Study & Identify Cables (PVC, XLPE & VIR) and Catenary Cable of Different Current Ratings

Experiment No.: 3

Experiment Name:

Study & Identify Cables (PVC, XLPE AND VIR) and Catenary Cable of Different Current Ratings

Objective:

1. To identify PVC, XLPE, VIR, and Catenary cables.
2. To study their construction and insulation.
3. To understand their current ratings and applications.
4. To compare different types of cables used in electrical installations.

Theory:

Different electrical cables are used for different purposes. The insulation material and conductor size decide the current carrying capacity of a cable. Proper cable selection improves safety and efficiency in electrical systems.

1. PVC Cable :

PVC means Polyvinyl Chloride. It is the most common cable used in houses and buildings.

Features	Applications
Flexible Water resistant Low cost Temperature rating: about 70°C	House wiring Lighting circuits Small electrical appliances

2. XLPE Cable:

XLPE means Cross-Linked Polyethylene. It can carry higher current and temperature than PVC.

Features	Applications
High insulation strength Heat resistant Long service life Temperature rating: about 90°C	Industrial power supply Underground cables Distribution system

3. VIR Cable:

VIR means Vulcanized India Rubber. It is an old type of cable that is rarely used today.

Features	Applications
Rubber insulation Good flexibility Lower life compared to modern cables	Old electrical installations

4. Catenary Cable:

Catenary cables are tensioned wires suspended between two points that support their own weight and additional loads, forming a catenary curve. 
They are primarily used in railway electrification (as messenger wires) and for overhead support of cables, lighting, and signage in commercial or industrial settings.

Features	Applications
Strong mechanical support Suitable for overhead installation Can carry heavy loads	Railway electrification Street lighting Outdoor wiring Industrial overhead installations

Apparatus Used:

Sl. No.	Name of the Apparatus	Specification	Quantity
1.	PVC cable samples	Copper conductor, 1.1kV 2.5 sq. mm	1 m
2.	XLPE cable samples	Aluminum conductor, 11Kv 25 sq. mm	1 m
3.	VIR cable sample	Copper conductor, 650V 4 sq. mm	1 m
4.	Catenary cable sample	As available	1 m
5.	Digital Multimeter	0-650 V, 0-10A	1

Cables Observation:

Observation Table:

Cable Type	Insulation	Temperature	Common Use
PVC	Polyvinyl Chloride	70°C	House wiring
XLPE	Cross-Linked Polyethylene	90°C	Industrial power
VIR	Rubber	Around 60°C	Old wiring
Catenary	PVC/XLPE with messenger wire	Depends on cable	Overhead wiring

Common Current Rating:

Cable Size	Approx. Current
1.5 mm²	10–14 A
2.5 mm²	18–24 A
4 mm²	25–32 A
6 mm²	32–40 A
10 mm²	45–60 A

Note: Current rating may change depending on installation conditions.

Procedure:

1. Collect different cable samples.
2. Observe the insulation colour and thickness.
3. Identify each cable by its marking.
4. Measure the conductor size using a wire gauge or measuring tool.
5. Compare their insulation material.
6. Note the approximate current rating.
7. Record the application of each cable.

Observation Table:

Cable	Size	Insulation	Current Rating
PVC	2.5 mm², Copper	PVC	20 A
XLPE	25 mm², Aluminum	XLPE	100 A
VIR	4 mm², Copper	Rubber	24 A
Catenary	6 mm², Copper	PVC + Messenger	40 A

Conclusion:

PVC, XLPE, VIR, and Catenary cables were successfully identified. Their insulation type, current rating, and practical applications were studied and compared.

Viva Questions:

1. What is the full form of PVC?
2. Which cable has a higher temperature rating: PVC or XLPE?
3. Why is XLPE used in industries?
4. What is VIR cable?
5. Where is a Catenary cable commonly used?
6. Which cable is suitable for overhead installation?
7. What is the purpose of the messenger wire?
8. Does cable size affect current carrying capacity?

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