Power switching
Where would you find a simmerstat?
Electric oven
Hotplate
Name four types of Residual current devices
RCCB - Residual current without overcurrent protection
RCBO - Residual current with overcurrent protection
SRCD - Socket outlet RCD
PRCD - Portable RCD
What is the purpose of a legend on a plan?
Explains the meanings of symbols & explains any abbreviated terms on the plan
What are the Pythagoras formulas?
c2 = a2 + b2
a2 = c2 - b2
What is a precaution that must be taken with halogen lamps?
Do not touch the lamp with bare hands as you will leave oils on the glass which will cause it to degrade
Explain how an extra start button would be installed in a circuit
In parallel
Describe the rupturing capacity of an MCB
The maximum fault current a protective device can safely interrupt, normally measured in kA
Explain the operation of a block diagram
Drawn in block form, describing the operation of an installation. This only shows the sequence of the circuit
Draw on the whiteboard the three trigonomic formulas?
sin angle = Opp/Hyp
cos angle = Adj/Hyp
tan angle = Opp/Adj
ITS A ROBBERY!!
Explain the stroboscopic effect
The stroboscopic effect where equipment may appear to be not moving or moving slower than it is
Explain the three most common light switching circuits
DOUBLE POINTS!!
If you can accurately draw all three
One way
Two way
Intermediate
Name the types of electrical fault where protection must be provided
Short circuits
Leakage current
Overcurrent
Explain the purpose of a scale on a drawing
A scale is needed for workers to measure off the plan & be able to find the actual measurements to install equipment on site
ITS A ROBBERY!!
What is the RCD tripping time for a type 1 RCD in a school up to year 8?
10mA
300ms
What are the five considerations for good lighting
Minimum levels of glare
Uniform levels of illuminance throughout the area
Suitable colour rendering
Suitable colour appearance
Correct illuminance for the area
Explain how an extra stop button would be installed in a circuit
DOUBLE POINTS!!
If you can explain why this is so important
In series
DOUBLE POINTS!!
How many modes of operation does a MCB have?
Thermal, magnetic and Thermal-magnetic
Explain the operation of a schematic diagram
Shows the operational sequence of a circuit, components are shown in de-energised position
Where is the phase located in an Edison screw light fitting?
Connected to the centre terminal
Explain the Kelvin scale
The higher the Kelvin 5000K +, the bluer the colour.
The lower the Kelvin 2500K & below the more orange & red the colour
What does a PLC do?
Input - Recieves signals from sensors, switches & other inputs
Output - Sends signals to output devices motors, valves & actuators
ITS A ROBBERY!!
Describe the operating times and test currents for RCDs
Type 1
10mA 40ms
Type 2
30mA 300ms
Explain the purpose of a location diagram
A location diagram shows the position of electrical equipment on an architectural plan of a building
What is the maximum appliance resistance value?
1Ω
List the lifespan for lamps
Incandescent 1000 - 4000 hours
Compact fluro 8,000 - 12,000 hours
Linear fluro - +30,000
LED - 25,000 - 100,000 hours