Spool Insulators ANSI 53-2
A porcelain spool insulator to ANSI 53-2 with a cylindrical body and two metal fittings, used in overhead transmission and distribution lines for mechanical support and electrical insulation. The design provides a compact solution for low to medium voltage applications where space is limited. Transverse strength is 3,000 pounds (13.6kN) with a dry flashover voltage of 25kV and wet flashover voltages of 12kV (vertical) and 15kV (horizontal).
Key Benefits
- Compact cylindrical design fits in tight spaces on poles and towers
- Transverse strength of 3,000 pounds (13.6kN) supports line tension under wind and ice loading
- Dry flashover voltage of 25kV ensures reliable insulation under dry conditions
- Wet flashover voltage of 15kV (horizontal) provides performance in wet environments
- Glazed porcelain body resists tracking and erosion from moisture and pollution
- Standard ANSI 53-2 dimensions allow compatibility with existing hardware
Technical Features
- Cylindrical porcelain body with two metal fittings for mechanical attachment
- 79mm diameter (3 1/8 inches) provides a compact profile
- 76mm height (3 inches) reduces overall string length
- Transverse strength of 3,000 pounds (13.6kN) supports conductor tension
- Low frequency dry flashover voltage of 25kV meets dry condition insulation needs
- Low frequency wet flashover voltage of 15kV (horizontal) and 12kV (vertical) ensures performance in wet environments
- ANSI 53 2
- SPOOL INSULATORS
Specifications
| ANSI Class | 53-2 |
|---|---|
| Diameter (D) | 3 1/8 inches (79mm) |
| Height (H) | 3 inches (76mm) |
| Transverse Strength | 3,000 pounds (13.6kN) |
| Low Frequency Dry Flashover Voltage | 25kV |
| Low Frequency Wet Flashover Voltage Vertical | 12kV |
| Low Frequency Wet Flashover Voltage Horizontal | 15kV |
Figures are the published design values for this class. Imperial and metric are the same part. Download this table as a PDF datasheet.
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Who It Is For and What It Solves
Who It Is For
- Utility procurement engineers specifying insulators for distribution line projects
- EPC contractors integrating standard insulators into overhead line packages
- Transmission and distribution line contractors installing insulators on site
- Electrical wholesalers supplying ANSI standard insulators to regional markets
- Substation builders requiring compact insulators for low voltage switching gear
Problems It Solves
- Limited space on poles or towers requires a compact insulator with strong mechanical support
- Existing systems use ANSI 53-2 and require a direct replacement without hardware changes
- Wet conditions in coastal or rainy areas demand proven wet flashover performance
- Older insulators degrade in UV and pollution; porcelain offers long-term stability
- Uncertain flashover performance in wet conditions leads to system failures without proper ratings
Application Scenarios
- Supporting overhead conductors on distribution poles in urban or suburban areas with limited clearance
- Installing on transmission lines where mechanical load is moderate and space is constrained
- Replacements in existing systems where ANSI 53-2 is already specified and used
- Use in areas with moderate pollution levels where wet flashover performance is critical
- Applications requiring a compact insulator with predictable electrical and mechanical ratings
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
Electrical testing for flashover performance
Final inspection and packing
Quality Control
- Manufactured under an ISO 9001:2008 certified quality system
- Flashover voltage tests conducted to verify dry and wet performance
- Mechanical transverse strength tested to ensure 3,000 pounds (13.6kN) rating
- Visual inspection for glaze defects and cement bonding integrity
- Dimensional checks against ANSI 53-2 specifications
Certification held: ISO 9001:2008. No other certification is claimed.
Customization Options
- Glaze colour to match utility or project specification
- Alternative metal fittings for corrosion resistance or load requirements
- Non-standard designs developed with our engineers for a specific application
- Modified dimensions for space-constrained installations
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
| Pin type insulators | Spool insulators have a smaller footprint and are better suited for tight spaces, but pin types may offer higher mechanical strength in some configurations |
|---|---|
| Suspension insulators | Spool insulators are more compact and used in lower voltage applications, while suspension insulators are used for higher voltages and longer strings |
| Polymer insulators | Porcelain has better long-term stability in UV and pollution, but is heavier and more fragile than polymer alternatives |
Use Guide
Verify the system voltage and pollution level before selecting the insulator
Ensure the mounting hardware matches the ANSI 53-2 dimensions to avoid fit issues
Do not exceed the transverse strength of 3,000 pounds (13.6kN) under wind and ice loading
Inspect for glaze cracks and cement bonding damage before installation
Handle by the metal fittings to avoid porcelain damage during handling
Spool Insulators ANSI 53-2 FAQ
What is the transverse strength of an ANSI 53-2 spool insulator
The transverse strength is 3,000 pounds (13.6kN), which supports conductor tension under wind and ice loading.
What are the wet flashover voltages for this insulator
The low frequency wet flashover voltage is 12kV (vertical) and 15kV (horizontal), suitable for wet environments.
Can you supply a different glaze colour
Yes, we can supply glaze colours to match your utility specification. Please email us with the desired colour.
Do you offer non-standard designs
Yes, we design insulators for specific non-standard applications. Our engineers can assist with custom development.
What certification do you hold
Our manufacturing facilities are certified to ISO 9001:2008. We do not claim any other certification on this page.
What is the diameter and height
The diameter is 3 1/8 inches (79mm) and the height is 3 inches (76mm), providing a compact profile.
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.
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
How to Read ANSI Insulator Class Numbers
Learn how ANSI class numbers like 52-4, 56-3 and 57-2 identify porcelain insulators, and how they differ from IEC design
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
Quote Spool Insulators ANSI 53-2
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.