Road traffic signal systems

This European Standard specifies requirements for Road Traffic Signal Systems, including their
development, design, testing, installation and maintenance.
In particular, it forms the electrotechnical part of the following two standards issued by CEN:
– EN 12368, Traffic control equipment ― Signal heads
– EN 12675, Traffic signal controllers ― Functional safety requirements
Each of these standards above should be used with this standard either singly or together to define an
operational equipment or system. This should be achieved by using the electrotechnical methods and testing
defined in this standard.
Where Road Traffic Signal Systems are to be used with other systems, e.g. public lighting or railway
signalling and communication, this standard should comply with the other respective standard to ensure that
overall safety is not compromised.
Only permanently or temporarily installed Road Traffic Signal Systems are included in this standard. Central
office and portable signalling systems are not covered.

Straßenverkehrs-Signalanlagen

Diese Europäische Norm legt Anforderungen für Straßenverkehrs-Signalanlagen fest, einschließlich ihrer Entwicklung, Konstruktion, Prüfung, Errichtung und Instandhaltung.
Insbesondere bildet sie den elektrotechnischen Teil der folgenden zwei von CEN herausgegebenen Normen:
–   EN 12368, Anlagen zur Verkehrssteuerung – Signalleuchten;
–   EN 12675, Steuergeräte für Lichtsignalanlagen – Funktionale Sicherheitsanforderungen.
Jede der angegebenen Normen muss mit dieser Norm entweder einzeln oder zusammen angewendet werden, um ein betriebsfähiges Gerät oder eine betriebsfähige Anlage festzulegen. Dazu müssen die in der vorliegenden Norm festgelegten elektrotechnischen Methoden und Prüfungen angewendet werden.
Wenn Straßenverkehrs-Signalanlagen in Verbindung mit anderen Anlagen betrieben werden, z. B. Straßen¬beleuchtung oder Eisenbahnsignal- und  kommunikationstechnik, müssen die Anforderungen dieser Norm mit den entsprechenden Normen übereinstimmen, damit die Sicherheit des Gesamtsystems nicht beeinträchtigt wird.
Die vorliegende Norm gilt nur für fest oder vorübergehend errichtete Straßenverkehrs-Signalanlagen. Zentrale und ortsveränderliche Signalanlagen werden nicht behandelt.

Systèmes de signaux de circulation routière

La présente Norme Européenne définit les exigences pour les systèmes de signaux de circulation routière, et comprend leur étude, leur conception, leurs essais, leur installation et leur maintenance.
En particulier, elle constitue la partie électrotechnique des deux normes suivantes publiées par le CEN:
–   EN 12368, Equipement de régulation du trafic ― Signaux
–   EN 12675, Contrôleurs de signaux de circulation routière ― Exigences de sécurité fonctionnelle
Il convient que chacune des normes ci-dessus soit utilisée avec la présente norme, soit individuellement soit ensemble, pour définir un équipement ou un système opérationnel. Pour ce faire, il convient d’utiliser les méthodes et essais électrotechniques définis dans la présente norme.
Lorsque les systèmes de signaux de circulation routière sont utilisés avec d’autres systèmes tels que ceux d’éclairage public, de signalisation ferroviaire et de télécommunications, il convient que cette norme soit conforme à l’autre norme correspondante afin d’assurer que la sécurité de l’ensemble ne soit pas compromise.
Seuls les systèmes de signaux de circulation routière installés de façon permanente ou temporaire sont compris dans la présente norme. Les postes centraux et les systèmes de signalisation portables ne sont pas couverts.

Sistemi prometne signalizacije

Ta evropski standard določa zahteve za sisteme prometne signalizacije, vključno z njihovim razvojem, načrtovanjem, preskušanjem, vgradnjo in vzdrževanjem.
Predvsem tvori elektrotehnični del naslednjih dveh standardov, ki jih je izdal CEN:
- EN 12368, oprema za nadzor prometa – signalne glave,
- EN 12675, nadzorniki prometnih signalov – zahteve za funkcionalno varnost.
Vsak od zgornjih standardov se mora uporabljati s tem standardom, posamično ali skupaj, za določanje delovne opreme ali sistema. To naj se doseže z uporabo elektrotehničnih metod in preskušanja, določenega v tem standardu.
Kjer se sistemi prometne signalizacije uporabljajo z drugimi sistemi, kot so npr. javna razsvetljava, železniška signalizacija in komunikacija, mora biti ta standard v skladu z drugim tovrstnim standardom, da zagotovi celotno varnost.
V ta standard so vključeni samo stalni ali začasno postavljeni sistemi prometne signalizacije. Osrednji pisarniški in prenosni signalni sistemi niso zajeti.

General Information

Status
Published
Publication Date
24-Oct-2011
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
11-Oct-2011
Due Date
16-Dec-2011
Completion Date
25-Oct-2011

Relations

Effective Date
31-Jul-2018
Effective Date
29-Jan-2023
Effective Date
07-Jun-2022

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SLOVENSKI STANDARD
SIST EN 50556:2011
01-december-2011
1DGRPHãþD
SIST HD 638 S1:2002
SIST HD 638 S1:2002/A1:2007
Sistemi prometne signalizacije
Road traffic signal systems
Straßenverkehrs-Signalanlagen
Systèmes de signaux de circulation routière
Ta slovenski standard je istoveten z: EN 50556:2011
ICS:
93.080.30 Cestna oprema in pomožne Road equipment and
naprave installations
SIST EN 50556:2011 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 50556:2011

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SIST EN 50556:2011

EUROPEAN STANDARD
EN 50556

NORME EUROPÉENNE
February 2011
EUROPÄISCHE NORM

ICS 93.080.30 Supersedes HD 638 S1:2001 + A1:2006


English version


Road traffic signal systems



Systèmes de signaux de circulation Straßenverkehrs-Signalanlagen
routière





This European Standard was approved by CENELEC on 2011-01-02. 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 Central Secretariat 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 Central Secretariat 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, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels


© 2011 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
-
Ref. No. EN 50556:2011 E

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SIST EN 50556:2011
EN 50556:2011 - 2 -
Foreword

This European Standard was prepared by CENELEC Task Force BTTF 69-3, Road traffic signal systems.

The text of the draft was submitted to the Unique Acceptance Procedure and was approved by CENELEC as
EN 50556 on 2011-01-02.

This document supersedes HD 638 S1:2001 + A1:2006.

The main changes with respect to HD 638 S1:2001 + A1:2006 are the following:

− update of the normative-references;

− editorial revision;

− reduction of the classes;

− adaptation to the level of technology.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent rights.
The following dates were fixed:

– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2012-01-02

– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2014-01-02

__________

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Contents
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Electrical supply and limits . 10
4.1 Nominal voltages . 10
4.2 Operating voltage range . 10
4.3 Low voltage . 11
4.4 Overvoltage . 11
4.5 Voltage dip . 11
4.6 Mains frequency . 11
5 Safety . 12
5.1 Electrical safety . 12
5.2 Traffic safety . 14
6 Testing . 19
6.1 General . 19
6.2 Organisation of testing . 19
6.3 Environmental tests . 20
6.4 Electrical tests . 22
6.5 Electrical safety tests . 23
6.6 Traffic safety tests . 24
6.7 Electromagnetic compatibility testing . 25
7 Electrical interfaces . 26
7.1 General . 26
7.2 Detector interface . 26
8 Installation . 26
8.1 General . 26
8.2 Tests carried out during installation . 26
8.3 Test of cables following the installation of cables . 27
8.4 Inspection of terminations following the installation and termination of all equipment and cables . 27
8.5 Test of impedance . 27
8.6 Insulation of live parts to earth . 28
8.7 RCD (residual current detector / earth leakage breaker) . 28
8.8 Fuses . 28
8.9 Voltage and polarity of supply . 28
8.10 Connections between controllers, signals and ancillary equipment . 29
8.11 Safety covers . 29
8.12 Functional check of road traffic signal systems . 29
9 Maintenance . 29
9.1 General . 29

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9.2 Types of maintenance . 29
9.3 Documentation required for maintenance . 29
9.4 Equipment not covered by this standard . 30
9.5 Safety testing procedures . 30
9.6 Maintenance testing procedures . 30
10 Marking and labelling . 32
11 Classification of environmental test conditions . 33

Figure
Figure 1 − Failure consideration of a Road Traffic Signal System − Protection against accidents caused by
technical failures .18

Tables
Table 1 − Classification according to voltage dip .11
Table 2 − Requirements for maintenance measures (intervals (PTI) in months) .31
Table 3 − Environmental testing .33

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Introduction
To satisfy the legal and regulatory requirements and specific provisions of each CENELEC country, certain
characteristics in this standard contain a range which is defined by a number of discrete classes. The class to
be used in the country will be selected by the Standards Authority of the CENELEC member of that country
from the range specified.
Thus this European Standard contains the essential electrotechnical requirements of all CENELEC countries
and permits through the class selection procedure, countries to incorporate their own requirements.
It is believed that this first step will allow, over a period of time, a gradual alignment of Road Traffic Signal
Systems in Europe.

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1 Scope
This European Standard specifies requirements for Road Traffic Signal Systems, including their
development, design, testing, installation and maintenance.
In particular, it forms the electrotechnical part of the following two standards issued by CEN:
– EN 12368, Traffic control equipment ― Signal heads
– EN 12675, Traffic signal controllers ― Functional safety requirements
Each of these standards above should be used with this standard either singly or together to define an
operational equipment or system. This should be achieved by using the electrotechnical methods and testing
defined in this standard.
Where Road Traffic Signal Systems are to be used with other systems, e.g. public lighting or railway
signalling and communication, this standard should comply with the other respective standard to ensure that
overall safety is not compromised.
Only permanently or temporarily installed Road Traffic Signal Systems are included in this standard. Central
office and portable signalling systems are not covered.

2 Normative references
The following referenced documents are indispensable for the application 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.

EN 12368 Traffic control equipment - Signal heads
EN 12675:2000 Traffic signal controllers - Functional safety requirements
EN 50102 Degrees of protection provided by enclosures for electrical equipment against
external mechanical impacts (IK code)
EN 50110-1 Operation of electrical installations
EN 50129 Railway applications - Communication, signalling and processing systems - Safety
related electronic systems for signalling
EN 50293 Electromagnetic compatibility - Road traffic signal systems - Product standard
EN 60529 Degrees of protection provided by enclosures (IP Code) (IEC 60529)
EN 60950-1:2006 Information technology equipment - Safety - Part 1: General requirements
(IEC 60950-1:2005, mod.)
EN 61008 series Residual current operated circuit-breakers without integral overcurrent protection
for household and similar uses (RCCB's) (IEC 61008 series)
EN 61009 series Residual current operated circuit-breakers with integral overcurrent protection for
household and similar uses (RCBO's) (IEC 61009 series)
EN ISO 9001:2008 Quality management systems - Requirements (ISO 9001:2008)
HD 384.4 series Electrical installations of buildings - Part 4: Protection for safety (IEC 60364-4
series)
HD 60364-5-54 Low-voltage electrical installations - Part 5-54: Selection and erection of electrical
equipment - Earthing arrangements, protective conductors and protective bonding
conductors (IEC 60364-5-54)
EN 60068-2-1 Environmental testing - Part 2-1: Tests - Test A: Cold (IEC 60068-2-1)
EN 60068-2-2 Environmental testing - Part 2-2: Tests - Test B: Dry heat (IEC 60068-2-2)
EN 60068-2-5 Environmental testing - Part 2: Tests - Test Sa: Simulated solar radiation at ground
level (IEC 60068-2-5)

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EN 60068-2-14 Environmental testing - Part 2-14: Tests - Test N: Change of temperature
(IEC 60068-2-14)
EN 60068-2-30 Environmental testing - Part 2-30: Tests - Test Db: Damp heat, cyclic (12 h + 12 h
cycle) (IEC 60068-2-30)
EN 60068-2-64 Environmental testing - Part 2-64: Tests - Test Fh: Vibration, broadband random
and guidance (IEC 60068-2-64)
EN 61140 Protection against electric shock - Common aspects for installation and equipment
(IEC 61140)
CLC/TS 50509 Use of LED signal heads in road traffic signal systems
IEC 60050-191 International Electrotechnical Vocabulary - Chapter 191: Dependability and quality
of service
IEC 60050-826 International Electrotechnical Vocabulary - Part 826: Electrical installations
IEC 60183 Guide to the selection of high-voltage cables
IEC 60417 (database) Graphical symbols for use on equipment


3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 General
3.1.1
Road Traffic Signal Systems
include systems and devices, provided they are affiliated to them in terms of circuitry

NOTE They may consist of the following elements which is not in itself a complete list:
– Controllers;
– Signal heads, signalling devices and traffic signs
e.g. signal heads for traffic signals;
acoustic signal generators;
mechanical signal generators;
traffic signs connected to the Road Traffic Signal System;
– Traffic sensors and detectors
e.g. request push buttons;
vehicle detectors / Pedestrian Detectors;
– Monitoring equipment
e.g. photographic monitoring devices;
– Equipment Enclosures;
– Electrical Supply;
– Cables;
– Interconnections;
– Supports.

3.1.2
Failure Mode Analysis
means of examining all failure modes to ensure that signal states endangering the road users and/or risk of
electrical hazard cannot occur during normal conditions of operation of a Road Traffic Signal System or if
they do occur as a result of or whilst a failure (failure mode) exists that they signal states endangering the
road users are detected and prevented from continuing

3.1.3
Signal Safeguarding Facility
facilities intended to prevent states of signals endangering the traffic

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3.1.4
monitoring element
device that signals electrical and mechanical states of equipment, preferably for signal circuits, and which
converts the obtained information in such a manner that it can be processed in signal safeguarding facilities

3.1.5
hardware
complete Road Traffic Signal System or a (material) part of it

3.1.6
hardware fault
failures of components and any influence that will cause the equipment to fail
NOTE Systematic hardware faults constitute either design faults or systematic production faults.

3.1.7
software
all or part of the sequence instructions for a Road Traffic Signal System including the affiliated documentation
NOTE Software is exclusively immaterial, so that it is subject to no wear or failure mechanisms. Once implemented, software
cannot be falsified on its own.

3.1.8
software error
deviation between the realised and intended functional contents of the software
NOTE All errors in the software are systematic errors. They are caused by:
– invalid specification (incorrect formulation of intention);
– incorrect programming (incorrect translation of the specification to sequential instructions).
Apparent program falsification in memories is produced by hardware faults or failures or is caused by inadmissible influencing.

3.2 Traffic engineering

3.2.1
controllers (traffic)
electrical device to control signals

3.2.2
signal group
sequence of conditions applied to a group of signal heads, which always received identical signal light
indications

3.2.3
Operating System
principle software that allows a computer to operate, and which establishes the basic foundations, protocols
and functions that the computer can perform, including communication with internal and external resources

3.2.4
Application Program
software that determines specific tasks that a computer can perform, i.e. operate as a traffic controller

NOTE Application software rests on and extends the capabilities of the operating system to meet customer needs.

3.2.5
Traffic Data
data which specifies how the application program will perform in the particular circumstances of one traffic
system

NOTE This may be considered to be in two parts.

3.2.5.1
Traffic Safety Data

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all Traffic Data stored in non-volatile memory that has a direct impact on the safety of road users

3.2.5.2
Traffic Non Safety Data
all the remainder of the data which will not cause an unacceptable danger to the road user if the data is
changed

3.2.6
Design Authority
Design Responsible
individual or group (organisation) responsible for the safe design and manufacturing, including the
instructions for safe use, installation and maintenance of the equipment or system

3.3 Electrotechnical
3.3.1
live part
see IEC 60050-826

3.3.2
enclosure (EN 50102)
part providing protection of equipment against certain external influences and, in any direction, protection
against contact
NOTE This definition from the existing International Electrotechnical Vocabulary (IEC 60050-826) needs the following explanations
under the scope of this standard:
a) Enclosures provide protection of equipment against harmful effects of mechanical impacts and protection of persons and
livestock against access to hazardous parts.
b) Barriers, shapes of openings or any other means - whether attached to the enclosure or formed by the enclosed equipment -
suitable to prevent or limit the penetration of the specified test probes are considered as part of the enclosure, except when
they can be removed without the use of a tool.

3.3.3
complete protection
protection that achieves:
a) effective and durable prevention of contact with live parts by the attachment of obstacles at least
conforming to type of protection IP2x as defined in EN 60529;
or
b) complete enclosure of live parts by insulating material that can be removed only by destruction (protection
by insulating envelopment)

3.3.4
partial protection
protection that prevents the possibility of accidental contact by persons or by objects usually handled by them
in one of the following ways:
a) by placing live parts at a distance that the possibility of accidental contact by persons or objects usually
handled by them is excluded (protection against accidental contact by a safety clearance);
or
b) by attaching obstacles conforming at least to type of protection IP1x as defined in EN 60529 (protection
against accidental contact by the attachment of obstacles)
3.3.5
reinforced insulation
see EN 60529

3.3.6
nominal voltages
see IEC 60050-826

3.3.7
earthed systems
see IEC 60050-826

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3.3.8
Class 0 equipment
see EN 61140

3.3.9
Class I equipment
see EN 61140

3.3.10
Class II equipment
see EN 61140

3.3.11
Class III equipment
see EN 61140

3.3.12
safety extra-low voltage
SELV
see EN 61140

3.3.13
protective conductor (symbol PE)
see IEC 60050-826

3.3.14
earthing conductor
see IEC 60050-826

3.3.15
RCD
see EN 61008 series and EN 61009 series

3.3.16
voltage dip
see IEC 60050-161
3.3.17
insulation
see EN 60950-1:2006, 1.2.9

4 Electrical supply and limits
4.1 Nominal voltages
The standard nominal voltage for connection to the public supply shall be taken to be 230 V AC . Other
r.m.s
nominal voltages shall be permitted.
4.2 Operating voltage range
The system shall be classified according to its mains voltage range within which the Road Traffic Signal
System shall work as defined by EN 12675, as follows:
nominal voltage - 13 % .+ 10 %
The system shall not display signals which contravene EN 12675 when the supply voltage is outside the
above voltage ranges.

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4.3 Low voltage
4.3.1 Auxiliary state switch response voltage (V )
aux
It is expected that all controllers will have a point where low input supply voltage will mean that the monitoring
systems employed may be unable to operate and therefore would be unable to guarantee the detection or
prevention of signal states which endanger traffic. The controller shall be prevented from reaching this limit
and should switch to a safe state (see Note), in a controlled manner before this point is reached.

In a controlled manner means that it shall shut down in such a way as to prevent any likelihood of a
hazardous signal state being displayed during the process of switching to the safe state.

NOTE The safe state noted above may either be all signals off or a flashing display of either red or yellow or a combination of red and
yellow, which is recognised in the country in which the controller is to be used as a safe state, warning users to proceed carefully / give
way to others.

4.3.2 Power up activation voltage
The system shall become active when the supply voltage reaches a value within its operating voltage range.
The restart procedure shall normally be automatic or in exceptional circumstances it may be by manual or
remote control. No signalling state dangerous to traffic shall be possible and the signalling state shall conform
to EN 12675.

4.4 Overvoltage
The system shall be classified as follows according to whether or not a protective device is incorporated
which cuts off the supply voltage to prevent damage. Where incorporated, the protective device shall operate
when the supply voltage is greater than the operating voltage range.
– Class D0: no protective device is required;
– Class D1: a protective device is required to provide protection up to 1 500 V .
r.m.s

4.5 Voltage dip
The system shall be classified according to the duration of dips in supply which affect the operation. In order
to avoid undesirable reactions by the signal safeguarding facilities, the system shall operate as shown in
Table 1 according to the duration of the voltage dip below V .
aux
Period t is a timeperiod of a voltage dip in the supply which will not affect the normal operation of the system.
1
Period t is a timeperiod of voltage dip in the supply when the system shall change to signals OFF followed by
2
the start up sequence.

Table 1 − Classification according to voltage dip
Criterion Values
ms
Period t < 20
1
Period t > 100
2

For any voltage dip in the supply between t and t the controller may remain working correctly or change to
1 2
signals OFF followed by the start up sequence.

4.6 Mains frequency
The system shall be classified as follows according to the acceptable variations in mains frequency:
50 Hz ± 4 %

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5 Safety
5.1 Electrical safety
5.1.1 General
5.1.1.1 Introduction
The Road Traffic Signal System shall conform to HD 384.4 series. This subclause deals with the additional
requirements for Road Traffic Signal Systems.

5.1.1.2 Criteria − Leakage current
5.1.1.2.1 Road Traffic Signal Systems
Class T1:
For Road Traffic Signal Systems, leakage current protection facilities conforming to HD 384.4.41 shall be
fitted. Earth leakage circuit breakers conforming to EN 61008 series for nominal currents 20 % greater than
the expected current and nominal leakage currents ≤ 0,3 A shall be installed.
Class T2:
No requirement for leakage current protection facilities for the whole system, however the customer may
request facilities as class T1.
5.1.1.2.2 Maintenance equipment supply
To conform with HD 60364-4-41, an earth leakage circuit breaker conforming to EN 61008 series with
nominal leakage currents ≤ 0,03 A shall be installed.

5.1.1.3 Earthing
5.1.1.3.1 General
This subclause applies to the installation or part of the installation which is class I conforming to EN 61140.

5.1.1.3.2 Protective earth conductor (PE)
The system shall conform to HD 60364-5-54.
Protective earth conductors shall connect together all conductive parts and the PE terminals throughout the
system. They shall either be created by conductors in a cable or by separately installed wires and/or
construction parts.
In controllers the PE conductors shall be connected to the PE terminal / earth bus bar.
NOTE Metallic bodies which, by virtue of their location or smallness, cannot be touched or are unlikely to become live should be
designated excluded devices, i.e. they need not be connected to the PE conductor.
5.1.1.3.3 PE wiring of external equipment
NOTE 1 Examples of external equipment are poles, signal heads and detectors.
The system shall be classified according to the following methods.
Accessible conductive parts shall be connected to the PE conductors incorporated in the cables or a separate
PE cable.
NOTE 2 Armouring of cables may also be used as PE conductors where the cable construction permits.

5.1.1.4 Enclosure
The enclosure shall provide the mechanical protection to IK07 (see EN 50102) with the following criteria:
No damage shall occur to the equipment contained within the enclosure and the equipment shall continue to
operate to its specification. There shall be no degradation of the IP rating of the equipment.
Class V1:
Enclosures shall provide protection to IP44. When the manual panel is open, the protection provided shall be
to IP42. When the enclosure is open the protection shall be to IP20.
Class V2:
Enclosures shall provide protection to IP54. When the manual panel is open, the protection provided shall be
to IP23. When the enclosure is open the protection shall be to IP21.

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5.1.1.5 Access
Covers, doors, flaps, or similar allowing access to controls, circuits or live parts when opened, shall be
capable of being opened only with the aid of a key or a tool
...

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