PVC electrical tape is made of soft polyvinyl chloride film and coated with a specific pressure-sensitive adhesive. It is often used for insulation wrapping, bundling and fixing of wire and cable joints, and insulation protection of motor electronic parts. When purchasing electrical tape, do not ignore the quality for the sake of cheapness. Poor quality electrical tape is prone to overflow and dislocation over time, or when the electrical appliance is overloaded and the joints are heated, the hot zone melts and shrinks... These hidden dangers are likely to cause line abnormalities, or even short circuits and fires, directly endangering personal safety. Only by choosing high-quality, safe and stable performance products can you ensure the safety of yourself and others and achieve good construction results.
1. Touch method: Gently touch the adhesive surface of the tape with your hand and then quickly remove it. Generally, the stronger the adhesive force, the better the adhesion.
2. Pulling method: Repeatedly pull the rubber surface, with strong force and no debonding, good adhesion and good quality.
3. Stretching method: Stretch by hand. For tapes of the same thickness and width, the ones with greater force and longer elongation are of good quality. The ones that break easily are recycled materials and of poor quality.
4. Simple test method for flame retardancy: After igniting the tape with a lighter, remove the lighter, and if the burning length is within 15cm, it is flame retardant.
5. Smell method: After unwinding the PVC tape, smell the tape with your nose. If the smell is strong (pungent) or smells bad, it means that the tape is of poor quality.
Before applying insulating tape, ensure that the wires are securely twisted together in accordance with relevant wiring standards. Different materials, cross-sectional areas, and application scenarios may require specific wiring standards, which must be strictly followed.
Common types of insulating tape used by electricians include:
Vinyl (PVC) Tape: Widely used for general insulation purposes due to its flexibility and durability.
Rubber Tape: Self-fusing and ideal for high-voltage applications and moisture resistance.
Mastic Tape: Offers excellent conformability and is suitable for sealing and insulating irregular shapes.
Varnished Cambric Tape: Provides mechanical protection and is often used as an initial layer in high-voltage applications.
The standard width for insulating tape is typically 20mm, facilitating ease of use.
The half-overlap method is a fundamental technique for wrapping wire joints:
Begin wrapping the tape at a 75° angle to the wire axis.
Each subsequent wrap should overlap the previous layer by approximately 50%, ensuring a double layer of insulation.
Apply consistent tension to the tape during wrapping to ensure a tight and secure fit.
Proper tension prevents the tape from loosening over time, which could compromise insulation and safety.
For straight-line wire connections:
Initial Layer: Apply two layers of varnished cambric tape, starting from the intact insulation on one side, extending over the exposed conductor, and ending on the intact insulation on the opposite side.
Intermediate Layer: Wrap four half-lapped layers of rubber insulating tape over the cambric tape to provide primary insulation and moisture resistance.
Final Layer: Overwrap with at least two half-lapped layers of vinyl electrical tape, extending approximately two tape widths beyond the ends of the rubber tape to seal the assembly.
For 220V circuits, the use of varnished cambric tape may be omitted, and two layers of vinyl tape can suffice. In damp environments, PVC or polyester insulation tapes are recommended for enhanced moisture resistance.
For T-shaped branch connections:
Follow the same layering sequence as straight-line joints.
Wrap the tapes in a T-shaped pattern, ensuring each wire, including the branch, is covered with two layers of insulating tape.
Extend the wrapping to cover at least twice the tape width beyond the intact insulation on each wire.
For cross-shaped branch connections:
Apply the same wrapping technique as T-shaped joints, but in a cross-shaped pattern.
Ensure all four directions of the joint are wrapped with two layers of insulating tape, extending at least twice the tape width beyond the intact insulation.
