of the thermocouple circuit is precisely measured by a measur-
ing instrument. A thermocouple is electrically connected to the instrument by a proper pair of
electric cables. IEC 60584-3 standardizes these cables. It specifies identification and manu-
facturing tolerances for extension and compensating cables (mineral insulated extension and
compensating cables are not included) provided directly to users of industrial processes.
These tolerances are determined with respect to the e.m.f. versus temperature relationship of
IEC 60584-1. The requirements for extension and compensating cables for use in industrial
process control are specified.
Extension and compensating cables may consist of a single strand (solid) wire or multi-
stranded wire for which this document is applied. Specification for extension and compensat-
ing conductors of forms of rods, flat wires or strips can be established by agreement between
suppliers and users.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their con-
tent 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 60584-1, Thermocouples – Part 1: EMF specifications and tolerances
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 ad-
dresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
extension cables
cables manufactured from conductors having the same nominal composition as those of the
corresponding thermocouple
Note 1 to entry: The cables are designated by the letter "X" following the designation of the thermocouple, for
example "JX".
3.2
compensating cables
cables manufactured from conductors having a composition different from the corresponding
thermocouple
– 6 – IEC 60584-3:2021 © IEC 2021
Note 1 to entry: The cables are designated by the letter "C" following the designation of the thermocouple, for
example "KC". In some cases, different tolerances apply for the same thermocouple type over different temperature
ranges. These are distinguished by additional letters such as, for example, RCA and RCB.
3.3
tolerance
maximum allowable deviation in microvolts caused by the introduction of the extension or
compensating cable into the measuring circuit
4 General
Both extension and compensating cables are used for the electrical connection between the
open ends of a thermocouple and the reference junction in those installations where the con-
ductors of the thermocouple are not directly connected to the reference junction. A cable al-
ways consists of a specific pair (negative and positive conductor), to be connected to the cor-
responding thermocouple. The thermoelectric properties of extension and compensating ca-
bles shall be close to the properties of the corresponding thermocouple. Products are manu-
factured for each thermocouple type, using various alloy formulations for various purposes.
The key characteristic is that the pair of conductors meets the specified e.m.f. tolerance re-
quirements.
5 Tolerance values
Table 1 shows the specified tolerance for extension and compensating cables when used at
temperatures within the ranges indicated as "temperature range of validity". Temperature
range of validity can be restricted to figures lower than those shown in the table because of
temperature limitations imposed by the insulant.
Table 1 – Tolerance classes for extension and compensating cables
Tolerance class Measuring
Type Temperature range of validity junction
1 2
temperature
JX ±85 µV (±1,5 °C) ±140 µV (±2,5 °C) −25 °C to +200 °C 500 °C
TX ±30 µV (±0,5 °C) ±60 µV (±1,0 °C) −25 °C to +100 °C 300 °C
EX ±120 µV (±1,5 °C) ±200 µV (±2,5 °C) −25 °C to +200 °C 500 °C
KX ±60 µV (±1,5 °C) ±100 µV (±2,5 °C) −25 °C to +200 °C 900 °C
NX ±60 µV (±1,5 °C) ±100 µV (±2,5 °C) −25 °C to +200 °C 900 °C
KCA ±60 µV (±1,5 °C) ±100 µV (±2,5 °C) 0 °C to +200 °C 900 °C
KCB ±60 µV (±1,5 °C) ±100 µV (±2,5 °C) 0 °C to +100 °C 900 °C
NC ±60 µV (±1,5 °C) ±100 µV (±2,5 °C) 0 °C to + 200 °C 900 °C
RCA ±20 µV (±1,5 °C) ±30 µV (±2,5 °C) 0 °C to +100 °C 1 000 °C
RCB ±30 µV (±2,5 °C) ±60 µV (±5,0 °C) 0 °C to +200 °C 1 000 °C
SCA ±20 µV (±1,5 °C) ±30 µV (±2,5 °C) 0 °C to +100 °C 1 000 °C
SCB ±30 µV (±2,5 °C) ±60 µV (±5,0 °C) 0 °C to +200 °C 1 000 °C
BC  ±40 µV (±3,5 °C) 0 °C to +100 °C 1 400 °C
CC  ±110 µV (±8,0 °C) 0 °C to +200 °C 1 800 °C
ACA ±40 µV (±3,5 °C)  0 °C to +100 °C 1 800 °C
ACB  ±70 µV (±5,0 °C) 0 °C to +200 °C 1 800 °C
NOTE Tolerances are specified in microvolts. The table also includes, in parentheses, the approximate equiva-
lent tolerances in degrees Celsius. Because thermocouple e.m.f. temperature relationships are non-linear, the
tolerance in degrees Celsius depends on the temperature of the measuring junction of the thermocouple where
the reference junction is 0 °C. The figures shown in the table are those appropriate to the measuring junction
temperatures in the final column. In all cases, the deviations (expressed in degrees Celsius) are different at
lower temperatures.
A cable comprising two copper conductors may be used with Type B thermocouples. The ex-
pected maximum additional deviation within the cable temperature range 0 °C to +100 °C is
40 μV. The equivalent in temperature is 3,5 °C when the measuring junction of the thermo-
couple is at 1 400 °C.
6 Colour coding
6.1 Negative conductor
The insulation of the negative conductor shall be coloured in WHITE for all thermocouple
types.
6.2 Positive conductor
The insulation of the positive conductor shall be coloured correspondingly to the thermocou-
ple as indicated in Table 2.
6.3 Outer sheath
The outer sheath, if any, shall be coloured as indicated in Table 2. The outer sheath, if any,
shall be colored as given in Table 2. In the case of possible confusion with existing IEC color
code specification of cables, the color shall be indicated by other means, for instance by put-
ting a label, tag or sticker of the specified color in the Table 2.

Table 2 – Colour code of positive conductor insulation
for extension and compensating cables
Colour of positive conductor
Thermocouple type
and sheath insulation
T Brown
E Purple
J Black
K Green
N Pink
B Grey
R Orange
S Orange
C Red
A Dark blue
6.4 Connectors
The connectors, if any, used in conjunction with thermocouples and compensating or exten-
sion cables, shall be coloured as indicated in Table 2. The colouring may be a mass colouring
or a coloured dot on the connector’s surface.
7 Dimensions
The dimensions of conductors of cables should be agreed between supplier and user taking
into account, for example, the tensile strength and flexibility of the cable. Table 3 shows typi-
cal examples of nominal diameter of single strand (solid) wires. Table 4 shows typical exam-
ples of constructions of multi-stranded wires and estimated total cross-sectional areas of the

– 8 – IEC 60584-3:2021 © IEC 2021
conductors. The form of the conductors can be rods, flat wires and strips, and examples of
their sizes are shown in Annex A.
Table 3 – Nominal diameters of typical single strand (solid) wires
Nominal diameter of single strand (solid) wire
mm
0,10
0,12
0,18
0,20
0,30
0,32
0,40
0,45
0,50
0,60
0,63
0,64
0,65
0,80
0,81
1,00
1,25
1,29
1,295
1,38
1,60
Table 4 – Constructions and typical nominal
cross-sectional area of multi-stranded wires (1 of 2)
Nominal total cross- Construction
sectional area
number of strands × diameter of
mm
a strand in mm
0,05 7 × 0,10
0,11 12 × 0,12
7 × 0,20
0,22
3 × 0,30
0,38 12 × 0,20
0,41 13 × 0,20
16 × 0,20
0,50
7 × 0,30
0,60 19 × 0,20
0,72 23 × 0,20
0,75 24 × 0,20
Nominal total cross- Construction
sectional area
number of strands × diameter of
mm
a strand in mm
11 × 0,30
32 × 0,20
14 × 0,30
1,00 7 × 0,44
5 × 0,50
3 × 0,65
7 × 0,45
1,20
4 × 0,60
1,25 4 × 0,63
1,30 4 × 0,65
48 × 0,20
21 × 0,30
1,50
7 × 0,52
3 × 0,80
16 × 0,40
2,00
7 × 0,60
2,20 7 × 0,63
2,25 7 × 0,64
2,30 7 × 0,65
8 Requirements
8.1 Materials
8.1.1 Insulating materials
The choice of insulating materials shall be agreed between supplier and user.
8.1.2 Conductor materials
For the cable temperature range, the thermal e.m.f. of conductor materials of a cable shall
comply both with IEC 60584-1 and with the tolerances specified in Clause 5 of this document.
8.2 Electromagnetic shielding
To reduce the EMC interference, cables shall be manufactured by using pairs of twisted con-
ductors, and additional shielding can be used for a thermoelectric circuit.
8.3 Capacitance and inductance
The capacitance and inductance – both per metre – (conductors against conductors and con-
ductors against shield – if present) shall be made available.
8.4 Resistance of positive or negative conductor and loop resistance of a cable
The nominal value of the resistance of positive or negative conductors in Ω/m at (20 ± 5) °C
shall be declared by the manufacturer and the nominal loop resistance in Ω/m at (20 ± 5) °C
shall be made available.
– 10 – IEC 60584-3:2021 © IEC 2021
8.5 Insulation resistance
3 9
The minimum insulation resistance shall be 5 MΩ·km (5 × 10 MΩ·m = 5 ×10 Ω·m) for cables
with fibrous insulation and 500 MΩ·km (0,5 × 10 MΩ·m) for all other cables within the scope
of this document. The total electrical requirements of the system may take precedence over
this specification. For fibrous insulation, the insulation resistance specification shall be met at
the time of manufacturing. To maintain the specified insulation resistance, user shall store in
clean and dry condition.
The insulation resistance shall be measured between each conductor and all the other con-
ductors and shield. Test voltage shall be (500 ± 50) V DC and environmental conditions shall
be a temperature of (20 ± 15) °C and a relative humidity of less than 85 % (non-condensing).
8.6 Dielectric strength
A voltage of 500 V AC shall be applied for 1 min each time at ambient conditions between:
a) each conductor separately and all the others connected together,
b) all conductors and the shielding.
No breakdown shall occur during this test.
9 Identification and shipping form
9.1 Additional identification
The primary identification is the colour coding in Table 2. Additional identification shall be ap-
pl
...