7/31/2019 S05 Continuity Tests

http://slidepdf.com/reader/full/s05-continuity-tests 1/8

Installation (Building and Structures)

Inspection testing and commissioning

B&B Training Associates Ltd

Learning Materials for the Electrical Industry

7/31/2019 S05 Continuity Tests

http://slidepdf.com/reader/full/s05-continuity-tests 2/8

 © B & B Training Associates Ltd June 08 ‹#› 

Outcome 2

Select appropriate methods and use tools equipmentand instruments for inspection, testing and

commissioning of electrical installations

Session 5

Continuity of protective conductors

Aims and objectives

To understand how to carry out a continuity test

7/31/2019 S05 Continuity Tests

http://slidepdf.com/reader/full/s05-continuity-tests 3/8

 © B & B Training Associates Ltd June 08 ‹#› 

Inspection and testing is carried out because we have to ensure that the

installation complies with the Electricity at Work Regulations 1989.

EWR89 states that an installation is fit for use, used properly and appropriate for

the task.

We also have to comply with BS 7671.

New installation require an Electrical Installation Certificate

Existing installations require a Periodic Inspection Report.

Prior information is essential when carrying out inspection and testing, this will

include manufactures data, specifications, part 3 BS 7671, diagrams, EWR89

When testing the tester must be appropriate for the task, fit for use and used

properly

The range of testers must comply with BS EN 61557

7/31/2019 S05 Continuity Tests

http://slidepdf.com/reader/full/s05-continuity-tests 4/8

 © B & B Training Associates Ltd June 08 ‹#› 

That the instrument has batteries that are adequate for the task. They mustbe replaced regularly to maintain the current we require.

The connection leads and the instrument must be zeroed. This is a process inwhich the instruments needle is set at a known start point so that the resultsare accurate.

The test instrument has a current calibration certificate.

There are two methods for testing the continuity of protectiveconductors, irrespective of what the protective conductor is.

All though Regulation 612.2.1 requires that we test the continuity of protectiveconductors, including main and supplementary bonding conductors, it gives no

clear guidance on how to do so. which we will come on to shortly.

It is important that you understand the following:

That the instrument used in this test is a low-resistance ohmmeter.

Before beginning the test you must check;

7/31/2019 S05 Continuity Tests

http://slidepdf.com/reader/full/s05-continuity-tests 5/8

 © B & B Training Associates Ltd June 08 ‹#› 

This test must be done prior to the connection of

any supplementary bonding conductor

to an appliance or services etc.

If there are any supplementary bonding

conductors then you are not just testing

the circuit protective conductor,

you are testing a parallel combination

of earthing conductors.

As mentioned earlier there are two methods of testing the continuity of protectiveconductors. Irrespective of what the protective conductor is.

Method 1

7/31/2019 S05 Continuity Tests

http://slidepdf.com/reader/full/s05-continuity-tests 6/8

 © B & B Training Associates Ltd June 08 ‹#› 

Line and cpc connectedtogether at the fuseboard 

Continuity test madeusing the circuit itself 

7/31/2019 S05 Continuity Tests

http://slidepdf.com/reader/full/s05-continuity-tests 7/8

 © B & B Training Associates Ltd June 08 ‹#› 

To carry out the test;

1. Prove that the circuit is dead

If the circuits cannot be made safe (i.e. dead) you should not carry out thistest.

2. Connect the line conductor to the protective conductor at the

distribution switchboard.This can be done with a link, a connector block, or by connecting the cpc withthe line conductor at the top of the fuse board.

3. Test between the phase and the cpc at the remote appliance. Thisrecords the combined value of the line conductor and the R1 + R2.

The measurement of R1 + R2 should be measured in Ohms (Ω)

You do not need to test at every point, just the furthest points.

7/31/2019 S05 Continuity Tests

http://slidepdf.com/reader/full/s05-continuity-tests 8/8

 © B & B Training Associates Ltd June 08 ‹#› 

You should test in the same way asmethod 1 making sure that you are nottesting any parallel paths.

Make sure that any supplementarybonding conductors are not affectingthe test

Connect one lead of the continuity tester to the cpc or bonding conductor under test.

Connect the other lead (wandering lead) of the continuity tester to the other end of theconductor under test and record the results

This method of testing only tests the cpc or bonding conductor resistance.Testing of all the bonding and earthing conductors should be done using method 2 and thevalue should be lower than 0.05Ω.

Any continuity test must include circuit protective conductors, supplementary bondingconductors and earthing conductors.

End of session 5