LXP-420 (U420B) Glass Insulator Ball & Socket Disc Suspension — 420kN Toughened Glass Insulator for Ultra-High-Voltage Overhead Transmission Lines
The LXP-420 (U420B) Glass Insulator Ball & Socket Disc Suspension is an ultra-high-strength, ball-and-socket type disc suspension insulator with a rated mechanical failing load of 420kN (90,000 lbs).
Manufactured by TCI Insulators, this insulator is engineered for insulation and mechanical support of ultra-high-voltage and extra-high-voltage overhead transmission lines, including 500kV, 750kV, and higher voltage systems.
It combines high-strength toughened glass with hot-dip galvanized steel hardware, delivering reliable performance in transmission towers, substations, railway electrification systems, and heavy-load line applications.
The U420B designation follows the IEC naming convention: U = disc suspension insulator, 420 = rated mechanical failing load of 420kN, B = ball-and-socket coupling type.
The unit is fully compliant with IEC 60383-1 and GB/T 1001.1, with connection structures conforming to GB/T 4056-2008 (IEC 60120) and BS 3288 Part III.
LXP-420 (U420B) Glass Insulator Technical Specifications
Dimensions
| Parameter | Value |
| Diameter (D) | 14 3/16 inch (360mm) |
| Spacing (H) | 8 1/16 inch (205mm) |
| Leakage Distance | 21 11/16 inch (550mm) |
| Coupling Size | 28 |
The extended 205mm spacing and larger 360mm diameter provide maximum mechanical clearance and flexibility in string design. The 550mm leakage distance delivers superior electrical performance and pollution resistance. The optimized aerodynamic umbrella profile with deep concentric ribs effectively prevents water-film formation, reducing flashover risk in heavy rain, fog, and polluted environments.
Mechanical Values
| Parameter | Value |
| Mechanical Failing Load | 90,000 lbs (420kN) |
| Tension Proof | 45,000 lbs (210kN) |
The 420kN mechanical failing load provides exceptional tensile strength to withstand heavy conductor tension, wind loads, ice loads, and dynamic forces in ultra-high-voltage transmission lines. Each unit undergoes a routine proof test at 210kN to guarantee reliability.
LXP-420 (U420B) Glass Insulator Electrical Values
| Parameter | Value |
| Low Frequency Dry Flashover Voltage | 100kV |
| Low Frequency Wet Flashover Voltage | 65kV |
| Critical Impulse Flashover Voltage, Positive | 150kV |
| Critical Impulse Flashover Voltage, Negative | 150kV |
| Low Frequency Puncture Voltage | 130kV |
The toughened glass dielectric delivers superior insulation capability, withstanding power frequency voltages and impulse surges while maintaining stable performance across varying climatic conditions.
Radio Influence Voltage (RIV) Data
| Parameter | Value |
| Test Voltage RMS to Ground | 10kV |
| Maximum RIV at 1000 kHz | 50μV |
Packing and Shipping Data
| Parameter | Value |
| Net Weight, Approximate | 14.5kg |
LXP-420 (U420B) Glass Insulator Key Features
Ultra-High Mechanical Strength (420kN) — The 420kN rated failing load makes the LXP-420 (U420B) suitable for ultra-high-voltage transmission lines, long spans, and heavy-load applications where standard 70kN, 100kN, 120kN, 160kN, 210kN, 240kN, or 300kN insulators may be insufficient.
Coupling Size 28 — The size 28 ball-and-socket coupling provides a robust connection suitable for ultra-high-tension applications, ensuring mechanical integrity under severe loading conditions.
Automatic Zero-Value Self-Shattering — When an electrical or mechanical fault occurs, toughened glass self-shatters, leaving the mechanical string intact. Patrol teams can spot defects instantly from the ground without climbing towers or using expensive testing equipment.
Superior Anti-Aging & Weather Resistance — Unlike porcelain or composite materials, toughened glass resists chemical aging, UV radiation, and retains dielectric properties for decades of service.
Extended Leakage Distance (550mm) — The 550mm leakage distance provides excellent pollution performance, making it suitable for heavily polluted and coastal environments.
Flexible Locking Pin Options — The U420B accommodates either W-pin or R-pin locking mechanisms; R-pin is used as the standard configuration unless otherwise specified.
Hot-Dip Galvanized Hardware — The cap and pin are made from hot-dip galvanized ductile iron and forged steel, assembled with high-strength aluminous cement. A stainless steel split pin secures the coupling of units. An optional zinc sleeve (sacrificial anode) is available for heavy-pollution lines.
LXP-420 (U420B) Glass Insulator Applications
- 500kV–750kV overhead power transmission lines
- Ultra-high-voltage transmission towers and substations
- Railway electrification systems
- Heavy-load and long-span transmission projects
- Tension strings and suspension strings
- Industrial power grids and utility networks
Why Choose LXP-420 (U420B) Glass Insulator TCI Insulators?
TCI Insulators is a trusted manufacturer of composite and porcelain insulators, serving global utilities and contractors since 2002. With state-of-the-art testing facilities and rigorous quality assurance processes, TCI conducts comprehensive product tests including ultraviolet aging, hardness, flame-retardant, tracking, and leakage current tests according to national and international standards.
Our disc suspension insulator system supports mechanical and electrical loads from 10,000 to 90,000 lbs, available across all voltage levels for both distribution and transmission systems, fully compliant with IEC standards.
LXP-420 (U420B) Glass Insulator Related Products
- LXP-40 (U40B) Ball & Socket Disc Suspension Insulator — 40kN rated, for 10–35kV lines
- LXP1-70 (U70BS) Ball & Socket Disc Suspension Insulator — 70kN rated, standard spacing for 33–66kV lines
- LXP2-70 (U70BL, ANSI 52-3) Ball & Socket Disc Suspension Insulator — 70kN rated, long spacing for 33–66kV lines
- LXP-100 (U100BL) Ball & Socket Disc Suspension Insulator — 100kN rated, for high-voltage transmission
- LXP-120 (U120B, ANSI 52-5) Ball & Socket Disc Suspension Insulator — 120kN rated, ANSI 52-5 compatible
- LXP1-160 (U160BS, ANSI 52-8) Ball & Socket Disc Suspension Insulator — 160kN rated, standard spacing, ANSI 52-8 compatible
- LXP2-160 (U160BM) Ball & Socket Disc Suspension Insulator — 160kN rated, medium-long spacing
- LXP3-160 (U160BL) Ball & Socket Disc Suspension Insulator — 160kN rated, long spacing
- LXP-210 (U210B) Ball & Socket Disc Suspension Insulator — 210kN rated, extra-high-voltage transmission
- LXP-240 (U240B, ANSI 52-11) Ball & Socket Disc Suspension Insulator — 240kN rated, ANSI 52-11 compatible
- LXP-300 (U300B) Ball & Socket Disc Suspension Insulator — 300kN rated, ultra-high-voltage transmission
- Porcelain Disc Suspension Insulators — U40B through U420B IEC class range
- Composite Hollow Insulators — For instrument transformers and circuit breakers
Internal Links:
- TCI Insulators Homepage
- Disc Suspension Insulators
- Toughened Glass Insulators
- Composite Hollow Insulators
- Contact TCI Insulators
External Links:
- IEC 60383-1 — Insulators for Overhead Lines
- GB/T 1001.1 — Insulators for Overhead Lines with a Nominal Voltage Above 1,000 V
- IEC 60120 / GB/T 4056 — Ball and Socket Coupling Dimensions
- BS 3288 Part III — Insulator Connections
All specifications are subject to change without notice. For the most current technical data and pricing, please contact TCI Insulators directly at www.tcinsulators.com.
