Testing PRCD-S and Portable Personal Protection Switches: Correctly Testing Protective Conductor Monitoring and Tripping Function

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A portable personal protection switch can be switched on.

The status indicator shows:

Ready for operation

and when the test button is pressed, the device switches off.

Does this mean the PRCD-S has been fully tested?

No.

Compared with a simple residual current device, a PRCD-S has additional protection and monitoring functions. For this reason, simply pressing the test button is not sufficient during a periodic inspection.

Depending on the design and manufacturer, the following must be evaluated, among other things:

• protective conductor connection,
• insulation resistance,
• protective conductor current,
• touch current,
• residual current tripping,
• tripping time,
• protective conductor monitoring,
• undervoltage tripping,
• detection of conductor interruptions,
• detection of conductor reversal,
• where applicable, detection of external voltage on the protective conductor.

Particularly important:

A PRCD-S is not simply “an RCD in a cable”. Its extended safety functions must be taken into account during testing.

The current DGUV Information 203-070 therefore explicitly treats portable residual current devices as special electrical equipment and points out that the test procedure and measurement methods must be adapted to the specific PRCD design.

Suitable test instruments can be found at ICS Schneider under Electrical Measuring and Testing Instruments and specifically under Equipment Testing / VDE Test Instruments.

What is a PRCD-S?

PRCD stands for:

Portable Residual Current Device

meaning a:

portable residual current device

A PRCD-S provides an extended range of protection

It combines residual current protection with additional monitoring functions for the power supply.

Typical areas of application include

• construction and assembly sites,
• service and maintenance work,
• portable electrical equipment,
• temporary power supplies,
• workplaces where an existing socket outlet must be used and its protective measures cannot readily be assessed.

The PRCD-S is typically located

between:

existing socket outlet → PRCD-S → electrical equipment

Its purpose is not only

to detect a residual current.

Depending on the design, it must additionally evaluate whether certain safety-relevant conditions of the supply are fulfilled.

Distinguishing PRCD, PRCD-S and stationary RCDs

These terms are often confused in practice.

Stationary RCD

A stationary residual current device forms part of the fixed electrical installation.

PRCD

A PRCD, by contrast, is a portable residual current device.

PRCD-S

The additional designation:

S = Safety

denotes a version with an extended range of protection.

DGUV Information 203-070 therefore explicitly distinguishes

between:

• RCD,
• PRCD,
• PRCD-S,
• PRCD-K.

For testing practice, this means

The test procedure for a simple RCD must not automatically be applied to every PRCD-S.

The internal design can differ significantly due to, for example:

• a switched protective conductor,
• undervoltage tripping,
• additional protective conductor monitoring,
• internal electronics

.

Which protective functions does a PRCD-S provide?

Depending on the device version, the essential functions of a PRCD-S include:

• residual current protection,
• monitoring of the supply voltage,
• monitoring of the protective conductor,
• detection of a protective conductor interruption,
• detection of dangerous voltage on the protective conductor,
• maintenance of the protective conductor function under certain external-voltage conditions,
• neutral conductor monitoring, where applicable,
• detection of conductor reversal, where applicable,
• undervoltage tripping.

The device therefore monitors not only

the residual current of the connected load

but also certain properties of the:

supply side

This is precisely why

additional testing is required.

Why is the test button not sufficient?

Almost every residual current device has a test button.

When it is pressed

an internal condition is generated that is intended to cause the residual current device to trip.

This makes it possible in principle to determine

whether:

the mechanical or internal tripping function responds in principle

However, the test button does not fully determine

• at which actual residual current the PRCD trips,
• how quickly it trips,
• whether the protective conductor is electrically connected correctly,
• whether protective conductor monitoring functions correctly,
• whether conductor faults are detected,
• whether undervoltage tripping functions correctly,
• whether insulation and leakage-current values are permissible.

Therefore

Test button = functional check, but not a complete safety test.

Which testing basis is relevant?

For periodic testing of portable electrical equipment, the following is particularly relevant:

DIN EN 50699 (VDE 0702)

For practical implementation

the current:

DGUV Information 203-070

contains comprehensive guidance.

The April 2026 edition

explicitly addresses PRCDs in a dedicated section.

It emphasizes

that due to the different technical designs, the test person must be familiar with:

• the operating principle,
• the required test procedures,
• manufacturer information

.

This is an important point

The manufacturer of the specific PRCD-S may specify additional tests or special measuring methods. A universal test procedure for every design available on the market is therefore not appropriate.

1. Visual inspection: Checking the mechanical condition

As with other portable electrical equipment, testing begins with a careful visual inspection.

The following should be checked, among other things

• housing,
• mains plug,
• coupler or socket outlets,
• connecting cable,
• strain reliefs,
• bend protection sleeves,
• protective contacts,
• controls,
• test button,
• status indicators,
• markings.

Particularly critical are

• crushed cables,
• damaged outer sheaths,
• visible conductors,
• burnt contacts,
• loose plug contacts,
• broken housing parts,
• moisture ingress,
• heavy contamination.

When used on construction sites

the mechanical stress is often significantly higher than with typical office equipment.

For this reason, the visual inspection alone can

identify a safety-relevant defect before any electrical measurement is carried out.

2. Correctly measuring protective conductor resistance

The protective conductor is a central safety function of the PRCD-S.

In principle, the test is intended to determine

whether a sufficiently low-resistance and reliable connection exists between the intended protective conductor contacts.

With a simple extension lead

the principle is relatively straightforward:

PE input → cable → PE output

With a PRCD-S, it can be more complicated

because, depending on the design, the protective conductor:

• is switched,
• is routed through monitoring components,
• may only be connected through when mains voltage is present.

Therefore

a resistance measurement on a switched-off PRCD-S may appear to indicate an:

interrupted protective conductor

even though this is a consequence of the design.

The decisive question is therefore

Under which operating conditions is the PE connected through in this PRCD-S?

In this case

the device instructions, manufacturer information and the appropriate test procedure are decisive.

Why the switched protective conductor is a special feature

A switched protective conductor may initially seem unusual.

In a PRCD-S

it forms part of the additional safety logic.

DGUV Information 203-070 explicitly points out

that with a PRCD-S, the protective conductor may only be connected through when mains voltage is present.

For the test person, this means

a simple:

Connect an ohmmeter to input and output

is not necessarily sufficient.

A suitable test instrument or designated test adapter

must take the actual operating state of the PRCD-S into account.

Important

An apparently “open PE” must not be prematurely assessed as a defect if the protective conductor switching is structurally dependent on the mains supply and the internal safety check.

3. Testing insulation resistance on the input and output sides

With a normal extension lead, the entire current path is directly accessible.

With a PRCD-S, however

the device contains:

• switch contacts,
• monitoring circuits,
• electronic components

internally.

Current DGUV Information 203-070 therefore specifies for PRCDs

an insulation resistance measurement:

on the input side and output side

This is particularly important

if the PRCD-S disconnects certain conductors when switched off.

If testing were performed from only one side

part of the internal or downstream insulation might not be fully included in the measurement.

Another special feature

Internal components used to monitor safety functions can influence the measured insulation resistance.

If a measured value is unexpectedly low

this should therefore not immediately be interpreted as an insulation fault.

Instead, the following must be taken into account

• manufacturer specifications,
• permissible test voltage,
• internal circuitry,
• specified measuring method

.

4. Testing protective conductor current and touch current

For a complete assessment, active current measurements may also be required.

DGUV Information 203-070 specifies for this purpose

• protective conductor current,
• touch current.

Depending on the equipment under test, these measurements can be performed using the

direct method

or:

differential current method

A special feature of the PRCD-S

is:

For this active measurement, the PRCD-S must be switched on.

For conductive housing parts

that are not connected to the protective conductor, an additional touch-current measurement may be required.

This makes it clear

that a purely passive resistance measurement does not fully describe the condition of a PRCD-S.

5. Correctly evaluating the test button

The test button is nevertheless part of the test procedure.

It is used for functional testing

of the integrated residual current device.

When operated

the intended disconnection must occur.

A problem exists

if, for example:

• the PRCD does not trip,
• the button is mechanically damaged,
• tripping occurs only intermittently,
• the device cannot subsequently be reset correctly.

However, even if tripping is successful

Test button passed ≠ complete PRCD-S test passed

6. Measuring residual current tripping

The actual tripping function must be checked using a suitable test instrument.

A defined residual current is generated

and it is determined:

• whether the PRCD trips,
• at which test current it trips,
• how long the disconnection takes.

The rated residual operating current

of the specific device is decisive.

Typical values may be, for example

IΔn = 10 mA

or:

IΔn = 30 mA

The test current must therefore

match the:

rating of the PRCD

A test using any arbitrary residual current

does not provide a reliable statement about the correct protective function.

Correctly interpreting tripping time

In addition to the tripping current, the:

disconnection time

is important.

For PRCD testing, DGUV Information 203-070 points out

that actual disconnection times should normally be significantly below:

0,3 s

However, this value should not be considered in isolation

The assessment must be based on:

• device type,
• rated residual operating current,
• manufacturer specifications,
• applicable technical rules

.

A test instrument should therefore

not only indicate:

Tripped / Not tripped

but, where possible, also document the:

measured tripping time

7. Testing protective conductor monitoring

Protective conductor monitoring is one of the key additional functions of a PRCD-S.

Depending on its design, the device should be capable of detecting

if, for example:

no proper protective conductor is present

This function is particularly relevant

when portable electrical equipment is connected to existing socket outlets whose condition is not fully known before use.

A complete test must therefore

assess more than just the continuity of the PE.

Where applicable, it must also be tested

whether the:

monitoring function responds correctly to a simulated fault

However

improvised and dangerous mains wiring must not be used for this purpose.

Suitable methods include

designated:

• test adapters,
• test circuits,
• PRCD test programs of a suitable appliance tester.

8. Considering external voltage on the protective conductor

Another special protective function of certain PRCD-S designs is the detection of:

dangerous external voltage on the protective conductor

This function is particularly important for electrical safety

because a live protective conductor can cause:

accessible conductive housing parts to carry dangerous voltage

DGUV Information 203-070 points out

that manufacturers of PRCD-S devices may specify additional test methods for checking this function.

Fault simulation

can be carried out, for example, using:

• a suitable mains adapter,
• touch-safe test sockets,
• specially designed switching devices

.

Important

External-voltage detection must not be tested by arbitrarily applying a dangerous voltage to an exposed protective conductor contact.

9. Testing undervoltage tripping

Many PRCD-S devices have an undervoltage trip function.

This ensures

that the device switches off in the event of certain supply interruptions or voltage conditions.

Depending on the design

manual:

reconnection

may then be required.

This is intended, for example, to prevent

connected equipment from unexpectedly being re-energized automatically when the supply voltage returns.

During testing, it must therefore be checked

whether the manufacturer-specified:

undervoltage and restart function

operates correctly.

10. Testing conductor interruption and conductor reversal

Depending on the PRCD-S type, additional fault conditions may be monitored.

These include, for example

• protective conductor interruption,
• neutral conductor interruption,
• conductor reversal.

The current DGUV Information explicitly mentions

the testing or functional verification of such additional safety functions.

However, whether and which of these functions are present

must be checked for the specific device.

Therefore

Not every PRCD-S may be assessed using a blanket list of identical fault conditions. Manufacturer specifications and device design are decisive.

Fault simulation only with a suitable test setup

Testing protective conductor monitoring sometimes requires simulation of a faulty supply condition.

Such tests must not

be carried out by improvising changes to the wiring of a normal mains socket.

Instead, a test setup should be used

that:

• is designed for the respective test task,
• has touch-safe connections,
• generates defined fault conditions,
• does not unnecessarily endanger the test person,
• is suitable for the specific PRCD version.

Particularly practical

is an appliance tester in which:

PRCD-S test procedures

are already provided.

This makes

• test sequence,
• connection,
• measurement,
• evaluation,
• documentation

significantly more reproducible.

Distinguishing functional checks before use from formal periodic testing

Two procedures should not be confused.

Check before use

The user checks, for example:

• housing,
• cable,
• plug,
• correct switching-on function,
• test button, where applicable.

Periodic testing

The recurring electrical safety test is considerably more comprehensive.

Depending on the design, it includes

• visual inspection,
• measurement,
• functional testing,
• evaluation,
• documentation.

Therefore

Functional check before use ≠ periodic electrical safety test

Both measures

serve different purposes and complement each other.

PRCD-S on mobile distribution units and extension leads

In practice, a PRCD-S is often not present as an individual component on the test bench.

It may form part of

• extension leads,
• mobile power distribution units,
• machine connection cables,
• construction-site distribution systems,
• service equipment.

In this case, the test

must take the entire relevant unit into account.

For an extension lead, for example

the following are additionally relevant:

• condition of the cable,
• protective conductor resistance,
• insulation condition,
• plug and coupling wiring,
• wiring test, where applicable.

The PRCD-S function is an additional requirement

and does not replace these tests.

For this reason, an appliance tester with

cable testing + PRCD testing

is particularly useful in such applications.

What must a test instrument for PRCD-S be capable of?

A universal appliance tester can perform numerous electrical safety tests.

However, this does not automatically mean

that it can also:

fully test a PRCD-S

When selecting a test instrument, it should therefore be specifically checked

whether the instrument or corresponding option supports the required PRCD design.

Useful functions include, for example

• protective conductor resistance measurement,
• insulation resistance measurement,
• active leakage-current measurement,
• RCD/PRCD tripping test,
• measurement of tripping time,
• PRCD-S-specific test sequence,
• wiring test,
• automatic test steps,
• pass/fail evaluation,
• measured-value memory,
• equipment-under-test database,
• test reporting.

Automatic test procedures are particularly useful

when larger quantities of equipment have to be tested.

They reduce the risk

that, for example:

• a partial test is forgotten,
• an incorrect test current is selected,
• measured values are assigned to the wrong item under test.

Correctly documenting test results

An electrical safety test does not end with:

Device works

Traceable documentation should at least show

• clear identification of the item under test,
• PRCD type or design,
• manufacturer and type designation,
• test date,
• test person,
• test instrument used,
• result of the visual inspection,
• relevant measured values,
• tripping behavior,
• result of additional safety functions,
• overall assessment.

For the RCD function

for example, it is useful to store not only:

PASSED

but also:

• rated residual operating current,
• test current used,
• measured tripping time.

In the event of a fault

it should also be clearly documented:

which protective function does not operate correctly

This is considerably more informative than

PRCD defective

Recommended test procedure for PRCD-S

1. Clearly identify the item under test: Record manufacturer, type, rated current and rated residual operating current.
2. Check the device documentation: Take the manufacturer’s instructions and any special testing requirements into account.
3. Determine the design: Do not confuse PRCD, PRCD-S, PRCD-S+ and PRCD-K.
4. Perform a visual inspection: Check housing, connecting cable, plug, coupling, strain relief, controls and markings.
5. Check the test instrument: Select a suitable appliance tester, adapter and correct test function.
6. Assess the protective conductor path: Check whether the PE is switched by design.
7. Measure protective conductor resistance: Perform the measurement according to the PRCD design and manufacturer specifications.
8. Test insulation resistance on the input side: Take the specified test voltage and internal electronics into account.
9. Test insulation resistance on the output side: Also take into account the section disconnected by the switch contacts.
10. Switch on the PRCD-S: Establish the specified operating state for active measurements.
11. Test protective conductor current: Use an appropriate active measurement method.
12. Test touch current: Where required by the design.
13. Press the test button: Check the basic tripping function.
14. Set the rated residual operating current: Select test parameters to match the specific PRCD.
15. Perform the tripping test: Check the effectiveness of residual-current disconnection.
16. Record the tripping time: Evaluate the measured value against the applicable requirements.
17. Test undervoltage tripping: If this function is present.
18. Test protective conductor monitoring: Use the designated test sequence or test adapter.
19. Test conductor interruption: Where supported by the instrument and specified by the manufacturer.
20. Test conductor reversal: Only with a suitable safe test setup.
21. Test external-voltage detection: If the manufacturer specifies such a test.
22. Test restart behavior: If this forms part of the specific PRCD function.
23. Evaluate the overall result: Assess all protective functions together.
24. Store measured values: Do not document only the pass/fail status.
25. Create a test report: Clearly assign the test to the item under test.

Typical errors when testing PRCD-S

Observation	Possible cause	Recommended check
PRCD-S cannot be switched on	Supply fault, protective conductor problem or internal fault	Check the supply and intended protective functions using a suitable test setup
Protective conductor appears interrupted during passive resistance measurement	PE is switched within the PRCD-S	Take manufacturer specifications and intended operating state into account
Test button works, but tripping test does not	RCD function outside permissible characteristics or unsuitable test setup	Check rated residual operating current and tripping test
PRCD trips, but tripping time is unusual	Ageing, internal fault or unsuitable test parameters	Measure tripping time reproducibly and check manufacturer specifications
Insulation value is unexpectedly low	Internal monitoring electronics influence the measurement	Check manufacturer requirements and permissible test voltage
Input side is normal, output side shows a fault	Insulation fault downstream of the internal switch contacts	Evaluate input and output sides separately
Protective conductor resistance fluctuates	Cable damage, contact problem or damaged plug connection	Move the cable and inspect the plug contacts
PRCD-S does not respond as expected to simulated PE fault	Protective conductor monitoring faulty or incorrect test procedure	Use the manufacturer-specific PRCD-S test sequence
Undervoltage does not result in the expected state	Undervoltage trip faulty or design implemented differently	Compare device function with manufacturer documentation
Device switches on unexpectedly after voltage returns	Restart function or device design must be checked	Verify the intended behavior of the specific PRCD-S
Testing produces different results with different test persons	Manual test steps or different test parameters	Use a standardized automatic test procedure
Measured values are available, but there is no clear statement about PE monitoring	Only conventional appliance testing was carried out	Test the PRCD-S-specific additional functions separately

Practical example: testing a PRCD-S in a mobile construction-site power supply

A mobile connection lead with integrated PRCD-S is regularly used on various construction sites.

Device data

Rated residual operating current:

IΔn = 30 mA

Task

Periodic testing of the complete unit including:

• cable,
• plug,
• PRCD-S,
• protective conductor function.

Step 1: Visual inspection

The cable has no visible damage.

Plug, housing and strain reliefs are mechanically intact.

Step 2: Identify the design

It is determined that the device is a:

PRCD-S with extended range of protection

Step 3: Protective conductor test

The test procedure takes into account that the protective conductor is switched within the PRCD-S.

The measurement is therefore performed in the test state specified for this design.

Step 4: Insulation

The input and output sides are checked in accordance with the specified test procedure.

Step 5: Active measurements

The PRCD-S is switched on and the required protective conductor current and/or touch current measurements are performed.

Step 6: Test button

The integrated test device trips the PRCD-S.

Step 7: RCD test

Using the test procedure appropriate for:

IΔn = 30 mA

the tripping function and tripping time are measured.

Step 8: Additional functions

Using the designated test adapter, the functions relevant to the specific design are tested, including:

• protective conductor monitoring functions,
• conductor faults,
• undervoltage function

.

Step 9: Documentation

The following are stored:

• item-under-test ID,
• measured values,
• tripping time,
• result of the additional protective functions,
• overall assessment.

Result

Only the combination of conventional appliance testing, an actual RCD tripping test and verification of the additional PRCD-S safety functions enables a reliable assessment.

Suitable ICS products for testing PRCD-S

MultiTest HT700 – RCD DGUV Regulation 3 Tester

Particularly suitable for the task described here is the:

MultiTest HT700 – RCD

offered by ICS.

ICS explicitly specifies

• testing of portable personal protection switches, 2- and 3-pole PRCDs,
• PRCD type S,
• PRCD type S+,
• PRCD type K,
• testing of RCD types AC, A, F, B and B+,
• automatic and manual test sequences,
• standard, extended and customer-specific visual inspections,
• database management of customers and equipment,
• individual test sequences and test intervals,
• clear pass/fail evaluation,
• data storage via SD card.

Particularly relevant for PRCD-S testing

is the fact that the instrument does not merely offer general RCD measurements, but is explicitly specified by ICS for:

PRCD S / S+ / K

This makes the MultiTest HT700 – RCD particularly suitable

for testing organizations that regularly need to test and document:

• portable personal protection switches,
• extension leads,
• electrical equipment

.

C.A 6108 Appliance Tester

Another solution available from ICS is the:

C.A 6108 Appliance Tester

ICS specifies, among other things

• protective conductor resistance measurement with 200 mA and 10 A test current,
• testing of extension leads,
• RCD type A/B for corresponding applications,
• PRCD, PRCD-S and PRCD-K as an option,
• automatic test sequence with plain-text instructions,
• connection pictograms,
• pass/fail indication via LEDs,
• functional test with power measurement,
• memory for up to 100.000 measurements,
• data exchange via USB,
• database software.

This makes the C.A 6108 particularly interesting

when:

conventional appliance testing + cable testing + optional PRCD testing

are to be combined in a single instrument.

HT-Power 0701/0702 3P CL

For comprehensive single- and three-phase testing tasks, ICS also offers the:

HT-Power 0701/0702 3P CL

The system offers, among other things

• testing of Schuko and CEE equipment,
• wiring test for extension leads,
• automatic and manual test sequences,
• testing of the mains connection for phase sequence and PE,
• active power measurement,
• equipment-under-test memory.

For RCD or PRCD applications

a corresponding:

RCD test option

is available.

Which solution is suitable?

Application	Suitable ICS solution
Targeted testing of PRCD type S, S+ and K	MultiTest HT700 – RCD
Appliance and extension-lead testing with optional PRCD-S testing	C.A 6108
Comprehensive testing of single- and three-phase equipment with RCD/PRCD option	HT-Power 0701/0702 3P CL with corresponding RCD option
Testing with structured automatic sequences and comprehensive documentation	MultiTest HT700 – RCD or C.A 6108 depending on the specific test task

Additional solutions can be found under Electrical Measuring and Testing Instruments at ICS Schneider and under Equipment Testing / VDE Test Instruments.

Conclusion

A PRCD-S is considerably more than a portable residual current device.

It combines

residual current protection + monitoring of additional safety-relevant mains conditions

This is why simply pressing the test button is not sufficient

A complete periodic test must take additional characteristics into account depending on the design and manufacturer.

The protective conductor is particularly important

In a PRCD-S, it may be switched by design and integrated into additional monitoring circuits.

For this reason, protective conductor testing must also

be adapted to the specific device function.

Insulation measurement also has a special feature

Depending on the PRCD design:

input side + output side

must be taken into account.

The RCD function must be measured in practice

In addition to the test button, the following must be evaluated:

• rated residual operating current,
• tripping,
• tripping time

.

Additional PRCD-S functions must be tested

Depending on the version, these may include:

• protective conductor monitoring,
• undervoltage tripping,
• conductor interruption,
• conductor reversal,
• detection of external voltage on the protective conductor.

A suitable test instrument simplifies this procedure considerably

The MultiTest HT700 – RCD is explicitly offered by ICS for PRCD types S, S+ and K.

The C.A 6108 supports PRCD, PRCD-S and PRCD-K with the corresponding option.

For practical applications

Identify the PRCD type → check manufacturer documentation → perform a visual inspection → take the protective conductor design into account → measure protective conductor resistance → test insulation on the input and output sides → switch on the PRCD → measure protective conductor current and, where applicable, touch current → test the test button → set the rated residual operating current → measure tripping function and tripping time → test additional protective conductor and mains monitoring functions using a suitable test setup → check restart behavior → document all measured values → perform an overall assessment.

FAQ: Correctly Testing PRCD-S and Portable Personal Protection Switches

What does PRCD mean?

PRCD stands for Portable Residual Current Device and refers to a portable residual current device.

What does PRCD-S mean?

PRCD-S refers to a portable residual current device with an extended range of protection.

Is a PRCD-S the same as a normal RCD?

No. In addition to the residual current function, a PRCD-S has additional monitoring functions, particularly relating to the supply and protective conductor.

What does a PRCD-S monitor?

Depending on the design, among other things residual current, supply voltage, protective conductor condition, protective conductor interruption and possible dangerous voltage on the protective conductor.

Where are PRCD-S devices used?

Typical areas of application include construction and assembly sites, service work, maintenance work and mobile power supplies.

Is the test button sufficient for testing a PRCD-S?

No. The test button is only one part of the functional test. A complete periodic test includes additional measurements and functional verification of additional protective functions.

Does the protective conductor resistance have to be tested?

Yes. However, it must be taken into account whether the protective conductor is switched within the specific PRCD-S.

Why does a switched-off PRCD-S sometimes show no PE continuity?

With certain designs, the protective conductor is only connected through when mains voltage is present and after a successful internal safety check.

Does missing PE continuity on a switched-off PRCD-S automatically indicate a defect?

No. It must first be checked how the protective conductor is designed and switched in the specific device version.

Does the insulation resistance of a PRCD-S have to be tested?

Yes. DGUV Information 203-070 describes testing on both the input and output sides for PRCDs.

Why must insulation be tested on both sides?

Internal switch contacts may disconnect parts of the current path when switched off. A one-sided measurement might therefore fail to include all relevant sections.

Can internal electronic components influence insulation measurement?

Yes. For this reason, manufacturer specifications and the permissible test voltage must be taken into account if unusual measured values occur.

Does the PRCD-S have to be switched on for leakage-current measurements?

For the active protective conductor current and touch-current measurements described by the DGUV, the PRCD-S must be switched on.

What is measured during the RCD tripping test?

The test checks whether the PRCD switches off at a defined residual current and determines the tripping time.

Which test current must be used?

The test current must match the rated residual operating current of the specific PRCD, for example 10 mA or 30 mA.

How quickly must a PRCD trip?

The assessment depends on the device, ratings, manufacturer specifications and applicable rules. DGUV Information 203-070 points out that actual disconnection times should normally be significantly below 0,3 seconds.

What is protective conductor monitoring in a PRCD-S?

It is used to detect certain faults in the protective conductor or supply and, depending on the device version, to prevent switching on or to respond accordingly.

What does external voltage on the protective conductor mean?

This means an unwanted dangerous voltage on the PE that could, for example, cause accessible conductive housing parts to become hazardous.

Does external-voltage detection have to be tested?

If this function is present and the manufacturer specifies a corresponding test, it should be functionally checked as part of the intended test procedure.

May I manipulate the protective conductor of a normal socket outlet for this purpose?

No. Such fault simulations should only be performed using designated safe test adapters or test equipment by an appropriately qualified test person.

What is undervoltage tripping?

Depending on the device design, it ensures that the PRCD switches off if the supply voltage is lost or drops below an impermissible level.

Why is restart protection useful?

It prevents connected equipment from unintentionally being automatically re-energized when the supply voltage returns.

Does a PRCD-S have to detect conductor interruptions?

This depends on the specific design. The available safety functions must be determined from the manufacturer information and tested accordingly.

Can a PRCD-S detect conductor reversal?

Depending on the version, corresponding monitoring functions may be present.

Who is permitted to carry out a periodic test?

The test must be carried out and professionally evaluated by a person who is appropriately qualified or competent for the specific testing task.

What is the difference between a functional check and a periodic test?

A functional check before use serves as an immediate operational check. A periodic test, by contrast, includes systematic visual inspection, measurement, functional testing, evaluation and documentation.

Does a PRCD-S still have to be tested if the test button is operated regularly?

Yes. Regular operation of the test button does not replace the complete periodic test.

Which ICS test instrument is particularly suitable for PRCD-S?

The MultiTest HT700 – RCD is particularly suitable because ICS explicitly specifies testing of PRCD types S, S+ and K.

Which PRCD types can the MultiTest HT700 – RCD test?

ICS specifies portable 2- and 3-pole PRCD personal protection switches as well as types S, S+ and K.

Can the MultiTest HT700 – RCD also test standard RCDs?

Yes. ICS specifies RCD types AC, A, F, B and B+.

Does the C.A 6108 support PRCD-S?

Yes. ICS lists testing of PRCD, PRCD-S and PRCD-K as an option.

What else does the C.A 6108 measure?

Among other things, protective conductor resistance, electrical safety values, extension leads and the function or power of the equipment under test.

Why are automatic test sequences useful?

They help to carry out the intended test steps in a reproducible sequence and reduce the risk of individual tests being omitted.

What should be included in the test report?

At minimum, identification of the item under test, test date, test person, test instrument used, visual inspection, relevant measured values, tripping test, additional protective functions and overall assessment.

Should only Pass or Fail be stored?

No. Wherever possible, the underlying measured values such as tripping time, test current and resistance values should also be documented.

Where can I find the MultiTest HT700 – RCD at ICS Schneider?

Further information can be found under MultiTest HT700 – RCD at ICS Schneider.

Where can I find the C.A 6108 at ICS Schneider?

Further information can be found under C.A 6108 Appliance Tester at ICS Schneider.

Where can I find the HT-Power 0701/0702 3P CL at ICS Schneider?

Further information can be found under HT-Power 0701/0702 3P CL at ICS Schneider.

Where can I find additional electrical measuring and testing instruments at ICS Schneider?

An overview can be found under Electrical Measuring and Testing Instruments at ICS Schneider.