ETO Power Generation & Distribution 3

Question 1

According to classification society rules, what is the maximum allowable voltage drop for main lighting circuits on ships?

Accepted Answer

2.5%

Answer

Classification societies typically limit voltage drop in lighting circuits to 2.5% to ensure adequate and consistent illumination levels throughout the vessel and preserve lamp life.

Question 2

Which source provides emergency electrical power to essential services if all main generators fail on a ship?

Accepted Answer

Emergency generator

Answer

An emergency generator, required by SOLAS, automatically starts and connects to the emergency switchboard to supply essential services whenever main power is lost.

Question 3

According to SOLAS requirements, what is the minimum duration for which an emergency generator on a cargo ship must be capable of supplying power?

Accepted Answer

18 hours

Answer

SOLAS Chapter II-1 requires the emergency source of electrical power on cargo ships to supply essential services for a minimum of 18 hours without refueling.

Question 4

What is the primary purpose of performing an insulation resistance test on a ship's electrical equipment?

Accepted Answer

To detect deterioration of electrical insulation that may lead to earth faults or electric shock hazards

Answer

Insulation resistance testing detects moisture ingress, physical damage, or aging insulation before they cause earth faults, equipment damage, or dangerous electric shock hazards.

Question 5

Why do ships typically use an IT (Insulated Neutral) earthing system rather than a solidly earthed neutral system?

Accepted Answer

To allow continued operation during a single earth fault while crew locates and repairs it

Answer

The IT system allows the ship to continue operating safely with a single earth fault present, giving crew time to identify and correct the fault without immediate power interruption to essential services.

ETO - Electro-Technical Officer Practice Test

ETO - Electro-Technical Officer Practice Test

ETO Power Generation & Distribution 3