🔒 Closed HELPP

[llachica014]

• a. The voltage drop from a main switchboard to an appliance must be less than________
• A cable is used in stranded form to ensure_________
• The current rating of a cable is _________.
• What do you understand by ‘Current Rating’? How does temperature affect this in cables?
• What are the various types of cables used in electrical installations? Give suitable examples of their usage onboard ships.
• a. Class A insulation means that the device can operate up to ________°C. b. Class B insulation means that the device can operate up to ________°C.
• c. Class E insulation means that the device can operate up to ________°C. d. Class F insulation means that the device can operate up to _______ °C.
• e. Class H insulation means that the device can operate up to _______ °C.

 

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a. The voltage drop from a main switchboard to an appliance must be less than 5%.

A cable is used in stranded form to ensure flexibility and resistance to fatigue.

The current rating of a cable depends on various factors such as its size, material, insulation type, and installation method.

Current Rating is the maximum amount of current that a cable can carry continuously under specific installation conditions without exceeding its temperature rating. Temperature affects the current rating of cables as the resistance of the conductor increases with temperature, resulting in higher heat generation.

Various types of cables used in electrical installations are:

1. Power Cables - Used for power transmission and distribution. Example: XLPE cables, PVC cables.
2. Control Cables - Used for signal transmission and control. Example: Instrumentation cables.
3. Communication Cables - Used for data transmission. Example: Coaxial cables, Fiber optic cables.
4. Special Cables - Used for specific applications. Example: Fire-resistant cables, Submarine cables.

a. Class A insulation means that the device can operate up to 105°C. b. Class B insulation means that the device can operate up to 130°C.

c. Class E insulation means that the device can operate up to 120°C. d. Class F insulation means that the device can operate up to 155°C.

e. Class H insulation means that the device can operate up to 180°C.