Earth-moving machinery -- Electrical safety of machines utilizing electric drives and related components and systems

ISO 14990-2:2016 the particular safety requirements for the electrical equipment and its components incorporated in externally-powered (mains-connected, including machines powered by external dedicated generators), electrically-driven earth-moving machines (EMMs). It is applicable to those machines using on-board voltages in the range of 50 V?36 kV AC r.m.s. at any frequency and 75 V?36 kV DC ? including any repetition rate of pulsating DC ? intended for outdoor use. Voltages occurring within devices are not considered to be on-board voltages and are thus not within its scope. It is intended to be used in conjunction with ISO 14990‑1, which gives general requirements for EMMs regardless of how they are powered. Requirements specific to self-powered machines are given in ISO 14990‑3. However, it is possible for an EMM to be both self-powered and externally-powered (e.g. a battery-powered machine having a built-in charger with power supply function), in which case ISO 14990‑3 is also applicable.

Engins de terrassement -- Sécurité électrique des machines utilisant des moteurs électriques et composants et systèmes connexes

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Published
Publication Date
25-Oct-2016
Current Stage
6060 - International Standard published
Start Date
26-Sep-2016
Completion Date
26-Oct-2016
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INTERNATIONAL ISO
STANDARD 14990-2
First edition
2016-11-01
Earth-moving machinery — Electrical
safety of machines utilizing electric
drives and related components and
systems —
Part 2:
Particular requirements for
externally-powered machines
Engins de terrassement — Sécurité électrique des machines utilisant
des moteurs électriques et composants et systèmes connexes —
Partie 2: Exigences particulières pour les machines à moteur externe
Reference number
ISO 14990-2:2016(E)
ISO 2016
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ISO 14990-2:2016(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form

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ii © ISO 2016 – All rights reserved
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ISO 14990-2:2016(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms, definitions and abbreviated terms ................................................................................................................................ 1

4 General requirements ..................................................................................................................................................................................... 2

4.1 General ........................................................................................................................................................................................................... 2

4.2 Special conditions ................................................................................................................................................................................. 2

4.3 Supplies ......................................................................................................................................................................................................... 2

4.3.1 AC supplies ............................................................................................................................................................................ 2

4.3.2 DC supplies ........................................................................................................................................................................... 2

5 Protection against electric shock hazards ................................................................................................................................. 3

5.1 General ........................................................................................................................................................................................................... 3

5.2 Guidance for type of neutral earthing system .............................................................................................................. 3

6 Protection against electrical fire hazards .................................................................................................................................. 4

7 Protection against thermal hazards ................................................................................................................................................. 4

8 Protection against mechanical hazards........................................................................................................................................ 4

9 Protection against abnormal operation hazards ................................................................................................................ 5

9.1 General ........................................................................................................................................................................................................... 5

9.2 Supply conductors................................................................................................................................................................................ 5

9.3 Socket outlets ........................................................................................................................................................................................... 5

9.4 Protection against supply interruption or voltage reduction and subsequent restoration . 5

9.5 Phase sequence protection ........................................................................................................................................................... 5

9.6 Protection against overvoltages due to lightning and to switching surges ........................................ 5

10 Electric power source ...................................................................................................................................................................................... 6

10.1 Incoming supply conductor terminations ....................................................................................................................... 6

10.2 Terminal for connection to the external protective earthing system ...................................................... 6

10.3 Protection against unauthorized, inadvertent and/or mistaken connection ................................... 7

11 Wiring .............................................................................................................................................................................................................................. 7

11.1 Flexible cables.......................................................................................................................................................................................... 7

11.2 Conductor wires, conductor bars, and slip-ring assemblies — Clearances ....................................... 7

11.3 Connections and routing — Conductor and cable runs ....................................................................................... 8

11.4 Connection to moving elements of the EMM ................................................................................................................ 8

12 Electric motors ....................................................................................................................................................................................................... 9

12.1 Criteria for motor selection or design ................................................................................................................................. 9

13 Non-motor loads ................................................................................................................................................................................................... 9

14 Controls .......................................................................................................................................................................................................................... 9

14.1 Control circuit supply ........................................................................................................................................................................ 9

15 Manuals and documentation ................................................................................................................................................................10

15.1 Information to be provided .......................................................................................................................................................10

15.2 Installation documents .................................................................................................................................................................10

16 Marking .......................................................................................................................................................................................................................11

16.1 Marking of equipment ...................................................................................................................................................................11

17 Tests ................................................................................................................................................................................................................................11

Annex A (informative) Enquiry form for electrical equipment of externally-powered machines ....12

Bibliography .............................................................................................................................................................................................................................15

© ISO 2016 – All rights reserved iii
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ISO 14990-2:2016(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,

as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the

Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.

The committee responsible for this document is ISO/TC 127, Earth-moving machinery, Subcommittee SC

3, Machine characteristics, electrical and electronic systems, operation and maintenance.

This document is intended to be used in conjunction with ISO 14990-1.
iv © ISO 2016 – All rights reserved
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ISO 14990-2:2016(E)
Introduction
This document is a type-C standard as defined in ISO 12100.

The machinery concerned and the extent to which hazards, hazardous situations, or hazardous events

are covered are indicated in ISO 14990-1:2016, Annex A.

When requirements of this type-C standard are different from those stated in type-A or type-B

standards, the requirements of this type-C standard take precedence over the requirements of the

other standards for machines that have been designed and built according to the requirements of this

type-C standard.

Electrification is an enabling technology providing increased flexibility in machine form packaging.

Because in the past earth-moving machinery (EMM) electrical systems have predominately been in the

12–24 V DC range, two safety aspects require particular attention:

— significantly higher voltages, such as are utilized in industrial or structural applications and in

other transportation sectors;
— greater available electrical energy.

Portions of this document appear to govern electrical design practices (e.g. Clauses 9, 11, 12, and 17). Their

requirements are necessary because certain aspects of design cannot be separated from electrical safety.

Some of the content of this document is based on IEC 60204-1 and IEC 60204-11, adapted to the needs of

earth-moving machinery. Non-electrical hazards are addressed in the ISO 20474 series.

Figure 1 is provided as an aid to the understanding of the interrelationship of the various elements of a

machine and its associated equipment. Figure 1 is a block diagram of a typical machine and associated

equipment showing the various elements of the electrical equipment addressed in this document.

© ISO 2016 – All rights reserved v
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ISO 14990-2:2016(E)
Figure 1 — Block diagram of a typical machine
vi © ISO 2016 – All rights reserved
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INTERNATIONAL STANDARD ISO 14990-2:2016(E)
Earth-moving machinery — Electrical safety of machines
utilizing electric drives and related components and
systems —
Part 2:
Particular requirements for externally-powered machines
1 Scope

This document specifies the particular safety requirements for the electrical equipment and its

components incorporated in externally-powered (mains-connected, including machines powered by

external dedicated generators), electrically-driven earth-moving machines (EMMs).

It is applicable to those machines using on-board voltages in the range of 50 V–36 kV AC r.m.s. at any

frequency and 75 V–36 kV DC — including any repetition rate of pulsating DC — intended for outdoor

use. Voltages occurring within devices are not considered to be on-board voltages and are thus not

within its scope.

It is intended to be used in conjunction with ISO 14990-1, which gives general requirements for EMMs

regardless of how they are powered. Requirements specific to self-powered machines are given

in ISO 14990-3. However, it is possible for an EMM to be both self-powered and externally-powered

(e.g. a battery-powered machine having a built-in charger with power supply function), in which case

ISO 14990-3 is also applicable.
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.

ISO 14990-1:2016, Earth-moving machinery — Electrical safety of machines utilizing electric drives or

related components and systems — Part 1: General requirements

ISO 14990-3, Earth-moving machinery — Electrical safety of machines utilizing electric drives or related

components and systems — Part 3: Particular requirements for self-powered machines

IEC 60071-1:2006, Insulation Coordination — Part 1: Definitions, principles and rules. Amended by

IEC 60071-1:2006/Amd. 1:2010

IEC 60364-5-52, Low-voltage electrical installations — Part 5-52: Selection and erection of electrical

equipment — Wiring systems

IEC 60445, Basic and safety principles for man-machine interface, marking and identification —

Identification of equipment terminals, conductor terminations and conductors

IEC 60664-1, Insulation coordination for equipment within low-voltage systems — Part 1: Principles,

requirements and tests
3 Terms, definitions and abbreviated terms

For the purposes of this document, the terms, definitions and abbreviated terms given in

ISO 14990-1 apply.
© ISO 2016 – All rights reserved 1
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ISO 14990-2:2016(E)

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
4 General requirements
4.1 General

The requirements of ISO 14990-1:2016, Clause 4, shall apply except as modified by this clause.

4.2 Special conditions

The enquiry form given in Annex A can be used as the basis for an agreement between user and supplier

to address special conditions, or where certain provisions of this document might not be applicable.

The waiver of any requirement shall be limited to situations not covered by this document.

4.3 Supplies
4.3.1 AC supplies
Voltage: Steady-state voltage: 0,9 to 1,1 of nominal voltage.

Frequency: 0,99 to 1,01 of nominal frequency continuously; 0,98 to 1,02 short time.

Harmonics: Harmonic distortion not exceeding 10 % of the total r.m.s. voltage between live conductors

for the sum of the 2nd to the 5th harmonic. An additional 2 % of the total r.m.s. voltage between live

conductors for the sum of the 6th to the 30th harmonic is permissible.

Voltage unbalance: Neither the voltage of the negative sequence component nor the voltage of the zero

sequence component in three-phase supplies exceeding 2 % of the positive sequence component.

Voltage interruption: Supply interrupted or at zero voltage for not more than 3 ms at any random time

in the supply cycle with more than 1 s between successive interruptions.

Voltage dips: Voltage dips not exceeding 20 % of the peak voltage of the supply for more than one cycle

with more than 1 s between successive dips.
4.3.2 DC supplies
4.3.2.1 From batteries

Voltage: 0,85 to 1,15 of nominal voltage; 0,7 to 1,2 of nominal voltage in the case of battery-operated

vehicles.
Voltage interruption: Not exceeding 5 ms.
4.3.2.2 From converting equipment
Voltage: 0,9 to 1,1 of nominal voltage.

Voltage interruption: Not exceeding 20 ms with more than 1 s between successive interruptions.

NOTE This is a variation on IEC Guide 106 for ensuring the proper operation of electronic equipment.

Ripple (peak-to-peak): Not exceeding 0,15 of nominal voltage.
2 © ISO 2016 – All rights reserved
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ISO 14990-2:2016(E)
5 Protection against electric shock hazards
5.1 General

The requirements of ISO 14990-1:2016, Clause 5 shall apply except as modified by this clause.

5.1.1 See Figure 2 for an example of equipotential bonding for electrical equipment of an externally-

powered EMM.

5.1.2 For EMM where the connection to the earthing system (machine bonding conductor) is provided

solely by flexible cables, the continuity of the protective conductor shall be ensured by appropriate design

of the cable. Where there is a possibility that the cable and hence the machine bonding conductor could

become damaged (e.g. a trailing cable dragged on the ground), the continuity of the protective bonding

circuit shall be monitored. The supply to the electrical equipment of the machine or to the relevant part

of the machine shall be switched off whenever
— loss of continuity of the protective bonding circuit is detected, or
— failure of the monitoring means occurs.

Exception: Maintenance operations involving devices such as battery chargers, block heaters and

similar devices, and GFCI/RCD protected circuits.

5.1.3 Each protective conductor connecting point on a machine shall be marked or labelled as such

using the symbol IEC 60417-5019 or with the letters “PE”, or by use of the bicolour combination

GREEN-AND-YELLOW, or by any combination of these. The graphical symbol is preferred.

5.2 Guidance for type of neutral earthing system

For high-voltage equipment, the following general limitations for different voltage ranges and lengths

of supply cable apply.
a) Direct earthing of the neutral

Only appropriate for system voltages less than 2 kV, (automatic disconnection of supply is always

required).
b) Low impedance earthing of the neutral

May be appropriate for system voltages up to 36 kV and cable length up to 4 km (automatic

disconnection of supply is normally necessary).
c) Isolated or high impedance earthing of the neutral

Appropriate for system voltages up to 36 kV and cable length up to 8 km, with the permissible cable

length depending upon the capacitive reactance of all cables connected to the supply (automatic

disconnection of supply is not normally necessary).

1) ISO Online browsing platform: available at http://www.iso.org/obp. Search using 5019.

© ISO 2016 – All rights reserved 3
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ISO 14990-2:2016(E)
Figure 2 — Example of equipotential bonding for externally-powered EMM
(based on IEC 60204–1: 2009, Figure 2)
6 Protection against electrical fire hazards
The requirements of ISO 14990-1:2016, Clause 6 shall apply.
7 Protection against thermal hazards
The requirements of ISO 14990-1:2016, Clause 7 shall apply.
8 Protection against mechanical hazards
The requirements of ISO 14990-1:2016, Clause 8 shall apply.
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ISO 14990-2:2016(E)
9 Protection against abnormal operation hazards
9.1 General

The requirements of ISO 14990-1:2016, Clause 9 shall apply except as modified by this clause.

9.2 Supply conductors

Unless otherwise specified by the user, the supplier of the electrical equipment is not responsible for

providing the overcurrent protective device for the supply conductors to the electrical equipment.

The supplier of the electrical equipment shall state on the installation diagram the data necessary for

selecting the overcurrent protective device.
9.3 Socket outlets

Overcurrent protection shall be provided in the unearthed live conductors of each circuit feeding

general-purpose socket outlets intended primarily for supplying power to maintenance equipment.

9.4 Protection against supply interruption or voltage reduction and subsequent
restoration

Where a supply interruption or a voltage reduction can cause a hazardous situation, damage to the

machine, or to the work in progress, undervoltage protection shall be provided by, for example, shutting

down the machine at a predetermined voltage level.

Where the operation of the machine can allow for an interruption or a reduction of the voltage for a

short time period, delayed undervoltage protection may be provided. The operation of the undervoltage

device shall not impair the operation of any stopping control of the machine.

Upon restoration of the voltage or upon switching on the incoming supply, automatic or unexpected

restarting of the machine shall be prevented where such a restart can cause a hazardous situation.

Where only a part of the machine or of the group of machines working together in a coordinated manner

is affected by the voltage reduction or supply interruption, the undervoltage protection shall initiate

appropriate control responses to ensure coordination.
9.5 Phase sequence protection

Where an incorrect phase sequence of the supply voltage can cause a hazardous situation or damage to

the machine, protection shall be provided.
NOTE Conditions of use that can lead to an incorrect phase sequence include
— a machine transferred from one supply to another,

— a mobile machine with a facility for connection to an external power supply,

— supply cable repairs.
9.6 Protection against overvoltages due to lightning and to switching surges

Protective devices can be provided to protect against the effects of overvoltages due to lightning or to

switching surges. If provided,

— devices for the suppression of overvoltages due to lightning shall be connected to the incoming

terminals of the supply disconnecting device;
© ISO 2016 – All rights reserved 5
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ISO 14990-2:2016(E)

— devices for the suppression of overvoltages due to switching surges shall be connected across the

terminals of all equipment requiring such protection.
10 Electric power source

The requirements of ISO 14990-1:2016, Clause 10 shall apply except as modified by this clause.

NOTE Externally-powered (mains-connected) EMMs include machines powered by external dedicated

generators, which in turn include any off-board electric power generation equipment intended to provide power

to the machine.
10.1 Incoming supply conductor terminations

Where a neutral conductor is used it shall be clearly indicated in the technical documentation of the

machine, such as in the installation diagram and in the circuit diagram, and a separate insulated

terminal, labelled “N” in accordance with 16.1, shall be provided for the neutral conductor.

There shall be no connection between the neutral conductor and the protective bonding circuit inside

the electrical equipment nor shall a combined PEN terminal be provided.

Exception: a connection may be made between the neutral terminal and the PE terminal at the point of

the connection of the power supply to the machine for TN-C systems.

TN, TT, and IT systems are defined by IEC 60364-1, which covers voltages up to 1 000 V AC and

1 500 V DC This document extends the range of application for TN, TT, and IT systems to 36 kV AC or DC.

All terminals for the incoming supply connection shall be clearly identified in accordance with

IEC 60445 and 16.1. For the identification of the external protective conductor terminal, see 10.3.

The following practices are recommended:

— the electrical equipment of EMM should, if practicable, be connected to a single incoming supply;

— if one or more additional supplies are necessary for certain parts of the equipment (e.g. equipment

that operates at a different voltage), those supplies should be derived, as far as is practicable, from

devices such as transformers or converters forming part of the electrical equipment of the machine;

— unless a plug is provided with the machine for the connection to the supply, the supply conductors

should be terminated at the supply disconnecting device (for some systems, such as cable drum, this

is not practical, but there should be a disconnecting device at the closest practical point to the power

source).
10.2 Terminal for connection to the external protective earthing system

A terminal shall be provided near the phase conductor terminals for each incoming supply. Depending

upon the supply distribution system, this terminal shall be for connection of the EMM to the external

protective earthing system or to the external protective conductor.

The terminal shall be sized to accommodate an external protective copper conductor with a

cross-sectional area given by Table 1. If an external protective conductor of a material other than

copper is used, the terminal size shall be selected accordingly (see also ISO 14990-1:2016, 5.10.2.2).

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ISO 14990-2:2016(E)

Table 1 — Minimum cross-sectional area of the external protective copper conductor

Cross-sectional area of copper phase conduc- Minimum cross-sectional area of the exter-

tors supplying the equipment nal protective copper conductor
S S
2 2
mm mm
S ≤ 16 S
16 < S ≤ 35 16
S > 35 S/2
Based on IEC 60364-5-54:2011 Table 54.2.
PEN conductors shall be in accordance with IEC 60364–5-52.

At each incoming supply point, the terminal for connection of the external protective earthing system

or the external protective conductor shall be marked or labelled with the letters PE (see IEC 60445).

10.3 Protection against unauthorized, inadvertent and/or mistaken connection

Devices which are described in ISO 14990-1:2016, 10.2 and 10.3, and which are located outside

an enclosed electrical operating area shall be equipped with means to secure them in the OFF

(disconnected) position (e.g. by provisions for padlocking or trapped key interlocking). Such a lock-off

arrangement shall prevent remote as well as local reconnection.

If a non-lockable disconnecting device (e.g. withdrawable fuse-links or withdrawable links) is provided,

other means of protection against reconnection (e.g. warning labels in accordance with 16.1) may be

provided.

However, when a plug/socket combination according to ISO 14990-1:2016, 11.10.5 e) is so positioned

that it can be kept under the immediate supervision of the person carrying out the work, means for

securing in the disconnected state need not be provided.
11 Wiring

The requirements of ISO 14990-1:2016, Clause 11 shall apply except as modified by this clause.

11.1 Flexible cables

For high-voltage equipment, each flexible cable (e.g. trailing cable) for the high voltage power supply to

the electrical equipment of EMM shall contain a protective conductor (see ISO 14990-1:2016,

...

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