EUROPEAN STANDARD EN 50107
Signs and luminous-discharge-tube installations
operating from a no-load rated output voltage exceeding 1000 V but not
exceeding 10000 V.
1.
SCOPE
This European Standard
specifies the requirements and method of installation for signs and
luminous-discharge-tube installations operating from a no-load rated output
voltage exceeding 1000V but not exceeding 10000V, including the electrical
components and wiring.
The standard covers
inatallations used for publicity, decorative or general lighting purposes,
either for external or internal use. Such signs or luminous-discharge-tube
installations may be either fixed or portable supplied from a low-voltage (L.V)
or extra-low-voltage (E.L.V) source by means of a transformer, invertor or convertor.
Although the
requirements are not specified in this Standard, attention is drawn to the need
for an effective maintenance programme to be carried out on all signs or
luminous-discharge-tube installations. The inspection and testing requirements included
in any maintenance programme should closely follow those specified in Clause 18
of this Standard.
2.
NORMATIVE
REFERENCES
This European Standard
incorporates by dated or undated reference, provisions from other publications.
These normative references are cited at the appropriate places in the text and
the publications are listed hereafter. For dated references, subsequent
amendments to or revisions of any of these publications apply to the European
Standard only when incorporated in it by amendment or revision. For undated
references the latest edition of the publication referred to applies.
EN50143 - Cables for
signs and luminous-discharge-tube installations operating from a no-load rated
output voltage exceeding 1 000 V but not exceeding 10 000 V.
EN 55015 - Limits and
methods of measurement of radio interference characteristics of fluorescent
lamps and luminaries.
EN 60529 - Degrees of
protection provided by enclosures (IP Code).
EN 61000 -
Electromagnetic compatibility (EMC). Part 3, Limits. Section 2, Limits for
harmonic current emissions (equipment input current not exceeding 16 A/phase).
EN 60598–1 - Luminaries:
Part 1, General requirements and tests.
EN 61050 - Transformers
for tubular discharge lamps having a no-load output voltage exceeding 1 000 V
(generally called neon-transformers). General and safety requirements.
HD 384 - Electrical
installations of buildings.
ISO 3864 - Safety
colours and safety signs.
3.
DEFINITIONS
For the purposes of this
European Standard, the definitions given in IEC 50 (IEV) apply, together with
the following.
Note: Where the terms
'voltage' and 'current' are used, they imply the r.m.s. values unless otherwise
specified.
3.1.
luminous-discharge
tube: Any tube, or other vessel or device, which is constructed of translucent
material, hermetically sealed, and designed for the emission of light arising
from the passage of an electric current through a gas or vapour contained
within it.
Note: The tube may be
with or without a fluorescent coating.
3.2.
no-load rated
output voltage: Maximum rated Voltage between the terminals of the output
winding(s) of the transformer connected to the rated supply voltage at rated
frequency, with no load on the output circuit. It is the peak value divided by
the square root of 2.
3.3.
creepage
distance: The shortest path between two conductive parts or between a
conductive part and the bounding surface of the installation, measured along
the surface of the insulating material.
Note: The bounding
surface of the installation is the inner surface of the enclosure, considered
as though a metal foil were pressed into contact with all interior surfaces of
insulating material.
3.4.
clearance: The
shortest distance between two conductive parts or between a conductive part and
the bounding surface of the installation, measured through the air.
Note: See note to 3.3.
3.5.
transformer: A
unit for the conversion of an a.c. supply at one voltage and frequency to an
a.c. supply at a different voltage and the same frequency.
Note: The high output
impedance of most transformers designed for cold-cathode discharge tubes allows
the characteristics of transformer and current-limiting components to be
combined in one unit.
3.6.
invertor: An
electric energy transducer that converts direct current to alternating current.
3.7.
convertor: A unit
for the electronic conversion of an a.c. supply at one frequency to an a.c.
supply at another frequency.
Note: The voltage may
or may not be altered during the conversion.
3.8.
insulating
sleeve: Insulation designed to be placed over the exposed high-voltage
connections at tube electrodes or over cable-end insulator.
3.9.
Installer: The
person, qualified in sign installation practice, who takes responsibility for
the installation and its testing in accordance with this standard.
3.10. earth-leakage protective device: A device which
will remove the output. power from a transformer(s), invertor(s) or
convertor(s) in the event of a short circuit between any part of the secondary
high voltage circuit and earth.
Note: The device may be
in two parts, a sensor and a protective switch (see 3.12 and 3.13), or may be
combined in one unit.
3.11. open-circuit protective device: A device which
will remove the output power from a transformer(s), invertor(s) or convertor(s)
in the event of an interruption of the secondary high voltage circuit.
Note: The device may be
in two parts, a sensor and a protective switch (see 3.12 and 3.13), or may be
combined in one unit.
3.12. sensor: That part of a protective device which
detects the presence of a secondary earth fault and/or an open circuit condition
and provides a signal to operate a protective switch.
3.13. protective switch: That part of a protective
device which disconnects the mains supply to a transformer(s), invertor(s) or
convertor(s) or otherwise removes the output power. It is operated by an electrical
signal obtained from a sensor.
3.14. live part: A conductor or conductive part
intended to be energised in normal use, including the neutral conductor but, by
convention, not a PEN conductor.
3.15. input end (low-voltage circuit): The part of
the device between the point at which electrical energy is supplied to an
installation and the input terminals of the transformer, convertor or
invertor.
3.16. output end (lamp circuit): The part of the
device between the output terminals of the transformer, convertor or invertor
and the discharge tubes inclusive.
3.17. arm's reach: A zone extending from any point on
a surface where persons usually stand or move about to the limits which a
person can reach with the hand in any direction without assistance.
Note: This zone of
accessibility is shown in figure 1 in which the values refer to bare hands
without any assistance, e.g. from tools or from a ladder.
3.18. outdoor sites: Sites where all or part of a
sign or luminous-discharge-tube installation or its components are situated out
of doors and are subject to the effects of weather.
3.19. dry rooms and places: Rooms ox places where
condensation does not usually occur or the air is not saturated with moisture.
3.20. damp and wet rooms and places: Rooms or places
where the safety of the sign ox' luminous-discharge-tube installation may be
affected by humidity, condensation, chemical or similar influences.
3.21. small portable signs: Small signs which can
easily be moved from one place to another; which are supplied with an integral
transformer, invertor or convertor, together with a flexible mains supply lead
and plug; and which are intended to be installed and connected by the customer
to a socket outlet of the mains supply.
3.22. flasher: A device for automatically switching
one or more lamp circuits on and off continuously. The sequence of switching of
the various lamp circuits may be suitably arranged to provide the impression of
movement and other animated effects.
4.
MEANS OF
ATTACHMENT OF SIGNS
Electrical conductors
shall not be used as means of suspension or attachment of signs.
5.
DRAIN HOLES
In sign enclosures
intended for external use, arrangements shall be made to allow moisture to
drain away. Drain holes or similar apertures used for this purpose shall be
sufficiently large to ensure that they do not become blocked with dirt or
debris between maintenance visits.
6.
INSTALLATION OF
THE MAINS SUPPLY
Installation of the
mains supply for signs and luminous - discharge-tube installations shall be
carried out in accordance with HD 384.
Note: Attention is
drawn to the fact that wiring rules are not fully harmonised in CENELEC
countries and, for this reason, national standards apply.
7.
ENCLOSURES AND
PROTECTION OF LIVE PARTS
7.1.
All high-voltage
connections to discharge tubes shall be protected by means of insulating
sleeves conforming to clause 13.
7.2.
High-voltage
connections situated within arm's reach shall have additional protection
conforming to 7.4 and 7.5.
Note: The description
of arm's reach is shown in figure l.
7.3.
High-voltage
connections situated out of arm's reach shall have additional protection
conforming to 7.4 or 7.6.
7.4.
Additional
protection shall consist of an enclosure or other means of protection
conforming to the following:
a) It shall provide a degree of protection
corresponding to at least IP 2X in Table 1 of EN 60529.
Note 1: The
requirements for protection against ingress of solid objects, specified in
Table 2 of EN 60529,do not apply.
b) If it is constructed from metal parts, these
shall be earthed in accordance with
clause 8.
c) If it is constructed from other materials,
these shall be certified by the supplier as suitable for use in the environment
existing close to a tube electrode. The materials shall be guaranteed by the
supplier for the expected lifetime of the installation.
Note 2: Suppliers of
such materials should be informed of the temperature, ultraviolet (UV)
radiation, ozone and other conditions existing near a tube electrode. They
should also be informed that such materials may be used in exterior situations.
d) Access to the interior of an enclosure shall be
by means of a tool, e.g. a screwdriver.
Note 3: Other means of
additional protection may be permanent., e.g. it may have to be cut away using
a knife.
Note 4: A
fully-enclosed sign letter or box sign is considered to be a suitable enclosure
for this purpose.
7.5.
Additional
protection shall consist of either:
a) An enclosure as specified in 7.4 where the
degree of protection (IP 2X) is maintained even if any external parts of a tube
are broken; or
b) the circuit shall be provided with open-circuit
protection complying with the requirements of 10.6. This being in addition to
the mechanical enclosure specified in 7.4.
Note: The requirement
of 7.5(a) means that it is not possible to insert the appropriate test finger
into the broken end of a tube and touch a live electrode.
7.6.
Additional
protection shall consist of open-circuit protection complying with the
requirements of 10.6.
7.7.
Symbols for
'caution, risk of electric shock' conforming to B.3.6 of ISO 3864: 1984 shall
be fixed at points of access to any sign, luminous-discharge-tube installation
or enclosure containing high-voltage transformers, invertors or convertors. The
length of side of the triangle enclosing the symbol shall be not less than 50
mm.
Note: In small
installations of limited extent, one such symbol should normally be adequate.
More than one symbol should be used for larger installations and these should
be arranged so that at least one is visible from any likely direction of
approach to the installation.
7.8.
A conductor which
is in metallic contact with a discharge tube operating at high voltage shall
not be in connection (except in respect of its connection to earth) with any
other conductor of the mains supply or with the primary winding of the
transformer.
7.9.
Creepage distances
and clearances in millimetres between live parts carrying different voltage
supplies, between live parts and earthed metalwork or between live parts and
parts which may become conductive when wet or are flammable shall be as
follows.
a) for equipment which is installed in dry rooms
and similar protected situations: shortest creepage distance: d = 8 + 4U;
shortest clearance: c = 6 + 3U;
b) for equipment which is installed outdoors or in
damp or wet rooms:
shortest creepage distance: d = 10 + 5U; shortest clearance: c = 7,5 +
3,75U;
c) for equipment operating at. frequencies greater
than 1 kHz, whether this is installed in dry or damp situations:
shortest creepage distance: d
= 12 + 6U; shortest clearance: c = 9 + 4,5U;
where:
U is the rated no-load output voltage of the transformer, invertor or convertor
supplying the circuit in kilovolts.
8.
PROTECTION
AGAINST INDIRECT CONTACT
8.1.
The protection against
indirect contacts shall be provided by an equip-potential bonding, generalised
between all metal parts and then connected to earth.
8.2.
All exposed
metalwork with the exception of clips and clomps for fixing cables and tubes,
shall be bonded together by means of a protective conductor and, unless this
metalwork is connected to earth by other means, shall be provided with an
earthing terminal.
8.3.
The protective
conductor shall be one of the following:
a) a separate cable having insulation coloured
yellow/green and having the following cross-sectional area:
i)
in situations
where it may suffer mechanical stress, 4 mm2;
ii)
in other
situations, 2,5 mm2 ; or
b) a stranded or solid copper conductor having a
minimum cross-sectional area of not less than 1,5 mm2, Manufacturerd
as part of a sheathed high-tension cable and protected by the overall sheath of
that cable; or
c) the braided metal screen of a high-voltage
cable, provided that the total cross-sectional area of the individual strands comprising that screen is not less
than 1,5 mm2. Connections to the screen shall be made by unravelling
the braid and twisting the individual strands together to form a suitable
length of conductor to attach to an earth terminal. The connection shall not be
by means of a metal clamp around the braid.
8.4.
Where adhesive is
used between metal parts, or where painted metal parts are bolted or screwed
together, unless a bonding conductor is connected between the parts, means
shall be employed to ensure that earth continuity is maintained across the
joint.
8.5.
Equipotential
bonding conductors shall not be connected to the neutral terminal of the mains
supply to the sign or luminous-discharge-tube installation, except as specified
in HD 384 for protective multiple earthing arrangements in TN-C systems.
9.
TRANSFORMERS
Transformers shall
conform to EN 61050 except that the no-load rated output voltage shall not
exceed 5 kV to earth or exceed 10 kV between terminals.
10. EARTH-LEAKAGE AND OPEN-CIRCUIT PROTECTION
10.1. The requirements for earth-leakage protection
are specified in 10.2 to 10.5. Those for open-circuit protection are specified
in 10.6 to 10.9- The requirements in 10.10 to 10.15 apply to both types of
protection.
10.2. High-voltage circuits supplied from
transformers, invertors or convertors shall be protected by an earth-leakage
protective device conforming to 10.3 and 10.4. The installer shall ensure that
performance of the earth-leakage protective device is certified by the
Manufacturer of the device as conforming to 10.5.
10.3. In the event of accidental contact between the
high-voltage circuit and earth, the earth-leakage protective device shall
either disconnect the mains supply to the input circuit, or otherwise
remove the output power. If single-pole
mains-supply switching is provided, the switch shall be connected in the phase
lead of that supply.
Note: A standard
residual-current-operated circuit-breaker is not a suitable protective device
for this application since, when connected to the primary side of a
transformer, invertor or convertor, it
does not protect against faults to earth on the secondary side.
10.4. Detection of a fault condition shall be made by
means of suitable sensor(s) connected in the output circuit(s), or other
suitable means, and these shall either operate switches to disconnect the mains
supply to the input circuit or otherwise remove the output power.
Note 1: The sensors and
switches for the device may be combined into one unit.
Note 2: Earth-leakage
protective devices may be designed to protect more than one sign circuit.
10.5. The earth-leakage protective device shall conform to the following.
a) If the sensor and/or the protective device to
remove the output power is mounted in a position not within the case of the
transformer, invertor or convertor, it shall operate correctly over a temperature range - 25 °C to +65 °C.
b) If any part of the sensor and/or the protective
switch or device to remove the output power is mounted within the case of the
transformer, invertor or convertor, that part shall operate correctly over the
temperature range expected to occur within that case. The installer shall
obtain information from The Manufacturer of the transformer, invertor or
convertor in order to verify that the maximum operating temperature of that
part of the sensor and/or the protective device is not exceeded when the
transformer, invertor or convertor is operating at its maximum ambient
temperature and under specified abnormal conditions.
c) The rated operating current shall be less than
the earth-leakage current (measured over the expected supply voltage range into
a short circuit to earth) of the transformer, invertor or convertor to be
protected and shall not exceed 25 mA.
Note: The actual
current which flows through the sensor circuit during earth fault is determined
by the impedance of that fault path and the output characteristics of the
transformer, invertor or convertor feeding the fault. It does not depend on the
operating current of the protective device.
d) The time to operate, at rated current, shall be
not more than 200 ms.
e) The voltage across that part of a sensor which
is detecting the earth-leakage current shall not exceed 50 V. The installer
shall obtain information from the Manufacturer of the earth-leakage protective
device in order to verify that this voltage shall not be exceeded with the
protective switch circuit disconnected and with the highest anticipated fault
current.
Note: The highest
anticipated fault current is the short circuit current through one half of the
output winding of the highest rated current transformer, invertor or convertor to be protected.
f)
Means shall be
provided to facilitate maintenance. Such means shall be accessible only with
the aid of a tool and shall be automatically reset when the supply voltage to
the earth-leakage protective device is switched off and then switched on again.
The installer shall ensure that suitable maintenance procedures are provided by
the Manufacturer of the earth-leakage protective device.
g) The installer shall ensure that suitable test
procedures conforming to 18.3(a) are provided by the Manufacturer of the
earth-leakage protective device.
10.6. Where specified in 7.4 and 7.6, high-voltage
circuits supplied from transformers, invertors or convertors shall be protected
by an open-circuit protective device conforming to 10.7 and 10.8. The installer
shall ensure that performance of the open-circuit protective device is
certified by the Manufacturer of the device as conforming to 10.9.
10.7. In the event of an open circuit occurring in
the high-voltage circuit., the open-circuit protective device shall either
disconnect the mains supply to the input circuit, or otherwise remove the
output power. If single-pole mains-supply switching is provided, the switch
shall be connected in the phase lead of that supply.
10.8. Detection of a fault condition shall be made by
means of suitable sensor(s) connected in the output circuit(s), or other
suitable means, and these shall either operate switches to disconnect the mains
supply to the input circuit or otherwise remove the output power.
Note 1: The sensors and
switches for the device may be combined into one unit.
Note 2: Open-circuit
protective devices may be designed to protect more than one sign circuit.
10.9. The open-circuit protective device shall
conform to the following.
a) If the sensor and/or the protective device to
remove the output power is mounted in a position not within the case of the
transformer, invertor or convertor, it shall operate correctly over a
temperature range -25 °C to +65 °C.
b) If any part of the sensor and/or the protective
switch or device to remove the output power is mounted within the case of the
transformer, invertor or convertor, that part shall operate correctly over the
temperature range expected to occur within that case. The installer shall
obtain information from the Manufacturer of the transformer, invertor or
convertor in order to verify that the maximum operating temperature of that
part of the sensor and/or the protective device is not exceeded when the
transformer, invertor or convertor is operating at its maximum ambient
temperature and under specified abnormal conditions.
c) If the installation is switched on with an
open-circuit condition existing in any part of the output circuit or tube load,
the protective device shall operate in
a time of not less than 3 seconds and not more than 5 seconds.
Note: Attention is
drawn to the fact that certain types of transformer having a semi-resonant
capacitive output characteristic are capable of operating greater tube loads
than can be accommodated on transformers having similar output voltages, but with the normal inductive output
characteristics. However, tubes operated by such transformers may be slow to
start, particularly at low temperatures. If starting is delayed too much, it
may give rise to spurious tripping of open-circuit protective devices.
d) If an open circuit occurs in any part of the
output circuit or tube load whilst the installation is switched on, the
protective device shall operate in a time not exceeding 200 ms. If the mains
supply is then switched off and switched on again, with the open-circuit
condition still persisting, the device shall operate in a time of not less than
3 seconds and not more than 5 seconds.
e) Means shall be provided to facilitate
maintenance. Such means shall be accessible only with the aid of a tool and
shall be automatically reset when the supply voltage to the open-circuit
protective device is switched off and then switched on again- The installer
shall ensure that suitable maintenance procedures are provided by the
Manufacturer of the open-circuit protective device.
f)
The installer
shall ensure that suitable test procedures conforming to 18.3(a) are provided
by the Manufacturer of the open-circuit protective device.
10.10. The sensor (or sensors) shall be connected to
the earth-leakage or open-circuit protective device to remove the output power
by either:
a) connecting each sensor to its own device, which
may or may not be incorporated within the housing of the transformer, invertor
or convertor; or
b) connecting the sensors of a number of
transformers, invertors or convertors to a single protective device which is
connected in the mains supply to their input circuit. The number of sensors
which may be connected to one protective device shall be in accordance with the
instructions of the Manufacturer of the protective device.
10.11. If the protective device is arranged to
disconnect the mains supply in the event of an earth fault or open circuit, the
means to do this shall use mechanical contacts. The use of semiconductor
switches (thyristors, triacs, etc.) shall not be permitted except where
invertors or convertors provide galvanic isolation between input and output. In
this case the output voltage may be removed by electronic means, e.g.
disablement of the oscillator circuit.
10.12. After a secondary earth fault or open circuit
has caused the protective device to operate, it shall remain as it is until the
mains supply is also switched off. When the mains supply is switched on again,
the protective device to remove the output voltage shall automatically reset.
If the earth-leakage or open-circuit fault is still present at the time of the
reset, the protective device shall operate in accordance with 10.5 or 10.9 as
appropriate.
Note: This requirement
ensures that spurious tripping, caused by the presence of rain water or
condensation or possible brief periods of extra slow starting is cleared on the
next switching of the mains supply.
10.13. If the circuit includes a flasher, any
protective switch and its reset circuit shall be installed on the mains-supply
side of the flasher.
Note: If they were on
the other side of the flasher, the switch would keep re-setting and re-tripping
during fault conditions.
10.14. If the circuit includes a flasher and the
device(s) to remove the output power is incorporated within the housing of the
transformer(s), invertor(s) or convertor(s), a protective switch shall be
connected on the mains-supply side of the flasher and the incorporated sensor
circuits shall be capable of operating this second switch.
10.15. Sensors and protective devices shall be
compatible with each other.
11. INVERTORS AND CONVERTORS
Note: The requirements
for invertors and convertors for neon tubes will be discussed by a panel to be
convened by WG-COMEX. This panel will produce a draft specification IEC 1347, Part 2.11. When this standard
is issued, its requirements will replace those of Clause 11.
11.1. The installer shall ensure that invertors and
convertors are suitable for their intended application in respect of:
a) supply voltage, or voltage range;
b) input current or input power;
c) input and output frequencies;
d) no-load output voltage, including tolerance
(see 11.2);
e) rated output current and current range;
f)
earth connections
to the output circuit (see 11.3).
Note: Invertors and
convertors provide a high-frequency, high-voltage output. The effects of high
frequency supplies on the insulation and operation of circuits and components
should be carefully considered.
11.2. Invertors and convertors shall have an
open-circuit voltage to earth, at rated supply voltage and frequency, not
exceeding 5 kV, this voltage being either the r.m.s. value or 0,5 times the
peak value, whichever is the greater. The tolerance on this voltage shall be
-0/+10 %. The installer shall obtain information about the output voltage from
the Manufacturer of the invertor or convertor.
11.3. Invertors and convertors shall have one point
on the output circuit. connected to earth and there shall be no direct
connection between any output terminal and either mains supply terminal.
11.4. Invertors and convertors shall be installed in accordance
with the instructions of the Manufacturer.
11.5. The length and type of cable connecting the
high-voltage terminal of an invertor or convertor to a discharge tube shall not
exceed that specified by the Manufacturer.
12. AUXILIARIES
Independent auxiliaries
for signs and luminous-discharge-tube installations operating at high voltage,
such as inductors, capacitors and resistors, shall be protected by being placed
within an enclosure conforming to clause 7.
13. INSULATING SLEEVES
13.1. Insulating sleeves, used for the protection of
electrodes and the connections, shall be made from one of the following:
a) glass having a minimum wall thickness of 1 mm,
or
b) high-tear silicone rubber, with a Shore
hardness of 50 +/ - 5, a minimum wall thickness of 1 mm and an operating temperature
of at least 180 °C, or
c) material with insulating, resistance to UV
radiation and ozone and heat-resistance characteristics at least equivalent to
those given in item (b).
14. SPECIFICATION AND INSTALLATION OF HIGH-VOLTAGE
CABLES
14.1. The high-voltage cables used shall be selected,
as appropriate, from the list of cables conforming to EN50143, given in annex
A.
14.2. All cables shall be suitable for the
environmental conditions expected in the sign or luminous-discharge-tube
installation.
14.3. Cable type 'K' shall be used only for
continuous operation at voltages up to 2,5 kV to earth.
Note: Cables type 'A'
to 'H' may be used for continuous operation at voltages up to 5 kV to
earth.
14.4. Provided they are not likely to suffer
mechanical damage, cables shall be used without further mechanical protection
in accordance with the requirements of Table 1.
Table 1. Installation requirements for cables complying
with EN50143
|
|
Cables may be used for installations: |
||
|
Cable type |
within protective enclosures |
in all situations other than in or under surfaces |
in or under surfaces |
|
A |
X |
X |
X |
|
B |
X |
- |
- |
|
C |
X |
X |
- |
|
D |
X |
X |
X |
|
E |
X |
X |
X |
|
F |
X |
X |
- |
|
G |
X |
- |
- |
|
H |
X |
X |
- |
|
K |
X |
X |
- |
Note 1: The cable
insulation may be allowed to come into contact with earthed metalwork or other
materials within an enclosure.
Note 2: Examples of
protective enclosures include sign boxes, enclosed letters, cable ducting,
steel tubes and flexible armoured conduit.
14.5. Cables installed in situations where mechanical
damage is likely shall be protected by trunking or similar means, constructed
either of earthed metal or from a low-flammability material having
self-extinguishing characteristics as defined in 13.3 of EN 60 598-1: 1993.
14.6. Cable type 'A' shall not be drawn into conduits
or other restricted enclosures, other than short lengths, such as may exist
through walls and floors. If these short lengths of conduit are made of metal,
they shall be earthed.
14.7. Except where temporary connections are made to
complete a high-voltage circuit when a tube is removed for repair, high-voltage
cables shall be continuous and no joints shall be permitted.
14.8. The length of the high-voltage cable shall be
as short as practicable.
Note: This requirement
is particularly critical for cables having an earthed metal screen. The
self-capacitance between the cable conductor and its metal screen may cause
short-duration high-amplitude current peaks to occur through the tube. Such
peaks are particularly troublesome with discharge tubes filled with neon and
can lead to radio interference problems, flicker and short tube lives. Table 2
shows recommended maximum cable lengths for neon or mercury tubes connected by
screened or unscreened cables to transformers operating at a frequency of 50
Hz. The maximum lengths are related to the transformer no-load output voltage to
earth.
Caution. This table is
provided for guidance only. It is not guaranteed to ensure correct operation
for all operating currents and tube diameters.
Table 2: Recommended
limiting values for simple wiring length
|
Voltage to earth |
1 kV |
2 kV |
3 kV |
4kV |
5kV |
|||||
|
Type of gas
inside tube |
Hg |
Ne |
Hg |
Ne |
Hg |
Ne |
Hg |
Ne |
Hg |
Ne |
|
Cable type
B,C,F,G,H,J (in metres) |
40 |
20 |
30 |
15 |
20 |
10 |
15 |
7 |
10 |
5 |
|
Cable type A,D,E
(in metres) |
24 |
12 |
16 |
8 |
12 |
6 |
9 |
4 |
6 |
3 |
14.9. The cable between the output terminals of an
invertor or convertor and the discharge tube shall be of a type specified by
the Manufacturer and shall:
a) be suitable for operation at high frequency;
and
b) be suitable for operation at the output voltage
of the invertor or convertor.
14.10. Where transformers, invertots or convertors
have only one high-voltage terminal, the cable between the discharge tube and
the earth, or return, terminal of the transformer, invertor or convertor shall
conform to 14.1 to 14.9.
14.11. Supports for cables shall be of metal or
non-hygroscopic material having 8elf extinguishing characteristics as defined
in 13.3 of EN 60 598 - 1: 1993.
14.12. The distance between supports for cables and
conductors shall not be greater than the appropriate value given in table 3.
Table 3: Distance between cable and conductor supports
|
Type of cable or conductor |
Distance between supports for cable or conductors with an angle to the
horizontal |
|
|
|
up to 45° |
over 45 ° |
|
Cables having a
flexible conductor |
500 mm |
800 mm |
|
Cables having a
solid conductor |
800 mm |
1250 mm |
14.13. The first support of a cable shall be at a
distance no greater than 150 mm from the terminal to which it is connected.
14.14. Cables with metal screens shall not be formed
into a radius less than eight times the diameter of the cable.
14.15. Points of entry of cables into enclosures shall
be provided with glands or bushes to protect cables against abrasion and
shearing. Where the enclosure is installed out of doors, the gland or bush
shall also offer protection to at least IPX4 of EN 60529.
15. HIGH-VOLTAGE CONNECTIONS
15.1. Connections to the tube shall be by means of
terminals or other suitable means conforming to 15.2 and 15.3.
15.2. Connections shall be protected against the
effects of rusting and other corrosion.
15.3. The mechanical strength of high voltage
connections shall be adequate for all normal service conditions.
15.4. Cable insulation or a metal screen exposed by
the removal of the plastic sheath shall, where necessary, be protected from the
effects of weather, UV radiation or ozone.
Note: For guidance,
typical arrangements for high-voltage connections are shown in figures 2, 3 and
4.
16. SUPPORTS FOR LUMINOUS-DISCHARGE TUBES
16.1. Supports for luminous-discharge tubes shall be
insulated from earth to withstand the no-load output voltage of the
transformer, invertor or convertor supplying those tubes.
Note: They may be
Manufacturerd from metal which is mounted on an insulator or Manufacturerd
entirely from insulating material.
16.2. The creepage distance and clearance between the
glass wall of the tube or any metal clip attached to the tube and earthed
metalwork, in millimetres, shall not be less than the following:
creepage distance D = U clearance C = 0,75 x U,
where:
U = the no-load output voltage of the transformer, invertor or convertor
supplying the equipment, in kilovolts.
16.3. The insulating material shall not deteriorate
when subjected to the UV radiation and ozone present in the vicinity of the
tube. It shall have self-extinguishing flammability characteristics as defined
in 13.3 of EN 60 598-1: 1993.
Note: Examples of
suitable materials include, glass, glazed ceramics and polycarbonates.
16.4. The supports shall hold the tube securely under
normal service conditions without strain or damage to the tube.
Note: Supports should
include a means for adjustment to allow for manufacturing tolerance between the
discharge tube and its mounting.
17. ELECTROMAGNETIC COMPATIBILITY
17.1. Signs and luminous-discharge-tube installations
shall conform to the requirements of EN 55015 for the suppression of radio
interference and EN 61000-3-2 for limits for harmonic current emissions.
Note: The requirements
for radio interference from neon signs are under discussion.
17.2. Components fitted to comply with 17.1 shall be
rated for the voltages and frequencies to which they will be subjected.
18. INSPECTION AND TESTING OF INSTALLATIONS
18.1. Except for small portable signs, which are
accompanied by a certificate from their Manufacturer, indicating compliance
with this Standard, signs or luminous-discharge-tube installations shall be
inspected in accordance with 18.2 and tested in accordance with 18.3.
18.2. When the installation has been completed, the
installer shall check that the sign or luminous-discharge-tube installation
conforms to this standard.
Note: Particular care
should be taken to ensure conformance of the following items:
a) the types of high-voltage cable used and their
installation;
b) the high-voltage connections;
c) the creepage distances and clearances;
d) the earthing connections;
e) the mechanical details of the sign or
luminous-discharge-tube installation necessary to ensure compliance with this
Standard.
18.3. After the inspection of the sign or
luminous-discharge-tube installation, specified in 18.2, the following
electrical tests shall be made.
a) Earth-leakage and open-circuit protective
devices shall be tested in accordance with the instructions of the supplier of
those devices. Such tests shall ensure that the units are functioning properly
and have been installed correctly (see 10.5(g) and 10.9(f)).
Note 1: Such tests are
not intended to test the performance of the devices. The specification will be
certified by the supplier of the device.
b) Unless operated from a constant-current
transformer, invertor or convertor, the tube current in each circuit shall be
measured to ensure that it lies within the tolerance specified by the
Manufacturer of the transformer, invertor or convertor.
Note 2: This test is
preferably carried out at premises where the sign is Manufacturerd and where the
particular set of tubes together with their transformer, invertor or convertor
can be conveniently assembled on a bench.
19. MARKING AND SITE RECORDS
19.1. The following details shall be marked
permanently and legibly on a suitable plate or label attached to, or positioned
in a clearly visible place close to, the sign or luminous-discharge-tube
installation.
a) the name and address of the sign Manufacturer
or company responsible for the installation,
b) the year of the installation.
19.2. To assist in the maintenance of the sign or
luminous-discharge-tube installation, the sign installer shall supply the sign
operator a simplified circuit diagram, data sheet or other means identifying
which transformers, invertors or convertors are operating which tubes.
19.3. The information provided in accordance with
19.2 shall be amended following any maintenance leading to alterations in the
circuits of the sign or luminous-discharge-tube installation.
Figure 1: Zone of Accessibility for the Definition ‘Arm’s Reach’
Figure 2: Example of an Arrangement Within an Internally Illuminated
Letter.
Figure 3: Example of an Electrode Housing Passing
Through a Fascia Panel.
Figure 4: Example of an Arrangement of a Surface-Mounted Tube with the
Electrode
Passing Through a Metal Panel.
Annex A
(Informative)
List of
high-voltage cables specified in EN50143.
Cable type 'A': A
rigid, single-core, 85 0C elastomer insulated cable, with a lead-alloy
screen and no sheath.
Cable type 'B': A
flexible, single-core, 150 0C silicone elastomer insulated cable.
Cable type 'C': A
flexible, single-core, 150 0C silicone elastomer insulated cable and
sheathed, either with PVC or a polymeric compound having low emission of smoke
and poisonous gases when affected by fire.
Cable type 'D': A
flexible, single-core, 150 0C silicone elastomer insulated cable,
wire-braided and sheathed, either with PVC or a polymeric compound having low
emission of smoke and poisonous gases when affected by fire.
Cable type 'E': A
flexible, single-core, PVC-insulated cable with a metal zinc tape screen and a
flexible protective conductor. The cable has an overall sheath of PVC.
Cable type 'F': A
flexible, single-core, PVC-insulated cable with a flexible protective conductor
and an overall sheath of PVC.
Cable type 'G': A
flexible, single-core, PVC-insulated cable.
Cable type 'H': A
flexible, single-core, polyethylene-insulated cable with an overall sheath of
PVC. The nominal thickness of the polyethylene insulation is 3 mm.
Cable types 'K': A
flexible, single-core, polyethylene-insulated cable with an overall sheath of
PVC. The nominal thickness of the polyethylene insulation is 1.5 mm.