H1: XZSP1-420 DC Suspension Insulator (U420B) — 420kN, 650mm Creepage, 400mm Diameter, 28R Coupling, Ultimate Strength, Zinc Sleeve Protection, Brown/Light Gray Glaze, IEC 60383
The XZSP1-420 DC Suspension Insulator (U420B) is the absolute ultimate flagship cap‑and‑pin disc insulator in our entire DC product portfolio, engineered for the most extreme ultra‑high‑voltage direct current (UHVDC) overhead transmission lines. Designed to meet the unique challenges of DC transmission — including DC ageing and electrolytic corrosion — this insulator delivers unmatched performance with its 420kN mechanical rating, 650mm creepage distance, 400mm diameter, and 28R coupling.
Manufactured in compliance with IEC 60383 international standards, this DC insulator features a robust porcelain body with superior characteristics to resist DC ageing. The pins are equipped with zinc sleeves to prevent DC electrolytic corrosion, ensuring long‑term reliability in the most demanding HVDC and UHVDC applications. The unit is available in either brown (standard) or light gray (optional) glaze, both offering identical mechanical and electrical performance.
With a combined mechanical and electrical (M&E) failing load of 420kN — the absolute highest in the entire DC product portfolio — an industry‑leading creepage distance of 650mm, and a massive 400mm diameter, the XZSP1-420 delivers unparalleled performance on ±800 kV UHVDC transmission lines in the most challenging environments. The industry‑leading 400mm diameter, 205mm spacing, and advanced Figure 3 shed design provide the greatest surface area for maximum pollution flashover performance and mechanical stability.
The advanced DC‑optimized Figure 3 shed design incorporates a specialized profile that maximizes the industry‑leading 650mm creepage length while maintaining superior self‑cleaning properties. The porcelain material’s superior DC ageing resistance, combined with zinc sleeve protection against electrolytic corrosion and the heavy‑duty 28R coupling, ensures decades of reliable service in the most extreme UHVDC applications.
Whether you are designing ±800 kV and above UHVDC transmission corridors, critical national grid backbone infrastructure, or the most demanding river crossings requiring absolute ultimate strength and performance, the XZSP1-420 DC suspension insulator offers the ultimate flagship choice for your HVDC infrastructure, with the flexibility to select your preferred glaze color.
H2: XZSP1-420 DC Suspension Insulator — Technical Specifications (Brown & Light Gray Glaze)
The XZSP1-420 DC suspension insulator is rated with a combined mechanical and electrical (M&E) failing load of 420kN — the absolute highest in the entire DC product portfolio — making it suitable for tangent suspension, light‑tension, strain, and dead‑end applications on ±800 kV and above UHVDC transmission lines where ultimate mechanical strength is required.
Its industry‑leading creepage distance of 650mm — 105mm longer than standard 545mm DC designs — provides superior pollution flashover performance in the most severe industrial, coastal, and desert environments. The DC dry withstand voltage reaches 140kV, and the DC wet withstand voltage is 55kV. The dry lightning impulse withstand voltage is 140kV (positive) and 150kV (negative).
The nominal diameter is 400mm — the largest in the entire DC portfolio — with a unit spacing (height) of 205mm — also the tallest in the series. These maximum‑in‑series dimensions provide the greatest surface area for improved pollution performance, enhanced self‑cleaning, and superior mechanical stability under the highest mechanical loads.
The coupling hardware is the largest 28R ball‑and‑socket type, ensuring full interchangeability with existing heavy‑duty UHVDC fittings per IEC dimensional requirements. The “R” designation indicates the heavy‑duty rotary coupling design, accommodating the absolute highest mechanical loads associated with the 420kN rating.
The pins are equipped with zinc sleeves to prevent DC electrolytic corrosion — a critical feature for HVDC and UHVDC applications where standard galvanised pins would degrade due to unidirectional current flow.
The Figure 3 advanced shed design provides optimized DC pollution performance for the most severe contamination environments.
The glaze is available in both brown (standard) and light gray (optional). All other technical parameters — mechanical, electrical, and dimensional — are identical between the two color options.
Every unit undergoes a routine tension load test of 210kN — the highest in the entire DC series — to verify mechanical integrity prior to dispatch. The SF₆ puncture withstand voltage reaches 210kV, demonstrating exceptional dielectric robustness.
H2: XZSP1-420 DC Suspension Insulator — Complete Technical Data (Brown vs. Light Gray Glaze)
The following table lists all technical parameters for both glaze color options. All values are identical except for the glaze color.
| Parameter | XZSP1-420 (Brown Glaze) | XZSP1-420 (Light Gray Glaze) |
| Glaze Color | Brown | Light Gray |
| Type Designation | XZSP1-420 (U420B) | XZSP1-420 (U420B) |
| Figure No. | 3 | 3 |
| Diameter D (mm) | 400 | 400 |
| Unit Spacing H (mm) | 205 | 205 |
| Nominal Creepage Distance L (mm) | 650 | 650 |
| Coupling Size | 28R | 28R |
| Rated M&E Failing Load (kN) | 420 | 420 |
| Routine Tension Load (kN) | 210 | 210 |
| Impact Load (N·m) | — | — |
| DC Dry Withstand Voltage (kV) | 140 | 140 |
| DC Wet Withstand Voltage (kV) | 55 | 55 |
| Dry Lightning Impulse Withstand (Positive) (kV) | 140 | 140 |
| Dry Lightning Impulse Withstand (Negative) (kV) | 150 | 150 |
| SF₆ Puncture Withstand Voltage (kV) | 210 | 210 |
| Net Weight, Approximate (kg) | 16.3 | 16.3 |
| Applied Standard | IEC 60383 | IEC 60383 |
Note: The XZSP1-420 DC suspension insulator is the absolute ultimate flagship model in our DC series, combining the highest 420kN mechanical rating with the industry‑leading 650mm creepage distance, the largest 400mm diameter, the tallest 205mm spacing, the largest 28R coupling, and advanced Figure 3 shed design — delivering ultimate mechanical strength, superior flashover performance, and maximum surface area for the most demanding ±800 kV and above UHVDC applications. Both brown and light gray glazes offer the same outstanding performance.
H2: XZSP1-420 DC Suspension Insulator — DC‑Specific Design Features
The XZSP1-420 DC suspension insulator incorporates the most advanced design features specifically developed for ultra‑demanding UHVDC transmission applications, setting it apart from conventional AC insulators and standard DC insulators:
- Zinc sleeve protection — The pins are equipped with zinc sleeves that prevent DC electrolytic corrosion. In HVDC and UHVDC applications, unidirectional current flow can cause accelerated corrosion of standard galvanised components. The zinc sleeves act as a sacrificial anode, protecting the critical pin components and ensuring long‑term mechanical integrity even at the highest 420kN loads.
- DC‑optimized porcelain material — The high‑grade porcelain body is formulated with superior characteristics to resist DC ageing. Unlike AC insulators, DC insulators are subject to continuous unidirectional voltage stress that can accelerate dielectric ageing. Our special porcelain formulation maintains consistent dielectric strength throughout the insulator’s service life.
- Advanced Figure 3 shed profile — The advanced DC‑optimized Figure 3 shed geometry is specifically designed to maximise the industry‑leading 650mm creepage distance while maintaining effective self‑cleaning properties. The optimized Figure 3 profile enhances pollution flashover performance in heavy contamination areas where DC insulators are particularly vulnerable.
- Largest physical dimensions — The 400mm diameter and 205mm spacing — the largest in the entire DC series — provide the greatest surface area for maximum pollution performance and mechanical stability under the most extreme conditions.
- Heavy‑duty 28R coupling — The largest coupling size in the DC series, accommodating the absolute highest mechanical loads and ensuring compatibility with the most robust UHVDC hardware.
- Industry‑leading 650mm creepage distance — The longest creepage distance in the entire DC portfolio, providing maximum pollution flashover performance.
- IEC 60383 compliance — Full compliance with international standards ensures global interchangeability and quality assurance.
Each XZSP1-420 DC suspension insulator is produced from high‑grade porcelain, fired at over 1,300 °C using the wet process, achieving maximum density and near‑zero porosity. The zinc sleeves are precision‑applied to ensure optimal corrosion protection throughout the insulator’s service life.
The cement bonding between the porcelain body and metal parts uses high‑quality Portland cement, guaranteeing mechanical stability across extreme thermal cycling from ‑70 °C to +105 °C.
The hard, glossy glaze — available in brown or light gray — further enhances self‑cleaning and maintains surface integrity over decades of service. Both glaze colors are applied using the same high‑quality process, ensuring identical durability, hardness, and electrical performance.
H2: XZSP1-420 DC Suspension Insulator — Applications and Installation
The XZSP1-420 DC suspension insulator is the ultimate flagship solution for the most demanding ±800 kV and above UHVDC transmission lines, as well as ultra‑long‑span major river crossings, national grid backbone infrastructure, and the most extreme HVDC applications where ultimate mechanical strength and performance are required.
The 420kN mechanical rating — the absolute highest in the entire DC portfolio — combined with the industry‑leading 650mm creepage distance, largest 400mm diameter, 205mm spacing, largest 28R coupling, and advanced Figure 3 shed design makes it particularly suitable for:
- ±800 kV and above UHVDC transmission lines – Where the highest reliability and ultimate mechanical strength are required for bulk power transmission over the longest distances.
- National grid backbone infrastructure – Where system reliability and security of supply are paramount, and maximum mechanical and pollution margins are required.
- Ultra‑long‑span major river crossings – Where conductor weight and tension are at their absolute maximum, requiring the highest possible mechanical rating.
- Extreme heavy icing zones – Where ice accretion adds extreme weight and mechanical stress, requiring the highest mechanical rating in the DC series.
- Heavy pollution areas with extreme conditions – Industrial zones, coastal regions, and desert environments where maximum surface area and pollution performance are essential.
- UHVDC converter stations – Heavy‑duty strain and dead‑end towers at UHVDC converter station entries where flagship DC insulators are required.
- Critical international interconnections – Cross‑border HVDC links requiring the highest performance insulators.
- Seismic zones – Where maximum mechanical robustness is required for earthquake‑prone regions.
The 28R coupling with zinc sleeves ensures compatibility with existing heavy‑duty UHVDC hardware and provides maximum protection against electrolytic corrosion. The DC‑optimized Figure 3 shed design facilitates hot‑stick handling for live‑line maintenance.
Typical application scenarios include:
- ±800 kV UHVDC lines – Flagship strain and dead‑end towers requiring ultimate mechanical strength and largest dimensions.
- ±1100 kV UHVDC lines – Ultra‑high‑voltage DC transmission where only the highest performing insulators are acceptable.
- Major river crossings – Critical infrastructure requiring the absolute highest mechanical rating and performance.
- National grid backbone – Core transmission corridors where reliability is paramount.
The 28R ball‑and‑socket coupling ensures compatibility with existing heavy‑duty UHVDC clevis pins, yokes, and socket hardware. The DC‑specific design features — zinc sleeves, DC‑optimized Figure 3 shed profile, and special porcelain formulation — ensure maximum reliability in the most demanding UHVDC applications.
For higher voltage requirements, multiple units of the XZSP1-420 DC suspension insulator can be assembled in strings. Explore our full range of suspension insulators and transmission hardware for more options.
H2: XZSP1-420 DC Suspension Insulator — Quality and Performance Advantages
The XZSP1-420 DC suspension insulator represents the absolute ultimate flagship pinnacle of mechanical strength, creepage distance, physical dimensions, and DC‑specific protection in our entire DC product portfolio — the ultimate engineering achievement for the most extreme UHVDC applications.
Key performance advantages include:
- 420kN mechanical rating – The absolute highest in the entire DC series, providing 260kN (163%) more strength than the XZP-160, 210kN (100%) more than the XZP-210, and 120kN (40%) more than the XZWP-300.
- 650mm creepage distance – The longest in the entire DC series, 105mm (+19%) longer than standard 545mm DC designs, providing maximum pollution flashover performance.
- 400mm diameter – The largest diameter in the entire DC series, providing the greatest surface area for maximum pollution performance and self‑cleaning.
- 205mm spacing – The tallest spacing in the entire DC series, providing enhanced mechanical stability and maximum surface area.
- 28R coupling – The largest coupling size in the DC series, accommodating the highest mechanical loads.
- Figure 3 advanced shed design – The most advanced DC‑optimized shed configuration in the series, providing superior pollution performance.
- DC‑optimized porcelain formulation – Superior resistance to DC ageing, ensuring decades of reliable dielectric performance.
- Zinc sleeve protection – Prevents DC electrolytic corrosion, extending mechanical service life significantly.
- 210kN routine tension load – The highest routine tension test load in the entire DC series, demonstrating superior mechanical integrity.
- IEC 60383 compliance – Manufactured to international standards for global quality assurance.
Remarkably, at just 16.3kg, the XZSP1-420 offers an exceptional strength‑to‑weight ratio for a 420kN flagship DC insulator — the same weight as the XZWP-300 (16.3kg) while delivering a 120kN (40%) higher mechanical rating, a 40mm larger diameter, a 10mm taller spacing, and a 105mm longer creepage distance.
With an expected service life exceeding 50 years under normal UHVDC operating conditions, the XZSP1-420 requires minimal routine maintenance. Every unit undergoes 100% routine testing before dispatch, including:
- Visual and dimensional inspections.
- Routine tension load verification (210 kN).
- DC dry and wet withstand voltage tests.
- Porosity and temperature‑cycle prototype testing per IEC 60383.
Each insulator is individually foam‑cushioned and securely packed in durable wooden crates or corrugated cartons. This prevents damage during transit. We offer flexible shipping arrangements (FOB, CIF, EXW) with lead times of 15–30 days, depending on order quantity.
For detailed product datasheets, CAD drawings, or competitive pricing on the XZSP1-420 DC suspension insulator (brown or light gray), please contact our sales team via the inquiry form below.
We also provide OEM services and complimentary technical consultation for UHVDC string assembly design. For installation guidance, refer to our insulator string assembly guide.
H2: XZSP1-420 DC Suspension Insulator — Why Choose Our Product?
Selecting the right DC suspension insulator for your HVDC infrastructure is critical to long‑term grid reliability — especially in ±800 kV and above UHVDC projects where absolute ultimate mechanical strength, the longest creepage distance, and the largest physical dimensions are required. Our XZSP1-420 DC suspension insulator is manufactured under stringent quality control protocols at every production stage.
From raw material sourcing (DC‑optimized high‑grade porcelain clay) to final high‑voltage DC testing, every step aligns with IEC 60383. We understand that the most demanding UHVDC transmission projects — ±800 kV and above corridors, ultra‑long‑span river crossings, and national grid backbone infrastructure — require the absolute highest levels of mechanical strength, creepage distance, and pollution performance that even 300kN DC insulators cannot provide.
That is why the XZSP1-420 DC suspension insulator is specifically engineered with a 420kN mechanical rating — the absolute highest in our entire DC series — combined with an industry‑leading 650mm creepage distance, the largest 400mm diameter, the tallest 205mm spacing, the largest 28R coupling, advanced Figure 3 shed design, zinc sleeve protection against DC electrolytic corrosion, and DC‑optimized porcelain with superior resistance to DC ageing to deliver ultimate flagship performance in the most demanding UHVDC applications. Additionally, we offer both brown and light gray glaze options to match regional preferences or project specifications.
With over a decade of experience in porcelain insulator production — including specialized DC and UHVDC insulator manufacturing — we offer competitive factory pricing, prompt delivery, and dedicated after‑sales technical support.
Whether you require a small sample batch for project validation or a full container shipment, the XZSP1-420 DC suspension insulator (brown or light gray) is available with short lead times. Contact us today to discover how the XZSP1-420 DC suspension insulator can strengthen your UHVDC grid reliability with its ultimate flagship combination of highest mechanical strength, longest creepage distance, and largest dimensions.
XZSP1-420 — Key Specifications
| Parameter | XZSP1-420 (U420B) |
| M&E Failing Load | 420 kN |
| Routine Tension Load | 210 kN |
| Impact Load | — |
| Nominal Diameter D | 400 mm |
| Unit Spacing H | 205 mm |
| Creepage Distance L | 650 mm |
| Coupling Size | 28R |
| Figure No. | 3 |
| DC Dry Withstand Voltage | 140 kV |
| DC Wet Withstand Voltage | 55 kV |
| Lightning Impulse (+/-) | 140 / 150 kV |
| SF₆ Puncture Withstand | 210 kV |
| Zinc Sleeve Protection | ✓ |
| DC Ageing Resistance | ✓ |
| Net Weight | 16.3 kg |
| Glaze Options | Brown / Light Gray |
| Best Application | ±800kV – ±1100kV UHVDC (ultimate flagship) |
XZP / XZWP / XZSP1 DC Series — Complete Comparison
| Parameter | XZP-160 (U160BL) | XZP-210 (U210B) | XZWP-300 (U300B) | XZSP1-420 (U420B) |
| M&E Failing Load | 160 kN | 210 kN | 300 kN | 420 kN |
| Routine Tension Load | 80 kN | 105 kN | 150 kN | 210 kN |
| Impact Load | 10 N·m | 10 N·m | — | — |
| Diameter D | 320 mm | 320 mm | 360 mm | 400 mm |
| Unit Spacing H | 170 mm | 170 mm | 195 mm | 205 mm |
| Creepage Distance L | 545 mm | 545 mm | 545 mm | 650 mm |
| Coupling Size | 20R | 20R | 24R | 28R |
| Figure No. | 1 | 1 | 2 | 3 |
| DC Dry Withstand | 140 kV | 140 kV | 140 kV | 140 kV |
| DC Wet Withstand | 55 kV | 55 kV | 55 kV | 55 kV |
| Lightning Impulse (+/-) | 140 / 150 kV | 140 / 150 kV | 140 / 150 kV | 140 / 150 kV |
| SF₆ Puncture | 210 kV | 210 kV | 210 kV | 210 kV |
| Zinc Sleeve | ✓ | ✓ | ✓ | ✓ |
| DC Ageing Resistance | ✓ | ✓ | ✓ | ✓ |
| Net Weight | 13.2 kg | 13.6 kg | 16.3 kg | 16.3 kg |
| Relative Strength | Baseline | +31% | +88% | +163% |
| Key Advantage | Standard DC | Higher strength | Flagship strength + largest dimensions | Ultimate flagship: highest strength + longest creepage + largest dimensions |
| Best Application | ±400-800kV | ±400-800kV | ±400-800kV | ±800-1100kV UHVDC (ultimate flagship) |
