BS EN 50395-2005+A1-2011

BRITISH STANDARD

BS EN

50395:2005

Electrical test methods

for low voltage energy

cables

ICS 29.060.20

+ A1 :201 1

Copyright British Standards Institution Provided by IHS under license with BSI - Uncontrolled Copy

Not for ResaleNo reproduction or networking permitted without license from IHS

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National foreword

This British Standard is the UK implementation of EN 50395:2005+A1:2011. It supersedes BS EN 50395:2005, which is withdrawn.The start and finish of text introduced or altered by amendment is indicated in the text by tags. Tags indicating changes to CENELEC text carry the number of the CENELEC amendment. For example, text altered by CENELEC amendment A1 is indicated by !".The UK participation in its preparation was entrusted by Technical Committee GEL/20, Electric cables, to Subcommittee GEL/20/17, Electric Cables - Low voltage.A list of organizations represented on this subcommittee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.

BS EN 50395:2005+A1:2011

This British Standard waspublished under the authorityof the Standards Policy andStrategy Committeeon 14 November 2005

BSI 2011

ISBN 978 0 580 67085 5

Amendments/corrigenda issued since publication

Date Comments

31 October 2011 Implementation of CENELEC amendment A1:2011



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EUROPEAN STANDARD EN 50395:2005+A1

NORME EUROPENNE

EUROPISCHE NORM

CENELEC

European Committee for Electrotechnical Standardization

Comit Europen de Normalisation Electrotechnique

Europisches Komitee fr Elektrotechnische Normung

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

2005 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 50395:2005 E

ICS 29.060.20 Partly supersedes HD 21.2 S3:1997 + A1:2002 &

HD 22.2 S3:1997 + A1:2002

English version

Electrical test methods for low voltage energy cables

Mthodes d'essais lectriques Elektrische Prfverfahren

fr Niederspannungskabel und -leitungen

This European Standard was approved by CENELEC on 2005-07-01. 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, Cyprus, Czech

Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,

Switzerland and United Kingdom.

March 2011



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2

Foreword

This European Standard was prepared by the Technical Committee CENELEC TC 20, Electric cables.

In accordance with the decision of TC 20 at its Setubal meeting (June 2004), the text of the draft was

submitted to the formal vote. It was approved by CENELEC as EN 50395 on 2005-07-01.

This European Standard, together with EN 50396:2005, supersedes HD 21.2 S3:1997 + A1:2002 and

HD 22.2 S3:1997 + A1:2002.

The following dates were fixed:

latest date by which the EN has to be implemented

at national level by publication of an identical

national standard or by endorsement (dop) 2006-07-01

latest date by which the national standards conflicting

with the EN have to be withdrawn (dow) 2008-07-01

__________

Foreword to amendment A1

This amendment was prepared by the Technical Committee CENELEC TC 20, Electric cables.

The text of the draft was submitted to the Unique Acceptance Procedure and was approved by CENELEC as amendment A1 to EN 50395:2005 on 2011-03-14.

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)

2012-03-14

latest date by which the national standards conflicting with the amendment have to be withdrawn

(dow)

2014-03-14

__________

BS EN 50395:2005+A1:2011 EN 50395:2005+A1:2011 (E)



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3

Contents

Page

Introduction.............................................................................................................................................5

1 Scope................................................................................................................................................5

2 Normative references......................................................................................................................5

3 General requirements .....................................................................................................................6

3.1 Pre-conditioning......................................................................................................................6

3.2 Test temperature ....................................................................................................................6

3.3 Test voltage ............................................................................................................................6

3.4 Test values .............................................................................................................................6

4 Definitions........................................................................................................................................6

5 Electrical d.c. resistance of conductor .........................................................................................6

6 Voltage test on completed cable ...................................................................................................6

7 Voltage test on cores in water .......................................................................................................7

7.1 Test sample ............................................................................................................................7

7.2 Procedure ...............................................................................................................................7

7.3 Requirement ...........................................................................................................................7

8 Insulation resistance test ...............................................................................................................7

8.1 Insulation resistance for cables having maximum conductor temperatures

not exceeding 90 C ...............................................................................................................7

8.1.1 Test sample ...............................................................................................................7

8.1.2 Procedure ..................................................................................................................8

8.1.3 Requirement ..............................................................................................................8

8.2 Insulation resistance for cables with maximum conductor temperatures

exceeding 90 C .....................................................................................................................8

8.2.1 Test sample ...............................................................................................................8

8.2.2 Procedure ..................................................................................................................8

8.2.3 Requirement ..............................................................................................................8

9 Long term resistance of insulation to d.c.....................................................................................9

9.1 Test sample ............................................................................................................................9

9.2 Procedure ...............................................................................................................................9

9.3 Requirement .........................................................................................................................10

10 Check for the absence of faults in insulation ............................................................................10

10.1 General .................................................................................................................................10

10.2 Spark test..............................................................................................................................10

10.2.1 Procedure ................................................................................................................10

10.2.2 Requirement ............................................................................................................10

10.3 Voltage test...........................................................................................................................10

10.3.1 Procedure ................................................................................................................10

BS EN 50395:2005+A1:2011 EN 50395:2005+A1:2011 (E)



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4

10.3.2 Requirement ............................................................................................................10

11 Surface resistance of sheath .......................................................................................................11

11.1 Test samples ........................................................................................................................11

11.2 Procedure .............................................................................................................................11

11.3 Requirement .........................................................................................................................11

12 Transfer impedance ......................................................................................................................11

Annex A .................................................................................................................................................12

A.1 Basic formula........................................................................................................................12

A.2 Rounding ..............................................................................................................................12

A.3 Examples of calculation........................................................................................................12

Annex B (informative) Source of electrical test methods in EN 50395.............................................13

Bibliography..........................................................................................................................................14

Figure 1 Positioning of electrodes .........................................................................................................9

BS EN 50395:2005+A1:2011 EN 50395:2005+A1:2011 (E)



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5

Introduction

EN 50395 contains the electrical test methods that are used for harmonized low voltage energy

cables. These electrical test methods include all those previously contained in HD 21 and HD 22.

Annex B gives a comparison between the original location of each test method and its place in this

new European Standard.

The content of EN 50395 is not, and will not be, restricted only to test methods for cables to HD 21

and HD 22. Other test methods for harmonized LV cables may be included. Furthermore, the use of

test methods in EN 50395 for cables outside HD 21 and HD 22 is not prohibited, but it is strongly

recommended that expert advice be taken before such use, or before any proposal for incorporation

into another standard.

1 Scope

EN 50395 contains electrical test methods required for the testing of harmonized low voltage energy

cables, especially those rated at up to and including 450/750 V.

NOTE 1 A description of the origin of these test methods and the background to this European Standard is given in the

Introduction and in Annex B.

The particular cable standard dictates the tests which need to be performed on the relevant cable

type. It also specifies whether the specific test is a type test (T), a sample test (S) or a routine test (R)

for the particular cable type.

NOTE 2 T, S and R are defined in the relevant cable standard.

The requirements to be met during or after the test are specified for the particular cable type in the

relevant cable standard. However, some test requirements are obvious and universal, such as the fact

that no breakdown shall occur during voltage tests, and these are stated in the particular test method.

Test methods for use specifically in utility power cables are not covered by this European Standard.

They can be found in HD 605.

Test methods for use specifically in communications cables are the responsibility of the Technical

Committee CENELEC TC 46X, Communication cables. At present such test methods are given in

EN 50289 series.

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 50289-1-6 2002 Communication cables Specifications for test methods -

Part 1-6: Electrical test methods Electromagnetic performance

EN 60228 2005 Conductors of insulated cables

EN 62230 2007 Electric cables Spark test method ! "

BS EN 50395:2005+A1:2011 EN 50395:2005+A1:2011 (E)



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3 General requirements

3.1 Pre-conditioning

All the tests shall be carried out not less than 16 h after the extrusion or cross-linking, if any, of the

insulating or sheathing compounds.

3.2 Test temperature

Unless otherwise specified, tests shall be made at an ambient temperature of (20 15) C.

3.3 Test voltage

Unless otherwise specified in the individual clause of this European Standard or in the product

standard, the test voltage shall be a.c. of approximately sine-wave form and of frequency between

49 Hz and 61 Hz. The ratio of peak value to r.m.s. value shall be equal to 2 with a tolerance of 7 %.

The values quoted are r.m.s. values.

3.4 Test values

Full test conditions (such as temperatures, durations, etc.) and full test requirements are not specified

in this European Standard; it is intended that they should be specified by the standard dealing with the

relevant type of cable.

Any test requirements which are given in this European Standard may be modified by the relevant

cable standard to suit the needs of a particular type of cable.

4 Definitions

For the purposes of this document, the following terms and definitions apply.

4.1

median value

when several test results have been obtained and ordered in an increasing or decreasing succession,

the median value is the middle value if the number of available values is odd, and is the mean of the

two middle values if the number is even

5 Electrical d.c. resistance of conductor

The test shall be carried out in accordance with Annex A of EN 60228.

6 Voltage test on completed cable

If the cable has no metallic layer, a sample of the cable as manufactured shall be immersed in water.

The length of the sample, the temperature of the water and the period of immersion shall be as

specified in the cable standard. A voltage shall be applied between conductor(s) and groups of

conductors in such a way that the insulation on each core is tested against all adjacent cores and the

water.

BS EN 50395:2005+A1:2011 EN 50395:2005+A1:2011 (E)



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7

If the cable has a metallic layer, a sample of the cable shall be taken of the length specified in the

cable standard. A voltage shall be applied between conductor(s) and groups of conductors in such a

way that the insulation on each core is tested against all adjacent cores and the metallic layer, which

shall be earthed.

If the cable has a metallic strain-bearing member, this shall be connected to the water or to the

metallic layer, as appropriate.

In each case, the voltage and the duration of its application shall be as specified in the cable standard.

The voltage shall be increased gradually on each occasion to the specified value.

No breakdown of the insulation shall occur during the test.

7 Voltage test on cores in water

The test applies to sheathed cables, braided cables and flat unsheathed cords.

NOTE For 1-core unsheathed cables, the test in Clause 6 generally applies, in which case this test on cores is not required.

7.1 Test sample

Prepare a sample of cable 5 m long, by carefully removing, without damaging the cores, the sheath or

the overall braid and any other covering or filling from a length of completed cable.

In the case of flat unsheathed cord, make a cut in the insulation between the cores, and separate the

cores by hand for a length of 2 m.

7.2 Procedure

Immerse the sample in water at the temperature, and for the period, specified in the cable standard.

Ensure that the ends of the cores protrude above the water by a distance sufficient to prevent

excessive surface leakage when the test voltage is applied. Apply a voltage, of the magnitude

specified in the cable standard, between the conductors and the water for the time specified in the

cable standard.

7.3 Requirement


8 Insulation resistance test

8.1 Insulation resistance for cables having maximum conductor temperatures not

exceeding 90 C

8.1.1 Test sample

Make the test on a sample of cable 5 m long, previously submitted to the test specified in Clause 7 or,

in the case of 1-core unsheathed cable, to the test described in Clause 6.

BS EN 50395:2005+A1:2011 EN 50395:2005+A1:2011 (E)



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8.1.2 Procedure

Immerse the sample in water previously heated to the temperature specified in the cable standard,

with a length of about 250 mm at each end of the sample projecting above the water, for the period of

time specified in the cable standard.

Apply a d.c. voltage of between 80 V and 500 V between each conductor and the water.

Measure the insulation resistance of each core 1 min after application of the voltage. Use this value to

calculate the insulation resistance of a 1 km length of each core.

8.1.3 Requirement

None of the resulting values shall be below the minimum insulation resistance value specified in the

cable standard.

8.2 Insulation resistance for cables with maximum conductor temperatures

exceeding 90 C

NOTE Further basic information on this test method may be obtained from HD 429, Clause 6 Test pieces for the volume

resistivity measurement.

8.2.1 Test sample

Make the test on the same sample of cable used for the voltage test in Clause 7 or, in the case of

1-core unsheathed cable, to the test described in Clause 6.

8.2.2 Procedure

Cut a test piece 1,40 m long from the cable or core to be tested. Cover this test piece with a semi-

conducting layer, and over this layer apply a metal braid or a metal tape in such a way as to obtain an

active measuring length of 1,0 m.

At both ends of the active measuring length, leaving a gap 1 mm wide, apply a protective wire binding

of approximately 5 mm length (see Figure 1).

Wind the test piece to form a ring with a diameter of approximately 15D but at least 0,20 m

(D = nominal outer diameter of insulation).

Maintain the test piece in an air oven for at least 2 h at the test temperature specified in the relevant

cable standard, leaving a clearance between the sample and the walls of the air oven of at least

50 mm.

After the conditioning period a d.c. voltage between 80 V and 500 V shall be applied between the

conductor and the screen (semi-conducting layer and metal braid/metal tape including the protective

wire binding), the sample still being kept in the air oven.

The insulation resistance shall be measured 1 min after application of the voltage and this value shall

be used to calculate the insulation resistance of a 1 km length of cable.

8.2.3 Requirement

None of the resulting values shall be below the minimum insulation resistance value specified in the

cable standard.

NOTE Annex A shows the calculation method for minimum insulation resistance.

BS EN 50395:2005+A1:2011 EN 50395:2005+A1:2011 (E)



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9

Key

1 guard electrode (protective wire binding) 2 screen electrode

Figure 1 Positioning of electrodes

9 Long term resistance of insulation to d.c.

9.1 Test sample

Carry out the test on a sample of cable of 5 m length from which all coverings have been removed.

The cores of flat unsheathed cords shall not be separated.

For cables having up to five cores, each core shall be tested. For multicore cables having more than

five cores, one core of each colour in the cable shall be tested, and where the number of colours is

less than 5, duplicate coloured cores shall be tested as necessary to bring the number of cores tested

up to a minimum of 5.

Take care to avoid damage to the core(s) during removal of the coverings.

9.2 Procedure

Immerse the sample, for the period and at the temperature given in the relevant cable standard, in an

aqueous solution of sodium chloride having a concentration of 10 g/l, with a length of about 250 mm at

each end of the sample projecting above the solution. Connect the negative pole of a 220 V d.c.

supply to the conductor(s) of the sample and the positive pole to a copper electrode immersed in the

solution for the time given in the relevant cable standard.

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9.3 Requirement

No breakdown of the insulation shall occur during the test and, after the test, the exterior of the

insulation shall show no sign of damage.

NOTE Discoloration of the insulation should be ignored.

10 Check for the absence of faults in insulation

10.1 General

Test all cable that is in the final stage of manufacture, whether it is in delivery lengths or in

manufacturing lengths prior to being cut into delivery lengths.

Test single core cables, whether sheathed or unsheathed, by the spark test in accordance with 10.2.

Test all other cables, including sheathed flat cables, by the voltage test in accordance with 10.3.

The requirements of 3.1 of this European Standard do not apply when the check for absence of faults

is carried out as a Routine (R) test.

10.2 Spark test

10.2.1 Procedure

Carry out the test according to , except that the option to use a pulsed

waveform high

voltage source is not permitted.

10.2.2 Requirement

No faults shall be detected during the test.

10.3 Voltage test

10.3.1 Procedure

With the cable in the dry state and at ambient temperature apply a voltage of the magnitude given in

the relevant cable standard, supplied either from an a.c. source or from a d.c. source, between each

conductor and all the other conductors and, if any, the metallic layer connected to earth.

Increase the voltage gradually and maintain it at the full value for the duration given in the relevant

cable standard.

10.3.2 Requirement


EN 62230! "

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11 Surface resistance of sheath

11.1 Test samples

Carry out the test on three samples of completed cable, each about 250 mm in length.

11.2 Procedure

Clean the sheath of each of the samples with industrial methylated spirit, and apply to each sample

two electrodes, consisting of wire helices of copper wire of between 0,2 mm and 0,6 mm diameter, at a

distance of (100 2) mm from each other. After the wire has been applied, clean the surface of the

sheath again thoroughly between the electrodes.

Condition the samples with electrodes attached in a conditioning chamber at a temperature of

(20 2) C and a relative humidity of (65 5) % for 24 h.

Immediately after removal from the conditioning chamber, apply a d.c. voltage of between 100 V and

500 V between the electrodes, and measure the resistance after 1 min.

Multiply the measured resistance of each sample, in ohms, by a/100, where a is the circumference of

the sheath of the sample, in millimetres. Record the median of the three values so obtained as the

surface resistance of the sheath.

11.3 Requirement

The median of the three values so obtained shall be not lower than the value in the cable standard.

12 Transfer impedance

The test shall be carried out in accordance with EN 50289-1-6, clause 6.

NOTE EN 50289-1-6 is maintained by the Technical Committee CENELEC TC 46X, Communication cables.

BS EN 50395:2005+A1:2011 EN 50395:2005+A1:2011 (E)



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Annex A

(informative)

Calculation of minimum insulation resistance

A.1 Basic formula

The general basic formula is:

=

d

D

R log.10..0367,0

8

where:

R = insulation resistance in M.km

= volume resistivity in .m

d = the diameter of the bare conductor as given in EN 60719 Table 1 (class 1 and class 2

conductors) or Table 2 (class 5 and class 6 conductors)

D = d + twice the specified mean value of the thickness of the insulation and any

mandatory separator between conductor and insulation.

A.2 Rounding

As the requirement in cable standards is for a minimum value the calculated value of R should be

rounded down to two significant figures.

A.3 Examples of calculation

HD 21.3 S3, Table 1, H07V-R

Conductor

cross-

section

Insulation

thickness

Conductor

diameter

(d)

Overall

diameter

R

R (rounded)

mm mm mm mm

M.km M.km

1,5

35

50

0,7

1,2

1,4

1,45

7,0

8,2

2,85

9,4

11,0

0,010 77

0,004 699

0,004 682

0,010

0,004 6

0,004 6

NOTE For many common insulation compounds, for instance those based on PVC or on thermoplastic polyolefines, the volume

resistivity at the operating temperature of the relevant cable is assumed to be 810 m+ . In these cases the general formula reduces to:

kmM log0,0367 =

dDR

!

"

BS EN 50395:2005+A1:2011 EN 50395:2005+A1:2011 (E)



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Annex B

(informative)

Source of electrical test methods in EN 50395

Source (subclause number)Test

HD 21.2 S3 HD 22.2 S3

Clause in EN 50395

Electrical resistance

of conductor

2.1 2.1 5

Voltage test on

completed cable

2.2 2.2 6

Voltage test on cores 2.3 2.3 7

Insulation resistance 2.4 2.4 8

Long term resistance

of insulation to d.c.

2.5 2.5 9

Test to check

absence of faults on

insulation

2.6 2.6 10

Transfer impedance

(Screening efficiency)

2.7 - 12

Surface resistance of

sheath

2.8 2.7 11

BS EN 50395:2005+A1:2011 EN 50395:2005+A1:2011 (E)



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Bibliography

The following documents are referred to in the text for information.

HD 21.2 S3:1997 Cables of rated voltages up to and including 450/750 V and having

thermoplastic insulation - Part 2: Test methods

HD 22.2 S3:1997 Cables of rated voltages up to and including 450/750 V and having cross-

linked insulation - Part 2: Test methods

HD 429 Methods of test for volume resistivity and surface resistivity of solid electrical

insulating materials (IEC 60093)

HD 605 Electric cables - Additional test methods

EN 50289 Series Communication cables - Specifications for test methods

BS EN 50395:2005+A1:2011 EN 50395:2005+A1:2011 (E)



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BS EN 50395-2005+A1-2011