Station Post Insulators ANSI TR-208
A porcelain station post insulator to ANSI TR-208 design, used to support and isolate conductors in substation busbar systems and switchgear arrangements. The insulator provides mechanical support and electrical isolation under high voltage conditions. It is designed for fixed mounting applications where rigid conductor positioning is required.
Key Benefits
- Cantilever strength of 2,000 pounds (9kN) supports conductors under lateral load
- Tensile and compression strength of 10,000 pounds (44.5kN) each ensures stability under axial forces
- Torsion strength of 8,000 inch-pounds (904Nm) resists twisting from conductor movement
- 610mm leakage distance per unit supports performance in polluted and coastal environments
- Dry flashover voltage of 110kV and wet flashover voltage of 75kV meet ANSI TR-208 electrical requirements
- Impulse withstand voltage of 150kV provides protection against transient overvoltages
Technical Features
- 6 9/16 inches (167mm) diameter body with 14 inches (356mm) height for compact substation mounting
- 610mm leakage distance per unit supports insulation coordination in polluted environments
- Cantilever strength of 2,000 pounds (9kN) resists lateral conductor forces
- Tensile and compression strength of 10,000 pounds (44.5kN) each for axial load handling
- Torsion strength of 8,000 inch-pounds (904Nm) resists twisting from conductor movement
- Low frequency dry flashover voltage of 110kV and wet flashover voltage of 75kV for AC system performance
- Critical impulse flashover voltage positive: 170kV, negative: 250kV for transient overvoltage protection
- Impulse withstand voltage of 150kV ensures reliability during switching surges
- ANSI TR 208
- STATION POST INSULATORS
- HIGH VOLTAGE INSULATORS
Specifications
| ANSI Class | TR-208 |
|---|---|
| Diameter (D) | 6 9/16 inches (167mm) |
| Height (H) | 14 inches (356mm) |
| Leakage Distance | 24 inches (610mm) |
| Cantilever Strength | 2,000 pounds (9kN) |
| Tensile Strength | 10,000 pounds (44.5kN) |
| Compression Strength | 10,000 pounds (44.5kN) |
| Torsion Strength | 8,000 inch-pounds (904Nm) |
| Low Frequency Dry Flashover Voltage | 110kV |
| Low Frequency Wet Flashover Voltage | 75kV |
| Critical Impulse Flashover Voltage Positive | 170kV |
| Critical Impulse Flashover Voltage Negative | 250kV |
| Impulse Withstand Voltage | 150kV |
Figures are the published design values for this class. Imperial and metric are the same part. Download this table as a PDF datasheet.
More Views of This Product
Who It Is For and What It Solves
Who It Is For
- Substation builders specifying insulators for new switchgear and busbar systems
- Utility procurement engineers sourcing replacements for existing ANSI TR-208 post insulators
- EPC contractors integrating insulators into substation packages
- Electrical wholesalers supplying substation components in ANSI standard markets
Problems It Solves
- Existing post insulators with insufficient cantilever strength fail under lateral conductor load
- Mismatched insulator dimensions prevent proper fit in switchgear or busbar supports
- Insufficient leakage distance leads to flashover in polluted or coastal substations
- Lack of torsion strength causes insulator failure under conductor sway or seismic events
- Inadequate impulse withstand voltage increases risk of failure during switching surges
Application Scenarios
- Substation busbar systems where rigid conductor support is required at switchgear and disconnectors
- High voltage switchgear installations with fixed conductor routing and minimal movement
- Replacements in existing substation layouts where ANSI TR-208 dimensions must be matched
- Industrial sites with high pollution levels where extended leakage distance prevents flashover
- Applications requiring high torsional resistance due to conductor vibration or seismic loading
Materials and Manufacture
Materials
- Glazed electrical porcelain dielectric body
- Galvanized malleable iron or forged steel metal fittings
- Portland cement bonding the fittings to the porcelain
Manufacturing Steps
Body preparation and forming of the porcelain shell
Glazing and high temperature firing
Cementing of the metal fittings to the porcelain body
Mechanical strength testing to verify cantilever, tensile, compression and torsion values
Electrical testing to verify flashover and impulse withstand voltages
Quality Control
- Mechanical strength tests performed on sample units to verify cantilever, tensile, compression and torsion ratings
- Electrical tests conducted on sample units to verify dry and wet flashover voltages
- Impulse withstand voltage tested on sample units to confirm 150kV rating
- Critical impulse flashover voltage tested on sample units to confirm positive and negative ratings
- Manufactured under an ISO 9001:2008 certified quality system
Certification held: ISO 9001:2008. No other certification is claimed.
Customization Options
- Glaze colour to suit the utility specification
- Alternative metal fittings where the mechanical or corrosion resistance requirements differ
- Higher leakage variants for polluted or coastal substation environments
- Non-standard designs developed with our engineers for a specific application
No Published Class Fits
We design insulators for specific non-standard applications. Send the mounting interface, the mechanical duty and the system voltage and our engineers will work through it with you.
Compared With the Alternatives
| Suspension insulators | Station post insulators provide rigid support for fixed conductors while suspension insulators allow conductor movement under wind and ice loading |
|---|---|
| Polymer post insulators | Porcelain is heavier and more brittle but does not age in UV and can be visually inspected for damage |
| Pin type insulators | Station post insulators are designed for higher mechanical and electrical ratings and are used in fixed substation applications |
Use Guide
Verify the mounting dimensions and mechanical load requirements match the existing switchgear or busbar layout
Use the 610mm leakage distance to assess performance in polluted or coastal environments
Ensure the cantilever strength of 2,000 pounds (9kN) is sufficient for lateral conductor forces including wind and ice
Handle by the metal fittings and store on the pallet supplied to protect the porcelain body
Inspect for glaze damage, cement cracks or fitting corrosion before installation
Station Post Insulators ANSI TR-208 FAQ
What is the mechanical rating of an ANSI TR-208 station post insulator
Cantilever strength is 2,000 pounds (9kN), tensile and compression strength are each 10,000 pounds (44.5kN), and torsion strength is 8,000 inch-pounds (904Nm).
Can you supply a non-standard version for my substation
Yes. We design insulators for specific non-standard applications and our engineers are available to help develop an insulator for your particular application.
What is the leakage distance and how does it affect performance
The leakage distance is 24 inches (610mm) per unit. This length helps prevent flashover in polluted or coastal environments by increasing the surface path for leakage current.
What certification do you hold
Our manufacturing facilities are certified to ISO 9001:2008. We do not claim any other certification on this page. If your tender needs a specific test report, ask us before you bid.
What is the impulse withstand voltage
The impulse withstand voltage is 150kV, which ensures the insulator can withstand transient overvoltages during switching surges.
What markets do you supply
Customers in more than 40 countries use our insulators, including America, Canada, Australia, Brazil, Ecuador, Russia, Greece, Cyprus, India, Viet Nam, Sri Lanka, Pakistan, Tanzania and Kenya.
What is the minimum order quantity
MOQ depends on the ANSI class and glaze colour. Email us with the class and quantity and we will confirm.
Guides That Cover This Product
ANSI and IEC Porcelain Insulator Standards Compared
How ANSI classes like 52-4 and 57-2 and IEC designations like C4-125 describe a porcelain insulator, and what to check o
Creepage Distance and Pollution Performance
Creepage distance values for IEC C4-125 (500mm), ANSI TR-208 (610mm), ANSI 57-2 (559mm), and ANSI 56-3 (533mm) insulator
Flashover Voltage Explained Dry Wet and Impulse
Understanding dry flashover, wet flashover, impulse flashover, puncture voltage, and impulse withstand voltage in porcel
Quote Station Post Insulators ANSI TR-208
Send the quantity, the coupling type and the destination and we will quote against the published figures on this page. The datasheet PDF has the same table.