SIST EN 50556:2019
(Main)Road traffic signal systems
Road traffic signal systems
This document 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 will be used with this standard either singly or together to define an operational equipment or system. This will 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 document will be used with any other respective standard(s) for the other associated systems to ensure that overall safety is not compromised.
This document is applicable to traffic signal control equipment permanently and temporarily installed, and portable traffic control equipment, with the exception of portable traffic signal equipment only capable of controlling alternate / shuttle working lanes (as further defined in 3.2.10).
Straßenverkehrs-Signalanlagen
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.
Systèmes de signaux de circulation routière
Sistemi prometne signalizacije
Vsak od zgornjih standardov se bo uporabljal s tem standardom posamezno ali skupaj pri opredeljevanju
operativne opreme ali sistema. To se bo zagotovilo z uporabo elektrotehničnih metod in preskušanja, opredeljenih v tem standardu.
Kjer se bodo sistemi prometne signalizacije uporabljali z drugimi sistemi, npr. javno razsvetljavo ali železniško
signalizacijo in komunikacijo, se bo ta dokument uporabljal skupaj z drugimi zadevnimi standardi za druge povezane sisteme, da se zagotovi celotna varnost.
Ta dokument se uporablja za trajno in začasno nameščeno opremo za nadzor prometa ter prenosno opremo za nadzor prometa, razen za prenosno opremo za prometno signalizacijo, ki lahko nadzoruje samo izmenične/zožane delovne pasove (kot je dodatno opredeljeno v 3.2.10).
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2019
Nadomešča:
SIST EN 50556:2011
Sistemi prometne signalizacije
Road traffic signal systems
Straßenverkehrs-Signalanlagen
Systèmes de signaux de circulation routière
Ta slovenski standard je istoveten z: EN 50556:2018
ICS:
93.080.30 Cestna oprema in pomožne Road equipment and
naprave installations
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN 50556
NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2018
ICS 93.080.30 Supersedes EN 50556:2011
English Version
Road traffic signal systems
Systèmes de signaux de circulation routière Straßenverkehrs-Signalanlagen
This European Standard was approved by CENELEC on 2017-12-18. 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: Rue de la Science 23, B-1040 Brussels
© 2018 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 50556:2018 E
Contents Page
European foreword . 6
Introduction . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Electrical supply and limits . 17
4.1 Nominal voltages . 17
4.2 Operating voltage range . 17
4.3 Low voltage . 18
4.3.1 Auxiliary state switch response voltage (V ) . 18
aux
4.3.2 Power up activation voltage . 18
4.4 Overvoltage . 18
4.5 Voltage dip . 18
4.6 Mains frequency . 19
5 Safety . 19
5.1 Electrical safety . 19
5.1.1 General . 19
5.1.2 Controller Signal outputs . 20
5.1.3 Interconnections . 21
5.1.4 Cables . 21
5.1.5 Insulation . 22
5.2 Traffic safety . 23
5.2.1 General . 23
5.2.2 Requirements of signal intensity for safety . 23
5.2.3 Requirements for signal states . 23
5.2.4 Failure consideration (Failure mode analysis) . 25
5.2.5 Location of monitoring elements for signals . 28
6 Testing . 28
6.1 Object . 28
6.2 Organization of testing . 28
6.2.1 Ordering of tests . 28
6.2.2 Presentation of equipment . 29
6.3 Environmental tests. 30
6.3.1 General conditions for the tests . 30
6.3.2 Random vibration test (in accordance with EN 60068-2-64) . 31
6.3.3 Impact tests . 31
6.3.4 Degree of protection (in accordance with EN 60529) . 31
6.3.5 Dry heat (in accordance with EN 60068-2-2) . 32
6.3.6 Cold (in accordance with EN 60068-2-1) . 32
6.3.7 Damp heat (in accordance with EN 60068-2-30) . 32
6.3.8 Solar radiation (in accordance with EN 60068-2-5) . 32
6.4 Electrical tests . 33
6.4.1 Scope of electrical compatibility tests . 33
6.4.2 Output to signal heads . 33
6.4.3 External input tests . 33
6.4.4 External output tests . 33
6.4.5 Communications interface circuits . 34
6.5 Electrical safety tests . 34
6.5.1 General . 34
6.5.2 Typical test conditions . 34
6.5.3 Protective conductors continuity test . 34
6.5.4 Labelling . 34
6.5.5 Access to hazardous voltages . 35
6.5.6 Protection against fire risks . 35
6.5.7 Test of residual current protection means for the installation . 35
6.5.8 Test of residual current protection means for maintenance supplies . 35
6.5.9 Electrical strength test . 35
6.6 Traffic safety tests . 35
6.6.1 Safety tests (EN 12675) . 35
6.6.2 Undervoltage tests . 36
6.6.3 Power up activation voltage test . 36
6.6.4 Overvoltage test . 36
6.6.5 Power supply voltage dips . 36
6.7 Electromagnetic compatibility testing . 36
7 Electrical interfaces . 37
7.1 General . 37
7.2 Detector interface . 37
8 Installation . 37
8.1 General . 37
8.2 Tests carried out during installation . 38
8.3 Test of cables following the installation of cables . 38
8.4 Inspection of terminations following the installation and termination of all equipment and
cables . 38
8.5 Test of impedance . 39
8.5.1 Protective conductors continuity . 39
8.5.2 Earth impedance test . 39
8.5.3 Fault loop impedance test . 39
8.6 Insulation of live parts to earth . 39
8.7 RCD (residual current device / earth leakage breaker) . 40
8.8 Fuses . 40
8.9 Voltage and polarity of supply . 40
8.10 Connections between controllers, signals and ancillary equipment . 40
8.11 Safety covers . 40
8.12 Functional check of road traffic signal systems . 40
9 Maintenance . 41
9.1 General . 41
9.2 Types of maintenance . 41
9.3 Documentation required for maintenance . 41
9.4 Equipment not covered by this standard . 42
9.5 Safety testing procedures . 42
9.6 Maintenance testing procedures . 43
10 Marking and labelling . 44
11 Classification of environmental test conditions . 45
Bibliography . 49
European foreword
This document (EN 50556:2018) has been prepared by CENELEC Task Force CLC/BTTF 69-3 "Road traffic
signal systems".
The following dates are fixed:
• latest date by which this document has (dop) 2019-03-28
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2021-09-28
standards conflicting with this document
have to be withdrawn
This document supersedes EN 50556:2011.
— change in the Scope to cover non-permanent signals of a certain level of complexity;
— correct the normative usage of shall and should within the whole document;
— update of the normative references to add EN 50159;
— updated invalid reference in 3.3.5 to IEC 60050-826;
— updated invalid reference from HD 384.4 to the HD 60364-4 series;
— updated invalid reference from IEC 60536 to EN 61140;
— clarified wording of requirements in 5.2.3.2;
— change of the definition of “Road traffic signal system” to fulfil formal requirements;
— additions to terms and definitions in 3.2.7 to 3.2.10;
— modification of 5.1.2 to accommodate new forms of architecture that are seen as possible in the future,
an adaptation to the level of technology;
— modification of 5.2.3.3 (last sentence) to reference the changes made to 5.1.2;
— modification of 5.2.3.4, Class X1 last paragraph, to reference the changes made to 5.1.2;
— modification of 5.2.3.4, Class X2 note added to reference the changes made to 5.1.2;
— added a note at 6.3.1.3 b) for clarification about the test setup.
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.
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.
1 Scope
This document 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 will be used with this standard either singly or together to define an
operational equipment or system. This will 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 document will be used with any other respective standard(s) for the other
associated systems to ensure that overall safety is not compromised.
This document is applicable to traffic signal control equipment permanently and temporarily installed, and
portable traffic control equipment, with the exception of portable traffic signal equipment only capable of
controlling alternate / shuttle working lanes (as further defined in 3.2.10).
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.
EN 12368, Traffic control equipment - Signal heads
EN 12675:2017, 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 – Part 1: General requirements
EN 50129, Railway applications - Communication, signalling and processing systems - Safety related
electronic systems for signalling
EN 50159:2010, Railway applications - Communication, signalling and processing systems - Safety-related
communication in transmission systems
EN 50293, Road traffic signal systems - Electromagnetic compatibility
EN 60068-2-1:2007, Environmental testing – Part 2-1: Tests – Test A: Cold (IEC 60068-2-1:2007)
EN 60068-2-2:2007, Environmental testing – Part 2-2: Tests – Test B: Dry heat (IEC 60068-2-2:2007)
EN 60068-2-5:2011, Environmental testing – Part 2: Tests – Test Sa: Simulated solar radiation at ground
level (IEC 60068-2-5:2010)
EN 60068-2-14:2009, Environmental testing – Part 2-14: Tests – Test N: Change of temperature
(IEC 60068-2-14:2009)
EN 60068-2-30:2005, Environmental testing – Part 2-30: Tests – Test Db: Damp heat, cyclic (12 h + 12 h
cycle) (IEC 60068-2-30:2005)
EN 60068-2-64:2008, Environmental testing – Part 2-64: Tests – Test Fh: Vibration, broadband random and
guidance (IEC 60068-2-64:2008)
HD 60364-4-41:2007, Low-voltage electrical installations – Part 4-41: Protection for safety - Protection
against electric shock (IEC 60364-4-41:2005)
HD 60364-4 (all parts), Low-voltage electrical installations – 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 and protective conductors (IEC 60364-5-54)
EN 60529:1991, Degrees of protection provided by enclosures (IP Code) (IEC 60529:1989)
EN 60950-1:2006, Information technology equipment – Safety – Part 1: General requirements
(IEC 60950-1:2005, modified)
EN 61008 (all parts), Residual current operated circuit-breakers without integral overcurrent protection for
household and similar uses (RCCB's) (IEC 61008 series)
EN 61140:2016, Protection against electric shock - Common aspects for installation and equipment
(IEC 61140:2016)
IEC 60050-191, International Electrotechnical Vocabulary – Chapter 191: Dependability and quality of service
IEC 60050-192, International electrotechnical vocabulary – Part 192: Dependability
IEC 60183, Guidance for the selection of high-voltage A.C. cable systems
IEC 60417, Graphical symbols for use on equipment [database]
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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 General:
3.1.1
road traffic signal systems
systems for the safe control of the traffic flow at junctions, pedestrian crossings and other places with
conflicting traffic using light signals
Note 1 to entry: 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 the 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
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 1 to entry: 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 1 to entry: 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 1 to entry: 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 1 to entry: 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 1 to entry: This may be considered to be in two parts.
3.2.5.1
traffic safety data
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
3.2.7
centralised power supply and centralised intelligence
example traffic control system, close coupled within a cabinet where both the power supply and intelligence
(the safety elements that switch the lamps and monitor the states of those switches) are centralised
Key
1 cabinet in which all elements are close coupled
2 central processing / controller application
3 safety signal switching and monitoring elements
4 close coupled communication within controlled environment
5 power
6 power switch to remove power from external elements (part of signal safeguarding facility)
7 switched power to illuminate signals
8 traffic / Pedestrian signals (filament / LED)
9 power to signal switching elements that can be switched off / removed.
Figure 1 — Example of conventional close coupled safety system
3.2.8
centralised power supply, distributed Intelligence system
system in which the distributed intelligence safety data is transferred between a central control process and
distributed switching elements and in which, however, power is still distributed from a central source and can
be switched off at this point in case of emergency
Key
1 cabinet in which all elements are close coupled
2 central processing / controller application
3 safety signal switching and monitoring elements
4 close coupled communication within controlled environment
5 power
6 power switch to remove power from external elements (part of signal safeguarding facility)
7 switched power to illuminate signals
8 traffic / Pedestrian signals (filament / LED)
9 power to signal switching elements that can be switched off / removed (controlled from a central switch point
distributed to external elements).
10 communication / transmission
Figure 2 — Example of Central Power, Distributed Intelligence
3.2.9
distributed power supply and distributed intelligence system
system in which the distributed intelligence safety data is transferred between a central control process and
distributed switching elements, and the switching elements have their own local power sources
Key
1 cabinet (power and intelligence distributed externally)
2 central processing / controller application
3 safety signal switching and monitoring elements
4 not applicable in this system (Close coupled communication within controlled environment)
5 local / Distributed power at each signal / group of signals
6 power switch to remove power from signal switching elements (part of signal safeguarding facility)
7 switched power to illuminate signals
8 traffic / pedestrian signals (filament / LED)
9 power to signal switching elements that can be switched off / removed (now distributed).
10 communication / transmission
Figure 3 — Example of Distributed Intelligence and Power
3.2.10
alternate / shuttle working
applications in which controllers serve the alternating release of vehicle traffic in one direction at a time
(typical examples being road works or narrow bridges) and in which there is no crossing traffic (pedestrian or
vehicular)
Key
1 single carriage way / bridge.
2 carriageway restriction / road works
Figure 4 — Examples of Alternate / Shuttle working
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 1 to entry 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 so 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
insulation of hazardous-live-parts which provides protection against electric shock equivalent to double
insulation
Note 1 to entry: Reinforced insulation may comprise several layers which cannot be tested singly as basic insulation or
supplementary insulation.
[SOURCE: EN 61140:2016, 3.10.4]
3.3.6
nominal voltages
value of the voltage by which the electrical installation or part of the electrical installation is designated and
identified
[SOURCE: IEC 60050-826:2004, 826-11-01]
3.3.7
Class 0 equipment
equipment in accordance with the definition in EN 61140:2016, 7.2
3.3.8
Class I equipment
equipment in accordance with the definition in EN 61140:2016, 7.3
3.3.9
Class II equipment
equipment in accordance with the definition in EN 61140:2016, 7.4
3.3.10
Class III equipment
equipment in accordance with the definition in EN 61140:2016, 7.5
3.3.11
safety extra-low voltage
SELV
electric system in which the voltage cannot exceed the value of extra-low voltage:
— under normal conditions and
— under single fault conditions, including earth faults in other electric circuits
[SOURCE: IEC 60050-826:2004, 826-12-31]
3.3.12
protective conductor (symbol PE)
conductor provided for purposes of safety, for example protection against electric shock
[SOURCE: IEC 60050-195:1998, 195-02-09]
3.3.13
earthing conductor
conductor which provides a conductive path, or part of the conductive path, between a given point in a
system or in an installation or in equipment and an earth electrode
[SOURCE: IEC 60050-195:1998, 195-02-03]
3.3.14
RCD
Residual current-operated protective devices (RCDs) according to the EN 61008 series and EN 61009 series
3.3.15
voltage dip
sudden reduction of the voltage at a particular point of an electricity supply system below a specified dip
threshold followed by its recovery after a brief interval
Note 1 to entry: Typically a dip is associated with the occurrence and termination of a short circuit or other extreme
current increase on the system or installations connected to it.
Note 2 to entry: A voltage dip is a two-dimensional electromagnetic disturbance, the level of which is determined by both
voltage and time (duration).
[SOURCE: EN 61000-4-11:2004, 3.3]
3.3.16
insulation
insulation according to 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
rms
nominal voltages shall be permitted.
4.2 Operating voltage range
The system Road Traffic Signal System shall work as defined by EN 12675, in the mains voltage range, 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.
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 recognized 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 .
rms
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 time period of a voltage dip in the supply, which will not affect the normal operation of the
system.
Period t is a time period of voltage dip in the supply when the system shall change to signals OFF followed
by the start up sequence.
Table 1 — Criteria for voltage dips
Criterion Values
ms
Period t1 < 20
Period t2 > 100
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 work correctly and to specification with variations in mains frequency in the following range:
50 Hz −6 %, +4 %
5 Safety
5.1 Electrical safety
5.1.1 General
5.1.1.1 Introduction
The Road Traffic Signal System shall conform to HD 60364-4 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 60364-4-41 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 Protective 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.
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 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.
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.
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. Keys may be specified either on a country basis
or by the customer.
5.1.1.6 Over-current protection
Supply voltages within the enclosure or external to the enclosure shall have fault current protection, in
accordance with HD 60364-4 series, or other internationally recognized equivalent.
5.1.1.7 Terminations
The system shall be classified according to its access to mains terminations as follows:
Class H0: No separate access to mains terminations.
Class H1: Separate access to meters or parts of a mains terminal, etc.
5.1.2 Controller Signal outputs
Electrical details of compatible signal heads shall be specified by the controller manufacturer in order to
ensure the safety of the system. This should list either those signals known to be compatible or the type of
signals in CLC/TS 50509 that would by definition make them compatible with the control system's required
monitoring performance and prevention of hazardous displays.
There are a number of possible configurations for both distributing power to the signals and the switching of
that power. These can be one of the following:
1) centralized signal power supply and centralized intelligence that switches and monitors the signals
(3.2.7),
2) centralized signal power supply and distributed intelligence (3.2.8),
3) distributed power supply and distributed intelligence (3.2.9).
To enable the distribution of elements for the powering and/or switching of signals, the intelligence in the
traffic controller alone is not sufficient. Intelligence then needs to be distributed throughout the road traffic
signal system e.g. in the signal heads. This type of distributed intelligence architecture requires a robust and
fail safe method of communicating switching commands and status reports throughout the control system, to
prevent wrong signalisation, signa
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