SIST EN 50550:2011

SLOVENSKI STANDARD
SIST EN 50550:2011
01-april-2011
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SRGREQRXSRUDER323
Power frequency overvoltage protective device for household and similar applications
(POP)
Schutzeinrichtung gegen netzfrequente Überspannungen für Hausinstallationen und für
ähnliche Anwendungen
Dispositif de protection contre les surtensions à fréquence industrielle pour les
applications domestiques et analogues
Ta slovenski standard je istoveten z: EN 50550:2011
ICS:
29.120.50 9DURYDONHLQGUXJD Fuses and other overcurrent
PHGWRNRYQD]DãþLWD protection devices
SIST EN 50550:2011 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 50550:2011

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SIST EN 50550:2011

EUROPEAN STANDARD
EN 50550

NORME EUROPÉENNE
February 2011
EUROPÄISCHE NORM

ICS 29.120.50


English version


Power frequency overvoltage protective device for household and similar
applications (POP)



Dispositif de protection contre les Schutzeinrichtung gegen netzfrequente
surtensions à fréquence industrielle pour Überspannungen für Hausinstallationen
les applications domestiques et analogues und für ähnliche Anwendungen





This European Standard was approved by CENELEC on 2011-01-17. 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 50550:2011 E

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SIST EN 50550:2011
EN 50550:2011 – 2 –
Foreword
This European Standard was prepared by the CENELEC BTTF 128-1, Power frequency overvoltage
protective device for household and similar applications.
It was submitted to the formal vote and was approved by CENELEC as EN 50550 on 2011-01-15.
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 are proposed:
– latest date by which the EN has to be implemented

at national level by publication of an identical

national standard or by endorsement
(dop) 2012-01-15

– latest date by which the national standards conflicting

with the EN have to be withdrawn
(dow) 2014-01-15
This European Standard has been prepared under a mandate given to CENELEC by the European
Commission and the European Free Trade Association and covers essential requirements of
EC Directive 2004/108/EC. See Annex ZZ.
__________

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Contents
1 Scope . 5
2 Normative references . 6
3 Terms and definitions . 7
4 Classification . 8
4.1 According to the method of construction . 8
4.2 According to the main protective device . 8
4.3 According to the range of ambient air temperature (only for POP according to 4.2.2 and 4.2.3) . 8
4.4 According to the number of monitored line to neutral conductor voltages . 8
5 Characteristics. 9
5.1 Summary of characteristics . 9
5.2 Limit values of the break times and non-actuating times . 9
6 Marking and other product information . 9
6.1 Standard marking . 9
6.2 Additional marking . 10
7 Standard conditions for operation in service . 11
7.1 General. 11
7.2 Conditions of installation . 11
7.3 Pollution degree . 11
8 Requirements for construction and operation . 11
8.1 Mechanical design . 11
8.2 Protection against electric shock . 16
8.3 Dielectric properties and isolating capability . 16
8.4 Temperature rise . 16
8.5 Operating characteristic . 16
8.6 Mechanical and electrical endurance . 16
8.7 Performance at short-circuit currents . 17
8.8 Resistance to mechanical shock and impact . 17
8.9 Resistance to heat . 17
8.10 Resistance to abnormal heat and to fire . 17
8.11 Ageing of electronic components . 17
8.12 Behaviour at low ambient air temperature . 18
8.13 Electromagnetic compatibility . 18
8.14 Safety performance of overstressed POPs. 18
9 Tests . 18
9.1 General. 18
9.2 Test condition . 19
9.3 Verification of the influence of the POP on the correct operation of the main protective device . 19
9.4 Test of dielectric properties . 21
9.5 Temperature rise . 21
9.6 Verification of the operating characteristics . 21
9.7 Verification of the mechanical and electrical endurance . 23
9.8 Tests of creepage distances and clearances for electronic circuits (abnormal conditions) . 24
9.9 Requirements for capacitors and specific resistors and inductors used in electronic circuits . 27
9.10 Electromagnetic compatibility . 28
9.11 Test of safety performance of overstressed POPs . 32
9.12 Test of reliability of screws, current-carrying parts and connections . 32
9.13 Test of reliability of terminals for external conductors . 32
9.14 Verification of protection against electric shock . 32
9.15 Verification of resistance to mechanical shock and impact . 33
9.16 Test of resistance to heat . 33
9.17 Resistance to abnormal heat and to fire . 33
9.18 Verification of the correct operation at low ambient air temperatures for RCDs for use at
temperatures between -25 °C and +40 °C . 33

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SIST EN 50550:2011
EN 50550:2011 – 4 –
Annex A (normative) Test sequences . 36
Annex B (normative) Determination of clearances and creepage distances . 37
Annex C (informative) Examples of terminal designs . 39
Annex D (normative) Number of samples for full test procedure . 42
Annex ZZ (informative) Coverage of Essential Requirements of EC Directives . 44
Bibliography . 45
Figures
Figure 1 – Minimum creepage distances and clearances measured in millimetres . 34
Figure 2 – Minimum creepage distances and clearances as a function of peak value of operating
voltage . 35
Figure B.1 – Illustrations of the application of creepage distances . 38
Figure C.1 – Examples of pillar terminals . 39
Figure C.2 – Examples of screw terminals and stud terminals . 40
Figure C.3 – Examples of saddle terminals . 41
Figure C.4 – Examples of lug terminals . 41
Tables
Table 1 – Limit values of break times and non-actuating times . 9
Table 2 – Minimum clearances and creepage distances . 13
Table 3 – Maximum permissible temperatures under abnormal conditions . 26
Table 4 – Low frequency immunity test conditions . 29
Table 5 – High frequency immunity test conditions . 30
Table 6 – Test conditions for electrostatic discharges . 31
Table 7 – Emissions test conditions . 31
Table A.1 – Test sequences . 36
Table D.1 – Number of samples for full test procedure . 42
Table D.2 – Additional tests for POP already fully tested together with one kind of main protective
device . 43

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1 Scope
This European Standard applies to power frequency overvoltage protection devices (hereafter referred to
as “POP”) for household and similar uses, with a rated frequency of 50 Hz, a rated voltage 230 V a.c.
(between phase and neutral), intended to be used in combination with a main protective device being
either a CB in compliance with EN 60898-1 or EN 60898-2, a RCCB in compliance with EN 61008-1 or a
RCBO in compliance with EN 61009-1.
NOTE 1 Requirements for POPs in combination with switching devices other than a main protective device, or a POP integrated in
a MPD, are under consideration.
NOTE 2 Requirements for POP with functional earth connection regarding temporary overvoltage withstand are under
consideration.
NOTE 3 A POP is not a protective device to be used for automatic disconnection of the supply in the meaning of HD 60364-4-41.
They are intended for use in an environment with pollution degree 2 and overvoltage category III.
They can be designed for factory assembly or for assembly on site.
These devices are intended to mitigate the effects of power frequency overvoltages between phase and
neutral conductor (e.g. caused by loss of neutral conductor in the three phase supply upstream the POP)
for downstream equipment by actuating the main protective device when an overvoltage between phase
and neutral is detected.
NOTE 4 To mitigate means in this context that the POP will provide protection in most cases of power frequency overvoltages.
NOTE 5 Protection in case of overvoltage between phases is under consideration. In case of phase to phase electrical supply
system with rated voltage between phases 230 V a.c. and no neutral conductor, one line monitored POP in compliance to this
standard can be used according to manufacturer’s instruction.
The POP does not impair the protective function of the main protective device.
This European Standard does not apply for protection against common mode over voltages.
This European Standard does not apply to surge protective devices.
This European Standard states:
– the definitions of terms used for POP (Clause 3);
– the classification of POP (Clause 4);
– the characteristics of POP (Clause 5);
– the preferred values of the operating and influencing quantities (Clause 5);
– the marking and information to be provided for POP (Clause 6);
– the standard conditions for installation and operation in service (Clause 7);
– the requirements for construction and operation (Clause 8);
– the list of minimum requirements to be tested (Clause 9).

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SIST EN 50550:2011
EN 50550:2011 – 6 –
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 50160:2010 Voltage characteristics of electricity supplied by public electricity networks
EN 55014-1:2006 Electromagnetic compatibility – Requirements for household appliances, electric
+ A1:2009 tools and similar apparatus – Part 1: Emission (CISPR 14-1:2005 + A1:2008)
EN 55022:2010 Information technology equipment – Radio disturbance characteristics –
Limits and methods of measurement
(CISPR 22:2008, mod.)
EN 60065:2002 + Audio, video and similar electronic apparatus – Safety requirements
corr. Aug. 2007 (IEC 60065:2001, mod.)
EN 60384-14 Fixed capacitors for use in electronic equipment – Part 14: Sectional
specification – Fixed capacitors for electromagnetic interference suppression
and connection to the supply mains (IEC 60384-14)
EN 60664-1:2007 Insulation coordination for equipment within low-voltage systems –
Part 1: Principles, requirements and tests (IEC 60664-1:2007)
EN 60664-3 Insulation coordination for equipment within low-voltage systems –
Part 3: Use of coating, potting or moulding for protection against pollution
(IEC 60664-3)
EN 60898-1:2003 Electrical accessories – Circuit breakers for overcurrent protection for household
+ corr. Feb. 2004 and similar installations – Part 1: Circuit-breakers for a.c. operation
+ A1:2004 (IEC 60898-1:2002, mod. + A1:2002, mod.)
+ A11:2005
+ A12:2008
EN 60898-2:2006 Electrical accessories – Circuit-breakers for overcurrent protection for household
and similar installations – Part 2: Circuit-breakers for a.c. and d.c. operation
(IEC 60898-2:2000, mod. + A1:2003, mod.)
EN 60998-2-3 Connecting devices for low-voltage circuits for household and similar purposes –
Part 2-3: Particular requirements for connecting devices as separate entities
with insulation-piercing clamping units (IEC 60998-2-3)
EN 61000 series Electromagnetic compatibility (EMC) (IEC 61000 series)
EN 61008 series Residual current operated circuit-breakers without integral overcurrent protection
for household and similar uses (RCCB's) (IEC 61008 series)
EN 61008-1:2004 Residual current operated circuit-breakers without integral overcurrent protection
+ A11:2007 for household and similar uses (RCCB's) – Part 1: General rules
+ A12:2009 (IEC 61008-1:1996, mod. + A1:2002, mod.)
EN 61009 series Residual current operated circuit-breakers with integral overcurrent protection
for household and similar uses (RCBO's) (IEC 61009 series)
EN 61009-1:2004 Residual current operated circuit-breakers with integral overcurrent protection
+ corr. Jul. 2006 for household and similar uses (RCBO's) – Part 1: General rules
+ A11:2008 (IEC 61009-1:1996, mod. + A1:2002, mod. + corrigendum May 2003)
+ A12:2009
+ A13:2009

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SIST EN 50550:2011
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EN 61543:1995 Residual current-operated protective devices (RCDs) for household and similar
+ corr. Dec. 1997 use – Electromagnetic compatibility (IEC 61543:1995 + A2:2005)
+ A11:2003
+ corr. May. 2004
+ A12:2005
+ A2:2006
EN 61558-1 Safety of power transformers, power supplies, reactors and similar products –
Part 1: General requirements and tests (IEC 61558-1)
EN 61558-2 series Safety of power transformers, power supplies, reactors and similar products –
Part 2-X: Particular requirements and tests (IEC 61558-2 series)
EN ISO 306 Plastics – Thermoplastic materials – Determination of Vicat softening
temperature (VST) (ISO 306:2004)
EN 61249-2 series Base materials for printed circuits – Part 2: Specifications
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 60898-1:2003,
EN 61008-1:2004, EN 61009-1:2004 and the following apply.
3.1
power frequency overvoltage
increase of the voltage at the rated frequency in the electrical supply system, above a specified threshold
3.2
Power frequency Overvoltage Protective device
POP
device intended to mitigate the effects of power frequency overvoltages between phase and neutral
conductor (e.g. caused by loss of neutral conductor in the three phase supply upstream the POP) for
downstream equipment
NOTE One line monitored POP can be used also to mitigate the effects of power frequency overvoltages between two phase’s
conductors in phase to phase electrical supply system.
3.3
main protective device
device to which the POP is intended to be associated, directly or through a release unit, with and that
trips under specified conditions
NOTE The main protective device is a circuit breaker (EN 60898-1 or EN 60898-2) or a RCCB (EN 61008-1) or a RCBO
(EN 61009-1).
3.4
actuating voltage
U
a
voltage values, measured between phase and neutral conductor, for which POP device shall actuate the
main protective device
3.5
release unit
device mechanically connected to a main protective device, which releases the holding means and
permits the automatic opening of the main protective device

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SIST EN 50550:2011
EN 50550:2011 – 8 –
3.6
POP assembly
combination of the POP device assembled as for normal use with the main protective device and release
unit, if any
NOTE The main protective device is a circuit breaker (EN 60898-1 or EN 60898-2) or a RCCB (EN 61008-1) or a RCBO
(EN 61009-1).
3.7
break time
t
B
time that elapses between the instant when the overvoltage is suddenly attained, and the instant when
the MPD associated to the POP has switched off the circuit
NOTE For POP assembly.
3.8
non-actuating time
t
0A
maximum delay during which a given overvoltage can be applied to the POP without causing it to operate
4 Classification
4.1 According to the method of construction
4.1.1 POP assembled to the main protective device in factory by the manufacturer;
4.1.2 POP to be coupled by mechanical means on site with the main protective device;
4.1.3 POP to be assembled on site with the release unit associated or integrated to the main
protective device.
4.2 According to the main protective device
4.2.1 POP for circuit breakers;
4.2.2 POP for RCBOs;
4.2.3 POP for RCCBs.
NOTE The same POP may be designed for more than one main protective device.
4.3 According to the range of ambient air temperature (only for POP according to 4.2.2 and
4.2.3)
4.3.1 POP for use at ambient air temperatures between - 5 °C and + 40 °C.
4.3.2 POP for use at ambient air temperatures between - 25 °C and + 40 °C.
NOTE Only applicable if at least one MPD to be assembled to the POP is suitable for this temperature range.
4.4 According to the number of monitored line to neutral conductor voltages
4.4.1 1 monitored line to neutral conductor voltages;
4.4.2 3 monitored lines to neutral conductor voltages.

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NOTE POP according to classification 4.4.1 can be used to monitor voltage between two phases in phase to phase electrical
supply system with rated voltage 230 V according to the instruction sheets accompanying the product. In this case, the voltage is
not monitored between line and neutral but between two lines.
5 Characteristics
5.1 Summary of characteristics
The characteristics of the standard of the main protective device and the followings apply:
– protection against external influences;
– method of mounting;
– method of connection;
– value of rated operational voltage;
– value of rated frequency;
– limit values of break times and non actuating times;
– range of ambient air temperature.
5.2 Limit values of the break times and non-actuating times
The limit values of break time (see 3.7) and non-actuating time (see 3.8) for the POP are given in Table 1.
Table 1 – Limit values of break times and non-actuating times
Standard values of break time and non-actuating time
at a voltage (U ) equal to
a
255 V 275 V 300 V 350 V 400 V
Maximum break time 15 s 5 s 0,75 s 0,20 s
No tripping
Minimum non-actuating time 3 s 1 s 0,25 s 0,07 s

6 Marking and other product information
6.1 Standard marking
In general, each POP shall be marked in a durable manner with all the following data:
a) manufacturer’s name or trade mark;
b) type designation, catalogue number or serial number;
c) rated voltage with the symbol ~;
d) POP or EN 50550;

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SIST EN 50550:2011
EN 50550:2011 – 10 –
e) protection degree (only if different from IP20).
NOTE For POP classified according to 4.1.1, marking according to item d) is sufficient.
Moreover the following markings shall be placed on the products or in the instruction sheets
accompanying the product:
f) the type designation and catalogue number of the main protective device for the POP intended to be
associated with;
g) assembling method and wiring;
h) instructions for checking operation after assembly to verify the mechanical operation of the main
protective device in case of devices according to classification 4.1.2;
i) range of the ambient air temperature;
j) for the devices classified according to 4.1.2 and 4.1.3, information about the needs to take into
consideration the range of the ambient air temperature of the main protective device.
Information on how to reach the isolation of the installation shall be given; such information shall be given
in the instruction sheet accompanying the product.
The information under a), b), c) and d) shall be visible when the POP is installed.
The information under i) shall not be visible when the POP is assembled with the MPD.
Marking shall be indelible, easily legible and not be placed on screws, washers or other removable parts.
Compliance is checked by inspection and by the test of 9.3.5.
With the POP assembled and enabled, the visible marking, required by the reference standard of the
main protective device, shall be visible.
6.2 Additional marking
For POP classified according to 4.1.1, additional marking to other standards (EN or IEC or other) is
allowed under the following conditions:
– the POP shall comply with all the requirements of the additional standard;
– the relevant standard to which the additional marking refers shall be indicated adjacent to this
marking and shall be clearly differentiated or separated from the standard marking according to 6.1.
Compliance is checked by inspection and by carrying out all the test sequences required by the relevant
standard. Equivalent or less severe test sequences need not be repeated.

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7 Standard conditions for operation in service
7.1 General
The POP complying with this European Standard shall be capable of operating under the standard
conditions given by the relevant MPD standard(s).
7.2 Conditions of installation
POP shall be installed in accordance with the manufacturer's instructions.
POP according to 4.1.2 and 4.1.3 shall only be installed together with the main protective device declared
by the manufacturer.
7.3 Pollution degree
POP according to this European Standard are intended for environment with pollution degree 2, i.e.:
normally, only non-conductive pollution occurs; occasionally, however, a temporary conductivity caused
by condensation may be expected.
8 Requirements for construction and operation
NOTE For test purposes the association of the POP and the MPD will be referred hereafter as POP assembly.
8.1 Mechanical design
8.1.1 General
POP shall be so designed and constructed that, in normal use, their performance is reliable and without
danger to the user or surrounding.
The POP, the release unit, if any, and the main protective device shall be of the same manufacturer or
trademark.
Compliance is checked by inspection and carrying out all the relevant tests specified.
The POP shall be constructed according to one of the methods of classification 4.1.
Compliance is checked by inspection.
When the main protective device is a CB it shall complied with EN 60898-1 or EN 60898-2.
When the main protective device is a RCD it shall comply either with EN 61008 series for RCCB or
EN 61009 series for RCB
...