Types of Screening

Types of Screening in Cable Manufacturing

Screening (shielding) is provided to control the electric field, reduce electromagnetic interference (EMI), and provide a path for fault current.

1. Copper Tape Screening (CTS)

• Metallic screen made of copper tape.
• Applied helically or longitudinally.
• Used in MV and some HV cables.
• Provides shielding and fault current path.

2. Copper Wire Screening (CWS)

• Consists of annealed copper wires around the insulation.
• Higher short-circuit current capacity than copper tape.
• Common in MV and HV power cables.

3. Copper Wire and Tape Screen (CWTS)

• Combination of copper wires and copper tape.
• Improves screen continuity and fault current capacity.
• Widely used in XLPE power cables.

4. Aluminium Foil Screening (AFS)

• Polyester-backed aluminium foil wrapped around conductors.
• Excellent protection against EMI.
• Used in instrumentation and communication cables.

5. Copper Braid Screening (CBS)

• Braided copper wires surrounding the core.
• Flexible and provides good shielding.
• Used in control, instrumentation, and data cables.

6. Individual Pair Screening (IPS)

• Each pair is separately screened with foil or braid.
• Minimizes crosstalk between pairs.
• Used in instrumentation and communication cables.

7. Overall Screening (OS)

• One common screen around all cores.
• May consist of foil, braid, or tape.
• Used in multi-core control and instrumentation cables.

8. Semi-Conductive Screening

• Conductor Screen
• Insulation Screen

These are non-metallic layers used mainly in XLPE medium- and high-voltage cables to ensure uniform electric stress.

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Summary Table

Type	Abbreviation	Material	Typical Application
Copper Tape Screen	CTS	Copper Tape	MV/HV Power Cables
Copper Wire Screen	CWS	Copper Wires	MV/HV Power Cables
Copper Wire & Tape Screen	CWTS	Copper Wires + Tape	XLPE Power Cables
Aluminium Foil Screen	AFS	Aluminium Foil	Instrumentation Cables
Copper Braid Screen	CBS	Copper Braid	Control and Data Cables
Individual Pair Screen	IPS	Foil/Braid	Instrumentation Cables
Overall Screen	OS	Foil/Braid/Tape	Multi-core Cables
Semi-Conductive Screen	—	Semi conductive  Compound	MV/HV XLPE Cables

Copper Tape Screening (CTS) 

CTS = Copper Tape Screening

Copper Tape Screening is a layer of copper tape wound helically or longitudinally around the insulated cores of a cable. It acts as a metallic screen (shield).

Functions of Copper Tape Screening

1. Provides a path for earth fault current.
2. Reduces electromagnetic interference (EMI).
3. Improves electric field distribution.
4. Protects communication and control signals from external noise.
5. Enhances cable safety and reliability.

Typical Construction

Conductor
    ↓
Conductor Screen
    ↓
Insulation (XLPE/PVC)
    ↓
Insulation Screen
    ↓
Copper Tape Screening (CTS)
    ↓
Inner Sheath
    ↓
Armour (if required)
    ↓
Outer Sheath

Applications

• Medium Voltage (MV) power cables
• High Voltage (HV) cables
• Instrumentation cables
• Control cables
• Communication cables

Abbreviation:

CTS = Copper Tape Screening
Material: Annealed copper tape
Main Purpose: Shielding and carrying fault current in screened cables.

Copper Wire Screening (CWS)

CWS = Copper Wire Screening

Copper Wire Screening consists of annealed copper wires placed helically around the insulated core of a cable to form a metallic screen (shield).

Functions of Copper Wire Screening

1. Provides a low-resistance path for earth fault current.
2. Reduces electromagnetic interference (EMI).
3. Controls the electric field around the conductor.
4. Improves cable reliability and safety.
5. Protects nearby communication and control circuits from electrical noise.

Typical Construction

Conductor
    ↓
Conductor Screen
    ↓
Insulation (XLPE/PVC)
    ↓
Insulation Screen
    ↓
Copper Wire Screening (CWS)
    ↓
Binder Tape
    ↓
Inner Sheath
    ↓
Armour (if required)
    ↓
Outer Sheath

    Applications

• Medium Voltage (MV) power cables
• High Voltage (HV) cables
• Power distribution cables
• Industrial cables
• Substation cables
• 
  

Abbreviation

Symbol	Meaning
CWS	Copper Wire Screening
Material	Annealed Copper Wires
Main Purpose	Shielding and carrying earth fault current

     Difference between CTS and CWS:

CTS	CWS
Copper Tape Screen	Copper Wire Screen
Uses copper tape	Uses multiple copper wires
Lower fault current capacity	Higher fault current capacity
Common in some MV cables	Common in MV and HV cables requiring                     higher short-circuit ratings