H1: 56/57-3 Pin Post Insulator — 12.5kN Porcelain Line Post Insulator for Distribution Lines
The 56/57-3 Pin Post Insulator is a solid-core porcelain pin post insulator designed for mechanical support and electrical insulation of conductors in overhead power distribution lines.
Manufactured in strict accordance with ANSI Standard, this insulator provides reliable performance for distribution applications with a typical application voltage of 30kV.
The pin post design features a compact and robust porcelain body, ensuring easy installation and stable performance under extreme temperature cycling.
The glaze color is available in brown or light gray. Whether used in crossarm-mounted distribution lines, pole-top structures, or dead-end and angle applications, the 56/57-3 Pin Post Insulator offers a cost-effective and durable solution for modern distribution infrastructure.
H2: 56/57-3 Pin Post Insulator Technical Specifications
The 56/57-3 Pin Post Insulator features a cantilever strength of 2,800 lbs (12.5kN), making it ideal for pin post applications in distribution networks.
Key electrical, mechanical, and dimensional ratings are detailed below:
| S/N | Technical Standard Particulars/Details | Brown (56/57-3B) | Light Gray (56/57-3G) |
| 1 | Product Item No./SKU Code | 56/57-3B | 56/57-3G |
| 2 | Glaze Color | Brown | Light Gray |
| 3 | Standard | ANSI | ANSI |
| 4 | Type / Mounting | Pin Post Type | Pin Post Type |
| 5 | Diameter (D) | 6 11/16 Inches (170 mm) | 6 11/16 Inches (170 mm) |
| 6 | Height (H) | 15 Inches (381 mm) | 15 Inches (381 mm) |
| 7 | Leakage Distance | 27 1/2 Inches (699 mm) | 27 1/2 Inches (699 mm) |
| 8 | Dry Arcing Distance | 14 Inches (356 mm) | 14 Inches (356 mm) |
| 9 | Cantilever Strength | 2,800 Pounds (12.5 kN) | 2,800 Pounds (12.5 kN) |
| 10 | Cantilever Strength Routine Test | 1,000 Pounds (5 kN) | 1,000 Pounds (5 kN) |
| 11 | Typical Application Voltage | 30 kV | 30 kV |
| 12 | Low Frequency Dry Flashover Voltage | 120 kV | 120 kV |
| 13 | Low Frequency Wet Flashover Voltage | 85 kV | 85 kV |
| 14 | Critical Impulse Flashover Voltage, Positive | 210 kV | 210 kV |
| 15 | Critical Impulse Flashover Voltage, Negative | 230 kV | 230 kV |
| 16 | Radio Influence Voltage – Test Voltage RMS to Ground | 30 kV | 30 kV |
| 17 | Radio Influence Voltage – Maximum RIV at 1000 kHz | 200 μV | 200 μV |
| 18 | Net Weight (approx.) | 12.8 kg | 12.8 kg |
| 19 | Applicable Standard | ANSI | ANSI |
Material: Manufactured from high-grade wet-process porcelain per ANSI requirements.
Mounting: Pin post type design.
H2: Material & Construction
Every unit of the 56/57-3 Pin Post Insulator is made from high-grade wet-process porcelain, fired at high temperature to achieve maximum density and near-zero porosity.
The solid-core pin post design ensures easy handling and reliable performance under extreme thermal cycling. The hard, glossy glaze coating offers good self-cleaning properties, reducing maintenance frequency.
The pin post design provides secure conductor mounting for overhead distribution lines. Metal parts are made of galvanized malleable iron, ductile iron, steel, or aluminum, with ferrous parts hot-dip galvanized per applicable standards.
Both brown and light gray glaze colors are available. For more on porcelain manufacturing standards, visit the American National Standards Institute (ANSI): https://www.ansi.org
H2: 56/57-3 Pin Post Insulator Applications & Installation
The 56/57-3 Pin Post Insulator is widely used in overhead power distribution lines, typically installed on crossarms and pole-mounted structures. It is ideal for:
- Overhead distribution line conductor support
- Crossarm-mounted applications
- Pole-top structures
- Dead-end and angle applications in distribution networks
- Pin post conductor mounting
The pin post design allows easy mounting and secure conductor support. Explore our full range of line post insulators: https://www.tcinsulators.com/product/line-post-insulators/ and transmission hardware for more options.
H2: 56/57-3 Pin Post Insulator Quality & Performance Advantages
Compared to polymer alternatives, porcelain offers unmatched resistance to UV radiation, bird pecking, and scratch damage. Its glaze reduces continuous water film formation, significantly raising pollution flashover voltage.
Moreover, the 56/57-3 Pin Post Insulator requires minimal routine maintenance and delivers a service life of over 30 years under normal operating conditions. Full testing procedures are detailed in ANSI standards, published by the American National Standards Institute.
Every unit undergoes 100% routine electrical and mechanical testing before dispatch, including visual inspection, dimensional checks, mechanical load tests, and high-voltage withstand tests. Design tests — such as low frequency dry flashover, low frequency wet flashover, critical impulse flashover, radio influence voltage, and thermal shock — are performed per ANSI standards on new designs.
Quality conformance tests including porosity, galvanizing, and cantilever-strength tests are conducted on each lot. Full test reports and traceability records are provided for each batch. For installation guidance, refer to our insulator string assembly guide: https://www.tcinsulators.com/insulator-manufacturer-5/
H2: Packing & Shipping
Each insulator is individually packed with foam cushioning and secured in sturdy cartons to prevent transit damage. We offer flexible shipping options (FOB, CIF, EXW) with lead times of 15-30 days depending on order quantity.
For detailed datasheets, CAD drawings, or competitive pricing on the 56/57-3 Pin Post Insulator, please contact our sales team via the inquiry form below. We also offer OEM services and free technical consultation for distribution line design.
H2: Why Choose Our 56/57-3 Pin Post Insulator
When selecting a 56/57-3 Pin Post Insulator for your distribution project, quality and reliability are paramount. Our 56/57-3 Pin Post Insulator is subject to strict quality control at every production stage — from raw material inspection to final electrical testing.
We understand that distribution line outages are costly, which is why each 56/57-3 Pin Post Insulator is designed for long-term durability. With years of experience in porcelain insulator manufacturing, we provide competitive pricing, fast delivery, and dedicated technical support.
Whether you need a small sample batch or a full container order, our 56/57-3 Pin Post Insulator is available with short lead times. Contact us today to learn how the 56/57-3 Pin Post Insulator can enhance your distribution grid reliability.
Internal Links
56/57-3 Pin Post Insulator: https://www.tcinsulators.com/product/56-57-3-pin-post-insulator/
Line Post Insulators: https://www.tcinsulators.com/product/line-post-insulators/
Contact TC Insulators: https://www.tcinsulators.com/contact/
Insulator String Assembly Guide: https://www.tcinsulators.com/insulator-manufacturer-5/
External Links
TC Insulators Official Website: https://www.tcinsulators.com
American National Standards Institute (ANSI): https://www.ansi.org
