3rd Year Electrical Trades Qualification (TQ) Practice Exam

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• What is the primary purpose of a 3-way mixing valve in a heating system?
• How are boilers rated?
• Hipot test is used to assess what aspect of electrical equipment?
• In a simple resistive circuit with a 9 V source and a 3 Ω resistor, what is the current?
• Why are earthing and bonding essential for electrical safety and fault clearance?
• What is the purpose of earth electrode resistance measurements and how would you interpret a high reading?
• An additional circuit vent is required after what angle change?
• What is the function of an RCD and what is a typical domestic trip current?
• What sensing element is used in a gas stove?
• On a commercial hot-water tank, why is the vacuum relief located on top of the tank?
• Branch and building drains downstream of the third WC fixture drain connections shall not be less than?
• State the standard domestic supply in Australia.
• In steam systems, a pigtail protects components from which condition?
• What is the standard formula for real power in a balanced three-phase circuit?
• Non-positive vent pressure is categorized as which category?
• Which surface transmits heat away from a propane container?
• Which protection is provided by a MCB as opposed to an RCCB?
• What voltage is used on the power control side?
• Which device is a thermistor?
• What is the primary role of a distribution board in a building electrical system?
• For gas pressure testing of lines 200 ft or longer, what pressure is used?
• How far should discharge from a regulator be from a building?
• What kind of diagram is described in the notes?
• What does selectivity in protection design aim to achieve?
• What is the gas line size for a #8 gas line?
• Piping must be tested to what pressure?
• Is a dip tub required on a bottom feed in the example?
• How should a termination vent located 20 feet outside a building be installed?
• What is the typical sequence for testing a new installation before energisation?
• Which gas appliances can be vented using B vent according to the data?
• In the data, what value is associated with gas meters?
• In a three-phase system, an L-G fault is an example of which fault type?
• What is the specified spacing between gang showers?
• What is the numeric value corresponding to 3360 cf in the example?
• What is the sum of 0.7854 and 0.3927?
• In a mechanical room, what is the ideal location for the fresh air intake?
• For a conductor with ampacity 25 A, what is the maximum protective device rating that should be used?
• Which statement reflects the minimum vertical height for a duct vent?
• What is the size of the vent header mentioned?
• What pressure is a second stage regulator set at?
• Which statement correctly differentiates soft starters from variable frequency drives?
• What test voltages are typically used for insulation resistance testing on low-voltage circuits?
• Name two ways to limit inrush current for motor loads and when each is appropriate.
• Which action can improve power factor?
• How can a trap seal be maintained?
• What is considered proactive when installing a heating supply?
• How far above the roof must a vent terminate?
• Rate of flammability C3H8
• Armoured cable description.
• What is the min height of duct vent?
• Location of relief valve from top of the tank?
• Which factors influence selection of cable insulation type and temperature rating?
• Which set correctly defines the three types of electrical power and their standard symbols?
• What is the maximum length of a 3-inch trap arm installed with a slope of 1/4 inch per foot (1:50)?
• If you have a chimney with a dirty number, what should you do?
• A semi-continuous flow pump has a discharge of 8.3 GPM. What is the fixture unit load?
• How would you decide between using an RCCB, an RCBO, or both on a circuit?
• Where should radiant floor heating not be installed?
• What does T.C.A stand for in the context of gas volumes?
• Spacing for gang showers?
• Where should the relief vent be added on a bank of eight lavatories?
• How far from the top of a tank should the relief valve be located?
• Which statement about the neutral conductor in a balanced three-phase system is correct?
• A distribution board provides which of the following protections for branch circuits?
• What is the square root of (1.1781 divided by π) approximately equal to?
• In insulation resistance testing, what does a low leakage resistance reading indicate?
• Which test is used to blow out the pilot?
• What is the calorific value of propane (C3H8)?
• What is protective device coordination and why is it important?
• The specific gravity of propane liquid is which value?
• What is the purpose of the heat anticipator in a room thermostat?
• Which valve is typically equipped with a strainer?
• To differentiate a steam boiler from a water boiler, which feature is commonly used?
• Which earthing arrangement uses a local earth electrode?
• On an exterior wall, how many propane tanks are allowed?
• What causes harmonic distortion and what issues may result?
• What is half of 0.7854?
• What is the minimum clearance required around a gas appliance?
• FU stands for Fixture Units, used to represent which in drainage calculations?
• How would you verify the polarity of a newly installed single-phase receptacle?
• What is the gas allowed as a fuel in the example?
• Which three factors are used to calculate heat loss?
• Armoured cable is used where?
• What is the size of the domestic cold water supply noted for the scenario associated with the entry labeled 'question 6'?
• What is the gas line size for a #4 gas line?
• How do ambient temperature and weather affect conductor ampacity and why?
• Under what condition can multiple floor drains share a single trap?
• What piping arrangement is considered the most balanced?
• A 750 square foot area using 1/2 inch PEX requires how many loops?
• Which symbol represents a solenoid in circuit diagrams?
• Tempered water is produced at the output of which device?
• Core losses in transformers are comprised of hysteresis and eddy currents.
• In a wet vent system with seven lavatories, where is the vent connected?
• To adjust the grade on a flush valve WC, which component is adjusted?
• To size a pump, which two parameters are required?
• What is the grade on a 6 inch pipe?
• Which valve is specified on the hot water tank piping recirculation line?
• What is the primary purpose of the AS/NZS 3000 Wiring Rules in electrical installations?
• Which loads typically cause harmonic distortion and what issues may result?
• Which venting option is named for the double-wall scenario?
• What is the purpose of the vacuum relief on a commercial hot water tank?
• Which height is appropriate for vent termination above the roof?
• How do you calculate voltage drop along a conductor and what typical limits apply?
• Which vent type is explicitly named as a fix option in the material?
• Why are two vents required when venting an oil interceptor?
• Outline the procedure and purpose of an insulation resistance test.
• In a multi-purpose system, which load takes priority?
• What is the area of a circle with radius 0.5 units?
• What is the purpose of a LWCO?
• In steam systems, the pigtail is used to protect components from exposure to which condition?
• Which device provides earth-leakage protection by sensing residual current?
• Which type of solar heating requires careful placement of windows?
• Which hydrocarbon name corresponds to CH4?
• Which losses primarily determine transformer efficiency?
• In TN-S earthing, what is true?
• Where is the relief valve on a propane tank positioned?
• What is the final value after multiplying 0.6124 by 2 and rounding to the nearest quarter inch?
• Which value represents the calorific value of methane in the given data?
• What is the role of protective bonding across exposed metal services in a building?
• Which of the following represents the three hydrocarbons listed?
• Which earthing arrangement uses a PEN conductor up to a point, then splits into PE and N?
• Which valve is associated with a strainer?
• What is the size of the domestic cold water supply noted for the scenario associated with the entry labeled 'question 10'?
• What is the required gas pressure test for piping 200 feet or less?
• Name two common motor starting methods and a design consideration for choosing between them.
• In motor control circuits, which device acts as the main switch controlled by control signals to energize or de-energize the motor?
• For a transformer with turns ratio n = N_secondary / N_primary, which statement is true?
• Copper losses in a transformer are caused by winding resistance.
• In a three-phase circuit with VL = 400 V, IL = 20 A, and PF = 0.85, calculate real power.
• For gas pressure testing of lines 200 ft or longer, how long should the test be held?
• What size pipe is used to dual vent two toilets?
• Rate of flammability CH4
• Which formulas correctly define P, Q, S, and PF for an AC circuit?
• How far should the pilot flame engulf the thermocouple?
• What is the primary benefit of proper protective device coordination?
• What is the GPM discharge value used in the fixture unit calculation?
• In a three-phase winding, what is a key difference between Y (star) and Δ (delta) connections?
• Define earth fault loop impedance and its significance for protective devices.
• Which option lists the fuel quantity for a 250 MBH appliance in the example?
• Where should combustion air terminate indoors?
• Distinguish between equipotential bonding and protective bonding.
• What step should be taken for a chimney issue described as dirty (pull a liner)?
• What is the expansion rate of propane per pound?
• What is the minimum concrete cover over tubing?
• Discharge of the air inlet for a regulator should be directed in which orientation relative to the inlet and at what distance?
• What is the primary function of a motor starter in electrical installations?
• Which option represents propane in the given options?
• What is the size of the building drain in the notes?
• A three-way mixing valve is used to maintain return temperature by blending which streams?
• Which term describes the feature distinguishing steam boilers from hot-water boilers?
• What is the effect of taking an amp reading across a valve coil?
• In a star-connected system, the line voltage equals the phase voltage multiplied by √3.
• What is the purpose of bonding continuity testing during commissioning?
• Propane combustion products consist of which substances?
• Which factor is essential when designing lighting to meet prescribed illuminance levels?
• Clocking a meter with a two-foot dial for 45 seconds yields which reading?
• As part of commissioning, which combination of tests verifies insulation, bonding, polarity, and device settings before energisation?
• To convert a GPM discharge to a fixture unit load, which operation is used in the example?
• If earth electrode resistance is very high, what consequence is likely?
• The power control side typically operates at which voltage?
• When using a clamp-on ammeter, how many wires are clamped?
• In the example, which gas-quantity option is listed for a 250 MBH appliance input?
• For a double-wall single-appliance, fan-assisted vent, if the chart number didn’t work, which vent should be installed?
• In a single-phase circuit with V = 230 V and R = 20 Ω, what is the current?
• When air supply source is mechanically controlled, it should be
• Poor voltage regulation effects.
• Which expression correctly computes active power P in a balanced AC circuit?
• What is a simple way to decrease the output of a cast iron radiator?
• Which expression correctly defines apparent power S in terms of P and Q?
• To adjust the grade of a flush valve WC, which component is adjusted?
• In a mechanical room, the fresh air intake should be located how far from the floor and near which appliance?
• What is the net rating range for transmission losses?
• Define symmetrical and asymmetrical faults in a three-phase system.
• What is the calorific value of methane (CH4)?
• What are the products of combustion stated?
• Voltage regulation describes how output voltage changes with load. Which option best expresses this?
• Outline the sequence for commissioning a new installation from documentation to energisation.
• Which is a correct step in lockout/tagout procedure before electrical maintenance?
• What is the clean out size on a branch serving six lavatories?
• For a vent termination located 20 feet outside, which orientation and feature are required?
• Gas pressure test for lines 200 ft or more requires which pressure and duration?
• What is the maximum temperature on a fan high-limit switch?
• The storm drain or rain water leader is sized at what diameter?
• Which set of substances is listed as products of combustion?
• Propane combustion products include which substances?
• What is the common vent size for a regulator vent at 19 feet?
• What is the required stub-out length for gas pipe installed through a floor, excluding threads?
• What is a continuity test and what does a low resistance reading indicate?
• Grade on a 6" pipe?
• How is the rain water leader sizing determined?
• If a circuit has impedance Z = 10 + j30 Ω and supply voltage V = 230 V, what is the current magnitude?
• How many hangers are required for a 1-1/4 inch gas line spanning 120 feet?
• Who is identified as the prime contractor?
• How is AC conductor voltage drop typically calculated in practice?
• Which material would collect the most grease?
• What is the specific gravity value of natural gas as given in the material?
• Which material would accumulate the most grease?
• Define impedance and its effect on current in an AC circuit.
• With a slope of 1:50, what is the maximum length for a 3-inch trap arm?
• What is a primary advantage of using a variable frequency drive over a soft starter?
• What is the best way to equalize a heating system?
• In boiler rating terminology, which term describes the output after losses are accounted for?
• Which vent type is installed when the chart number doesn’t work?
• Which piping arrangement provides the most balanced flow in a heating system?
• Radiant floor systems overshoot most in which space?
• What are the main considerations when designing lighting to meet prescribed illuminance levels?
• What is an important consideration when selecting a steam trap?
• Line-to-line vs line-to-neutral voltages in a three-phase system are related how in a Y system?
• Which unit is commonly used to describe pump flow?
• The regulator air inlet discharge should be directed how, to maintain proper clearance?
• What is the slope ratio for a 150 mm storm drain?
• When pouring concrete over pipes, what must be maintained to prevent damage?
• Which symbol is used to represent a solenoid in schematics?
• If you measure current across a valve coil, what is the likely outcome?
• In a distribution board, what is the typical role of MCCBs and fuses?
• Identify the symbol used for a resistor in circuit diagrams.
• The specific gravity of propane liquid is equal to which value?
• What type of meter is used to measure current without breaking the circuit?
• What is the maximum working pressure for a fixture?
• How much gas pipe has to stub out of the floor not including threads
• Which unit is used to measure gas quantities in the example?
• Gas stoves typically use which sensing element?
• If the air supply is mechanically controlled, its operation must be connected to what other system component?
• How much gas is required to heat 200 imperial gallons of water from 50°F to 150°F in a 90% efficient hot water heater?
• Why is reducing inrush current important and which methods can be used?
• How much of the pilot flame should engulf the thermocouple?
• In a balanced three-phase system, what is the neutral current?
• Where should the relief vent be placed when venting a bank of lavatories?
• If 750 divided by 300 equals 2.5, rounding up gives how many loops?
• Which protective device is commonly used for adjustable overcurrent protection in distribution circuits?
• HWT stands for which term in the piping notes?
• Where is the relief valve placed on a propane tank?
• Which gas has a flammability range that includes 2-10 percent?
• The notes indicate that multiple floor drains may share a trap only if they are in the same room and not located near which of the following?
• What is the minimum obstructed walkway size to an appliance?
• In the heat loss formula design temp x U value x area, which term represents the material's conductive property?
• Which symbol is used to represent a resistor in schematics?
• The test used to extinguish the pilot is called which of the following?
• Which diameter is used for the storm drain or rain water leader?
• If a turndown test fails, what corrective action should be taken?