EN 50124-1:2001/A1:2003

SLOVENSKI SIST EN 50124-1:2002/A1:2004

STANDARD
september 2004
Železniške naprave – Uskladitev izolacije – 1. del: Osnovne zahteve –
Izolacijske in plazilne razdalje za vso električno in elektronsko opremo –
Dopolnilo A1
Railway applications - Insulation coordination - Part 1: Basic requirements;
Clearances and creepage distances for all electrical and electronic equipment -
Amendment A1
ICS 29.080.01; 29.280 Referenčna številka
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

EUROPEAN STANDARD EN 50124-1/A1
NORME EUROPÉENNE
EUROPÄISCHE NORM October 2003

ICS 29.080.00; 45.020
English version
Railway applications -
Insulation coordination
Part 1: Basic requirements -
Clearances and creepage distances
for all electrical and electronic equipment

Applications ferroviaires -  Bahnanwendungen -
Coordination de l'isolement Isolationskoordination
Partie 1: Prescriptions fondamentales - Teil 1: Grundlegende Anforderungen -
Distances d'isolement dans l'air et Luft- und Kriechstrecken für alle
lignes de fuite pour tout matériel elektrischen und elektronischen
électrique et électronique Betriebsmittel

This amendment A1 modifies the European Standard EN 50124-1:2001; it was approved by CENELEC
on 2003-10-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this amendment 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 amendment 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, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.

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

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 50124-1:2001/A1:2003 E

Foreword
This amendment to the European Standard EN 50124-1:2001 was prepared by the Technical
Committee CENELEC TC 9X, Electrical and electronic applications for railways.
The text of the draft was submitted to the formal vote and was approved by CENELEC as
amendment A1 to EN 50124-1:2001 on 2003-10-01.
The following dates were fixed:
- latest date by which the amendment has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2004-10-01
- latest date by which the national standards conflicting
with the amendment have to be withdrawn (dow) 2006-10-01
Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, Annexes A, B, C and D are normative and Annexes E, F and G are informative.
__________
Annex F (informative) Bibliography
Add the following documents:
EN 50123 series Railway applications - Fixed installations - D.C. switchgear
EN 50152 series Railway applications - Fixed installations - Particular requirements for a.c.
switchgear
EN 50153 Railway applications - Rolling stock - Protective provisions relating to
electrical hazards
EN 61558 series Safety of power transformers, power supply units and similar devices

– 3 – EN 50124-1:2001/A1:2003
Add the following annex:
Annex G
(informative)
Application guide
G.1 Introduction
The term "insulation co-ordination" explains the process for co-ordinating the constituents of an
electrical insulation, i.e. solid/liquid insulation, clearances and creepage distances.
NOTE The dimensioning of insulation thicknesses performed by solid insulation and insulation distances performed by liquid insulation
materials is not covered by this standard.
However, the use of this standard for the determination of clearances and creepages needs some
additional explanations: The values of the tables of Annex A are based on EN 60664-1 and
EN 60071-1 taking into account the severe electrical and mechanical situation of insulations in
railway systems and their expected reliability and long life time.
For example, the values for clearances are selected for inhomogeneous fields and, for locations
with typical railway pollutions are supplemented by safety margins. Thus, it is not necessary to
perform a high voltage test, when clearances required by this standard are achieved.
Where product standards for railway applications specify test voltages and clearances, the use of
these values is recommended. According to 1.1 it can be assumed that the insulation values in the
product standards were derived in accordance with this European Standard.
G.2 Determination of minimum clearances and creepage distances
G.2.1 Sections
For practical use when determining insulation values it is necessary to consider the following
factors when dividing into sections:
– is the considered part of the circuit exposed to the same electrical climate? (working voltage,
overvoltage category);
– are the location criteria of the regarded part of circuit the same? (pollution degree,
indoors/outdoors);
– for economical reasons it may be useful to subdivide sections (e.g. for lower insulation values
in areas with lower voltage stress);
– for reliability or safety reasons it may be useful to increase insulation values in endangered
areas, i.e. by introducing a separate section.
For floating sections consideration should be given to capacitive effects for defining the
dimensioning parameters of an insulation. Due to the actual or parasitic capacitances between the
regarded section and adjacent sections, creepage and clearances can be stressed by continuous
voltages greater than the nominal voltage of the circuit. The correct selection of U and U should
Nm Ni
take that effect into account.

G.2.2 Use of method 1 and 2 for determining U
Ni
Methods 1 and 2 are considered as equivalent for dimensioning clearances because both methods
lead to reliable distances.
Method 2 is a physical method to determine an insulation value taking into account the voltage
stress occurring across the regarded insulation but it can only be used if the expected overvoltages
are well known.
If the overvoltages are not known, method 1 should be used.
G.2.3 How to determine minimum clearances and creepage distances
The flowchart of Figure G.1 displays the procedure for determining the minimum clearances and
creepage distances by taking into account the relevant electrical, environmental and operating
conditions.
– 5 – EN 50124-1:2001/A1:2003
Step 1 3
Division of the electrical circuit into
sections which are to be handled separately.
For all points of this section
Sections 1,2,3.
the same voltage stress applies
The complete circuit or only a single point
For each section
of the circuit may be defined as a section
the following steps are to be
performed
Step 2
Determination of rated insulation voltage The section is powered direct by a
for the section of the circuit  standardised railway voltage U
n
U
Nm
yes no
Fixed installations:
Manufacturer’s determination
Rolling stock:
Manufacturer’s determination
determination according
according to 1.3.2.4 and Table A.1
Table D.1
according to 1.3.2.4 and table A.1
to 2.2.1
Rated insulation voltage
for the section of the circuit
U
Nm
Step 3 Selection of insulation type The section includes live parts.
The insulation provides a basic protection
According to 1.3.4 for the section
Product standards may state a preselection against electric shock
Insulation between conductive parts
In case of insulation failure,
only for proper functioning
the danger of an electric shock is given
no yes yes
Basic-
Functional Basic insulation
insulation insulation
+
Supplementary
insulation
(may be solid Insulation)
=
Reinforced insulation
Double insulation
(as a single insulation
Basic + Suppl.
system)
Step 4
Pollution degree
Choice of pollution degree Signalling
PD1.PD4A
6.1
for the section of the circuit
Table A.4 + Annex E
Pollution degree
Rolling stock
PD1.PD4
6.2
Pollution degree
Fixed installation
PD1.PD4B
6.3
Figure G.1 – Determination of minimum clearances and creepage distances

Step 5
rated impulse voltage All overvoltages
Determination of
are known by calculation
for this section of circuit
yes
yes / no
U or by measurement
Ni
and the minimum clearance in air
Method 1 Method 2 (2.2.2.2)
According to 2.2.2.1 Calculation or measurement
of this standard of working peak voltages
Determination of
Overvoltage categorie Calculation or measurement of
OV1.OV4 all working peak voltages
2.2.2.1 in this section (including transients
and clause 6 and induced voltages)
and Clause 6
The maximum of this peak
voltages is
U from Step 2
Nm
Table A.1
Table A.2
Rated impulse voltage for the section
UNi
PD from Step 4
Table A.3
Interpolation permitted
Minimum clearance for basic insulation
Minimum clearance distances designed or measured
for functional insulation smaller values are not allowed
smaller values are allowed
but voltage test obligatory
according to
Minimum clearance for reinforced insulation according to 1,6 x U
Ni
clause 5 and Table A.8
Clause 5 and Table A.8
distances designed or measured
smaller values are not allowed
Step 6 Determination of
Choice of the material group I, II, IIIa, or IIIb
minimum creepage distance
according 2.6 and 4.1
according to 2.6 and 4.1
for the section of the circuit
U from Step 2
Nm
Table A.5, A.6 or A.7
interpolation permitted
PD from Step 4
Minimum creepage distance
Minimum creepage distance for basic insulation
smaller values are not allowed
for functional insulation;
values are for basic insulation distances designed or measured according to Annex C
smaller values are not allowed
Minimum creepage ≥ minimum clearance
distances designed or measured
according to Annex C
Minimum creepage ≥ minimum
clearance
Minimum creepage distance
for reinforced insulation according to 2xU
Nm
smaller values are not allowed
distances designed or measured according to Annex C
Minimum creepage ≥ minimum clearance

Figure G.1 – Determination of minimum clearances and creepage distances (concluded)

– 7 – EN 50124-1:2001/A1:2003
G.2.4 Pollution
Table A.4 and Annex E may be used to identify the pollution degree applicable. A definition of a
pollution degree with numerical values is not practicable.
There is no direct relation between the protection level given by IP classes of EN 60529 and the
pollution to be expected. The IP classes are related to the protection against the ingress of solid
objects including dust and against the ingress of water (e. g. spraying, splashing, water jets,
immersion, etc.). Protection according to IP classes cannot prevent pollution created by the
equipment itself.
The pollution degree PD1 may be used in areas of fixed installations and of signalling equipment
where the temperature and the humidity are permanently controlled. These conditions are normally
not given in rolling stock.
Table A.3 shows that for indoor locations (PD1 to PD3A) the pollution has no additional influence
on clearances above 1,6 mm. On the contrary, for PD4 in rolling stock outdoor installations and for
PD4A and PD4B in fixed installations, the pollution has a significant influence on clearances
throughout the whole voltage range. Therefore these clearances are derived from the size of solid
particles and the accumulation of pollutants likely to reduce the clearances.
For outdoor fixed installations special conditions (PD4A and PD4B) apply. It is because the
pollution at any particular area is always present for that particular area and may be very severe.
Rolling stock may operate in areas where the levels will be different and then the average level of
pollution and time of application should be considered. Also fixed installations may be cleaned less
frequently.
For further guidance in selecting PD4A and PD4B the following, which is based on IEC 60815,
should be noted:
PD4A "heavy conditions"
– Areas with high density of industries and suburbs of large cities with high density of heating
plants producing pollution;
– Areas close to the sea or in any area exposed to relatively strong winds from the sea.
PD4B "very heavy conditions"
– Areas generally of moderate extent, subjected to conductive dusts and to industrial smoke
producing particular thick conductive deposits;
– Areas generally of moderate extent, very close to the coast and exposed to sea spray or to
very strong and polluting winds from the sea;
– Desert areas, characterised by no rain for long periods, exposed to strong winds carrying sand
and salt, and subjected to regular condensation.

G.2.5 Creepages
For creepages, the required distances increase with voltage for all pollution degrees. Values are
given in Tables A.5, A.6 and A.7 based on the rated insulation voltage U .
Nm
Creepage distances cannot be validated by voltage tests because, among other reasons, the
influence of pollution cannot be simulated. Product standards will address for tests taking into
account pollution, if existing. Reduction of creepage distances is not allowed for either functional or
basic insulation.
G.2.6 Insulations
G.2.6.1 Types of insulation
Figure G.2 gives an example of types of insulation.
functional surface of metallic
insulation
enclosure
solid
insulation
basic
basic
insulation
insulation
+ 1)
the creepage distance
1)
creepage
is regarded as
reinforced
=
supplementary insulation
insulation
double
insulation
Figure G.2 – Example for types of insulation
G.2.6.2 Supplementary insulat
...