EN 61515:1996

SLOVENSKI STANDARD
01-november-1998
Mineral insulated thermocouple cables and thermocouples (IEC 61515:1995)
Mineral insulated thermocouple cables and thermocouples
Mantelthermoelement-Leitungen und Mantelthermoelemente
Câbles et couples thermoélectriques à isolation minérale dits chemisés
Ta slovenski standard je istoveten z: EN 61515:1996
ICS:
17.200.20 Instrumenti za merjenje Temperature-measuring
temperature instruments
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

NORME CEI
IEC
INTERNATIONALE
INTERNATIONAL
Première édition
STANDARD
First edition
1995-07
Câbles et couples thermoélectriques à
isolation minérale dits «chemisés»
Mineral insulated thermocouple cables
and thermocouples
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1515 ©IEC:1995 — 3 —
CONTENTS
Page
FOREWORD
Clause
1 General
2 Definitions
Mineral insulated thermocouple cables
17 Mineral insulated thermocouples
Annex A
1515 ©IEC:1995 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
MINERAL INSULATED THERMOCOUPLE CABLES
AND THERMOCOUPLES
FOREWORD
The IEC (International Electrotechnical Commission) is a worldwide organization for standardization
1)
comprising all national electrotechnical committees (IEC National Committees). The object of the IEC is to
promote international cooperation on all questions concerning standardization in the electrical and
electronic fields. To this end and in addition to other activities, the IEC publishes International Standards.
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. The IEC
collaborates closely with the International Organization for Standardization (ISO) in accordance with
conditions determined by agreement between the two organizations.
The formal decisions or agreements of the IEC on technical matters, prepared by technical committees on
2)
which all the National Committees having a special interest therein are represented, express, as nearly as
possible, an international consensus of opinion on the subjects dealt with.
3) They have the form of recommendations for international use published in the form of standards, technical
reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
International Standard IEC 1515 has been prepared by sub-committee 65B: Devices, of
IEC technical committee 65: Industrial-process measurement and control.
The text of this standard is based on the following documents:
DIS Report on voting
65B/227/DIS 65/195/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.
Annex A forms an integral pa rt of this standard.

1515 ©IEC:1995 - 7 -
MINERAL INSULATED THERMOCOUPLE CABLES
AND THERMOCOUPLES
1 General
1.1 Scope and object
This International Standard establishes the requirements for mineral insulated thermo-
couple cables and for mineral insulated thermocouples but does not specify cold end
seals, terminations, connections and other accessories. This standard deals only with
cables and thermocouples having one pair of base-metal conductors and is intended for
use in general industrial applications.
NOTES
1 This standard does not deal with precious metal cables and thermocouples.
2 Mineral insulated cables and thermocouples also are available with more than one pair of conductors
or where there is one conductor and a sheath. In these cases the detailed prescriptions in this standard —
e.g. the dimensions — may not necessarily apply.
3 The special requirements for nuclear primary loop applications are dealt with in other standards.
1.2 Normative references
The following normative documents contain provisions which, through reference in this
text, constitute provisions of this International Standard. At the time of publication, the
editions indicated were valid. All normative documents are subject to revision, and parties
to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated
below. Members of IEC and ISO maintain registers of currently valid International
Standards.
IEC/DIS 584-1, Thermocouples - Part 1: Reference tables')
IEC 584-2: 1982, Thermocouples - Part 2: Tolerances
2 Definitions
For the purposes of this International Standard, the following definitions apply.
2.1 mineral insulated thermocouple cables: Bendable metal sheathed thermocouple
cables with conductors insulated by compacted metal oxide.
thermocouples: Thermocouples made from mineral insulated
2.2 mineral insulated
thermocouple cables.
2.3 measuring junction: Junction subjected to the temperature to be measured.
1) At present, at the stage of Draft International Standard for the second edition.

- 9 -
1515 ©IEC:1995
2.4 earthed junction: Measuring junction electrically connected to the metal sheath.
2.5 Insulated junction: Measuring junction electrically insulated from the metal sheath.
3 Mineral insulated thermocouple cables
3.1 Dimensions
Outside diameter, sheath thickness and conductor diameter dimensions shall be as stated
in table 1.
D = outside diameter
C = conductor diameter
S = sheath wall thickness
I = insulation thickness
Figure 1 - Transverse section of a cable
Table 1 - Dimensions
Sheath wall Diameter of
Outside diameter
Insulation thickness (1)
of cable (D), thickness (S) conductor (C)
minimum
minimum minimum
nominal ± tolerance
mm mm
mm mm
0,5 ± 0,025 0,05 0,08 0,04
1,0 t 0,025 0,10 0,15 0,08
0,15 0,23
1,5 ± 0,025 0,12
2,0 ± 0,025 0,20 0,30 0,16
0,30 0,45
3,0 ± 0,030 0,24
4,5 t 0,045 0,45 0,68 0,36
0,60 0,90 0,48
6,0 ± 0,060
8,0 ± 0,080 0,80 1,20 0,64
1515 ©IEC:1995 - 11 -
3.2 General requirements
3.2.1 Materials
3.2.1.1 Sheaths
Sheaths shall be of austenitic stainless steel, heat resistant NiCr (Fe) alloy or other
material to specifications agreed between manufacturer and user. Some commonly used
sheath materials are listed in table 2.
3.2.1.2 Conductors
Conductors (thermoelectric elements) shall be those forming thermocouple types T, J, E,
K and N as specified in IEC 584-1.
It should be noted that not all combinations of sheath materials and conductor materials
can be manufactured.
3.2.1.3 Insulation
The insulation shall consist of compacted powdered magnesia or alumina with a purity of
at least 96 %. The electrical properties of the insulation shall meet the insulation
resistance test requirements of 3.2.2.2.
Upper temperature limits
3.2.1.4
The recommended maximum operating temperatures for some commonly used sheath
materials are indicated in table 2 for each thermocouple type. For particularly corrosive
atmospheres, the indicated values may not apply and the manufacturer's recom-
mendations should be followed.
Table 2 - Recommended maximum operating temperatures
Sheath TC-type
NiCr alloy Steel Steel
76 Ni, 15 Cr, Fe 25 Cr, 20 Ni 18 Cr, 8 Ni
°C °C °C
T – – 400
E 800 800 800
J 750 750 750
K 1100 1 100 800
N 1 100 1 100 800
Bending radius
3.2.1.5
r of five times its outside dia-
The cable shall be capable of being bent through a radius
meter D (r= 5D) without visible damage.

1515©IEC:1995 – 13 –
3.2.2 Electrical characteristics
3.2.2.1 EMF values
EMF values shall comply with IEC 584-1 with initial calibration tolerance values as
specified for base metal conductors in IEC 584-2.
3.2.2.2 Insulation resistance
Insulation resistance shall be measured between each wire and sheath and between
wires, at test voltages of 75 V ± 25 V d.c. for outside diameters 55.1,5 mm and 500 V ± 50 V
d.c. for outside diameters >1,5 mm.
Sample length, temperature conditions and insulation resistance values expressed in
MS2 m for testing at ambient and elevated temperatures shall be as given in table 3.
Table 3 – Insulation resistance values at ambient and elevated temperatures
Minimum immersed
Minimum Insulation
length at test
Test temperature
resistance
temperature
m °c M52m
1 1 000
Ambient temperature 20 ± 15
Elevated temperature
0,5 500 ± 15 5
E, K,
...