Electrical Theory

Front 1

How quickly must an RCD trip for patients during treatment?

Back 1

40mSec

Front 2

State that following repairs electrical appliances must be tested to ensure they are safe in accordance with the requirements of …

Back 2

AS/NZS 5762

Front 3

Which certificate provides a legally recognisable statement that the connected installation or part installation, or any fitting that supplies an installation is safe to use?

Back 3

Electrical safety certificate

Front 4

True or False?

Related to protective devices, breaking capacity is the minimum value of current that the protective device can safely interrupt under fault conditions.

Back 4

False

Front 5

Briefly describe the construction and operation of a thermal overload relay

Back 5

Consists of a bi- metallic strip with electrical contacts attached, when heated by excess current the bi-metallic strip bends which opens the contacts, disconnecting the control circuit.

Front 6

What components are used for filtering the output of rectifier circuits?

Back 6

Resistors, chokes and capacitors

Front 7

The minimum recommended illuminance level required for circulation areas, corridors, passageways is

Back 7

100 lux measured at 1.2m

Front 8

The amount of light hitting a surface has the symbol E

Back 8

Lux

Front 9

Scr is a unidirectional current thyristor device

Back 9

True

Front 10

A transistor is used as a switching. When no base voltage it is on ,when a base voltage is present it is off

Back 10

False

Front 11

According to the possibility of adjusting the residual operating current,Rcbos are classified in the following

Back 11

Rcbo with a single value of rated current

Rcbo with multi setting of residual operating current by fixed steps

Front 12

A voltage transformer is a parallel connected type of instrument transformer

Back 12

True

Front 13

Motors over 2.2 kw requires over temperature protection

Back 13

True

Front 14

What voltage is the dc link in New Zealand

Back 14

350kv

Front 15

What type of motor starter suits low or no load ?

Back 15

DoL

Star delta

Front 16

Accordingly to method of operation, rcbos are classified in the following’s

Back 16

Rcbo functionally I dependent of line voltage

Rcbo dependant on line voltage

Front 17

Rcds that protect children must trip within?

Back 17

40mSec

Front 18

One copy of the Coc must be retained by the person carrying the work for how many years

Back 18

7

Front 19

Close excess current protection will operated within 4 hours at 1.5 times rated current

Back 19

True

Front 20

According to the protection against external influences, rcbo are classified in the following ways

Back 20

Enclosed type rcbo

Unenclosed rcbo

Front 21

The minimum recommend illuminance required for external covered walkways

Back 21

30 lux at ground level

Front 22

What type of installation work requires testing and certification by a registered electrician before connection to the supply

Back 22

High risk PEW

General PEW

Front 23

Total luminous flux on a surface. It is a messure of how much the light illuminates the surface. The SL UNIT IS LUX

Back 23

Illuminance

Front 24

With regards to the physiological effect of electric shock on the human body, when body current (ac)is 100ma and duration is 20 milliseconds, the likely physiological effect is

Back 24

Mild to pain full sensation. Usually no harm

Front 25

Lighting colour for grocery stores and garages

Back 25

Cool white 4000-5000k

Front 26

The personal danger tags can be removed by an authorised person in accordance with an approved procedure

Back 26

True

Front 27

Which type of motor starter gives step-less operation?

Back 27

Electronic soft start

Front 28

Electrical fires require an extinguisher labelled Class E, the two main types are

Back 28

Dry powder

Carbon dioxide

Front 29

List the common secondary voltages of a voltage transformer(VT) when supplied at its full primary voltage.

Back 29

120v

70v

Front 30

As the voltage across the Diac increases, a point is reached where the current increases rapidly, and at the same time the voltage falls.Select one:

Back 30

True

Front 31

For each of the following types of cable is used for this applications:General wiring applications. Commercial,domestic and industrial applications from lighting, power outlets and sub-mains.

Back 31

Tps

Front 32

Related to protective devicest, Current rating is the minimum current a protective device can carrycontinuously without deterioration.

Back 32

False

Front 33

RCDs do not provide protection against faults between live conductors

Back 33

True

Front 34

Select the motor starter that has the characteristic of a shortdisconnection of supply during start.

Back 34

Star delta

Front 35

Coarse Excess - Current Protection: Will not operate within 4 hours at 1.5 times rated current

Back 35

True

Front 36

When working on circuits which have capacitors connected or other sources of stored energy, if thecapacitors with values greater than _____ uf it shall be provided with discharge path.

Back 36

. 5

Front 37

A swtichboard shall not be located within _____ of the ground,floor or platform.

Back 37

1.2m

Front 38

Related to protective devicest, Current rating is the maximum current a protective device can carrycontinuously without deterioration.

Back 38

True

Front 39

Accoring to the method of mounting,RCBO are classified in the following ways that areSelect one or more:

Back 39

Surface-tyep RCBO, Flush-type RCBO, Panel board type RCBO, also referred to as distribution board type

Front 40

Regulation _____ specifies the installation work requiring inspection by aregistered electrical inspector prior to connection to the power supply.

Back 40

70