IEC 60393-4:2023

IEC 60393-4 ®
Edition 3.0 2023-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Potentiometers for use in electronic equipment –
Part 4: Sectional specification: Single-turn rotary power potentiometers

Potentiomètres utilisés dans les équipements électroniques –
Partie 4: Spécification intermédiaire: Potentiomètres rotatifs monotours à forte
dissipation
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IEC 60393-4 ®
Edition 3.0 2023-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Potentiometers for use in electronic equipment –

Part 4: Sectional specification: Single-turn rotary power potentiometers

Potentiomètres utilisés dans les équipements électroniques –

Partie 4: Spécification intermédiaire: Potentiomètres rotatifs monotours à forte

dissipation
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.040.20  ISBN 978-2-8322-7611-2

– 2 – IEC 60393-4:2023 © IEC 2023
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative reference . 6
3 Terms and definitions . 7
4 Preferred characteristics . 8
4.1 General . 8
4.2 Style and dimensions . 8
4.3 Preferred climatic categories . 9
4.4 Resistance law . 9
4.5 Nominal total resistance . 9
4.6 Tolerances on nominal total resistance . 9
4.7 Rated dissipation . 9
4.8 Limiting element voltage . 10
4.9 Insulation voltage . 10
4.10 Number of cycles of operation . 10
4.11 Shaft rotational speed . 10
5 Tests and test severities . 10
5.1 General . 10
5.2 Mounting . 11
5.3 Tests . 11
5.3.1 Drying . 11
5.3.2 Resistance measurement . 11
5.3.3 Vibration . 11
5.3.4 Bump . 11
5.3.5 Shock . 11
5.3.6 Temperature coefficients and temperature characteristics of resistance . 12
6 Performance requirements. 12
6.1 General . 12
6.2 Limits for change in resistance or output voltage ratio . 12
6.3 Limits for insulation resistance . 12
6.4 Limits of temperature rise . 13
6.5 Limits for resistance law . 13
6.6 Limits for operating torque . 13
6.7 Limits for end stop torque . 13
6.8 Limits for residual resistances . 14
6.9 Visual inspection . 14
6.9.1 General visual criteria . 14
6.9.2 Visual criteria after tests . 14
6.10 Solderability . 14
7 Marking, packaging, and ordering information . 14
7.1 Marking of the component . 14
7.2 Marking for packaging . 15
7.3 Additional marking . 15
7.4 Ordering information . 15
8 Detail specifications . 15
8.1 General . 15

8.2 Information to be specified in a detail specification . 15
8.2.1 Outline drawing or illustration . 15
8.2.2 Dimensions . 16
8.2.3 Mounting . 16
8.2.4 Resistance law . 16
8.3 Ratings and characteristics . 16
8.3.1 General . 16
8.3.2 Nominal total resistance range . 16
8.3.3 Marking . 16
8.3.4 Ordering information . 16
8.3.5 Additional information . 17
9 Quality assessment procedures . 17
9.1 General . 17
9.2 Definitions. 17
9.2.1 Primary stage of manufacture . 17
9.2.2 Structurally similar components . 17
9.3 Assessment level EZ . 17
10 Qualification approval . 17
10.1 General . 17
10.2 Qualification approval based on the fixed sample size procedure sampling . 17
10.3 Tests . 18
11 Quality conformance inspection . 25
11.1 Formation of inspection lots . 25
11.2 Test schedule . 26
11.3 Assessment levels . 26
11.4 Delayed delivery . 28
12 Apparatus for measuring mechanical accuracy . 28
12.1 Dial indicator . 28
12.2 Cylindrical shaft adaptor . 28
12.3 Potentiometer mounting fixture . 28
12.4 Potentiometer shaft holding fixture . 28
Annex A (informative) Letter symbols and abbreviations . 29
Bibliography . 31

Figure 1 – Schematic view . 7
Figure 2 – Outline drawing and dimensions . 8
Figure 3 – Rated dissipation curve . 9
Figure 4 – Rated dissipation curve (example of larger area). 10

Table 1 – Limits for change in resistance or output voltage ratio . 12
Table 2 – Limits for operating torque . 13
Table 3 – Limits for end stop torque . 13
Table 4 – Test schedule for qualification approval . 19
Table 5 – Quality conformance inspection: Lot-by-lot inspection . 26
Table 6 – Quality conformance inspection: Periodic testing . 27

– 4 – IEC 60393-4:2023 © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
POTENTIOMETERS FOR USE IN ELECTRONIC EQUIPMENT –

Part 4: Sectional specification:
Single-turn rotary power potentiometers

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
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Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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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) 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. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 60393-4 has been prepared by IEC technical committee 40: Capacitors and resistors for
electronic equipment. It is an International Standard.
This third edition cancels and replaces the second edition published in 1992 and constitutes a
technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) the document structure has been organized to follow new sectional specification structure
decided in TC 40;
b) the information on the assessment level EZ and FZ (zero nonconforming) has been revised.

The text of this International Standard is based on the following documents:
Draft Report on voting
40/3074/FDIS 40/3085/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, 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.
A list of all parts in the IEC 60393 series, published under the general title Potentiometers for
use in electronic equipment, 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 webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
– 6 – IEC 60393-4:2023 © IEC 2023
POTENTIOMETERS FOR USE IN ELECTRONIC EQUIPMENT –

Part 4: Sectional specification:
Single-turn rotary power potentiometers

1 Scope
This part of IEC 60393 is applicable to single-turn rotary power potentiometers wire-wound
technology. Enamelled, cemented, moulded, enclosed.
This specification is applicable to rotary potentiometers with nominal dissipation in excess of
10 W, the resistive element of which consists of a wire or a wound tape. All the potentiometers
specified by this specification are slider-driven without reduction. Their stroke less than 360° is
limited by stops.
This document specifies preferred ratings and characteristics and selects from IEC 60393-1,
appropriate quality assessment procedures, tests and measuring methods. It provides general
performance requirements for this type of potentiometer.
This document gives the minimum performance requirements and test severities.
Annex A lists the letters and symbols used in the clauses of this document.
2 Normative reference
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 60062:2016, Marking codes for resistors and capacitors
IEC 60062:2016/AMD1:2019
IEC 60063, Preferred number series for resistors and capacitors
IEC 60068-2-1, Environmental testing – Part 2-1: Tests – Test A: Cold
IEC 60068-2-2, Environmental testing – Part 2-2: Tests – Test B: Dry heat
IEC 60393-1:2008, Potentiometers for use in electronic equipment – Part 1: Generic
specification
IEC 60915, Capacitors and resistors for use in electronic equipment – Preferred dimensions of
shaft ends, bushes and for the mounting of single-hole, bush-mounted, shaft-operated
electronic components
IEC 61439-1, Low-voltage switchgear and control gear assemblies – General rules
IEC 61193-2:2007, Quality assessment systems – Part 2: Selection and use of sampling plans
for inspection of electronic components and packages

3 Terms and definitions
For this document, the terms and definitions given in IEC 60393-1, as well as the following,
apply.
ISO and IEC maintain terminological 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
3.1
potentiometer
component for use as a voltage divider with three terminals of which two are connected to the
ends of a resistive element and the third is connected to a moving contact which can be moved
mechanically along the resistive element
3.2
rheostat
rheostat which is a variable resistor with two terminals

Figure 1 – Schematic view
3.3
total resistance
R
t
resistance between terminal a and c (R ) resistance value for which the variable resistor has
ac
been designed and which is generally marked upon the variable resistor
3.4
minimum resistance
resistance measured between the wiper terminal and any terminal with the shaft positioned to
give the minimum value
3.5
end resistance
resistance measured between the wiper terminal and an end terminal with the shaft positioned
at the corresponding end point
3.6
category dissipation
fraction of the rated dissipation exactly defined by the relevant specification, applicable at the
upper category temperature, taking account of the derating curve determined by the relevant
specification
3.7
nominal dissipation
P
n
power dissipated over the entire resistive element in continuous operation, at the rated service
temperature
– 8 – IEC 60393-4:2023 © IEC 2023
3.8
shaft
mechanical input element of the variable resistor
4 Preferred characteristics
4.1 General
The values given in detail specifications shall preferably be selected from the following.
4.2 Style and dimensions
The dimensions of potentiometer are shown in Figure 2.

Figure 2 – Outline drawing and dimensions
The drawing shall give the following details:
– the dimensions of the shaft and bush. These may be given either on the outline drawing or
by reference to IEC 60915;
– any locating devices;
– the total mechanical travel;
– the effective electrical travel;
– the angle of ineffective mechanical travel;
– the dimensions and the location of terminations;
– the dimensions which shall be measured in accordance with IEC 60393-1:2008, 4.4.2;
– any other dimensional information which will adequately describe the potentiometer.
All dimensions shall preferably be stated in millimetres, however, when the original dimensions
are given in inches, the converted metric dimensions in millimetres shall be added.
When the potentiometer is not designed for use on printed boards, this shall be clearly indicated
in the detail specification.
4.3 Preferred climatic categories
The potentiometers covered by this specification are classified into climatic categories
according to the general rules given in IEC 60068-1:2013, Annex A.
The lower and upper category temperature and the duration of the damp heat, steady state test
shall be chosen from the following:
Lower category temperature: -65 °C, -55 °C, -40 °C, -25 °C and -10 °C.
Upper category temperature: +70 °C, +85 °C, +100 °C, +125 °C, +155 °C,
+175 °C and +200 °C
Duration of the damp heat, steady state test: 4, 10, 21 and 56 days.
The severities for the cold and dry heat tests are the lower and upper category temperatures
respectively. Because of the construction of some potentiometers, these temperatures will
occur between two of the preferred temperatures given in IEC 60068-2-1 and IEC 60068-2-2.
In this case, the nearest preferred temperature within the actual temperature range of the
potentiometer shall be chosen for this severity.
4.4 Resistance law
See 6.5.
4.5 Nominal total resistance
See IEC 60393-1:2008, 2.3.2.
4.6 Tolerances on nominal total resistance
The preferred tolerances on nominal total resistance shall be taken from the series specified in
IEC 60063 (E24 – E12 – E6) ± 20 %, ± 10 %, ± 5 %.
4.7 Rated dissipation
The preferred values of rated dissipation at 70 °C, are:
10 W, 16 W, 25 W, 40 W, 50 W, 63 W, 80 W, 100 W, 125 W, 160 W, 250 W, 315 W, 400 W,
500 W, 630 W, 800 W and 1 000 W.
The derated values of dissipation at temperatures in excess of 70 °C shall be as indicated by
the curve as shown in Figure 3.

Figure 3 – Rated dissipation curve

– 10 – IEC 60393-4:2023 © IEC 2023
A larger area of operation may be given in the detail specification, provided it includes all the
area given above. In this event, the detail specification shall state the maximum allowable
dissipation at temperatures other than 70 °C. All break points on the curve shall be verified by
test.
An example of a derating curve having a larger area of operation is given in Figure 4. In certain
circumstances, the rated dissipation may continue up to the upper category temperature.

Figure 4 – Rated dissipation curve (example of larger area)
4.8 Limiting element voltage
The preferred values of DC or AC r.m.s. limiting element voltage U are:
max
160 V; 250 V; 400 V; 630 V; 1 000 V and 1 600 V.
4.9 Insulation voltage
The detail specification shall determine the value of the insulation voltage, rounded off to the
nearest 10 V. The numerical value of the insulation voltage shall be:
– Normal air pressure: ≥ 1,42 times the limiting element voltage
– Low air pressure (at 8 kPa): ≥ two-thirds the value at normal air pressure
4.10 Number of cycles of operation
The preferred numbers of cycles of operation are:
5 5 5
Single turn/continuous rotation: 1,25 × 10 , 2,5 × 10 or 5 × 10
4.11 Shaft rotational speed
The preferred shaft rotational speeds in revolutions per minute (r.p.m.) are:
– 40 ± 5
5 Tests and test severities
5.1 General
The detail specification shall specify the method of mounting to be applied for the voltage proof
and the insulation resistance tests and for the application of the vibration and shock tests.

5.2 Mounting
The potentiometers shall be mounted by their normal means, but the design can be such that
special mounting fixtures are required. In this case, the detail specification shall describe the
mounting fixtures that shall be used for the voltage proof and the insulation resistance tests
and for the application of the vibration and shock tests. For the latter tests, the mounting shall
be such that there shall be no parasitic vibration.
5.3 Tests
5.3.1 Drying
See IEC 60393-1:2008, 4.3, Procedure 1 shall be used.
5.3.2 Resistance measurement
The methods described in IEC 60393-1:2008. 4.6 and 4.7 shall be used.
5.3.3 Vibration
See IEC 60393-1:2008, 4.35, with the following details:
Frequency range: 10 Hz to 55 Hz, or
10 Hz to 500 Hz.
Amplitude: 0,75 mm or acceleration 98 m/s (whichever is the less severe)
Sweep endurance: Total duration: 6 h
The detail specification shall determine the mounting method to be used (see
IEC 60393-1:2008).
5.3.4 Bump
See IEC 60393-1:2008, 4.36, with the following details:
Acceleration: 400 m/s
Number of bumps: 4 000 (total)
Or
Acceleration: 98 m/s
Number of bumps: 1 000 (total)
The detail specification shall determine the appropriate mounting method to be used (see
IEC 60393-1:2008, 4.3).
5.3.5 Shock
IEC 60393-1:2008, 4.37 applies with the following details:
Pulse shape: Half-sine
Acceleration: 490 m/s
Pulse duration: 11 ms
Severity: 3 successive shocks to be applied in each of the three directions
(total 3 shocks)
The detail specification shall determine the mounting method to be used (see IEC 60393-1:2008,
4.3).
– 12 – IEC 60393-4:2023 © IEC 2023
5.3.6 Temperature coefficients and temperature characteristics of resistance
The measurement of temperature coefficient, or temperature characteristics of resistance is not
applicable to this type of potentiometer.
6 Performance requirements
6.1 General
Test severities and requirements specified by detail specifications referring to this sectional
specification shall be of equal or superior performance level. Inferior performance levels are
not permitted.
The severities for the tests shall be determined by the detail specifications, following the
requirements of the generic specification IEC 60393-4 and Clause 5 of this sectional
specification.
Table 1 – Limits for change in resistance or output voltage ratio
(The subclause numbers in the heading of the table refer to IEC 60393-1:2008).
Stability 4.38 4.34 4.30 4.22 4.35
class
Climatic sequence Change of Robustness of Thrust and pull Vibration
temperature the terminals on the shaft (If applicable)
4.39 4.33 4.34 4.37
Damp heat, steady Resistance to Change of Shock
state soldering heat temperature
4.40 4.35
Mechanical Vibration
endurance
4.43.2 4.36
Electrical endurance Bump
at 70 °C
4.43.3 4.37
Electrical endurance Shock
at upper category
temperature
a
ΔR between terminations a and c
10 ±(10 % R + 0,5 Ω) ±(5 % R + 0,1 Ω) ±(5 % R + 0,1 Ω) ±(5 % R + 0,1 Ω) ±(5 % R + 0,1 Ω)
5 ±(5 % R + 0,1 Ω) ±(2 % R + 0,1 Ω) ±(2 % R + 0,1 Ω) ±(2 % R + 0,1 Ω) ±(2 % R + 0,1 Ω)
3 ±(3 % R + 0,1 Ω) ±(1 % R + 0,1 Ω) ±(1 % R + 0,1 Ω) ±(1 % R + 0,1 Ω) ±(1 % R + 0,1 Ω)
a
ΔR indicates the value of change in resistance.

6.2 Limits for change in resistance or output voltage ratio
The preferred combinations of limits for change in resistance or output ratio in each of the tests
listed in the heading of Table 1 are as indicated in the lines of the table.
6.3 Limits for insulation resistance
The preferred limits for insulation resistance shall be 1 GΩ minimum or, after humidity tests,
100 MΩ.
6.4 Limits of temperature rise
The temperature rise above a reference ambient of 35 °C (see IEC 61439-1) rise at specified
points shall not exceed values given below:
a) at the operating shaft
knob or lever made of Metal 15 °C
made of insulating material 25 °C
b) on touchable panel/outer surfaces
made of metal 30 °C
made of Insulating material 40 °C
6.5 Limits for resistance law
The measuring points and associated values of the output ratio for resistance laws shall be
determined in the detail specification. When requirements exist for forms of linearity, these shall
also be determined in the detail specification as shall any specified measuring points.
6.6 Limits for operating torque
Limits for operating torque are as in Table 2.
The torque needed to start and turn the cursor in both directions is measured over the entire
stroke and from each start.
The maximum moment in the clockwise and counterclockwise directions required to sustain
uniform shaft rotation at a specified speed throughout the total mechanical travel.
Table 2 – Limits for operating torque
Power Max Torque
(W) (Ncm)
15 8
30 10
55 20
150 25
250 60
1 000 100
6.7 Limits for end stop torque
The potentiometers are mounted on a metal panel by means of their normal fixing device.
Torque as appropriate from Table 3 is applied to the control shaft to the end stop position of
the cursor.
Table 3 – Limits for end stop torque
Power Maximum torque
(W) (Ncm)
15, 30 25
55 50
150 100
250, 1 000 200
– 14 – IEC 60393-4:2023 © IEC 2023
There shall be no movement of the cursor during the torque applied.
There shall be no deformation of the mechanical stop.
6.8 Limits for residual resistances
This is the resistance at the two ends of the rotary potentiometer.
– measure between a and b (cursor at counterclockwise stop);
– measure between b and c (cursor at clockwise stop).
Residual resistances shall not excess 0,2 Ω.
6.9 Visual inspection
6.9.1 General visual criteria
The detail specification shall determine acceptance criteria for the visual inspection
potentiometer and its terminations. These acceptance criteria shall consider the following
information.
6.9.2 Visual criteria after tests
Unless more specific requirements are specified by the relevant specification for the visual
inspection after tests, the following criteria shall apply:
– there shall not be any visible damage to the resistor body and to its terminations after the
test, except for an acceptable discoloration after endurance tests; and the markings shall
be readable
6.10 Solderability
See IEC 60393-1.
The requirement for the visual inspection for the assessment of good solderability shall be:
≥95 % of the surface shall be covered with new solder. The new solder shall show no more than
small amounts of scattered imperfections, such as pinholes or non-wetted or de-wetted areas.
These imperfections shall not be concentrated in one area.
7 Marking, packaging, and ordering information
7.1 Marking of the component
The information given in the marking is normally selected from the following list; the relative
importance of each item is indicated by its position in the list:
a) rated resistance;
b) tolerance on rated resistance;
c) resistance law (if other than linear) and degree of conformity;
d) detail specification and style reference;
e) year and month (or week) of manufacture;
f) details of shaft and bush (if not implicit in d) above). This may be in code form;
g) manufacturer's name and trademark.

7.2 Marking for packaging
The package containing the potentiometer(s) shall be clearly marked with all the information
listed of 7.1, and with the information below.
a) quantity;
b) country origin.
7.3 Additional marking
Any additional marking shall be so applied that no confusion can arise.
The detail specification shall specify the content of the marking on the potentiometer and on
the package. Deviations from 7.1 of this sectional specification shall be specifically stated.
If the marking is done by means of a letter and digit code, this may utilize one of the methods
given in IEC 60062:2016 and IEC 60062:2016/AMD1:2019, Clause 4, the code letter for the
tolerance given in IEC 60062:2016, 5.2, and the code letter for the temperature coefficient given
in IEC 60062:2016, 7.2.
7.4 Ordering information
The detail specification shall indicate that the following information, in clear or in coded form,
is required when ordering:
a) nominal total resistance and tolerance on nominal total resistance;
b) resistance law (if other than linear);
c) number and issue reference of the detail specification and style reference;
d) shaft and bush dimensions, if not implicit in the style reference.
8 Detail specifications
8.1 General
Detail specifications shall be derived from the relevant blank detail specification.
The detail specification shall incorporate an illustration of the potentiometer being specified.
Where space is insufficient to show the detail dimensions required for inspection purposes,
such dimensions shall appear on a drawing forming an annex to the detail specification, as
shown in Figure 1.
Detail specifications shall not specify requirements inferior to those of the generic specification,
sectional specification, or blank detail specification. When more severe requirements are
included, they shall be listed in a respective clause of the detail specification and indicated in
the test schedules, for example by a note.
The following information shall be given in each detail specification and the specified values
shall preferably be selected from those given in the appropriate clause of this sectional
specification.
8.2 Information to be specified in a detail specification
8.2.1 Outline drawing or illustration
There shall be an outline drawing or illustration of the potentiometer as an aid to easy
recognition and for comparison of the resistor with others.

– 16 – IEC 60393-4:2023 © IEC 2023
8.2.2 Dimensions
See 4.2.
All dimensions and their associated tolerances, which affect interchangeability and mounting,
shall be given in the detail specification, using a dedicated outline and dimensions drawing.
8.2.3 Mounting
The detail specification shall specify the method of mounting to be applied for the voltage proof
and the insulation resistance tests and for the application of the vibration and shock tests. The
potentiometers shall be mounted by their normal means, but the design can be such that special
mounting fixtures are required. In this case, the detail specification shall describe the mounting
fixtures that shall be used for the voltage proof and the insulation resistance tests and for the
application of the vibration and shock tests. For the latter tests, the mounting shall be such that
there shall be no parasitic vibration.
8.2.4 Resistance law
See 6.5.
8.3 Ratings and characteristics
8.3.1 General
The ratings and characteristics shall be in accordance with Clause 4 of this specification
together with the following:
8.3.2 Nominal total resistance range
See IEC 60393-1:2008, 2.3.2.
When products approved according to the detail specification have different ranges, the
following statement should be added:
The range of values available in each style is given in the register of approvals, available for
example on the website http://www.iecq.org/.
The qualified products list “QPL” style is given in the register of approvals, available for example
on the website as stated above.
8.3.3 Marking
The detail specification shall specify the content of the marking on the potentiometer and on
the package. Deviations from Clause 4 of this sectional specification shall be specifically stated.
8.3.4 Ordering information
The detail specification shall indicate that the following information, in clear or in coded form,
is required when ordering:
a) nominal total resistance and tolerance on nominal total resistance;
b) resistance law (if other than linear);
c) number and issue reference of the detail specification and style reference;
d) shaft and bush dimensions, if not implicit in the style reference.

8.3.5 Additional information
The detail specification may include information which is not required to be verified by the
inspection procedure, such as circuit diagrams, curves, drawings, and notes needed for the
clarification on the detail specification.
9 Quality assessment procedures
9.1 General
See IEC 60393-1:2008, Clause H.1.
9.2 Definitions
9.2.1 Primary stage of manufacture
For potentiometers, the primary stage of the manufacture is the winding of the resistance wire
(or ribbon) on the mandrel (insulation or insulated).
9.2.2 Structurally similar components
Potentiometers are considered as being structurally similar if they are produced with similar
processes and materials, having the same style and construction and the same or similar shaft
and bush dimensions, though they can have different resistance values and temperature
characteristics (or coefficients) of resistance.
9.3 Assessment level EZ
Assessment level EZ meets the requirements of “zero nonconforming” approach. It has been
...