1. Home
2. HSC
3. HSC Exams
4. 2015 HSC Exam papers
5. 2015 HSC Notes from the Marking Centre — Electrotechnology

# 2015 Notes from the Marking Centre – Electrotechnology

## Introduction

This document has been produced for the teachers and candidates of the Stage 6 Electrotechnology course. It contains comments on candidate responses to the 2015 Higher School Certificate examination, highlighting their strengths in particular parts of the examination and indicating where candidates need to improve.
This document should be read along with:

## Section II

Candidates showed strength in these areas:

• listing a number of specific forms of personal protective equipment (PPE) in relation to WHS requirements(Q16)
• identifying the relevant light or power circuit to be isolated (Q17)
• recognising the importance of isolating, locking-out, danger tagging and providing contact details of workers listed on the Danger tag (Q17)
• identifying the test equipment needed (Q17)
• recognising the centre line symbol (Q18a)
• determining marking out procedures, including ruling, scribing, measurements and centre punching (Q18b)
• providing two valid examples of faults that would prevent L1 from being illuminated (Q19)
• providing two valid testing methods for the identified faults for L1 (Q19)
• recognising that L1 could be faulty and swapping it with L2 as a testing method (Q19)
• constructing a series and parallel circuit from the components listed (Q20)
• correctly positioning the switch, ammeter and voltmeter in the circuit showing correct polarity (Q20)
• drawing a complete circuit diagram with resistors R1 and R2 being configured in parallel which were in turn in series with resistor R3 (Q20)
• choosing the correct formula to calculate the equivalent resistance of the circuit with S1 open (Q21a)
• recognising that R3 is in parallel to the supply voltage and using this value to calculate the current in R3 using the correct formula I=V/R (21b)
• demonstrating understanding of the parallel circuit by recognising that R5 is in series with R6 and that both R5 and R6 are in parallel with the supply (Q21c)
• recognising that the total resistance of each branch in the circuit is the same and therefore once S1 is closed 1 Ampere of current will flow in each branch giving a total circuit current of 4 Amperes (Q21d)
• selecting the correct power formula (Q21e).

Candidates need to improve in these areas:

• stating the basic PPE required when working outdoors on a construction site, for example, safety footwear, hard hat and high visibility clothing (Q16)
• providing a detailed list of test equipment needed to be used for light or power circuit isolation (Q17)
• outlining that part of the isolation procedure is testing the test equipment on a known power source, testing the isolated circuit, then testing the test equipment again to show the corrected operation in order to safely begin work on the circuit (Q17)
• identifying the symbol for a countersunk hole (Q18a)
• identifying feature A (Q18b)
•  identifying conventional drawing symbols including centre lines, countersink, external diameters, and metric thread sizing (Q18b)
• outlining the correct procedure for drilling and tapping a thread in mild steel, including the correct size of pilot drills and drills used to tap the internal M16 thread (Q18)
• using their knowledge of DC circuits in regards to voltage and current when troubleshooting faults in a circuit (Q19)
• recognising the correct relationship and connection of circuit components such as an ammeter, voltmeter, switch and fuse in a circuit, as well as the correct polarity indicators of specific circuit components (Q20)
• calculating the correct answer for the equivalent resistance value in Ohms with S1 open (Q21a)
• calculating a correct answer in Ohms (Q21b)
• understanding that the supply voltage with be dropped across R5 and R6 as they are series connected (Q21c)
• proving the increase in total circuit current of 1 Ampere is due to the addition of another branch resistance of 60 Ohms (Q21d)
• performing the correct substitution for multiple or submultiple calculations (Q21e).

## Section III

Question 22
Candidates showed strength in these areas:

• demonstrating a general knowledge of energy efficiency in relation to the design and construction of a new dwelling by including examples such as energy-efficient light fittings, solar panels, solar hot water and gas hot water systems, skylights, larger windows for light and natural ventilation, time switches, insulation in roof and under floor, and building and room orientation
• providing a number of specific examples of building design considerations and stating different types of materials, fittings and appliances that could be used
• demonstrating knowledge of the use of energy-efficient appliances based on the star rating of the energy consumption
• discussing in greater depth the operation and impact that materials, fittings and appliances have on building design and construction.

Candidates need to improve in these areas:

• addressing how energy efficiency can be achieved rather than simply providing examples of energy-efficient appliances
• justifying how these items can work together as a more complex system to provide energy efficiency
• using industry terminology.

## Section IV

Question 23
Candidates showed strength in these areas:

• identifying the need to coordinate between trades such as concreters, bricklayers, plumbers, gyprockers, carpenters and painters
• providing an in-depth discussion on trade coordination and their place in the construction sequence
• identifying the need for temporary builders’ supply and the underground electrical mains installation in relation to other services
• providing a task that an electrician would be required to undertake in the construction of a new dwelling
• providing risks hazards and some controls
• recognising the need for signage, barricades and PPE as part of a Safe Work Method Statement.

Candidates need to improve in these areas:

• specifically addressing where electrical installation fits into the construction sequence
• improving understanding of electrical installation work at a construction level, such as roughing in and fitting out
• providing examples of control measures, monitoring, and documentation
• using the Safe Work Method Statement as a potential guide to structuring a logical, sequenced extended response
• considering all aspects of the question
• providing more detail in procedure.