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WorksheetsL3 YR2 Revision 5 (Electrical)
Total questions: 34
Worksheet time: 17mins
A central heating system pump fails to start when the supply is switched on and it hums. The windings have been tested and have the correct continuity. What is the most likely cause of this?
break in the Neutral conductor
failure of the start capacitor
break in the cpc
Protective device has operated
While installing an electric water heater, it is noted that the TN-C-S supply has 25mm meter tails and 6mm main protective bonding conductors. What is the correct permitted size for the protective bonding?
is the correct permitted size
needs upgrading to 16mm
needs upgrading to 10mm
needs upgrading to 25mm
HSE G38 requires all test leads to be fused. What should be the fuse rating?
50 mA
500 mA
1.0 A
5.0 A
A mid-position valve fails to operate when the cylinder thermostat calls for operation. Which tool is most suitably used to test the valve components?
insulation resistance tester
RCD tester
low resistance ohmeter
neon screwdriver
The purpose of main protective bonding is to?
reduce earth fault loop impedance
reduce potential differences
reduce potential differences
increase earth fault loop impedance
When should a visual inspection take place?
upon completion
during installation
when the supply is switched on
during and upon completion of the installation
The most suitable instrument to check the resistance value of the windings of a single phase pump motor would be?
low resistance ohmeter
insulation resistance tester
earth electrode resistance tester
RCD tester
A 30 mA RCD can be used as additional protection in the event of failure of basic protection with a test current of 150 mA the device should trip within?
300 ms
0.4 seconds
40 ms
4 seconds
Which of the following would NOT be considered as part of functional testing?
isolate switch on and off
RCD test button operates the device
thermostats operate correctly
circuit breakers operate under short circuit conditions
Upon completion of the project, the mechanical services contractor shall hand over which of the following?
all bills of quantities, specifications, and payment certificates
electrical installation certificate, schedule of inspections, schedules of test results, and equipment operational and maintenance manuals
original installation drawings
a copy of the Construction (Design and Management) Regulations
Which of the following protective devices can safely interrupt the highest prospective fault current?
BS 3036 rewireable fuse
BS 88 high breaking capacity
BS1362 cartridge fuse
BS EN 60898 circuit breaker type 2
A permanent warning notice must be fixed at or near the point of connection of every earthing conductor to an earth electrode. Which one of the following MUST be displayed on the notice?
Earth bonding danger
Safety Electrical Earth - Do Not Remove
Electrical Safety Connection
Safety Electrical Connection - Do Not Remove
The minimum size of main protective bonding Conductor used within a TN-C-S system would be?
4 mm
6 mm
10 mm
16 mm
When isolating certain pumps used in central heating systems, a small electrical charge may remain in the equipment and circuit even though the circuit is safely isolated. Which of the following components causes this effect?
brushes
neon indicators
capacitors
cable runs
When making an addition to an existing electrical installation the maximum demand should be?
determined by the supply company
re-calculated by summing up the ratings of the circuit breakers
obtained from the customer
re-calculate and diversity taken into account
Which one of the following circuit breaker ratings would be suitable to supply a single-phase 230v 6 KW water heater?
20 A type B
32 A type B
40 A type B
63 A type B
The outer sheath of a twin and cpc cable is designed to provide?
double insulation
mechanical protection
additional conductor insulation
protection against excessive ambient temperatures
In a standard fused connection unit the type of cable termination for the supply cable are usually?
strip connectors
claw washer type termination
screwhead nut and washer termination
pillar terminals
Which of the following electrical water heating appliances does NOT need to be on its own electrical circuit?
9 KW instantaneous shower unit
12 litre 2 KW storage type heater
4 KW instantaneous water heater
18 litre 2 KW storage type heater
A fault requires rectification on the central heating control wiring in an occupied rented dwelling. Which one of the following is the MOST reliable source of information to find what the fault is?
the owner
the tenant
the supply company
the boiler manufacturer
Boiler manufacturers fault finding charts are usually found in the manufacturers?
product performance specification
installation specification
operation and maintenance instructions
product information sheet
Which of the following pieces of test equipment would be used to check the continuity of the motor windings of an electrically operated mid position valve?
insulation resistance tester
earth electrode tester
phase connection meter
low resistance ohmeter
A pump motor continually trips its overload after running for several minutes. The most suitable test instrument to check then current being drawn is?
ammeter
multi-meter
voltage indicator
RCD tester
The Electricity at Work Regulations requires test equipment to be checked and records kept. Which one of the following methods of checking instrument accuracy is NOT usually carried out by operatives?
comparison against existing instruments
checking against known resistance values
calibration and certification
proprietary checkbox method
When chasing walls or chopping in flush accessory boxes, what precautions should be taken to protect the customer's property?
dust sheets should be put down on the floor and any furniture unable to be moved covered
plaster and brick debris should always be swept off the carpets before leaving
after chopping out the plaster and brick debris should be cleared away from floor covering
the area should be taped off by the customer so that work can be completed safely
When using a portable electric drill in a wet location, reducing the risk of electric shock is best achieved by using a?
110v drill supplied from a transformer
class 11 double insulated 230v drill
battery operated drill
230v drill protected by an RCD
What is the maximum recommended over-current protective device rating for a final ring circuit?
16A
20A
32A
45A
What type of cable is needed for supplying a typical domestic immersion heater?
60 degree thermoplastic round cable
70 degree thermoplastic flat profile cable
90 degree thermosetting armoured cable
90 degree thermosetting rubber cable
What is a relay, an electromechanical device, designed to do?
switch a circuit off if overloaded
protect electronic components from over voltage and over current surcharges
amplify or reduce voltages within an electrical circuit
open and close electrical contact when the relay coil is energised
What type of board do equipment manufacturers typically mount electronic equipment on?
tag board
pcb
matrix board
pccb
The provision and use of work equipment Regulations requires equipment used on a construction site to be maintained in good order. The duty is placed on the?
site manager
employee
user
employer
Refer to the following activities. Which one would NOT result in the issue of a minor works certificate?
replacing an existing consumer unit
adding a fuse connection unit to an existing circuit
replacing a damaged socket outlet
replacing central heating control wiring
What type of electricity supply would be supplied to a typical domestic dwelling?
400v 3 phase 4 wire a.c.
240v single phase d.c.
400v 3 phase 3 wire a.c.
230v single phase a.c.
The consumer unit is provided at the installation intake point in order that?
The installation may function without the meter reading useage
The installation can be divided into circuits
under voltage protection is provided
class 1 and class 2 electrical equipment may be used within the installation
