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Assam HS Skill Electrical Mechanics and Electrician study materials
Assam HS Skill Electrical Mechanics and Electrician study resources

Assam HS Skill Electrical Mechanics and Electrician practice questions

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Question 1Basic Electrical Theory and Fundamentals

In a DC circuit, which quantity is defined as the rate at which electrical energy is converted into another form of energy?

  1. Electric power Correct answer.
  2. Capacitance
  3. Electric charge
  4. Resistance

Explanation

Electric power is the rate of energy transfer, measured in watts, where one watt equals one joule per second. Charge, resistance and capacitance describe stored charge, opposition to current and charge storage respectively, not energy conversion rate.

Question 2Basic Electrical Theory and Fundamentals

A resistor of 20 Ω carries a current of 0.5 A. What is the voltage across it?

  1. 4 V
  2. 0.025 V
  3. 40 V
  4. 10 V Correct answer.

Explanation

Ohm's law states V = I × R, so 0.5 A × 20 Ω = 10 V. Dividing instead of multiplying, or misplacing the decimal, gives the other values.

Question 3Basic Electrical Theory and Fundamentals

Which instrument is connected in series with a circuit to measure the current flowing through it?

  1. Megohmmeter
  2. Voltmeter
  3. Wattmeter
  4. Ammeter Correct answer.

Explanation

An ammeter has very low resistance and is placed in series so that the whole circuit current passes through it. A voltmeter is connected in parallel, a wattmeter needs both current and voltage connections, and a megohmmeter measures insulation resistance.

Question 4Basic Electrical Theory and Fundamentals

Two resistors of 6 Ω and 3 Ω are connected in parallel. What is the equivalent resistance?

  1. 9 Ω
  2. 2 Ω Correct answer.
  3. 18 Ω
  4. 4.5 Ω

Explanation

For two resistors in parallel, the product over sum gives (6 × 3)/(6 + 3) = 18/9 = 2 Ω. The equivalent value is always smaller than the smallest branch resistance, which rules out 9 Ω, 4.5 Ω and 18 Ω.

Question 5Basic Electrical Theory and Fundamentals

Which material is the best conductor of electricity among the following?

  1. Dry wood
  2. Copper Correct answer.
  3. Glass
  4. Rubber

Explanation

Copper has a large number of free electrons and very low resistivity, making it a standard conductor for wiring. Rubber, glass and dry wood have very few free charge carriers and behave as insulators.

Question 6Basic Electrical Theory and Fundamentals

In a purely capacitive AC circuit, the current does what relative to the applied voltage?

  1. Lags the voltage by 90 degrees
  2. Leads the voltage by 90 degrees Correct answer.
  3. Is exactly in phase with the voltage
  4. Leads the voltage by 45 degrees

Explanation

In a capacitor the current reaches its maximum before the voltage does, so current leads voltage by 90 electrical degrees. Inductors show the opposite behaviour, with current lagging by 90 degrees.

Question 7Basic Electrical Theory and Fundamentals

What is the frequency of a supply whose voltage completes 50 cycles in one second?

  1. 25 Hz
  2. 100 Hz
  3. 0.02 Hz
  4. 50 Hz Correct answer.

Explanation

Frequency is the number of complete cycles per second, measured in hertz. Fifty cycles in one second therefore equals 50 Hz, and the periodic time is the reciprocal, 0.02 s.

Question 8Basic Electrical Theory and Fundamentals

Which safety practice is correct before working on a domestic distribution board?

  1. Switch off the main switch, lock it off and confirm dead with a tester Correct answer.
  2. Ask an apprentice to hold the main switch lever in the off position
  3. Wear rubber slippers and work with both hands
  4. Stand on a dry wooden chair and touch the live busbar

Explanation

Isolation, locking off and proving dead are the essential steps to prevent accidental re-energisation and electric shock. Protective equipment alone does not make live working safe, and relying on another person is not a reliable lock-off.

Question 9Basic Electrical Theory and Fundamentals

A 100 W lamp runs for 10 hours. How many kilowatt-hours of energy does it consume?

  1. 0.1 kWh
  2. 1 kWh Correct answer.
  3. 10 kWh
  4. 1000 kWh

Explanation

Energy in kWh equals power in kilowatts multiplied by time in hours, so 0.1 kW × 10 h = 1 kWh. Forgetting to convert watts to kilowatts gives the wrong result.

Question 10Basic Electrical Theory and Fundamentals

Three 4 Ω resistors are connected in series across a 24 V supply. What current flows?

  1. 2 A Correct answer.
  2. 0.5 A
  3. 6 A
  4. 18 A

Explanation

Series resistances add to 12 Ω, and Ohm's law gives I = 24/12 = 2 A. Using a single resistor or adding voltages instead of resistances produces the other answers.

Question 11Basic Electrical Theory and Fundamentals

A wire of resistance 8 Ω is cut into two equal halves which are then connected in parallel. What is the resistance of the combination?

  1. 16 Ω
  2. 2 Ω Correct answer.
  3. 8 Ω
  4. 4 Ω

Explanation

Cutting the wire halves its length, so each piece is 4 Ω. Two 4 Ω resistors in parallel give 4/2 = 2 Ω, because resistance falls with both shorter length and parallel paths.

Question 12Basic Electrical Theory and Fundamentals

In a series circuit containing a 30 Ω and a 60 Ω resistor, which statement about current and voltage is correct?

  1. The voltage across both resistors is equal
  2. The current through the 60 Ω resistor is half that through the 30 Ω resistor
  3. The current through both resistors is the same, and the 60 Ω resistor drops twice the voltage Correct answer.
  4. The 30 Ω resistor drops twice the voltage of the 60 Ω resistor

Explanation

In a series circuit the same current passes through every element, and voltage divides in proportion to resistance. Since 60 Ω is twice 30 Ω, it develops twice the voltage drop.

Question 13Basic Electrical Theory and Fundamentals

What is the effective value of a sinusoidal AC voltage whose peak value is 100 V?

  1. 141.4 V
  2. 50 V
  3. 70.7 V Correct answer.
  4. 100 V

Explanation

The RMS or effective value equals the peak divided by the square root of two, so 100/1.414 ≈ 70.7 V. Multiplying by 1.414 instead gives the peak from the RMS value.

Question 14Basic Electrical Theory and Fundamentals

A coil has an inductive reactance of 30 Ω and a resistance of 40 Ω in series. What is the impedance of the coil?

  1. 70 Ω
  2. 10 Ω
  3. 50 Ω Correct answer.
  4. 1200 Ω

Explanation

Impedance is the phasor sum of resistance and reactance, so Z = √(40² + 30²) = √2500 = 50 Ω. Simple addition of the two values gives 70 Ω, which ignores the 90-degree phase difference.

Question 15Basic Electrical Theory and Fundamentals

Which statement correctly describes the magnetic field produced by a straight current-carrying conductor?

  1. It consists of concentric circles around the conductor, with direction given by the right-hand grip rule Correct answer.
  2. It runs parallel to the conductor in the direction of current
  3. It is a uniform field parallel to the conductor everywhere
  4. It exists only inside the conductor

Explanation

A current produces a circular magnetic field around the conductor, and the right-hand grip rule links current direction to field direction. The field strength falls with distance from the conductor and is not confined inside it.

Question 16Basic Electrical Theory and Fundamentals

Which device works on the principle of electromagnetic induction?

  1. A mercury switch
  2. A thermocouple
  3. A transformer Correct answer.
  4. A carbon resistor

Explanation

A transformer transfers energy between windings through a changing mutual flux, which is electromagnetic induction. Resistors, thermocouples and mercury switches rely on conduction, thermoelectric effect and mechanical contact respectively.

Question 17Basic Electrical Theory and Fundamentals

A capacitor of 10 µF is connected across a 100 V DC supply and fully charged. What charge does it store?

  1. 10 mC
  2. 1 mC Correct answer.
  3. 0.1 mC
  4. 1000 C

Explanation

Charge equals capacitance times voltage, Q = C × V = 10 × 10⁻⁶ F × 100 V = 1 × 10⁻³ C, which is 1 mC. Errors in handling microfarads produce the other values.

Question 18Basic Electrical Theory and Fundamentals

Why is a laminated core used in a transformer instead of a solid iron block?

  1. To increase the weight of the core for stability
  2. To eliminate hysteresis loss completely
  3. To reduce eddy current losses in the core Correct answer.
  4. To increase the resistance of the windings

Explanation

Laminations interrupt the paths of circulating eddy currents, greatly reducing eddy current heating in the core. Hysteresis loss depends on the core material, not on lamination, and winding resistance is unaffected.

Question 19Basic Electrical Theory and Fundamentals

Two lamps rated 60 W and 100 W at the same supply voltage are connected in series across that voltage. Which lamp glows brighter?

  1. Both glow equally because the current is the same
  2. The 100 W lamp, because it has higher rated power
  3. Neither glows because the circuit is incomplete
  4. The 60 W lamp, because it has higher resistance and carries the same current Correct answer.

Explanation

The 60 W lamp has the higher resistance, since P = V²/R. In series both carry the same current, so the higher-resistance lamp dissipates more power and glows brighter.

Question 20Basic Electrical Theory and Fundamentals

A cell of 12 V EMF and 1 Ω internal resistance supplies a 5 Ω load. What is the terminal voltage?

  1. 12 V
  2. 7 V
  3. 10 V Correct answer.
  4. 2 V

Explanation

The current is 12/(5+1) = 2 A, and the internal drop is 2 A × 1 Ω = 2 V, so terminal voltage is 12 − 2 = 10 V. Ignoring internal resistance gives the full EMF.

Question 21Basic Electrical Theory and Fundamentals

An AC circuit draws 5 A at 230 V with a power factor of 0.8. What is the active power consumed?

  1. 1840 W
  2. 575 W
  3. 1150 W
  4. 920 W Correct answer.

Explanation

Active power equals V × I × power factor, so 230 × 5 × 0.8 = 920 W. The product V × I gives apparent power in volt-amperes, not active power.

Question 22Basic Electrical Theory and Fundamentals

Kirchhoff's current law is applied at a junction where three currents meet: 4 A and 3 A enter, while one current leaves. What is the leaving current?

  1. 12 A
  2. 1 A
  3. 5 A
  4. 7 A Correct answer.

Explanation

Kirchhoff's current law states that the sum of currents entering a junction equals the sum leaving it. Therefore the leaving current is 4 + 3 = 7 A.

Question 23Basic Electrical Theory and Fundamentals

A 230 V, 50 Hz supply feeds a coil of inductance 0.1 H and negligible resistance. What is the inductive reactance?

  1. 5 Ω
  2. 31.4 Ω Correct answer.
  3. 314 Ω
  4. 15.7 Ω

Explanation

Inductive reactance is X = 2πfL = 2 × 3.14 × 50 × 0.1 ≈ 31.4 Ω. Using the supply voltage or forgetting the factor of 2π gives the other options.

Question 24Basic Electrical Theory and Fundamentals

Two 100 W, 230 V lamps are connected in parallel across a 230 V supply. What total current is drawn?

  1. 0.87 A Correct answer.
  2. 1.74 A
  3. 0.435 A
  4. 2.3 A

Explanation

Each lamp draws 100/230 ≈ 0.435 A, and parallel branches add, giving about 0.87 A total. Treating them as series or doubling incorrectly gives the other values.

Question 25Basic Electrical Theory and Fundamentals

In an RLC series circuit at resonance, which condition holds?

  1. The circuit current is zero because the reactances cancel
  2. Inductive reactance equals capacitive reactance and they cancel, leaving impedance equal to resistance Correct answer.
  3. The power factor becomes zero
  4. Resistance equals inductive reactance and capacitive reactance is zero

Explanation

At resonance X_L equals X_C, so the net reactance is zero and impedance reduces to resistance alone. The current is then maximum and the power factor is unity, not zero.

Question 26Basic Electrical Theory and Fundamentals

Which material is the standard conductor used for the coil winding in a transformer because of its low resistivity?

  1. Nichrome
  2. Carbon
  3. Tungsten
  4. Copper Correct answer.

Explanation

Copper has a low resistivity (about 1.68 × 10⁻⁸ Ω·m), so coils wound with it have low I²R losses and high efficiency. It is also ductile and easy to wind, making it the standard choice for transformer windings.

Question 27Basic Electrical Theory and Fundamentals

A 12 V battery is connected across a 4 Ω resistor. What power is dissipated in the resistor?

  1. 36 W Correct answer.
  2. 0.33 W
  3. 3 W
  4. 48 W

Explanation

Power can be calculated as P = V² / R. Substituting V = 12 V and R = 4 Ω gives P = 144 / 4 = 36 W. This is the rate at which electrical energy is converted to heat in the resistor.

Question 28Basic Electrical Theory and Fundamentals

Two resistors of 6 Ω and 3 Ω are connected in parallel across a 12 V supply. What is the total current drawn from the supply?

  1. 4 A
  2. 2 A
  3. 1.33 A
  4. 6 A Correct answer.

Explanation

The equivalent resistance of 6 Ω and 3 Ω in parallel is (6 × 3)/(6 + 3) = 2 Ω. The total current is then I = V / R = 12 / 2 = 6 A. Alternatively, branch currents are 2 A and 4 A, summing to 6 A.

Question 29Basic Electrical Theory and Fundamentals

A coil has a resistance of 8 Ω and an inductive reactance of 6 Ω at a given frequency. What is the phase angle between the applied voltage and the current?

  1. 30.0°
  2. 53.1°
  3. 45.0°
  4. 36.9° Correct answer.

Explanation

The phase angle θ is given by tan θ = X_L / R = 6 / 8 = 0.75. Taking the arctangent gives θ ≈ 36.9°, with the voltage leading the current. This follows from the impedance triangle where R is the adjacent side and X_L is the opposite side.

Question 30Basic Electrical Theory and Fundamentals

A coil of inductance 0.2 H and resistance 10 Ω is connected to a 230 V, 50 Hz supply. Which value is closest to the current drawn by the coil?

  1. 1.8 A
  2. 23.0 A
  3. 11.5 A
  4. 3.7 A Correct answer.

Explanation

First find the inductive reactance: X_L = 2πfL = 2π × 50 × 0.2 ≈ 62.8 Ω. The impedance is Z = √(R² + X_L²) = √(10² + 62.8²) ≈ 63.6 Ω. The current is then I = V / Z = 230 / 63.6 ≈ 3.6 A, closest to 3.7 A.

Question 31Electrical Wiring, Joints and Installation Practice

Which conductor colour is specified for the earth (protective) conductor in a flexible three-core cable used for a portable appliance in India?

  1. Solid black
  2. Solid red
  3. Solid blue
  4. Green with a yellow stripe Correct answer.

Explanation

Indian and international practice reserves green-with-yellow-stripe insulation exclusively for the protective earth conductor so that it can never be confused with a live or neutral core. Solid black, red and blue are used for phase or neutral conductors depending on the wiring convention.

Question 32Electrical Wiring, Joints and Installation Practice

A joint in a 2.5 sq mm copper conductor of a lighting circuit is to be made inside a ceiling rose. Which practice is correct?

  1. Crimp the joint and leave it resting on the wooden batten
  2. Twist the conductors together and leave them bare inside the rose
  3. Solder the joint and wrap it with insulating tape only
  4. Make a proper joint, insulate it, and enclose it in a suitable box or connector Correct answer.

Explanation

Every joint must be mechanically and electrically sound, insulated, and protected from mechanical damage and moisture. Enclosing the insulated joint in a proper box or connector satisfies the requirement that joints are accessible and protected. Bare twisted or taped joints inside a rose are unsafe and not permitted.

Question 33Electrical Wiring, Joints and Installation Practice

In a domestic single-phase installation, what is the standard function of the main switch at the consumer's point of supply?

  1. It isolates the entire installation from the supply Correct answer.
  2. It steps down the supply voltage
  3. It provides earth leakage protection
  4. It limits the current to each individual sub-circuit

Explanation

The main switch is an isolating device that disconnects the whole installation from the supply for maintenance or emergency. It does not perform current limiting, earth leakage detection or voltage transformation; those duties belong to the MCB, RCCB and transformer respectively.

Question 34Electrical Wiring, Joints and Installation Practice

Which wiring system uses a continuous run of steel conduit with inspection bends and is preferred for concealed installation in a pucca wall?

  1. Concealed conduit wiring Correct answer.
  2. Cleat wiring
  3. Batton wiring
  4. Casing-and-capping wiring

Explanation

Concealed conduit wiring embeds the conduit inside the wall plaster so that conductors can be drawn in later and rewired without disturbing the structure. Cleat, casing-and-capping and batten wiring are all surface systems and cannot be concealed in the same way.

Question 35Electrical Wiring, Joints and Installation Practice

What is the primary purpose of tinning the strands of a copper conductor before making a soldered joint?

  1. To make the conductor flexible
  2. To protect the strands from corrosion and help solder flow evenly Correct answer.
  3. To increase the current-carrying capacity of the joint
  4. To remove the insulation from the conductor

Explanation

Tinning coats the cleaned copper strands with a thin layer of solder, which prevents oxidation and helps the final solder bond flow uniformly through the strands. It does not change the current rating, strip insulation, or affect flexibility.

Question 36Electrical Wiring, Joints and Installation Practice

Which type of joint is used to connect two conductors at right angles where they cross each other without being cut?

  1. Tee joint Correct answer.
  2. Western union joint
  3. Britannia joint
  4. Straight-through joint

Explanation

A tee joint is made where a branch conductor is connected to a main conductor at right angles, and the main conductor may remain continuous. Western union, Britannia and straight-through joints are all used to join conductors end to end.

Question 37Electrical Wiring, Joints and Installation Practice

A fuse in a domestic circuit blows repeatedly. What is the correct first action for the electrician?

  1. Increase the rating of the fuse to the next size
  2. Investigate and rectify the fault causing the overload Correct answer.
  3. Replace it with a fuse wire of thicker gauge
  4. Bridge the fuse holder with a copper wire

Explanation

A fuse is a protective device, and repeated blowing indicates an overload or fault that must be located and corrected. Upsizing or bridging the fuse defeats protection and creates a serious fire risk.

Question 38Electrical Wiring, Joints and Installation Practice

What is the standard purpose of an earth continuity conductor run along with a conduit installation?

  1. To carry the neutral return current
  2. To provide a low-resistance path from metal enclosures to earth Correct answer.
  3. To reduce the voltage drop in the phase conductor
  4. To supply power to the earth electrode

Explanation

The earth continuity conductor bonds all metal parts of the installation to the earth electrode so that fault current flows to earth and operates the protective device. It does not carry normal load current and does not reduce voltage drop in phase conductors.

Question 39Electrical Wiring, Joints and Installation Practice

In a staircase lighting circuit, which switch arrangement allows the lamp to be controlled from two different positions?

  1. Two two-way switches connected as a two-way circuit Correct answer.
  2. One intermediate switch and one one-way switch
  3. One-way switch at each end
  4. Two push-button switches in parallel

Explanation

A two-way lighting circuit uses two two-way (SPDT) switches with the lamp connected to the common of one switch and the supply to the common of the other, with the strapper wires joining the travellers. This allows either switch to change the lamp state independently.

Question 40Electrical Wiring, Joints and Installation Practice

Which wiring accessory is used to terminate a flexible cord entering a metal-clad distribution board so that the cord is not damaged by the sharp edge of the hole?

  1. Cable clip
  2. Junction box
  3. Ceiling rose
  4. Cable gland Correct answer.

Explanation

A cable gland grips the cable and provides a smooth entry through the enclosure wall, preventing abrasion of the sheath. Cable clips secure cables to surfaces, junction boxes enclose joints, and ceiling roses suspend luminaires; none of these protect a cable entry.

Question 41Electrical Wiring, Joints and Installation Practice

A 1.5 sq mm copper conductor is to be joined to a 4 sq mm copper conductor in a junction box. Which method gives a sound electrical joint?

  1. Twist the thinner wire around the thicker one and tape it
  2. Solder the wires side by side without mechanical interlocking
  3. Use a suitable connector or a Britannia-type joint with the thicker wire wrapped by the thinner one and solder it Correct answer.
  4. Crimp both wires into a single small ferrule without matching sizes

Explanation

Where conductors of unequal size are joined, the thicker conductor forms the straight run and the thinner one is wrapped around it, then the joint is soldered and insulated. A proper connector may also be used. Simply twisting, or crimping an undersized ferrule, does not give reliable mechanical and electrical continuity.

Question 42Electrical Wiring, Joints and Installation Practice

What is the main reason for providing a loop-in loop-out (loop-in) system at ceiling roses in domestic lighting wiring?

  1. To eliminate the need for an earth conductor
  2. To allow the lamp to be controlled by a dimmer
  3. To increase the current rating of the lighting circuit
  4. To reduce the number of joints in the live circuit and simplify fault finding Correct answer.

Explanation

The loop-in system carries the supply from rose to rose and drops a switched line to each luminaire, so joints are made at accessible roses rather than in the ceiling. This reduces inaccessible joints and makes testing and fault finding easier. It does not change current rating or earthing requirements.

Question 43Electrical Wiring, Joints and Installation Practice

Which test is performed on a completed installation to verify that the resistance of the earth path is within the permitted limit?

  1. Earth electrode resistance test
  2. Insulation resistance test
  3. Polarity test
  4. Earth continuity test Correct answer.

Explanation

The earth continuity test measures the resistance between the main earthing terminal and exposed metalwork to confirm a low-resistance fault path. Insulation resistance checks insulation integrity, polarity checks correct connection of live and neutral, and earth electrode resistance measures the electrode-to-soil resistance only.

Question 44Electrical Wiring, Joints and Installation Practice

Why is a fuse connected in the phase (line) conductor rather than in the neutral conductor of a single-phase circuit?

  1. Fuses operate only on alternating current in the phase
  2. A blown fuse in the neutral would leave the equipment live Correct answer.
  3. The neutral conductor carries less current than the phase
  4. The phase conductor is easier to reach

Explanation

Protection must disconnect the live supply. If a fuse were placed only in the neutral, blowing it would leave the equipment connected to the live phase, creating a shock hazard during maintenance. Fuses operate on current magnitude, not on which conductor they sit in.

Question 45Electrical Wiring, Joints and Installation Practice

What is the correct procedure for making a married joint between two single-core conductors in a wooden batten installation?

  1. Both conductors are twisted together and left bare
  2. The conductors are joined with a porcelain connector only
  3. Each conductor is wrapped around the other so that the joint is mechanically strong, then soldered and insulated Correct answer.
  4. The conductors are laid parallel and taped without twisting

Explanation

In a married joint the two conductors are wrapped around each other so that each binds the other, giving mechanical strength before soldering. The joint is then soldered and insulated to restore electrical and mechanical integrity. A bare twist, an untwisted taped joint, or a connector alone does not meet the requirement for this joint type.

Question 46Electrical Wiring, Joints and Installation Practice

In a three-phase distribution board, why are the phase conductors of consecutive single-phase sub-circuits distributed across the three phases?

  1. To reduce the number of MCBs required
  2. To increase the voltage available to each circuit
  3. To eliminate the need for an earth bar
  4. To balance the load and reduce neutral current Correct answer.

Explanation

Spreading single-phase loads evenly across R, Y and B phases keeps phase currents balanced, which reduces neutral current and prevents one phase from being overloaded. It does not change the number of protective devices, the circuit voltage or earthing requirements.

Question 47Electrical Wiring, Joints and Installation Practice

Which factor most directly determines the current-carrying capacity of a PVC-insulated copper cable installed in a conduit?

  1. The colour of the insulation
  2. The type of switch used on the circuit
  3. The cross-sectional area of the conductor and the installation conditions Correct answer.
  4. The length of the conduit run only

Explanation

Current rating depends mainly on conductor cross-sectional area and on how the cable is installed, since grouping, ambient temperature and enclosure affect heat dissipation. Insulation colour, conduit length alone and switch type do not determine the current rating.

Question 48Electrical Wiring, Joints and Installation Practice

A socket outlet in a bathroom is to be installed. Which practice is appropriate for safety?

  1. Install the socket at floor level below the shower
  2. Install a standard 6 A socket close to the wash basin
  3. Install the socket outside the bathroom and protect the circuit with a 30 mA RCCB Correct answer.
  4. Use an unearthed two-pin socket to avoid shock

Explanation

Bathrooms are wet locations where shock risk is high, so socket outlets are kept away from wet zones and the circuit is protected by a 30 mA residual current device. Placing sockets close to water or using unearthed outlets increases the risk of fatal shock.

Question 49Electrical Wiring, Joints and Installation Practice

What is the purpose of the earth electrode in a TT-type installation where the supply neutral is not earthed at the consumer's premises?

  1. To stabilise the supply voltage
  2. To give a path for fault current so that the RCCB operates Correct answer.
  3. To replace the main switch
  4. To provide a return path for normal load current

Explanation

In a TT system the installation's exposed metalwork is connected to a local earth electrode, so fault current flows through the earth and the RCCB senses the imbalance and trips. The electrode never carries normal load current and does not regulate voltage or replace the main switch.

Question 50Electrical Wiring, Joints and Installation Practice

When stripping PVC insulation from a 1.5 sq mm conductor before making a joint, which practice prevents damage to the copper?

  1. Use a sharp knife and cut deeply around the insulation
  2. Burn the insulation off with a flame
  3. Bite the insulation off with pliers
  4. Use a proper wire stripper set for the conductor size Correct answer.

Explanation

A wire stripper with the correct setting nicks only the insulation and leaves the copper intact, preserving current capacity and mechanical strength. Deep knife cuts, plier damage or burning remove copper or leave carbon residue and weaken the conductor.