CHECKING AND TESTING ELECTRICAL INSTALLING WORK · CHECKING AND TESTING ELECTRICAL INSTALLING WORK Preface It is a requirement of the Electricity ... Test 1: Obtain the resistance

Energy SafetyDepartment of Consumer and Employment Protection

CHECKINGAND TESTINGELECTRICALINSTALLING

WORK

CHECKING AND TESTING ELECTRICAL INSTALLING WORK

PrefaceIt is a requirement of the Electricity (Licensing) Regulations 1991 that allelectrical installing work carried out in Western Australia complies with therelevant standards, including Australian/New Zealand Standard AS/NZS 3000(known as the Wiring Rules) and the WA Electrical Requirements.

The application of minimum electrical requirements and Standards is essentialfor the safety of persons, livestock and property.

A clear understanding of these requirements is essential for those involved withelectrical installing work carried out in Western Australia.

All completed electrical work must be checked and tested by a licensedelectrician before the electrical contractor certifies the work to the relevant supplyauthority.

This booklet has been produced as a guide to meet the checking and testingrequirements for electrical installing work, as specified in the Wiring Rules. Whilstthe details are focussed on domestic electrical installations, the principles applyto all electrical installing work.

The testing methods in this booklet are not exclusive. Other test methods may beused provided that they meet the minimum requirements of the Wiring Rules.

More detailed testing information is contained in the Australian/New ZealandStandard AS/NZS 3017 Electrical installations - Testing and inspectionguidelines.



Table of ContentsChecking, Testing and Certification of Electrical Installing Work 1

Installation Test Certificate 2

Checking and Testing 4

Checking and Testing Procedure 5

1. Visual Inspection 5

2. Earth Resistance and Continuity Tests 5

Test Equipment 6

Test Procedure 7

3. Insulation Resistance Test 8

Test Equipment 8

Test Procedure 8

4. Polarity/Functional Test 10

Test Equipment 10

Test Procedure 10

5. Correct Circuit Connections 11

6. Fault-loop Impedance Test 11

Test Equipment 11

Test Procedure 11

7. Verification of RCD 12

Testing Alterations and Additions 12

Test Equipment 13

Table 1 - Maximum resistance values of final subcircuit 14protective earthing conductor

Table 2 - Comparison of voltage drop and fault-loop 15impedance to determine circuit maximum distance.

Further Information 16

Notes 17


IV


Checking, Testing and Certification ofElectrical Installing WorkAll completed electrical installing work must be checked and tested to confirmthat it complies with the Wiring Rules and is safe for connection to the electricitysupply. The required steps to comply with the current regulatory requirements areas follows:

1. When the electrical installing work has been completed, a licensed electrician(which may be the contractor or an employee) is required to carry out checksand tests of the installation, to ensure the electrical work meets therequirements of the Wiring Rules. The checking and testing should be carriedout in accordance with a formalised checking and testing procedure.

2. Once these checks and tests have been completed, the electrician confirmson the relevant section of the Notice of Completion or Notice of Completion-Minor Work, that the checking and testing has been carried out.

3. For electrical installing work that requires the supply authority to attend (eg. for electricity supply connection or alteration to the supply serviceapparatus), the electrician then completes an Installation Test Certificate andfixes it inside the meter enclosure of the installation.

4. Then, in the usual manner, the electrical contractor (or nominee) completesthe Notice of Completion, thereby certifying the work, and submits the Noticeto the supply authority.

5. When the Notice of Completion is received, the supply authority willdetermine if an inspection of the installing work will be carried out, to ensurethat the standards of electrical safety of the installation are being maintained.The supply authority will also arrange for the connection of the electricitysupply if necessary.

Notes

1. Minor work, ie. alterations and additions to existing electrical installations, isalso subject to a similar system except that the work is connected to theelectricity supply by the electrician.

2. Western Power’s Contractor Connect Scheme permits accredited electricalcontractors and authorised electrical workers to connect the electricity supplyto the installation and to then submit the Notice of Completion followingconnection.

1


Installation Test CertificateWhen a Notice of Completion is to be submitted for completed electrical installingwork that may require the supply authority to attend (eg. new connection orupgrade of supply), the electrician carrying out the checking and testing mustcomplete an Installation Test Certificate.

An Installation Test Certificate is an adhesive label (included in books ofPreliminary Notices/Notices of Completion and also available from supplyauthorities) that must be filled in by the electrician who performed the checkingand testing of the completed electrical installing work.

An Installation Test Certificate is to be fixed by the electrician to the inside of themeter enclosure to indicate to the supply authority and the customer that theinstallation is completed, has been checked and tested and is safe to beconnected to the electricity supply.

The electrician is requested to record the following key installation test resultsand the underground consumer’s mains cable route on a self adhesive labelwhich is also to be placed inside the meter enclosure:

• main earth conductor resistance;

• either the earth continuity or fault-loop impedance values for each sub circuit;and

• insulation resistance values for each sub circuit.

The information will benefit subsequent electrical work and inspection, as well asassist in preventing electric shocks and accidents.

2

3


INSTALLATION TESTCERTIFICATE

Installation Address: _________________________

I confirm that I have carried out the checks and testsof this electrical installation, as required by Electricity(Licensing) Regulations 1991.

Signature of “A Grade” Electrical mechanic

Date E.W. Licence No

This work has been carried out for and on behalf of:Electrical contractor’s name and licence No.

Note 1. The Electrical Mechanic is responsible forthe issue of this Test Certificate.

2. This Test Certificate is to be fixed to theinside of the meter enclosure.

DON’T MEDDLE WITH ELECTRICITY -ALWAYS USE A LICENSED ELECTRICAL CONTRACTOR


Checking and TestingOn completion of the electrical work and before the electricity supply isconnected and energised, the electrical contractor is responsible to ensure that:

• the electrical work has been carried out in accordance with the Electricity(Licensing) Regulations 1991; and

• the installation has been checked and tested and is safe for connection to theelectricity supply.

To achieve this, the following minimum checks and tests should be carried out bythe electrician:

1. Visual Inspection - should be carried out whilst referring to a plan (to ensurea systematic check to pick up any omissions and to verify that the workcomplies with the requirements of the applicable standards).

2. Earth Resistance and Continuity Tests - this test is to include the mainearthing conductor, protective earth conductor and bonding conductor.

3. Insulation Resistance Test - this test is necessary to ensure that theinsulation resistance between live parts/conductors and earth is adequate.

4. Polarity Test - used to ensure correct connection of active, neutral andearthing conductors.

5. Correct circuit connections - this test checks earthing conductors do not carrycurrent during normal operation and no short circuit exists.

6. Fault Loop Impedance - measures the fault loop impedance of each circuit toverify the protective device will operate.

7. Verification of RCD (residual current device) operation - testing of RCDs iscarried out to ensure that the RCD operates.

4


Checking and Testing ProcedureThe following procedure will meet the key checking and testingrequirements. Ensure that test results are recorded carefully. Other testingprocedures may be used, provided that they meet the minimumrequirements of the Wiring Rules.

It is also recommended that the tests be carried out whilst there is noelectricity supply connected (except for the Fault Loop Impedanceverification or the RCD operation test) to the installation, or, in the case ofalterations to an existing installation, that the circuits to be tested havebeen isolated from the electricity supply and have been securely taggedand where possible padlocked.

1. Visual Inspection

A visual inspection is carried out to ensure that all work has been correctlycompleted, by checking that:

• all cables and equipment have been correctly installed and terminated, and

• the installation complies with the relevant parts of the Wiring Rules and theWA Electrical Requirements.

2. Earth Resistance and Continuity Tests

Earth resistance tests are required to confirm the installed earthing system willcause circuit protective devices to operate and maintain cable integrity if there isa fault between live parts and exposed conductive parts.

Earthing System Impedance

The resistance from any point of the electrical installation required to be earthed,to the point where the main earthing conductor is connected to the neutralconductor (MEN connection) of the supply system, shall be low enough to permitthe passage of current necessary to operate the circuit protective devices. Toconfirm this value (which is dependent upon the type and rating of the protectivedevice and the fault-loop impedance of the associated conductors) requires thefollowing test to be performed:

Test 1: Obtain the resistance value of the protective earthing conductor using aquality ohm meter (see next page for procedure) and compare this valuewith the maximum allowable resistance as tabulated in Table 1, page 14of this booklet.

5


Or, where the electricity supply IS connected:

Test 2: Obtain the fault-loop impedance of each sub circuit using a quality fault-loop impedance meter (refer to manufacturer’s instructions and page 11of this booklet for procedure). Compare the measured fault-loopimpedance value with the maximum value provided at Appendix B, Table B4.1 of the Wiring Rules.

Notes:

1 If the application of a fault-loop impedance test onto an RCDprotected sub circuit results in the RCD operating, then:• the earth resistance and continuity test requirements are

considered to be satisfied; and• the fault-loop impedance value need not be considered further.

2 If the value measured is GREATER than the allowable maximum,then the following steps must be performed:Test 2.1 Check the MEN connection, active, neutral and earth

conductor/equipment connections are all solidly made.Repeat the fault-loop impedance test 2, above.If the fault-loop impedance values exceed the requirementsof Table B4.1, then perform Test 2.2

Test 2.2 Perform the earth continuity measurement, Test 1 andconfirm results.

Repeat the fault-loop impedance Test 2, above. If the fault-loopimpedance values do not satisfy the requirements of Table B4.1then you must contact the supply authority advising them of thediscrepancy.

Main Earthing Conductor

The resistance from the earthing electrode to the point where the main earthingconductor is connected to the neutral conductor of the supply system shall notexceed 0.5 ohms.

Test Equipment

• A multimeter set to ohms.

• Insulated copper conductor of suitable length (long lead).

6


Test Procedure

Preparation:

1. Ensure that the electricity supply has been disconnected.

2. Connect an insulated copper conductor of suitable length (long lead) to oneterminal of the ohm meter.

3. Connect a standard length test lead to the other terminal of the ohm meter(short lead).

4. Connect the two leads together, and

• zero the multimeter or, if this is not possible,

• record the resistance of the test leads.

5. Disconnect the water pipe equipotential bonding conductor and the waterheater earthing conductor (if applicable).Care must be taken that there are no parallel earth paths whenconducting this test, ie. the earthing system must not be connected toeither the water or gas pipes.

6. Disconnect the MEN link from the main neutral link and connect it to the longlead (ie. long lead now connected to the earth bar).

A: Main Earthing Conductor

• Connect the short lead to the earth electrode and measure the earthresistance of the main earthing conductor.

• The resistance shall not exceed 0.5 ohms for the main earthing conductor.

B: Earth Continuity Test

• Using the long lead and zeroed multimeter, measure, for each circuit, theearth conductor resistance from the circuit extremity to the switchboard.

• Confirm the measured values are LESS THAN those values as provided atTable 1, page 14 of this booklet for each sub circuit.

• This test is applicable to all circuits, including socket outlet circuits, lightingcircuits and fixed equipment (eg. water heater supply) circuits.

7. Re-connect the MEN link to the main neutral link.

8. Re-connect the water pipe equipotential bonding conductor.

7


3. Insulation Resistance TestAn insulation resistance test is performed to ensure that the resistance betweenall live conductors and earth, or as the case maybe, all live parts and earth, isadequate to prevent electric shock hazards, fire hazards and equipment damage.

It is a requirement of Clause 6.3.3.3.1 of the Wiring Rules that the insulationresistance between all live conductors (including the neutral) connected together,and earth, measured with all protective devices in circuit and all switches on, isnot less than 1 Megohm (see Note below). This applies to the completeinstallation and all parts of the installation.

This does not preclude the use of appliances incorporating heating elementsprovided that, when tested with all elements in circuit, the insulation resistancebetween live parts and the earthing terminal or earthing contact of the applianceis not less than 0.01 Megohm (10,000 ohms).

Note: Whilst the minimum reading is 1 Megohm, the ideal reading is infinity.This indicates a sound installation.

Test Equipment

Where the supply voltage does not exceed 250 volts between conductors andearth, a 500 volt insulation tester should be used to perform this test.

Test Procedure

1. Ensure that all protective devices are in circuit and that all switches are on. Ifthere are two way lighting circuits in the installation, tests must be carried outwith the two way switches in all positions, so all circuit conductors are tested.

2. Set the insulation tester (eg. Megger) to Megohms.

3. Connect one lead of the insulation tester to the main earthing bar (MEN Linkdisconnected) and the other lead to the actives and neutrals connectedtogether. Do not test between actives and neutrals.

4. Measure the insulation resistance of the total installation (including theconsumers mains).

If the insulation resistance is 1 Megohm or more - re-connect the MENLink and return the installation to normal.

8


If the insulation resistance is less than 1 Megohm - test all circuitsindividually, starting with circuits supplying appliances incorporating heatingelements.

Where a circuit is less than 1 Megohm, disconnect the appliance orappliances. Then test the circuit and appliance (separately) to ensure that theinsulation resistance of both the circuit and the appliance complies with thefollowing:

• not containing a heating element - is not less than 1 Megohm, or

• containing a heating element - is not less than 0.01 Megohm

Note: Where the insulation resistance of an appliance containing heatingelements is found to be less than 0.01 Megohm and the defect cannot berectified at the time of checking and testing, the electrical contractor mustmake arrangements for correction of the defect prior to submission of theNotice of Completion. Alternatively, the following procedure may be used:

a) Isolate the defective circuit, including the neutral conductor, bydisconnecting at the appropriate switchboard.

b) Attach an “out of service” tag to the circuit protection device, advising thatthe circuit has been disconnected due to low insulation resistance.

c) Check that the earth conductor has been reconnected at the MEN point.

d) Then submit the Notice of Completion.

Ensure that all circuits and the MEN connection are re-connected when thetesting is complete.

9


4. Polarity TestPolarity tests are carried out to ensure the correct connection of active, neutraland earth conductors to electrical equipment and to ensure that switches are notinstalled in neutral conductors. Clause 6.3.3.4 “Polarity” of the Wiring Rulesspecifies the testing requirements for this mandatory test.

Test Equipment

To carry out these tests, a continuity tester such as a multimeter (set to ohms)should be used.

Test Procedure

To ensure that the installation circuits/equipment will function as intended, it isnecessary that the following tests be performed:

• Isolate the active conductors by turning the main switch OFF and tagging.

• Confirm consumer and sub mains cables/connections by simply testing fromthe point of supply or distribution board to the main switchboard using anohm meter and long test loads. Test result ≈ 0 Ω.

• Confirm active conductor switching by using an ohm meter with the long leadconnected to the active conductor at the switchboard and the short leadconnected to the switch terminals (one at a time) in the following manner:i) Switch ON ≈ 0 Ω for both terminalsii) Switch OFF ≈ 0 Ω for one terminal and ‘infinity’ for the other terminal

• With the MEN link in place, confirm the polarity of socket outlets using a 10Ωresistor and an ohm meter. Connect the 10Ω resistor between the circuitactive conductor and the neutral bar then at each socket outlet connect onelead of the multimeter to the earth terminal and the second lead to the activeterminal. Test the resistance value for:i) socket outlet switch OFF ≈ ‘infinity’ii) socket outlet switch ON ≈ 10Ω.

10


5. Correct Circuit ConnectionsThese tests are required to ensure the following:

1. that protective earthing conductors do not carry current;

2. to prove there are no ‘short circuits’ within the installation; and

3. for the circuit continuity test to prove each circuit for electrical continuity andthat all switches operate in the active conductors.

6. Fault-loop Impedance TestThis test is carried out to confirm the fault-loop impedance value of each circuitwill be low enough to ensure the operation of the protective device during a fault.

Test Equipment

To perform the fault-loop impedance test, a fault-loop impedance meter isrequired.

Test Procedure

• Energise all circuits

• Using the fault-loop impedance meter, proceed to the equipment to be testedand measure the earth-loop impedance at this point. Repeat for other itemson the circuit.

• The measured value must be less than the maximum values as tabulated atTable B4.1 of the Wiring Rules.

• If an RCD operates during the test, the test result can be consideredsatisfactory.

11


7. Verification of RCD OperationThis is normally achieved by operation of the integral test device (typically testbutton on the RCD) to confirm:

1. the RCD is functioning correctly; and

2. the tripping device mechanisms are operating.

Warning: Operation of the integral test device does not provide a means ofchecking:

• continuity of the main earthing conductor or the associated circuit protectiveearthing conductor; or

• any earth electrode or other means of earthing or the associated electricalinstallation earthing.

Testing Alterations and AdditionsWhen alterations are carried out to an existing electrical installation, it is essentialthat the electrician tests the work to ensure compliance with the relevantstandards and specifications.

The tests described in this booklet must also be carried out on alterations andadditions to ensure the electrical installing work is safe to remain connected tothe electrical installation.

The majority of tests described in this booklet are designed to be carried outwithout power being connected. When performing these tests, make sure thatelectricity supplies are disconnected where necessary and that the appropriateisolation and tagging has been carried out.

A “Notice of Completion” form must be submitted to the supply authority tocertify this type of work.

12


Test EquipmentBefore performing any tests, ensure that the test equipment is correctly set, isfunctional and is in good condition, particularly the test leads.

Remember, when testing:

• check that the test equipment is operating correctly

• perform the required tests

• re-check the test equipment to confirm that it still operates correctly.

Some types of test equipment (eg. multimeters) are fitted with fuseprotection. Ensure that at all times only the correct type and rated fuse isused. This is for your protection.

Electrical test equipment is a very important part of an electrician’s tools. Testinstruments should be tested at intervals not exceeding one year and recordskept to verify this.

13


Table 1Maximum resistance values of final sub circuit protective earthing conductors

Protective Circuit - breakers FusesType B Type C Type D

Device Earthing Disconnection timesRating Conductor

0.4sec 0.4secSizeA mm2 Maximum final subcircuit earth conductor

resistance Ω6 1 3.08 1.65 1.00 3.69

10 1.5 1.85 1.00 0.60 2.06

16 2.5 1.16 0.62 0.38 0.99

20 2.5 0.93 0.50 0.30 0.68

25 2.5 1.07 0.57 0.34 0.76

32 2.5 0.72 0.38 0.23 0.51

40 2.5 0.66 0.35 0.21 0.44

50 4 0.54 0.29 0.17 0.34

63 6 0.44 0.23 0.14 0.26

14


Table 2Comparison of voltage drop and fault-loop impedance to determine circuitmaximum distance

This table details the single phase voltage drop for a combination of conductorsize, maximum demand current and distance. It also displays the maximumcircuit length for a Type ‘C’ circuit breaker (as normally used in most installations)to ensure the operation of the circuit breaker during an earth fault. You will noticethat compliance for voltage drop is the predominant requirement compared to thefault-loop distance for the given circuit breaker type.

15

Notes:

#1: Maximum demand determined using (a) full load, and (b) half the rating ofthe protective device assuming distributed load. Refer to Wiring RulesClause 3.6.2

#2: Voltage drop determined using 230V @ 5% = 11.5V maximum allowable.

#3: Distances obtained from Wiring Rules table B5.1.

mm2 A A #1 V (11.5V = maximum)

1.0 1010 10.3 - - - - 22* 55

5 5.2 7.7 10.3 - - 45* 55

1.5 1010 6.6 9.9 - - - 35* 82

5 3.3 5.5 6.6 9.9 - 70* 82

2.5 1616 5.8 8.6 - - - 40* 85

8 2.9 4.3 5.8 8.6 - 80* 85

4.0 2525 5.6 8.4 11.2 - - 41* 67

12.5 2.8 4.2 5.6 8.4 10.2 82 67*

* Denotes limiting parameter

ConductorSize

ProtectiveDeviceRating

MaximumDemand For

VoltageDrop #2

For Type CCircuit

Breaker #3

Distance

20m 30m 40m 60m 80m

Voltage Drop

Maximum Distancem


Further InformationFor further information on testing electrical installing work, please contact theElectrical Inspector at the relevant supply authority, as listed in the manual WAElectrical Requirements.

For further information, please contact:

ENERGY SAFETY20 Southport StreetWEST LEEDERVILLE WA 6007

Telephone: 08 9422 5200Facsimile:08 9422 5244

Email: [email protected]: www.energysafety.wa.gov.au

16

Issued byEnergy Safety

20 Southport StreetWest Leederville WA 6007Telephone: (08) 9422 5200Facsimile: (08) 9422 5244

Email: [email protected]: www.energysafety.wa.gov.au

ESWA E022 0104

Department of Consumer and Employment Protection

Documents

CHECKING AND TESTING ELECTRICAL INSTALLING WORK · CHECKING AND TESTING ELECTRICAL INSTALLING WORK Preface It is a requirement of the Electricity ... Test 1: Obtain the resistance