BS 7671 applies to electrical installations for

1.   ?    construction sites
2.   ?    electrical equipment on board ships
3.   ?    lightning protection systems
4.   ?    electrical traction equipment.

BS 7671 does not apply to

1.   ?    agricultural premises
2.   ?    domestic premises
3.   ?    suppliers' works
4.   ?    construction sites

A d.c. voltage of 125 V between conductors is classified as being

1.   ?    extra-low voltage
2.   ?    low voltage
3.   ?    reduced low voltage
4.   ?    SELV.

No additions or alterations should be made to an existing installation unless

1.   ?    a completion and inspection certificate can be produced for the existing installation
2.   ?    the work is undertaken by a registered contractor
3.   ?    the rating and condition of the existing installation is adequate
4.   ?    a request in writing has been made by the person requesting the work.

In the expression shown, S is

1.   ?    the fault current
2.   ?    a constant from the tables
3.   ?    the c.s.a. of the phase conductor
4.   ?    the nominal c.s.a. of the protective conductor

An Exposed Conductive Part of an installation is defined as a conductive part

1.   ?    liable to introduce a potential, usually earth potential and not forming part of the electrical installation
2.   ?    liable to introduce a potential, not including earth potential and forming part of the electrical installation
3.   ?    of equipment which cannot be touched and which is not a live part, but which may become live under fault conditions
4.   ?    of equipment which can be touched and which is not a live part, but which may become live under fault conditions.

A concise list of external influences can be found within BS 7671

1.   ?    chapter 32
2.   ?    chapter 52
3.   ?    appendix 3
4.   ?    appendix 5.

An external influence categorised as AG1 applies to a

1.   ?    quarry
2.   ?    factory
3.   ?    house
4.   ?    workshop.

Which one of the following is not an essential requirement when considering the frequency of maintaining installed electrical equipment during the life of an installation?

1.   ?    Any periodic inspection and testing may be readily and safely carried out.
2.   ?    Any protective measures for safety remain effective.
3.   ?    The reliability of equipment is sustained.
4.   ?    The name and address of the contractor is permanently displayed adjacent to the equipment.

When considering the compatibility of a large three-phase a.c. motor, installed with other equipment within an installation, it is important to avoid

1.   ?    over-voltages occurring within the installation
2.   ?    under-voltages being created within the installation
3.   ?    high frequency oscillations
4.   ?    the necessity for additional connections to earth.

Installations should be arranged so as to avoid danger in the event of a fault, and to facilitate safe operation, inspection, testing and maintenance. One method of complying with this is to

1.   ?    connect all circuits on the radial principle
2.   ?    connect all circuits on the ring principle
3.   ?    divide the installation into separate circuits
4.   ?    divide the installation into bands of circuits.

A final circuit is the wiring between the

1.   ?    main cut-out and the energy meter
2.   ?    main switch and the distribution board
3.   ?    distribution board and current-using equipment
4.   ?    consumer's main earth terminal and circuit protective device.

An electrical installation has the following single-phase circuits installed, using multicore thermoplastic cables (non-armoured)

2 x 5 A lighting
2 x 30 A ring final
1 x 15 A immersion heater 1 x 30 A cooker.

If the circuit cables are contained within a p.v.c. trunking prior to entering the consumer's control unit, how many live conductors would be present in the trunking?

1.   ?    6.
2.   ?    8.
3.   ?    16.
4.   ?    24.

Prior to the construction of a new electrical installation, the information to be given to the Local Electricity Supplier in order to establish the type and rating of supply is the

1.   ?    nature of current and frequency
2.   ?    nominal voltage
3.   ?    maximum demand
4.   ?    external impedance (Ze).

An electric fire having an element exposed to touch would increase the risk of an electric shock by

1.   ?    prospective contact
2.   ?    earthing contact
3.   ?    indirect contact
4.   ?    direct contact.

Protection against shock by indirect contact can be provided by

1.   ?    the use of Class II equipment
2.   ?    barriers or enclosures
3.   ?    placing out of reach
4.   ?    the insulation of live parts.

Protection against both direct and indirect contact can be provided by SELV. One suitable safety source of supply would be a

1.   ?    50 V storage battery
2.   ?    230 V diesel generator
3.   ?    230/110 V single-phase generator
4.   ?    230/50 V auto-transformer.

A method of protection against indirect contact from low voltage portable equipment is automatic disconnection of the supply within

1.   ?    0.4 s
2.   ?    5s with no other restriction
3.   ?    10s
4.   ?    10s but using 110 V supply

The value of the external loop impedance (Ze) can be found by either enquiring from the local electricity board or taking an earth loop impedance reading at

1.   ?    the supply point and subtracting the value of internal loop impedance (R1 + R2)
2.   ?    the furthest socket outlet from the supply
3.   ?    the origin of supply
4.   ?    both the supply and at the furthest socket outlet, and subtracting one result from the other.

When using a non-metallic hand-held piece of equipment, the maximum temperature of any accessible part in degrees Celsius is

1.   ?    30
2.   ?    45
3.   ?    55
4.   ?    65.

If the mechanical load being driven by an a.c. motor became seized, the electrical protection for the circuit should operate. This condition is termed as

1.   ?    overload
2.   ?    short circuit
3.   ?    indirect contact
4.   ?    direct contact.

The prospective fault current at the origin of an electrical installation must be taken into account when

1.   ?    estimating the external earth fault loop impedance
2.   ?    applying diversity to the installation
3.   ?    assessing the earthing arrangement
4.   ?    selecting the type of overcurrent device to be installed.

Devices providing protection against both overload and fault current shall be capable of breaking any overcurrent up to and including

1.   ?    the design current of the circuit
2.   ?    1.45 times the design current
3.   ?    1.45 times the rating of the protective device
4.   ?    the prospective fault current at the point of installation.

A fireman's switch shown in Figure 1 has been mounted in a position which is both conspicuous and accessible to firemen. The maximum mounting height (A) above standing level should not exceed

1.   ?    1.75 m
2.   ?    2.75 m
3.   ?    3.75 m
4.   ?    4.75 m

Which one of the following shall not be used as an isolator?

1.   ?    Circuit breakers.
2.   ?    Plug and socket outlets.
3.   ?    Semiconductor devices.
4.   ?    Fuselinks.

For the purpose of overvoltage control, a suspended cable having insulated conductors with earthed metallic covering is deemed to be

1.   ?    an uninsulated cable
2.   ?    a bare or p.v.c. covered cable
3.   ?    an underground cable
4.   ?    a catenary - supported cable.

In a location where a risk of danger from fire exists due to manufacture or storage of combustible materials, enclosures of heaters shall not attain a surface temperature under normal working conditions exceeding

1.   ?    70°C
2.   ?    90°C
3.   ?    100°C
4.   ?    115°C.

The spacing of saddles for a horizontal run of 25 mm rigid p.v.c. conduit should not exceed

1.   ?    1.0 m
2.   ?    1.5 m
3.   ?    1.75 m
4.   ?    2.0 m.

The ratio of the sum of the overall c.s.a. of cables enclosed to the internal c.a.. of trunking is termed the

1.   ?    group factor
2.   ?    space factor
3.   ?    area factor
4.   ?    ratio factor.

When selecting a cable for a single circuit installation, correction factors are to be used and applied to the

1.   ?    total current taken by the installation
2.   ?    current-carrying capacity of the cable
3.   ?    design current of the circuit
4.   ?    nominal current of the protective device

One method of calculating the earth fault loop impedance Zs is by the formula

1.   ?    Zs = R1 + R2 + R3
2.   ?    Zs = Ze + R1 + R2
3.   ?    Zs =Ze + R1 + R3
4.   ?    Zs = Ze + R2 + R3.

Where the main earth terminal is separate from main switchgear, a permanent label shall be fixed in a visible position with the wording

1.   ?    Danger Electrical Connection - Do Not Remove
2.   ?    Safety Electrical Connection - Do Not Remove
3.   ?    Danger Earth Connection - Do Not Remove
4.   ?    Safety Earth Connection Do Not Remove.

Where a person other than a skilled or instructed person may operate a circuit breaker, it shall be designed or installed so that it is not possible to modify the setting or calibration of its overcurrent release without

1.   ?    involving the use of a key or a tool
2.   ?    permission from a skilled person
3.   ?    consulting manufacturer's instructions
4.   ?    isolating the main supply switch.

Where a TT system is in use, the preferred device to provide earth fault protection is a

1.   ?    residual current device
2.   ?    circuit breaker
3.   ?    cartridge fuse link
4.   ?    disconnector.

The requirement that the metalwork of gas, water or other services is not to be used as a protective earth electrode does not preclude

1.   ?    its temporary use as an earth electrode
2.   ?    the permanent isolation of such metalwork
3.   ?    its use as an auxiliary earth electrode
4.   ?    the bonding of such metalwork as required.

Supplementary bonding conductors having mechanical protection connected between two extraneous conductive parts are subject to a minimum cross-sectional area of

1.   ?    1.5 mm²
2.   ?    2.5 mm²
3.   ?    4.0 mm²
4.   ?    6.0 mm².

A residual current device offers protection against

1.   ?    overload current
2.   ?    short circuit current
3.   ?    nominal current
4.   ?    earth fault current.

Where a socket outlet of rating 32 A or less is used to supply portable equipment outdoors, supplementary protection to reduce direct contact risk must be provided by means of a

1.   ?    fuse having a suitable time/current characteristic
2.   ?    Type B circuit breaker to BS EN 60898
3.   ?    residual current device having the specified characteristics
4.   ?    switch-disconnector to BS EN 60947-3.

Socket outlets supplying 230 V equipment used in the garden must be protected by a residual current device. This device is fitted because the equipment is being used

1.   ?    within the equipotential zone
2.   ?    where the earth loop impedance Zs is above 500 Ω
3.   ?    where the overload tripping time exceeds 5 seconds
4.   ?    outside the equipotential zone

In order to determine the breaking capacity of a protective device within an installation, the characteristic of the external supply to be ascertained is the

1.   ?    external loop impedance
2.   ?    prospective short circuit current
3.   ?    nominal voltage
4.   ?    maximum demand.

In order to reduce the effects of eddy currents when conductors enter a ferrous enclosure, they should be so arranged that

1.   ?    each conductor of an individual circuit takes approximately the same value of current
2.   ?    they are not individually surrounded by the ferrous material
3.   ?    they are terminated in the correct phase sequence
4.   ?    they are physically separated from conductors of other circuits within the enclosure.

Every motor having a rating exceeding 0.37 kW shall be provided with control equipment

1.   ?    preventing operation by uninstructed persons
2.   ?    incorporating protection against overload
3.   ?    preventing operation at high ambient temperatures
4.   ?    incorporating protection against overspeeding.

In a location that contains a shower cubicle (other than a bathroom or shower room), a 13 A socket outlet to BS 1363, backed up by an rcd, must be sited

1.   ?    0.6 m from the shower cubicle
2.   ?    2.4 m from the shower cubicle
3.   ?    outside zone 2
4.   ?    outside zone 3.

Cables required to supply an item of equipment in Zone C of a swimming pool must

1.   ?    not pass through Zones A or B
2.   ?    only pass through Zones A or B if they are insulated to withstand a test voltage of 500 V a.c., r.m.s. for one minute
3.   ?    only pass through Zones A or B if they are totally enclosed in earthed metal
4.   ?    pass through Zone B, but not Zone A.

The disconnection time for a construction site installation supplied from a 230 V TN system is

1.   ?    0.02 s
2.   ?    0.05 s
3.   ?    0.2 s
4.   ?    0.35 s.

In agricultural and horticultural installations, electrical equipment installed for normal use shall have a minimum degree of protection to

1.   ?    IP22
2.   ?    IP33
3.   ?    IP44
4.   ?    IP55.

Except where a caravan is constructed substantially of insulating material, any extraneous conductive parts must be bonded to the circuit protective conductor
a conductor having a minimum cross-sectional area of

1.   ?    1.5 mm²
2.   ?    2.5 mm²
3.   ?    4.0 mm²
4.   ?    6.0 mm².

To reduce the risk of shock from the metalwork of Class I street located equipment, protection should be by

1.   ?    non-conducting location
2.   ?    EEBAD
3.   ?    earth-free equipotential bonding
4.   ?    electrical separation.

For a TT installation where a protective conductor current is likely to exceed 3.5 mA the product of the total protective conductor current (in amperes) and twice the resistance of an installation earth electrode (in ohms) shall not exceed

1.   ?    25
2.   ?    50
3.   ?    100
4.   ?    200.

Which one of the following items should be included for checking during the initial verification of an installation?

1.   ?    Site works orders and alterations.
2.   ?    Presence of diagrams and instructions.
3.   ?    Minutes of all site meetings.
4.   ?    All variations of contract.

A durable copy of a schedule relating to a distribution board should be

1.   ?    forwarded to the local supplier
2.   ?    submitted to the installation designer
3.   ?    kept within or adjacent to the distribution board
4.   ?    retained by the electrical contractor.

The minimum size of trunking required to enclose ten 6 mm² and twenty 10 mm² single-core thermoplastic (p.v.c.) cables is

1.   ?    50 x 38 mm
2.   ?    100 x 25 mm
3.   ?    100 x 50 mm
4.   ?    100 x 100 mm.

For an insulation resistance test on a 230 V a.c. installation, the value of the test voltage is

1.   ?    50 V d.c.
2.   ?    230 V d.c.
3.   ?    500 V d.c.
4.   ?    1000 V d.c.

When testing a 230 V installation, the minimum value of insulation resistance to earth with all fuses in place and all the phase conductors connected together is

1.   ?    0.5 Ω
2.   ?    1 Ω
3.   ?    0.5 MΩ
4.   ?    1 MΩ

No alteration, temporary or permanent, shall be made to an existing installation unless the

1.   ?    electricity supplier has been informed
2.   ?    local authority has been informed
3.   ?    existing equipment is adequate for any additional load
4.   ?    existing equipment meets BS and BS EN standards.

A signed Electrical Installation Certificate must indicate responsibility for the installation's

1.   ?    design, construction, inspection and testing
2.   ?    design, materials and construction
3.   ?    construction, environment and design
4.   ?    environment, design, inspection and testing.

Which one of the following factors does not affect the frequency of periodic inspection?

1.   ?    Type of installation.
2.   ?    Installation use and operation.
3.   ?    Frequency of maintenance.
4.   ?    Supplies for safety services

A 63 A protective device to BS 88 Part 2, when carrying a fault current of 280 A should operate within

1.   ?    0.1 s
2.   ?    0.2 s
3.   ?    0.4 s
4.   ?    5 s.

A 230 V single-phase circuit supplying a pump motor is protected by a 20 A Type B circuit breaker to BS EN 60898. The minimum value of fault current to cause disconnection between 0.1 s and 5.0 s is

1.   ?    20 A
2.   ?    100 A
3.   ?    140 A
4.   ?    200 A.

Before PME (TN-C-S) supply will be granted by the local electricity supply company the installation must comply with the

1.   ?    British Standards 6907
2.   ?    IEE on-site guide
3.   ?    Codes of Practice
4.   ?    Electricity Safety, Quality and Continuity Regulations.