British Standards Bs 7671 Electrical Installation Exam Practice Test
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It’s easy to flip a light switch or turn on your television without thinking of the processes going on behind them. What powers them up? Electricity! How does that electricity work? That’s for you to tell us! In this quiz, we’ll be trying to gauge your knowledge on all things electricity, with specific reference to the United Kingdom. What do you know about it all? Let’s find out!
- 1.Requirements are included in BS 7671 for electrical installations of
- A.
Lift installations
- B.
Mobile offshore electrical systems
- C.
Distributor's networks
- D.
Locations containing a bath or shower
- 2.Which of the following is excluded from the scope of BS 7671?
- A.
Cabins containing sauna heaters
- B.
Fountains
- C.
Highway power supplies
- D.
Lightning protection
- 3.Which of the following is not included in BS 7671?
- A.
Demolition site installations
- B.
Electric fences
- C.
Medical locations
- D.
Motor caravans
- 4.Which of the following documents is non-statutory?
- A.
Electricity Safety, Quality and Continuity Regulations
- B.
Electricity at Work Regulations
- C.
The Building Regulations
- D.
Requirements for Electrical Installations
- 5.Protective equipotential bonding is achieved by
- A.
Preventing current from passing through the body
- B.
Ensuring adequate continuity between extraneous conductive parts
- C.
Automatic disconnection of supply in the event of a fault
- D.
Separation of equipment from the supply using a safety isolating transformer
- 6.The type of earthing arrangements requiring a consumer’s earth electrode to be installed is where
- A.
No earth facility is supplied by the distributor
- B.
The supply is from a low voltage generator
- C.
Earthing is via the distributor’s cable armour
- D.
The electrical system is TN-C
- 7.Low-voltage is defined in BS 7671 as having a value exceeding
- A.
24V ac
- B.
48V ac
- C.
50V ac
- D.
120V ac
- 8.Tables showing the classification of external influences when considering environmental conditions during the design of an installation can be found in BS 7671
- A.
Chapter 32
- B.
Chapter 53
- C.
Appendix 4
- D.
Appendix 5
- 9.An assessment must be made of harmful effects on other electrical systems when installing
- A.
Large electric motors
- B.
Fire alarm systems
- C.
Emergency lighting circuits
- D.
Reduced low voltage supplies
- 10.For a 32A ring final circuit in similar premises to a dwelling, the minimum size of thermoplastic insulated copper live conductors allowed is
- A.
1.0mm2
- B.
1.5mm2
- C.
2.5mm2
- D.
4.0mm2
- 11.In a domestic dwelling a 32A ring final circuit incorporating BS 1363 socket-outlets historically serves a floor area up to
- A.
75m2
- B.
100m2
- C.
50m2
- D.
200m2
- 12.The following final circuits are to be installed using thermoplastic insulated multicore non-armoured cables 3 x 6A lighting 1 x 20A UPS supply 3 x 32A ring 1 x 40A cooker If the cables are enclosed in a non-metalic trunking where entering the distribution board, how many live conductors would be enclosed?
- A.
9
- B.
16
- C.
22
- D.
32
- 13.The required current carrying capacity of a three-phase circuit conductor Iz is 26A. From the correct table, the minimum size of three single-core thermoplastic covered, heavy duty MICC cables, installed flat on a perforated cable tray and spaced by two cable diameters is
- A.
1.0mm2
- B.
1.5mm2
- C.
2.5mm2
- D.
4.0mm2
- 14.Which of the following is not a characteristic of the supply?
- A.
Nominal voltage
- B.
frequency
- C.
Earth loop impedance Ze
- D.
Power factor
- 15.The requirements for mobile or transportable units are applicable to the following types of unit
- A.
Health screening services
- B.
Pleasure craft
- C.
Mobile machinery to BS EN 60204-1
- D.
Traction equipment of electric vehicles
- 16.Basic protection by means of obstacles is intended to prevent
- A.
Ordinary persons from operating equipment
- B.
Intentional contact with exposed parts
- C.
Intentional bodily approach to a live part
- D.
Unintentional bodily approach to a live part
- 17.Which of the following is a method of fault protection?
- A.
Electrical separation
- B.
Barriers or enclosures
- C.
Insulation of live parts
- D.
Placing out of reach
- 18.The value of the external earth loop impedance Ze can be obtained by measurement at
- A.
The supply point and subtracting the value of internal loop impedance (R1 + R2)
- B.
The furthest socket-outlet from the supply
- C.
The origin of supply
- D.
both the supply and at the furthest socket-outlet, and subtracting one result from the other
- 19.In a TN system, final circuits not exceeding 32A supplying fixed equipment are subject to a maximum disconnection time of
- A.
0.4s
- B.
0.8s
- C.
4.0s
- D.
5.0s
- 20.The temperature limit for metalic equipment which is intended to be touched but not hand-held is
- A.
30 degrees Celsius
- B.
55 degrees Celsius
- C.
65 degrees Celsius
- D.
70 degrees Celsius
- 21.Overload current is defined as an overcurrent
- A.
Due to low insulation resistance
- B.
In a circuit which is electrically sound
- C.
Due to a fault of negligible impedance
- D.
In a line conductor in contact with earth
- 22.The prospective fault current at the origin of a single-phase installation is the greater of the prospective
- A.
Maximum demand and diversity value
- B.
Short circuit and overload current
- C.
Design current and distributor’s main fuse
- D.
Short circuit and earth fault currents
- 23.To meet the requirements of BS 7671, all overcurrent devices without upstream backup protection must
- A.
Be rated lower than the design current
- B.
Meet the requirements of BS 7846
- C.
Be able to withstand the prospective fault current
- D.
Not operate due to a line to earth fault
- 24.Which of the following devices can not be used for emergency switching?
- A.
A push-button controlling an all-pole contactor
- B.
A manually operated switch
- C.
A circuit-breaker
- D.
A luminaire support coupler
- 25.Which of the following arrangements of a firefighter’s switch controlling a discharge lighting installation would comply with BS 7671?
- A.
Switch with off position at the bottom and mounted at 2.75m from the ground
- B.
Switch with off position at the top and mounted at 3.75m from the ground
- C.
Switch with off position at the bottom and mounted at 3.75m from the ground
- D.
Switch with off position at the top and mounted at 2.75m from the ground
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