2391-50: Scenario 104

List all the certification documents that must be completed for the inspection and test for the entire site. q621

State the title given to the person carrying out the inspection and test as stated in EAWR q623

State the status of person carrying out an inspection and test. q624

State the four responsibilities of the person carrying out an inspection and test as defined in GN3. q625

List three items of information that should be available to the person carrying out an inspection and test q626

The insulation resistance of the lighting circuits in a shower and toilet block is to be tested. The fluorescent luminaire circuits are controlled using a timer, local time delay switches and a photocell.

State what action needs to be taken before a full insulation resistance test of the lighting circuits can be carried out. q627

Describe the procedure for carrying out an insulation resistance test on one lighting circuit. q628

If the values obtained for five lighting circuits are 100MΩ, 100MΩ, 200MΩ, 50MΩ and 50MΩ. Calculate the insulation resistance of the five circuits when connected together at the distribution board. Show all calculations. q629

The earth electrode, which is installed at the origin to separate the caravan pitch sockets from the TN-C-S system, has an earth electrode resistance of 48Ω.

State which document states that caravan pitch sockets would not be connected to a TN-C-S system. q630

Determine the maximum permissible residual operating current for the RCD protecting this TT system. Show all calculations. q631

State the maximum permissible rating for RCDs protecting individual pitch supply sockets, as given in BS7671. q632

The RCDs protecting a pitch socket outlets are to be tested. List the range of tests to be carried out. q633

The RCDs protecting caravan pitch socket outlets are to be tested. List the value of the test current used in each case. q634

The RCDs protecting caravan pitch socket outlets are to be tested. List the maximum permitted disconnection time in each case. q635

State why a 500mA RCD is used at the origin of these circuits. q636

Describe, with the aid of a fully labelled diagram, the earth fault loop path for one of the pitch supply sockets. q637

The ring circuit supplying the general purpose socket outlets in the shop/office area is being tested to confirm ring final circuit continuity. All the socket outlets are connected to the same circuit. The test results obtained are given in the table below.

State whether the values obtained are as expected in each case.

For any value which is not as expected, give one reason for the reading obtained. q639

The image below shows the measured and maximum tabulated values of earth fault loop impedance for all the circuits supplying the office and shop area. The single phase distribution for this area is located adjacent to the origin of the electrical installation.

Determine whether the measured results are acceptable in each case.

State three methods which may be used to rectify any circuits which do not comply.

State three methods which may be used to rectify any circuits which do not comply. q641

Determine the minimum acceptable breaking capacity for the circuit breakers installed in this distribution board. Show all calculations. q642

Explain briefly the importance of the rated breaking capacity of circuit breakers. q643