Insulation Treatment Process of Busbars: Performance Differences Between Heat Shrink Tubing BusBar, PVC Dipping Insulated Busbar and Epoxy Powder Coating Insulated Busbar
Sep 26, 2025
Products Description
In power distribution systems-from industrial switchgear and data centers to new energy storage facilities-busbars serve as the "backbone" for transmitting high currents. However, uninsulated products face risks of electrical leakage, short circuits, and corrosion, which can lead to equipment failure or safety hazards. This is where insulation treatment becomes critical: it creates a protective barrier that ensures electrical safety while maintaining the busbar's conductive efficiency. Among the most widely used insulation methods are heat shrink tubing, PVC dipping, and epoxy powder coating-each with unique production processes, performance strengths, and application scenarios. For engineers and system designers, understanding their differences is key to selecting the right solution for specific project needs.
Heat Shrink Tubing BusBar
Pre-Treatment of Busbars: The base product (typically copper or aluminum) is cleaned with isopropyl alcohol to remove grease, dust, and oxide layers-this ensures the tubing adheres tightly. For Heat Shrink Tubing busbars with sharp edges (e.g., cut ends), a deburring tool smooths the surface to prevent puncturing the tubing during installation.
Tubing Selection & Cutting: HST for busbars is made from cross-linked polyolefin (the most common material) or fluoropolymers (for high-temperature needs). It is manufactured in rolls with varying shrink ratios (2:1 or 3:1) and thicknesses (0.8–3mm). Technicians cut the tubing to match the length, adding 10–15mm extra at each end to ensure full coverage.
Heating & Shrinkage: The cut tubing is slid over the Heat Shrink Tubing busbar, then heated using a temperature-controlled hot air gun (120–180°C for polyolefin). The tubing shrinks forming a tight seal-this step takes 30–60 seconds per meter, making it ideal for fast-turnaround projects.
Post-Installation Inspection: A visual check ensures no bubbles or gaps (which cause insulation weaknesses), and a megohmmeter tests insulation resistance (target: >100 MΩ at 500V).
Key Performance Traits:
Flexibility: HST retains flexibility even at low temperatures (-55°C), making it suitable for busbars in vibrating environments (e.g., wind turbine converters).
Temperature Resistance: Polyolefin HST handles up to 105°C; fluoropolymer versions (e.g., PTFE) withstand 200°C+, fitting high-heat applications like industrial ovens.
Limitations: Less impact-resistant than other methods-prone to damage from heavy mechanical stress (e.g., in high-traffic electrical cabinets).
Typical Applications: New energy storage systems, portable power units, and small-to-medium industrial switchgear.
PVC Dipping Insulated BusBar
PVC dipping (also called PVC coating) is a liquid-based insulation process that creates a seamless, waterproof layer on busbars. It is widely used in low-to-medium voltage systems (up to 10kV) due to its affordability and moisture resistance. The production process involves five stages:
Busbar Preparation: The PVC Dipping Insulated busbar is degreased with a chemical solvent (e.g., trichloroethylene) and etched with acid to roughen the surface-this improves PVC adhesion. It is then dried in an oven at 80–100°C to remove residual moisture.
PVC Coating Preparation: A liquid PVC compound (mixed with plasticizers and stabilizers to enhance flexibility and durability) is heated to 60–70°C to reduce viscosity, ensuring smooth dipping.
Dipping & Coating: The prepared busbar is dipped into the PVC tank at a controlled speed (5–10 cm/s) to ensure a uniform coating thickness (0.5–2mm). Multiple dips may be needed for thicker layers.
Curing: The coated product is cured in a conveyor oven at 150–180°C for 15–30 minutes. This cross-links the PVC molecules, hardening the coating into a rigid, seamless layer.
Trimming & Testing: Excess PVC ends is trimmed with a knife. Insulation resistance is tested (target: >50 MΩ at 500V), and a water immersion test (IP67 rating) verifies moisture resistance.
Key Performance Traits:
Moisture Resistance: The seamless PVC layer prevents water ingress, making it ideal for outdoor or high-humidity environments (e.g., outdoor distribution boxes).
Cost-Effectiveness: PVC material and dipping equipment are lower-cost than epoxy powder coating, suiting budget-sensitive projects.
Limitations: Low temperature resistance (max 70–80°C)-not suitable for high-heat applications. Rigid coating may crack under thermal expansion (e.g., in PVC Dipping Insulated Busbars with frequent current fluctuations).
Typical Applications: Residential electrical panels, outdoor street lighting systems, and low-voltage industrial control cabinets.
Epoxy Powder Coating Insulated BusBar
Epoxy powder coating (EPC) is a dry-coating process that produces a hard, scratch-resistant insulation layer-ideal for high-voltage (10kV–35kV) and heavy-duty industrial applications. Its production process is more complex but delivers superior durability:
Pre-Treatment: The Epoxy Powder Coating Insulated BusBar undergoes a three-step cleaning process: degreasing (alkaline cleaner), pickling (to remove oxides), and phosphating (to form a corrosion-resistant layer). It is then dried at 120°C to ensure a clean, dry surface.
Epoxy Powder Preparation: A dry epoxy powder (mixed with curing agents and pigments) is electrostatically charged using a corona gun-this ensures it adheres to the grounded product.
Electrostatic Spraying: The charged epoxy powder is sprayed onto the Epoxy Powder Coating Insulated BusBar in a controlled booth. The powder adheres uniformly to the its surface, forming a layer 0.8–3mm thick.
Curing & Polymerization: The coated product is baked in a high-temperature oven at 180–220°C for 20–40 minutes. This melts the epoxy powder, which flows into a smooth layer and cures into a hard, cross-linked polymer.
Quality Testing: The coating is checked for thickness (using a magnetic gauge) and adhesion (pull-off test: target >5 MPa). A partial discharge test (PD test) verifies its suitability for high-voltage applications (target: <10 pC at rated voltage).
Key Performance Traits:
High Durability: The hard epoxy layer resists scratches, impact, and chemical corrosion (e.g., oil, solvents), making it suitable for heavy-industry environments (e.g., steel mills).
High-Voltage Compatibility: Excellent dielectric strength (20–30 kV/mm) enables use in high-voltage switchgear and power transformers.
Limitations: High equipment and energy costs (due to electrostatic spraying and high-temperature curing). Rigid coating may crack under severe vibration (e.g., in mining equipment).
Typical Applications: High-voltage power substations, steel mill electrical systems, and large-scale data center busway systems.
Performance Comparison: Choosing the Right Insulation Method
To simplify selection, here's a side-by-side comparison of the three insulation technologies across key metrics:
| Metric | Heat Shrink Tubing | PVC Dipping | Epoxy Powder Coating |
| Temperature Resistance | -55°C to 200°C (varies by material) | -10°C to 80°C | -30°C to 150°C |
| Dielectric Strength | 15–25 kV/mm | 10–15 kV/mm | 20–30 kV/mm |
| Moisture Resistance | Good (IP67) | Excellent (IP68) | Excellent (IP68) |
| Impact Resistance | Low-Medium | Medium | High |
| Installation Speed | Fast (30–60s/m) | Medium (15–30min/m) | Slow (20–40min/m) |
| Cost (per meter) | 2-5 | 1-3 | 4-8 |
Key Considerations for Insulation Selection
When choosing an insulation method, focus on three critical factors:
Application Environment: For outdoor/humid areas, prioritize PVC dipping or epoxy coating (IP68). For high-heat environments, select heat shrink tubing (fluoropolymer) or epoxy coating.
Voltage & Current Requirements: High-voltage systems (10kV+) need epoxy coating's superior dielectric strength. Low-voltage systems (≤1kV) can use cost-effective PVC dipping.
Mechanical Stress: Busbars in vibrating or high-traffic areas benefit from heat shrink tubing's flexibility; stationary, heavy-duty busbars (e.g., in substations) suit epoxy coating's impact resistance.
Contact us
At XIAMEN APOLLO, we offer a full range of busbar insulation solutions tailored to your project's unique needs-whether you require fast installation, moisture resistance, or high-voltage durability.
All our insulated busbars undergo rigorous testing-including insulation resistance, dielectric strength, and environmental durability-to ensure long-term performance. Our engineering team also provides custom design support, helping you match the right insulation method to your voltage, environment, and budget requirements.
