Supply
What is the percentage of hydro generation in New Zealand?
65%
Where must the neutral be connected in an Edison screw lamp fitting?
On the outer sheath
What is the definition of High voltage?
Exceeding 1000v AC or 1500v DC
How far into the ground does an earth stake need to be driven?
1800mm/ 1.8m
What is the purpose of earthing the neutral?
Limiting each phase voltage to 230v in reference to earth
What are suitable transmission voltages in New Zealand?
110-220kv
What are the series circuit rules?
Vt = V1 + V2
I is constant
Rt = R1 + R2
ITS A ROBBERY!!
In reference to high voltage, what does MAD stand for and explain how they relate to voltage
Minimum approach distance
The higher the voltage, the greater the minimum approach distance (M.A.D)
What does the square inside of a square indicate?
A double insulated appliance/tool
Explain a PELV transformers connections
PELV has an earth connection on both the primary and secondary sides of the transformer
DOUBLE POINTS!!
Name the types of Electrical generation in New Zealand
Hydro
Geothermal
Thermal
Wind
Solar
Give the symbol, factor and mathematical factor for micro
µ
10-6
0.000001
What are the dangers of working in high voltage?
Electric shock
Arc flash
Burns
Fire
What are the six essential parts of the earthing system?
Protective earthing conductors
Main earthing conductor
Main earthing bar
MEN Link
Earth electrode
Equipotential bonding
Explain a SELV transformers connections
DOUBLE POINTS!!
Explain the exception
There is an earth connection on the primary winding & the secondary winding has no earth connection.
A double insulated transformer will not have an earth connection to the primary side
Explain how a solar panel works
A thin junction of two semi conductors. Light is shone on the panel and converted to DC, the DC goes through an inverter and is converted into AC
What is the maximum main earth resistance value?
0.5Ω
Explain what "works" are
Fittings that are used, or designed or intended for use, in or in connection with generation, conversion, transformation, or movement of electricity
DOUBLE POINTS!!
What must an earth tag have written on it?
Where must this be located?
"Main earthing conductor - Do not disconnect"
At the connection to the earth electrode & at the earth busbar
Explain a MEN earthing system with its components
Earth electrode Equipotential bonding
Earth lead MEN link
Earth busbar
Explain the difference between Star & Delta configurations?
Star configuration is when one end of each of the three windings are connected to a common point an earthed neutral
Delta configurations are connected end to end in a closed loop
ITS A ROBBERY!!
What are the operating time & current for a type 2 RCD?
30mA
300ms
DOUBLE POINTS!!
Explain the difference between step & touch voltage
Step voltage is the voltage present in the ground near electrical equipment, a step voltage has their legs complete the circuit.
Touch voltage - Can be present on the surface of electrical equipment, a touch voltage will have current going through the heart
Where in a circuit must you test for earth loop impedance?
At the furthest point from the switch board
Why does the earth fault loop impedance have to be low?
If a large fault current flows, the protective device will operate quickly and effectively