Guidline Machines ANG

Verification of safety of machines according to IEC/EN 60204 Edition 5

Version 1.0,Code no. 20 751 202


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1 Introduction.............................................................................................................3 1.1 The new IEC/EN 60204, Edition 5.....................................................................3 1.2 Scope of the standard .......................................................................................3

2 Verification of safety of machines ........................................................................5 3 Visual inspection ....................................................................................................6 4 Measurements ........................................................................................................7

4.1 Verification of protection against indirect contact by automatic disconnection ..7 4.1.1 Selection of machine status and test extent ...............................................7 4.1.2 Selection of test limits...............................................................................10

4.2 Insulation resistance........................................................................................16 4.2.1 Selection of test limits ....................................................................................16

4.3 4.3 High voltage test........................................................................................17 4.3.1 Selection of test limits ....................................................................................17

4.4 Residual voltage test .......................................................................................17 4.4.1 Selection of test limits...............................................................................17

5 Connection diagramms........................................................................................19 5.1 Protection against indirect contact...................................................................19

5.1.1 Continuity of protective conductors ..........................................................19 5.1.2 Fault loop impedance ...............................................................................20 5.1.3 Suplemmentary bonding ..........................................................................21

5.2 Insulation resistance........................................................................................22 5.3 High voltage test..............................................................................................23 5.4 Residual voltage test .......................................................................................24 5.5 Functional tests ...............................................................................................25


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1 Introduction Foreword This booklet is inteneded to help defining correct procedures for verification of electrical safety of machines. New verification principles in the IEC/EN 60204 Edition 5 (released in 2006) are highlighted. 1.1 The new IEC/EN 60204, Edition 5 The IEC/EN 60204 norm deals with safety of electrical equipment in machines. The 5th edition edition cancels and replaces the fourth edition issued in 1997 and Ammendment 1 (1999). Compared to old versions the new edition:

• is amended to provide general requirements for machines, including mobile machines and complex (for example large) machine installations.

• it deals with determination of adequate risk reduction relevant to the machine’s electrical equipment.

• is significantly changed in part “Verification”. The simple test of protective conductors (Voltage Drop test) is substituted by a more thorough testing of protective measures against indirect contact. Now verification tests include appropriateness of protective conductors, of overcurrent disconnection devices and incoming supply impedance.

The IEC/EN 60204 Edition 5 is a harmonized EU standard and an important part of the EU Machine Directive. It is also harmonized with the US standard NFPA79. 1.2 Scope of the standard With help of this standard the risks associated with hazards relevant to electrical equipment can be assessed as apart of the overall requirements for risk assessment of the machine. On base of the assement adequate risk reduction and necessary protective measures can be defined. Typical hazardous situations related to electrical equipment are:

• failures or faults in the electrical equipment resulting in the possibility of electric shock or electrical fire

• failures or faults in control circuits resulting in the malfunctioning of the machine; • disturbances or disruptions in power sources as well as failures or faults in the

power circuits resulting in the malfunctioning of the machine • loss of continuity of circuits that depends on sliding or rolling contacts, resulting in

failure of a safety function • electrical disturbances either from outside the electrical equipment or internally

generated, resulting in the malfunctioning of the machine; • release of stored energy (either electrical or mechanical) resulting in, for

example, electric shock or unexpected movement that can cause injury; • audible noise at levels that cause health problems to persons; • surface temperatures that can cause injury.


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Part 18 (Verifications) of the standard determines the measurements (methods, limits) that are to be performed to verify the electrical safety of machines. The verification is applicable:

• after erection of machine • after installation of machine • after upgrading or changing of machine • and during periodic retests of machine


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2 Verification of safety of machines According to IEC/EN 60204, Ed.5 verification of electrical safety of machines is perfomed by inspection and measurements: 1. Inspection that the electrical equipment complies with its technical

documentation 2. Verification of protection against indirect contact by automatic disconnection, 3. Insulation resistance test 4. High voltage test 5. Protection against residual voltages 6. Functional tests The norm describes general requirements regarding electrical equipment of a machine. The extent of verification in usually given in the product standard and/ or technical documentation for a particular machine. Where there is no dedicated product standard for the machine, the verifications shall always include the items 1, 2 and 6 and may include one or more of the items 3,4,5. The decision should be taken by a competent person on site, after evaluation of machine’s condition. In Table 1 a legend of tables and flowcharts in this document is shown. They include.detailed information about limits, sequences and connection diagrams. Measurement Limits, parameters, extent of

test Connection diagram

Protection against indirect contact: Continuity of PE conductors

Extent of test: flowchart 1 Test sequence: flowcharts 1,2 Conductor resistance: table 3

Fig. 1

Protection against indirect contact: Fault loop impedance test*

Extent of test: flowchart 1 Test sequence: flowcharts 1,2 Disconnection times: table 4 Fuse table with limits: table 5

Fig. 2

Protection against indirect contact: Equipotential bonding

Test sequence and limits: flowchart 2

Fig. 3

Insulation resistance test Test sequence and limits: flowchart 3 Fig. 4 High voltage Tests Test sequence and limits: flowchart 4 Fig. 5 Protection against residual voltages

Test sequence and limits: flowchart 5 Fig. 6

Functional test Fig. 7 * TN systems. For TT systems RCD tests, for IT systems IMD check should be performed.

Table 1: Legend of tables, flowcharts


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3 Visual inspection Maybe it sounds strange but visual check is the most important and effective part of a machine test. The visual inspection discloses most of faults! Electrical testing often does not disclose failures that become apparent on visual inspection. A thorough visual check must be carried out before each electrical safety test. Scope of test: Check of: • Wiring connection points. Especially PE connections are important ! • Protection covers, housings • Inscriptions and markings related to safety must be clearly readable. • Cable layout, radiuses, isolation • Switches, regulators,lamps, keys • Parts subjected to wear out • Electrical and mechanical protection devices (barriers, switches, fuses, alarms) • Openings, filters • Technical documentation, instructions for use available • Installation of the appliance must be performed according to the user manuals. • During visual inspection the measuring points for the electrical testing have to be

determined too. Check that there are no signs of: • damage • pollution, moisture, dirt that can jeopardize safety • corrosion • overheating


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4 Measurements 4.1 Verification of protection against indirect contact by automatic

disconnection This verification step is quite complex and must always be carryed out in some form. The standard allows simplified testing procedures regarding to the status of machine. 4.1.1 Selection of machine status and test extent The status of the machine can be selected on base of

• condition of supplied machine (dismantled, fully assembled) • technical documentation (availability of existing verification report of electrical

wiring of machine) • length of conductors after installation • incoming supply characteristics – loop impedance

Flowchart 1 describes how to select the apropriate machine status and test extent. It shows when continuity and fault loop ompedance tests can be omitted. Note:

• Visual inspection of protection measures must always be carryed out. • If in doubt it is recommended to carry out the complete verification procedure

(marked bold in flowchart 1): - visual inspection - complete continuity test - complete fault loop impedance test

Table 2 shows the maximal lenghts of conductors for given disconnection times / conductor /fuse or breaker type). If the lengths are shorter the loop impedance test may be omitted (if source impedance is low enough). The table should be used only if the machine’s documentation include a verification report of continuity of protective bonding. Note:

• The distance from the disconection device to all loads must be considered. • Especially the most remote connection point must be considered.


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Flowchart 1: Protection against indirect contact – selection of test sequence (according to EN/IEC 60204, Table 9)


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Supply source impedance to each protective device

Cross-sectional

area

Nominal rating or setting of the protective device (IN)

Fuse disconnect time 5 s

Fuse disconnect time 0,4 s

Miniature circuit-breaker char.B Ia = 5 x IN disconnect time 0,1 s

Miniature circuit-breaker char.C Ia = 10 x IN disconnect time 0,1 s

Adjustable circuit-breaker Ia = 8 x IN disconnect time 0,1 s

mΩ mm2 A Maximum cable length in m from each protective device to its load

500 1,5 16 97 53 76 30 28 500 2,5 20 115 57 94 34 36 500 4,0 25 135 66 114 35 38 400 6,0 32 145 59 133 40 42 300 10 50 125 41 132 33 37 200 16 63 175 73 179 55 61

200 25 (line) / 16 (PE) 80 133 38

100 35 (line) / 16 (PE) 100 136 73

100 50 (line) / 25 (PE) 125 141 66

100 70 (line) / 35 (PE) 160 138 46

50 95 (line) / 50 (PE) 200 152 98

50 120 (line) / 70 (PE) 250 157 79

The values of the maximum cable length in the table are based on the following assumptions:

• PVC cable with copper conductors, conductor temperature under short circuit conditions 160ºC • cables with line conductors up to 16 mm2 provide a protective conductor of equal cross

sectional area to that of the line conductors; • cables above 16 mm2 provide a reduced size protective conductor as shown; • 3-phase system, nominal voltage of the power supply 400 V; • maximum supply source impedance to each protective device in accordance with column 1; .

A deviation from these assumptions can require a complete calculation or measurement of the fault loop impedance. Further information is available from IEC 60228 and IEC 61200-53.

Table 2: Maximal cable lengths that allow omitting loop impedance tests

(EN/IEC 60204, table 10)


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4.1.2 Selection of test limits Once the machine status and test extent are defined the limits for the Continuity and/ or ZLOOP test should be defined. Flowchart 2 shows how to define test limits for the continuity and fault loop test. 4.1.2.1 Continuity test limits Table 3 shows expected limit resistance values for the continuity test (for typical conductor lengths and sizes). On base of given specific resistance of copper and influence of temperature limit resistance values for other conductor shapes and temperatures can be calculated. 4.1.2.2 ZLOOP test limits – disconnection time In general 5s disconnection time should be considered for the ZLOOP test. Disconnection times for circuits that:

• supply, through socket-outlets or directly without socket-outlets, Class I hand-held equipment or portable equipment (typical examples are socket-outlets on a machine for accessory equipment) are lower than 5s. Disconnection times for TN systems and standard nominal voltages are shown table 4.

4.1.2.3 ZLOOP test limits – fault impedance/ prospective fault current IPFC (prospective fault current) and ZLOOP (fault impedance) limit values are defined on base of:

• fuse type and size • relevant disconnection time • nominal voltage

The increase of resistance of the conductors with the increase of temperature due to the fault current must be taken into account as specified below: ZLOOPcalculated = ZLOOPmeasured · 1.5 Eq. 1 IPFCcalculted = IPSCmeasured · 0.66 Eq. 2 ZLOOP.................fault loop impedance IPSC.....................prospective fault current 1.5, 0.66.....temperature correction factors Table 5 shows limit values for nominal voltage of 230V, with the temperature correction factor considered.


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4.1.2.4 Protection against indirect contact – selection of limit values

Flowchart 2: Protection against indirect contact – selection of limits


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4.1.2.5 Expected resistance limit values for the continuity test

Wire Size

Gauge No Cross-sectional area d.c. resistance of copper at

20°c

Circular mils

mm2 (AWG) mm2 inches2 Ohms per km

0,2 0,196 0,000 304 91,62 387 24 0,205 0,000 317 87,60 404 0,3 0,283 0,000 438 63,46 558 22 0,324 0,000 504 55,44 640 0,5 0,500 0,000 775 36,70 987 20 0,519 0,000 802 34,45 1 020 0,75 0,750 0,001 162 24,80 1 480 18 0,823 0,001 272 20,95 1 620 1,0 1,000 0,001 550 18,20 1 973 16 1,31 0,002 026 13,19 2 580 1,5 1,500 0,002 325 12,20 2 960 14 2,08 0,003 228 8,442 4 110 2,5 2,500 0,003 875 7,56 4 934 12 3,31 0,005 129 5,315 6 530 4 4,000 0,006 200 4,700 7 894 10 5,26 0,008 152 3,335 10 380 6 6,000 0,009 300 3,110 11 841 8 8,37 0,012 967 2,093 16 510 10 10,000 0,015 50 1,840 19 735 6 13,3 0,020 610 1,320 26 240 16 16,000 0,024 800 1,160 31 576 4 21,1 0,032 780 0,829 5 41 338 25 25,000 0,038 800 0,734 0 49 740 2 33,6 0,052 100 0,521 1 66 360 35 35,000 0,054 200 0,529 0 69 073 1 42,4 0,065 700 0,413 9 83 690 50 47,000 0,072 800 0,391 0 92 756

Table 3: Expected copper conductor resistance (at 20ºC) on base length and

crosssection (EN/IEC 60204, Table G.1) The resistance for temperatures other than 20°C can be found using the formula: R = R1 [1+0,003 93 (t-20)] Eq.3 R1........ resistance at 20°C; R......... the resistance at a temperature t°C.


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4.1.2.6 Disconnection times for TN systems (supplying parts of machines)

Uo (V) a) Disconnecting time s

120 0,8 230 0,4 277 0,4 400 0,2

>400 0,1 a) Uo is the nominal a.c. r.m.s. voltage to earth. For voltages which are within the tolerance band stated in IEC 60038, the disconnecting time appropriate to the nominal voltage applies. For intermediate values of voltage, the next higher value in the above table is to be used.

Table 4: Maximum disconnection times for TN supplying circuits – part of machines

(EN/IEC 60204, Table A.1)


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4.1.2.7 Disconnection times for TN systems Fuse tables for disconnection time of 5 seconds.

Fuse type Fuse trip-out time

Fuse current rating

Min. prospective short- circuit current (A) – with

correction factor included

Zloop for Un= 230V/400V – with correction factor included

NV 5 s 2 A 25.3 9.1NV 5 s 4 A 12.3 18.7NV 5 s 6 A 8.6 26.7NV 5 s 10 A 5.0 46.4NV 5 s 16 A 3.5 66.3NV 5 s 20 A 2.7 86.7NV 5 s 25 A 2.1 109.3NV 5 s 35 A 1.4 169.5NV 5 s 50 A 0.9 266.9NV 5 s 63 A 0.7 319.1NV 5 s 80 A 0.5 447.9NV 5 s 100 A 0.4 585.4NV 5 s 125 A 0.3 765.1NV 5 s 160 A 0.2 947.9NV 5 s 200 A 0.2 1354.5NV 5 s 250 A 0.1 1590.6NV 5 s 315 A 0.1 2272.9NV 5 s 400 A 0.1 2766.1NV 5 s 500 A 0.1 3952.7NV 5 s 630 A 0.0 4985.1NV 5 s 710 A 0.0 6423.2NV 5 s 800 A 0.0 7252.1NV 5 s 1000 A 0.0 9146.2NV 5 s 1250 A 0.0 13070.1gG 5 s 2 A 25.3 9.1gG 5 s 4 A 12.3 18.7gG 5 s 6 A 8.6 26.7gG 5 s 10 A 5.0 46.4gG 5 s 13 A 4.1 56.2gG 5 s 16 A 3.5 66.3gG 5 s 20 A 2.7 86.7gG 5 s 25 A 2.1 109.3gG 5 s 32 A 1.4 159.1gG 5 s 35 A 1.4 169.5gG 5 s 40 A 1.2 190.1gG 5 s 50 A 0.9 266.9gG 5 s 63 A 0.7 319.1gG 5 s 80 A 0.5 447.9gG 5 s 100 A 0.4 585.4B 5 s 6 A 7.7 30B 5 s 10 A 4.6 50B 5 s 13 A 3.5 65B 5 s 16 A 2.9 80


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B 5 s 20 A 2.3 100B 5 s 25 A 1.8 125B 5 s 32 A 1.4 160B 5 s 40 A 1.2 200B 5 s 50 A 0.9 250B 5 s 63 A 0.7 315C 5 s 0.5 A 85.2 2.7C 5 s 1 A 42.6 5.4C 5 s 1.6 A 26.7 8.6C 5 s 2 A 21.3 10.8C 5 s 4 A 10.6 21.6C 5 s 6 A 7.1 32.4C 5 s 10 A 4.3 54C 5 s 13 A 3.3 70.2C 5 s 16 A 2.7 86.4C 5 s 20 A 2.1 108C 5 s 25 A 1.7 135C 5 s 32 A 1.3 172.8C 5 s 40 A 1.1 216C 5 s 50 A 0.9 270C 5 s 63 A 0.7 340.2D 5 s 0.5 A 85.2 2.7D 5 s 1 A 42.6 5.4D 5 s 1.6 A 26.7 8.6D 5 s 2 A 21.3 10.8D 5 s 4 A 10.6 21.6D 5 s 6 A 7.1 32.4D 5 s 10 A 4.3 54D 5 s 13 A 3.3 70.2D 5 s 16 A 2.7 86.4D 5 s 20 A 2.1 108D 5 s 25 A 1.7 135D 5 s 32 A 1.3 172.8

Table 5: Disconnection times for TN supplying circuits – part of machines

4.1.2.8 Limits for suplemmentary bonding Where the requirements for prospective falt current cannot be assured supplementary bonding may be used in order to reduce the touch voltage below 50V. Supplementary bonding means additional connection of simultaneously accessible exposed metal parts. The following condition below must be fullfilled: RPE < 50V / Ia (5s) Eq.3 Ia(5s).........5 s operating current of the protective device;


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RPE........... resistance of the protective bonding circuit between the PE terminal and the equipment anywhere on the machine, or between simultaneously accessible exposed conductive parts and/or extraneous conductive parts.

4.2 Insulation resistance 4.2.1 Selection of test limits Flowchart 3 shows how to define test limits for the insulation test. Normally the test may be made on individual sections of the complete electrical installation. Limitations are:

• Care must be taken if machine includes sensitive electrical equipment that could be damaged if a to high test voltage would be applied to them. In this case the sensitive part should be disconnected from the tested circuitry. Depending on the product standard, they should be tested with an apropriately lower test voltage.

• If surge protection devices are installed the test can be carryed out only in a limited manner.

Procedures in this case of is described in flowchart 3.

Flowchart 3: Insulation resistance – selection of limit


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4.3 4.3 High voltage test 4.3.1 Selection of test limits Flowchart 4 shows the methodology to define test limits for the high voltage. Normally the test may be made on individual sections of the complete electrical installation. Limitations are:

• Care must be taken if machine includes sensitive electrical equipment that could be damaged if a to high test voltage would be applied to them. The test may be made on individual sections of the complete electrical installation.

Withstanding voltage

Un < 500VrmsUn....nominal phase to neutral voltage

Un < 500Vrms

Utest = 1000Vac t = 1slimit = no breakdowntest

Utest = 2• Un t = 1slimit = no breakdowntest

Flowchart 4: High voltage test – selection of limit 4.4 Residual voltage test 4.4.1 Selection of test limits Flowchart 5 shows the methodology to define test limits for the residual voltage test. Live parts having a residual voltage greater than 60 V after the supply has been disconnected, shall be discharged to 60 V or less within a time period of 5 s after disconnection of the supply. Exempted from this requirement are components having a stored charge of Q = 60 µC or less.


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Q = C·U Eq. 4 Q................stored charge in Coloumbs C................capacitance in Farads U................voltage in Volts For plugs or similar devices with exposed conductors (for example pins) if plugged out the discharge time shall be discharged to 60 V or less within a time period of 1 s after disconnection of the supply. In case of longer discharging times the conductors / connectors shall be protected against direct contact to at least IP2X or IPXXB. If neither a discharge time of 1 s nor a protection of at least IP2X or IPXXB can be achieved (for example in the case of removable collectors on conductor wires, conductor bars, or slip-ring assemblies) additional switching devices or an appropriate warning device (for example a warning notice) shall be applied.

Residual voltage (discharging time)

Standard machine Plugs or similar devices with exposed pins if plugged out

Ulimit = 60V

tlimit = 5s

Ulimit = 60V

tlimit = 5s

Flowchart 5: Residual voltage test – selection of limit


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5 Connection diagramms 5.1 Protection against indirect contact 5.1.1 Continuity of protective conductors 5.1.1.1 Continuity test

• The resistance of each protective bonding circuit between the main PE terminal and individual relevant points that are part of each protective bonding circuit shall be measured.

• Size of test current should be between at least 0,2 A and approximately 10 A Higher currents are prefered ,especially for low resistance values, i.e. larger cross sectional areas and/or lower conductor length.

• The measured resistance shall be in the expected range according to the length, the cross sectional area and the material of the related protective bonding conductor(s).

Fig. 1: Continuity of protective conductors


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5.1.2 Fault loop impedance 5.1.2.1 ZLOOP, IPFC test

• The fault loop impedance is measured between L and PE conductors at connection points of machine’s loads. Result is compared with Ia of belonging disconnection devices (fuses, breakers)

• For three phase machines all three (L1-PE, L2-PE, L3-PE impedances must be considered).

Fig. 2: Fault loop impedance


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5.1.3 Suplemmentary bonding 5.1.3.1 Continuity test

• Suplemmentary bonding is measured between the main PE terminal and PE connections anywhere on the machine, or between simultaneously accessible exposed conductive parts and/or extraneous conductive parts.

• Size of test current should be between at least 0,2 A and approximately 10 A Higher currents are prefered ,especially for low resistance values, i.e. larger cross sectional areas and/or lower conductor length.

• The measured resistances shall be low enough to assure a contact voltage lower than 50V between two simultaneously accessible conductive parts.

Fig. 3: Equipotential bonding


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5.2 Insulation resistance 5.2.1.1 Insulation resistance test

• Insulation resistance is measured between connected live pins and PE terminal. The test may be made on individual sections of the complete electrical installation.

• Components and devices that are not rated to withstand the test voltage shall be disconnected during the testing.

• Lower test voltages should be used for sensitive electronic equipment and surge protective devices.

Fig. 4: Insulation resistance


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5.3 High voltage test 5.3.1.1 Withstanding voltage test

• The test voltage shall be applied between the power circuit conductors and the protective bonding circuit for a period of approximately 1 s.

• Components and devices that are not rated to withstand the test voltage shall be disconnected during the testing.

• Components and devices that have been voltage tested in accordance with their product standards may be disconnected during testing.

Fig. 5: Withstanding test


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5.4 Residual voltage test 5.4.1.1 Withstanding voltage test

• The measurement is performed on disconnected machine’s supply pins • There are different limit times for fixed connected machines and machines with

plug / socket connections.

Fig. 6: Residual voltage


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5.5 Functional tests In its simplest form a functional check is simply a check to ensure that the machine is working properly.

Fig. 7: Functional test


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Guidline Machines ANG

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