EN 61057:2017

SLOVENSKI STANDARD
01-januar-2018
1DGRPHãþD
SIST EN 61057:2001
Delo pod napetostjo - Izolacijske naprave za montažo na ohišja
Live working - Insulating aerial devices for mounting on a chassis
Ta slovenski standard je istoveten z: EN 61057:2017
ICS:
13.260 9DUVWYRSUHGHOHNWULþQLP Protection against electric
XGDURP'HORSRGQDSHWRVWMR shock. Live working
53.020.99 Druga dvigalna oprema Other lifting equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 61057
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2017
ICS 13.260; 29.260.99 Supersedes EN 61057:1993
English Version
Live working - Insulating aerial devices for mounting on a
chassis
(IEC 61057:2017)
Travaux sous tension - Dispositifs élévateurs isolants pour Arbeiten unter Spannung - Isolierende Hubarbeitsbühnen
montage sur un châssis für die Montage auf einem Fahrgestell
(IEC 61057:2017) (IEC 61057:2017)
This European Standard was approved by CENELEC on 2017-07-24. 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 61057:2017 E
European foreword
The text of document 78/1182/FDIS, future edition 2 of IEC 61057, prepared by IEC/TC 78 "Live
working" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
(dop) 2018-04-24
• 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) 2020-07-24
standards conflicting with the
document have to be withdrawn
This document supersedes EN 61057:1993.

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 61057:2017 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:

IEC 60270 NOTE Harmonized as EN 60270.
IEC 60743:2013 NOTE Harmonized as EN 60743:2013 (not modified).
IEC 60855-1 NOTE Harmonized as EN 60855-1.
IEC 61109 NOTE Harmonized as EN 61109.
IEC 61235 NOTE Harmonized as EN 61235.
IEC 61472:2013 NOTE Harmonized as EN 61472:2013 (not modified).
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 60060-1 -  High-voltage test techniques - EN 60060-1 -
Part 1: General definitions and test
requirements
IEC 60060-2 -  High-voltage test techniques - EN 60060-2 -
Part 2: Measuring systems
IEC 60212 2010 Standard conditions for use prior to and EN 60212 2011
during the testing of solid electrical
insulating materials
IEC 60417-DB -  Graphical symbols for use on equipment - -
IEC 61318 -  Live working - Conformity assessment EN 61318 -
applicable to tools, devices and equipment
IEC 62237 (mod) 2003 Live working - Insulating hoses EN 62237 2005
with fittings for use with hydraulic tools
and equipment
ISO 16368 2010 Mobile elevating work platforms - Design, - -
calculations, safety requirements and test
methods
ISO 13850 -  Safety of machinery - Emergency stop EN ISO 13850 -
function - Principles for design
SAE J343 -  Test and Test Procedures for SAE 100R - -
Series Hydraulic Hose and Hose
Assemblies
SAE J517 -  Hydraulic hose - -

IEC 61057 ®
Edition 2.0 2017-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Live working – Insulating aerial devices for mounting on a chassis

Travaux sous tension – Dispositifs élévateurs isolants pour montage sur un

châssis
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.260; 29.260.99 ISBN 978-2-8322-4427-2

– 2 – IEC 61057:2017 © IEC 2017
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 10
4 Specific terms and nomenclature . 19
5 Requirements . 22
5.1 Controls . 22
5.1.1 Activation and operation . 22
5.1.2 Duplicate controls . 23
5.1.3 Emergency stop . 23
5.1.4 Control of outriggers . 24
5.1.5 Monitoring of radio and optical fibre controls . 24
5.1.6 High electrical resistance upper control system(s) . 24
5.2 Failure of the source of power . 24
5.3 Restoration of power after failure . 24
5.4 Boom travel protection . 24
5.5 Chassis inclination . 25
5.6 Locking pins . 25
5.7 Electrical requirements . 25
5.7.1 Insulating systems . 25
5.7.2 Insulating booms (including lower boom insulating insert / chassis
insulating system) . 25
5.7.3 Non-conductive/insulating hydraulic hoses and lines . 26
5.7.4 Insulating fixed handling tools . 26
5.7.5 Insulating optical fibre cables. 26
5.7.6 Equipotential bonding . 26
5.7.7 Lower test electrode system . 27
5.7.8 Corona effect . 31
5.7.9 Gradient control devices . 31
5.7.10 Chassis insulating system bypass . 31
5.7.11 Chassis earthing system . 32
5.8 Particular mechanical requirements . 32
5.8.1 Structural design . 32
5.8.2 Stability . 33
5.8.3 Wind speed . 33
5.9 Speeds of the extending structure . 33
5.10 Load sensing . 33
5.11 Requirements for the hydraulic system . 33
5.11.1 Hydraulic depressurization (vacuum protection) . 33
5.11.2 Hydraulic pressure rise . 33
5.11.3 System protection . 33
5.11.4 Overriding safety devices . 34
5.11.5 Pressure limiting device . 34
5.11.6 Bursting strength – hoses and fittings . 34
5.11.7 Fluid level indicators . 34
5.11.8 Fluid cleanliness . 34

IEC 61057:2017 © IEC 2017 – 3 –
5.12 Requirements for the platforms . 34
5.12.1 Platform security . 34
5.12.2 Platform levelling . 34
5.12.3 Guardrail system . 35
5.12.4 Baskets . 35
5.12.5 Personnel safety attachments (and attachment for fall protection) . 35
5.13 Marking . 35
5.14 Instructions for use . 36
5.15 Dimensions and mass . 36
6 Tests . 36
6.1 General . 36
6.2 Visual and dimensional check . 37
6.3 Design check and functional testing . 37
6.4 Durability of markings . 37
6.5 Dye penetration test of insulating foam-filled booms . 37
6.6 Electrical tests . 38
6.6.1 General . 38
6.6.2 Electrical tests for insulating booms, insulating fixed handling tools and
optical fibre cables. 38
6.6.3 Test of insulating baskets or liners . 50
6.6.4 Dielectric test of the insulating fixed handling tools . 51
6.7 Dielectric tests of the insulating systems of the complete aerial devices . 52
6.7.1 General . 52
6.7.2 Aerial devices with lower test electrode system . 52
6.7.3 Aerial devices without lower test electrode system. 55
6.8 Lower test electrode system . 61
6.9 Equipotential bonding . 61
6.10 Mechanical tests . 61
6.10.1 Mechanical tests on insulating boom with its fittings . 61
6.10.2 Platform creep . 62
6.10.3 Hydraulic depressurization (vacuum protection) . 62
6.11 Design and functional tests . 63
7 Conformance testing of aerial devices after completion of the production phase . 63
8 Modifications . 63
Annex A (informative) Guidelines for selecting the characteristics of insulating aerial
devices as a function of the live working methods . 64
A.1 General . 64
A.2 Bare hand live working . 64
A.3 Live line tool, distance or hot stick working . 64
A.4 Insulating (rubber) glove working . 65
A.5 Use under DC . 65
A.6 Advice for buyers of insulating aerial devices meeting the requirements of
this document not intending to make use of them for live working . 65
Annex B (normative) Suitable for live working; double triangle IEC-60417-5216:2002-10 . 66
Annex C (normative) General type test procedure . 67
Annex D (normative) Classification of defects and tests to be allocated . 69
Annex E (informative) Care and maintenance . 71
E.1 General . 71

– 4 – IEC 61057:2017 © IEC 2017
E.2 Care of insulating components . 71
E.2.1 Care whilst in transit . 71
E.2.2 Care during work activities . 71
E.2.3 Storage. 72
E.3 Maintenance of insulating components . 72
E.3.1 General . 72
E.3.2 Cleaning . 72
E.3.3 Siliconing or waxing . 73
E.4 Inspection of insulating components . 73
E.4.1 General . 73
E.4.2 Pre-start inspection . 73
E.4.3 Frequent and annual inspections of aerial devices . 74
E.5 Tests . 74
E.5.1 Periodic electrical tests . 74
E.5.2 Mechanical test – Acoustic emission testing . 80
E.6 Records . 81
E.7 Repairing/refurbishing . 81
E.8 Overriding safety devices . 82
E.9 Care, maintenance and periodic inspection when insulating aerial devices
are for other uses than live working . 82
Annex F (informative) Hydraulic depressurization (vacuum protection) (see 5.11.1 and
6.10.3) . 83
F.1 General . 83
F.2 In-line check valves . 83
F.2.1 General . 83
F.2.2 Testing the in-line check valves (typical test procedure – reference
Figure F.1) . 83
F.3 Atmospheric check valve assembly . 84
F.3.1 General . 84
F.3.2 Testing the atmospheric check valves (typical test procedure –
reference Figure F.2) . 85
Bibliography . 87

Figure 1 – Specific terms . 21
Figure 2 – Nomenclature . 22
Figure 3 – Typical equipotential bonding arrangement . 27
Figure 4 – Leakage current monitoring . 30
Figure 5 – Example of temporary bypassing arrangement for chassis insulating system . 32
Figure 6 – AC dielectric test before and after exposure to humidity (method A) –
Typical test arrangement . 40
Figure 7 – AC dielectric tests before and after exposure to humidity (method A) –
Assembly diagram of the test piece to the guard electrodes . 42
Figure 8 – AC dielectric tests before and after exposure to humidity (method A) –
Constructional drawings for guard electrodes and parts . 43
Figure 9 – AC dielectric tests before and after exposure to humidity (method A) –
Constructional drawings for brass electrode and for insulating support parts according
to test piece . 44
Figure 10 – Details of electrode arrangement . 46
Figure 11 – Test arrangement . 46

IEC 61057:2017 © IEC 2017 – 5 –
Figure 12 – DC dielectric test before and after water soaking (method B) – Typical test
arrangement . 48
Figure 13 – Preparation of optical fibre cable test piece for test after the infliction of a
gash . 50
Figure 14 – Test of insulating basket or liner . 51
Figure 15 – Test of the upper insulating system of devices with lower test electrode
system . 53
Figure 16 – Test of the upper insulating system of devices without permanently
installed lower test electrode system . 57
Figure 17 – Dielectric test for insulating insert/chassis insulating system . 60
Figure 18 – Test of high electrical resistance component(s) . 60
Figure E.1 – DC only test of the upper insulating system of devices without
permanently installed lower test electrode system. 78
Figure E.2 – DC only test of insulating lower boom insert or chassis insulating system . 80
Figure F.1 – In-line check valve test for the insulating boom vacuum protection system . 84
Figure F.2 – Atmospheric check valve assembly test for the insulating boom vacuum
protection system. 85

Table 1 – Values for AC dielectric tests of the upper insulating system of devices with
lower test electrode system . 54
Table 2 – Values for DC dielectric tests of the upper insulating system of devices with
lower test electrode system . 55
Table 3 – Dielectric test for aerial devices without lower test electrode system . 58
Table C.1 – List and chronological order (where required) of type tests . 67
Table D.1 – Classification of defects and associated requirements and tests . 69
Table E.1 – Electrical test values for periodic electrical testing of insulating aerial
devices with lower test electrode system for AC applications . 75
Table E.2 – Electrical test values for periodic testing of insulating aerial devices
without lower test electrode system for AC applications . 75
Table E.3 – Electrical test values for periodic electrical testing of insulating
components of aerial devices for AC applications . 76
Table E.4 – Electrical test values for periodic electrical testing of insulating aerial
devices with lower test electrode system for DC applications . 76
Table F.1 – Allowable vacuum formation within hydraulic lines (adjusted for altitude) . 86

– 6 – IEC 61057:2017 © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LIVE WORKING –
INSULATING AERIAL DEVICES
FOR MOUNTING ON A CHASSIS
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 61057 has been prepared by IEC technical committee 78: Live
working.
This second edition cancels and replaces the first edition published in 1991 and
IEC TS 61813:2000. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) general review of the requirements and test provisions;
b) preparation of the elements of evaluation of defects, and general application of
IEC 61318:2007;
c) distinguishes between tests for hollow booms and those for foam filled booms;
d) references ISO 16368 for particular mechanical tests;

IEC 61057:2017 © IEC 2017 – 7 –
e) further information on vacuum protection and leakage current monitoring and a mandatory
requirement that aerial devices for bare hand work be fitted with a permanently installed
lower test electrode system;
f) controls of high electrical resistance;
g) reference to SAE for insulating hydraulic hoses;
h) inclusion of IEC TS 61813 for care, maintenance and in-service testing of aerial devices
with insulating booms.
The text of this standard is based on the following documents:
FDIS Report on voting
78/1182/FDIS 78/1183/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.
Terms defined in Clause 3 are given in italic print throughout this standard.
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.
– 8 – IEC 61057:2017 © IEC 2017
INTRODUCTION
This document covers insulating aerial devices for use at temperatures between −25 °C and
+55 °C. Where aerial devices are for use in unusual atmospheric conditions (for example,
higher or lower temperatures), other considerations may be appropriate and will be identified
by the manufacturer both in the markings and instructions for use.
The products covered by this document are primarily intended to be used for live working or
for work within the live working zone. It recognizes that a user may specify a product, or
products complying with this document where there is a risk of accidental contact with live
(energized) part(s). In such circumstances users are reminded that national or local
regulations regarding maintaining of Minimum Approach Distances to live parts, or those
obtained from IEC 61472 are to be applied. Annex A of this document gives advice and
information.
The product covered by this document may have an impact on the environment during some
or all stages of its life cycle. These impacts can range from slight to significant, be short-term
or long-term, and occur at the global, regional or local level.
Except for a disposal statement in the Instructions for use, this document does not include
requirements and test provisions for the manufacturers of the product, or recommendations to
the users of the product for environmental improvement. However, all parties intervening in its
design, manufacture, packaging, distribution, use, maintenance, repair, reuse, recovery and
disposal are invited to take account of environmental considerations.

IEC 61057:2017 © IEC 2017 – 9 –
LIVE WORKING –
INSULATING AERIAL DEVICES
FOR MOUNTING ON A CHASSIS
1 Scope
This document is applicable to insulating aerial devices for mounting on a chassis, to be used
for live working on electrical installations at nominal voltages above 1 000V r.m.s. AC in the
range 45 Hz to 65 Hz and 1 500V DC.
The primary purpose of an aerial device is for work positioning of personnel. Other devices,
such as jibs, may be fitted in order to assist the operator in performing the work.
This document also includes requirements and tests for the parts of the chassis influencing
the performance of the insulating aerial devices to be used for live working.
When mounted on a chassis, the insulating aerial device becomes a component of a mobile
elevating work platform (MEWP). Complementary requirements for the resulting MEWP are
included in ISO 16368.
NOTE 1 In Europe, EN 280 instead of ISO 16368 is often used as reference for complementary requirements.
The products designed and manufactured according to this document contribute to the safety
of users, provided they are used by skilled persons, in accordance with safe methods of work
and the instructions for use.
NOTE 2 Any requirements that are in conflict with or are meant to be complementary to ISO 16368 are delineated
herein.
Radial boom (digger) derricks are not covered by this document.
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 60060-1, High-voltage test techniques – Part 1: General definitions and test requirements
IEC 60060-2, High-voltage test techniques – Part 2: Measuring systems
IEC 60212:2010, Standard conditions for use prior to and during the testing of solid electrical
insulating materials
IEC 60417, Graphical symbols for use on equipment (available at http://www.graphical-
symbols.info/equipment)
IEC 61318, Live working – Conformity assessment applicable to tools, devices and equipment
IEC 62237:2003, Live working – Insulating hoses with fittings for use with hydraulic tools and
equipment
– 10 – IEC 61057:2017 © IEC 2017
ISO 16368:2010, Mobile elevating work platforms – Design, calculations, safety requirements
and test methods
ISO 13850, Safety of machinery – Emergency stop function – Principles for design
SAE J343, Test and Test Procedures for SAE 100R Series Hydraulic Hose and Hose
Assemblies
SAE J517, Hydraulic hose
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61318, ISO 16368
and the following 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
aerial device
insulating aerial device
any device, extensible, articulating or both, incorporating insulating components and which is
primarily designed and used to position personnel at or near an electric potential different
from that of earth
Note 1 to entry: An insulating aerial device may also be used to handle material if designed and equipped for that
purpose.
Note 2 to entry: An insulating aerial device does not include a chassis. When an aerial device is mounted on a
mobile chassis it becomes a component of a mobile elevating work platform (MEWP).
3.2
aerial device centre of gravity – horizontal
horizontal component of the distance from the axis of rotation to the centre of gravity of the
aerial device in the stowed position
SEE: Figure 1
3.3
aerial device centre of gravity – vertical
vertical component of the distance above the mounting surface of the aerial device to the
centre of gravity of the aerial device in the stowed position
SEE: Figure 1
3.4
aerial device mass
mass of the standard aerial device, less optional counterweights, accessories and auxiliary
equipment
3.5
bare hand working
live working carried out in accordance with a method where the worker is electrically bonded
to the energized parts on which live working is to be performed whilst being suitably isolated
from surrounding parts which are at different potentials

IEC 61057:2017 © IEC 2017 – 11 –
[SOURCE: IEC 60050-651:2014, 651-21-07, modified – The definition has been modified for
clarity.]
3.6
basket
bucket
totally enclosed type of platform which does not need guardrails or toe-guard
3.7
boom tip
furthest extremity of the upper boom from the turntable and the end of the upper boom to
which the platform is attached
SEE: Figure 2
3.8
brittle material
fibreglass-reinforced plastic material or material that does not meet the requirements for
ductile material
3.9
cab-axle dimension
distance between the back of the cab and the rear axle centreline of the chassis
recommended for mounting the aerial device
SEE: Figure 1
3.10
centre of rotation location
distance from the centreline of the rear axle to the axis of rotation of the turntable
SEE: Figure 1
3.11
chassis
base on which the aerial device is mounted
3.12
chassis frame height
height from ground level to the top of the chassis frame rail
SEE: Figure 1
3.13
chassis insulating system
all dielectric components installed between the chassis and the upper insulating boom and
designed to insulate the chassis should the portion of the aerial device between the upper
insulating boom and this system contact a live part
SEE: Figure 2
Note 1 to entry: A lower boom insulating insert is a type of chassis insulating system.
3.14
conductive shield
guard ring
device used to shield the lower test electrode system from capacitive coupling

– 12 – IEC 61057:2017 © IEC 2017
3.15
control
means by which operation of a function is effected
3.16
disruptive discharge
sparkover
flashover
passage of an arc following dielectric breakdown
Note 1 to entry: The term “sparkover” (in French “amorçage”) is used when a disruptive discharge occurs in a
gaseous or liquid dielectric.
Note 2 to entry: The term “flashover” (in French “contournement”) is used when a disruptive discharge occurs
over the surface of a solid dielectric surrounded by a gaseous or liquid medium.
Note 3 to entry: The term “puncture” (in French “perforation”) is used when a disruptive discharge occurs through
a solid dielectric.
[SOURCE: IEC 60050-604:1987, 604-03-38]
3.17
ductile material
material that has a minimum elongation at failure of 10 % in a gauge length of 51 mm of a
standardized test specimen
3.18
elbow
structure connecting the upper boom to the lower boom, about which one articulates relative
to the other
SEE: Figure 2
3.19
elbow pin
horizontal pin about which the upper boom rotates relative to the lower boom
SEE: Figure 2
3.20
extensible boom aerial device
aerial device on which the length of the upper boom can be varied within pre-determined
limits
EXAMPLE telescoping boom
3.21
fixed handling tool
tool that is mechanically mounted at the boom tip or platform
EXAMPLE jib, phase lifter
3.22
formally trained and qualified person
competent person possessing the appropriate practical and theoretical knowledge and having
adequate skill and experience to enable them to perform the required duty, interpret the
resultant information and from that information determine that the equipment is safe to use,
and report the importance of any defect found or suspected in relation to the safety and
continued use of the equipment

IEC 61057:2017 © IEC 2017 – 13 –
3.23
front overhang
maximum distance of any part of the aerial device forward of the front bumper
SEE: Figure 1
3.24
front projection
maximum distance of any part of the aerial device forward of the front axle centreline when
stowed for travel
SEE: Figure 1
3.25
gradient control device
corona ring
device at the upper end of an insulating boom that reduces electrical stress level(s) below
that considered to be disruptive
3.26
guardrail system
guard rail system
system of barriers intended to protect personnel from falling to lower levels
3.27
hot stick working
live working carried out in accordance with a method where the worker remains at a specified
distance from the energized parts and carries out the work by means of insulating sticks
[SOURCE: IEC 60050-651:2014, 651-21-05]
3.28
horizontal reach
maximum distance reached from the centreline of the rotating turntable to the outer edge of
the platform
SEE: Figure 1
3.29
instability
condition of a MEWP in which the sum of the moments tending to overturn the MEWP is equal
to or exceeds the sum of the moments tending to resist overturning
3.30
insulating boom
insulating component of the extending structure denominated the upper boom and, where
provided, the lower boom insert.
Note 1 to entry: ISO 16368 defines extending structure.
3.31
insulating glove working
live working carried out in accordance with a method where the worker is in direct contact with
an energized part and is electrically protected by electrical insulating gloves
[SOURCE: IEC 60050-651:2014, 651-21-06]

– 14 – IEC 61057:2017 © IEC 2017
3.32
insulation gap
minimum length of the upper insulating system being the shortest distance in
any boom position between conductive components at each end
SEE: Figure 1
3.33
insulation gap
minimum length of the chassis insulating system
SEE: Figure 1
3.34
jib
auxiliary arm
...