P-20T 20kV Porcelain Pin Insulator with Steel Spindle
The P-20T porcelain pin insulator is a rigid overhead-line insulator designed to support and electrically isolate conductors from grounded poles, crossarms and supporting structures in 20kV distribution networks.
The conductor is positioned in the upper groove of the porcelain body and secured with an approved conductor tie. The lower steel spindle is connected to the pole-top bracket or crossarm assembly. The glazed porcelain surface provides electrical insulation and helps reduce the accumulation of moisture and contamination.
Reference Technical Data
| Product Type | Porcelain Pin-Type Insulator |
|---|---|
| Reference Model | P-20T |
| Rated Voltage | 20kV |
| Insulating Material | Glazed electrical porcelain |
| Porcelain Body Height H | 165 mm |
| Maximum Shed Diameter D | 228 mm |
| Reference Assembly Dimension H1 | 245 mm |
| Reference Connection Dimension H2 | 45 mm |
| Mounting Thread | M20 |
| Nominal Creepage Distance | 370 mm |
| Reference Bending Failure Load | Approximately 13.2 kN |
| Dry Power-Frequency Flashover Voltage | Approximately 86 kV |
| Wet Power-Frequency Flashover Voltage | Approximately 57 kV |
| Power-Frequency Puncture Voltage | Approximately 111 kV |
| 50% Lightning Impulse Flashover Voltage | Approximately 140 kV |
| Reference Lightning Impulse Withstand Voltage | Approximately 110 kV |
| Reference Weight | Approximately 6.2 kg |
| Colour | White glazed porcelain; brown glaze available by specification |
Important: These values are representative P-20T catalogue data and must not replace the approved manufacturing drawing or test report. Different manufacturers may use different spindle dimensions, assembly heights and test values under the same model designation.
Key Features
- Designed for 20kV overhead distribution-line conductor support
- Glazed electrical-porcelain body provides electrical insulation and outdoor durability
- Upper conductor groove accepts the conductor and approved tie wire
- Steel spindle provides rigid installation on a pole or crossarm assembly
- 370 mm nominal creepage distance for standard service configurations
- M20 mounting connection in the representative P-20T configuration
- Available with white or brown porcelain glaze
- Dimensions, creepage distance and spindle construction can be produced according to approved drawings
Materials and Construction
| Insulating Body | High-strength electrical porcelain |
|---|---|
| Porcelain Surface | Uniformly glazed white or brown finish |
| Steel Spindle | Steel spindle according to the approved mechanical drawing |
| Metal Surface Treatment | Hot-dip galvanized for outdoor corrosion protection |
| Mounting Connection | M20 reference thread |
| Conductor Retention | Top or side groove with approved conductor tie |
Applications
- 20kV overhead distribution networks
- Rural electrification projects
- Utility distribution-line construction
- Pole-top and crossarm conductor support
- Straight-line conductor positions
- Light-angle line positions within the approved mechanical load
- Industrial and infrastructure distribution networks
- Distribution-network reconstruction and upgrading projects
Reference P-Series Models
| Model | Rated Voltage | Body Height | Maximum Diameter | Creepage Distance | Mounting Thread |
|---|---|---|---|---|---|
| P-10T | 10kV | 105 mm | 145 mm | 195 mm | M16 |
| P-15T | 15kV | 120 mm | 190 mm | 280 mm | M20 |
| P-20T | 20kV | 165 mm | 228 mm | 370 mm | M20 |
| P-35T | 35kV | 200 mm | 280 mm | 560 mm | M20 |
Information Required for Selection
- System nominal and maximum operating voltage
- Required creepage distance
- Pollution level and installation environment
- Conductor type, diameter and mechanical load
- Required top or side conductor groove
- Crossarm and mounting-hole dimensions
- Spindle thread and overall spindle length
- Required bending failure load
- Glaze colour
- Applicable standard and test-document requirements
Standards and Testing
IEC 60383-1:2023 provides definitions, test methods and acceptance criteria for ceramic and glass insulator units used on AC overhead lines above 1,000 V, including rigid overhead-line insulators.
P-20T insulators can be manufactured or tested according to IEC 60383-1, the applicable Chinese standard or a purchaser-approved utility specification. Compliance must only be claimed when the supplied product is supported by the corresponding drawing and valid test documentation.
Inspection and testing may include dimensional verification, visual examination, porosity testing, temperature-cycle testing, mechanical bending testing, power-frequency flashover testing, lightning impulse testing and puncture testing, according to the applicable standard.
Installation Notes
- Install the insulator with the conductor groove facing upward and the steel spindle facing downward
- Confirm that the spindle thread matches the pole-top or crossarm fitting
- Use an approved conductor tie suitable for the conductor material and diameter
- Do not exceed the specified bending load or approved line angle
- Inspect the porcelain for cracks, chips, glaze defects and loose metal fittings before installation
- Replace any insulator showing puncture damage, severe chipping or mechanical looseness
Frequently Asked Questions
What is the P-20T pin insulator used for?
It supports and electrically insulates conductors on 20kV overhead distribution lines, normally at straight-line or limited-angle pole positions.
What does the letter T mean in P-20T?
In the traditional P-series designation, T identifies a version supplied with a metal foot or spindle for installation on a steel crossarm. The exact spindle construction must be confirmed from the drawing.
Can a P-15T photograph be used for a P-20T product page?
No. The two models have different voltage ratings, dimensions and creepage distances. The photograph and visible model marking must match the listed product.
Is the steel spindle included?
The illustrated T-type configuration includes a steel spindle. Spindle dimensions, thread and galvanizing requirements must be confirmed when ordering.
Is the P-20T suitable for heavily polluted or coastal areas?
Suitability depends on the required specific creepage distance and the project pollution level. A longer-creepage or anti-pollution profile may be required for severe environments.
