ELECTRICAL INSTALLATION NECO QUESTION AND ANSWER 2023

ELECTRICAL INSTALLATION NECO QUESTION AND ANSWER 2023

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✅ EXAM SECRET SOLUTION TEAM

✅ Subject: Electrical Installation 

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QUESTION NO. 1

(1a)

(i) Voltage:

To calculate the voltage on the secondary winding, use the transformation ratio formula:

Transformation Ratio = Np / Ns = Vp / Vs

Where:

Np = Number of turns on the primary winding

Ns = Number of turns on the secondary winding

Vp = Voltage supplied to the primary winding (3000 V)

Vs = Voltage on the secondary winding (to be calculated)

Given the transformation ratio is 15:1, Np = 1650, and Vp = 3000 V:

15 = 1650 / Ns

Now, solve for Ns:

Ns = 1650 / 15

Ns = 110 turns

(ii) Turns:

To calculate the number of turns on the secondary winding, use the same formula:

Ns = Np / Transformation Ratio

Given Np = 1650 and the transformation ratio is 15:1:

Ns = 1650 / 15

Ns = 110 turns

(1b)

(i)Adequate Earthing: The installation should have proper earthing to ensure safety and protection against electrical faults.

(ii)Overcurrent Protection: Adequate fuses or circuit breakers should be installed to protect against excessive currents.

(iii)Cable and Wiring Selection: The use of appropriate cables and wiring that can handle the required load safely and efficiently.

(iv)Isolation and Switching: Temporary installations should have easily accessible and clearly labeled switches or isolators for safe disconnection when necessary.

(v)Inspection and Testing: Regular inspection and testing of the installation to ensure compliance with safety standards and identify potential hazards.

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QUESTION NO. 2

(2a)

{CHOOSE ANY BEST 3}

(i) Electrical Load: Understanding the anticipated electrical load of the building to ensure the selected wiring system can handle the demand.

(ii) Safety Standards and Codes: Complying with local electrical codes and safety standards to ensure a safe installation.

(iii) Voltage Rating: Selecting wiring with the appropriate voltage rating for the building's electrical system.

(iv) Insulation Type: Evaluating insulation options to protect the wiring from damage and ensure electrical safety.

(2bi)

An Earth Electrode is a conductive element buried in the ground or connected to a large conductive surface in direct contact with the earth.Its primary purpose is to establish an electrical connection between the electrical system or equipment and the ground.

(2bii)

(i) Single-Phase AC Supply.

(ii) Three-Phase AC Supply.

(iii) DC Supply.

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QUESTION NO. 3

(3a)

{CHOOSE ANY BEST 2}

(i) Preventive Maintenance.

(ii) Corrective Maintenance

(iii) Predictive Maintenance.

(3b)

Na Calculations My hand No dey ooo.

(3c)

Na Calculations My hand No dey ooo 

(3d)

Na Calculations

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QUESTION NO. 4

(4a)

A fuse is a protective device used in electrical circuits to interrupt the flow of current when it exceeds a certain limit, preventing damage to the circuit and connected equipment.

(4b)

(i) The commutator allows for the continuous flow of current through the armature coils as the rotor rotates.

(ii) To reverse the direction of current flow in the armature coils, creating a rotating magnetic field that drives the motor's rotation.

(iii) To provide a stable and constant direct current output.

(4c)

Coming....

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QUESTION NO. 5

ELECTRICAL INSTALLATION

(5a)

(5b)

{CHOOSE ANY BEST 4}

(i) Cleat Wiring.

(ii) Trunking Wiring.

(iii) Concealed Wiring.

(iv) Surface Wiring

(v) Conduit Wiring.

(5c)

{CHOOSE ANY BEST 2}

(i) Rewireable Fuse.

(ii) HRC Fuse (High Rupturing Capacity Fuse).

(iii) Cartridge Fuse.

(5d)

(i) 1.5 mm² - For Lighting Points and Probably Fans.

(ii) 6 mm² - For Heating Equipments e.g. Electric Kettle, A.C.s.

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QUESTION 

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COMPLETED ✅