Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D372-00 – Standard Test Method Technical Guide
📋 Classification and Types of Flexible Treated Sleeving
ASTM D372-00 defines seven types of flexible treated sleeving for electrical insulation based on base fiber material and temperature index. These tubular products are made from woven textile fibers impregnated or coated with insulating materials for use in electrical apparatus.
| 🟦 Type | 📏 Base Fiber Material | 🎯 Temperature Index | ⚡ Typical Coating |
|---|---|---|---|
| I | Organic (cotton, rayon, nylon) | 105 | Impregnated or coated |
| II | Inorganic (fibrous glass) | 130 | Impregnated or coated |
| III | Inorganic (fibrous glass) | 105 | Poly(vinyl chloride) |
| IV | Inorganic (fibrous glass) | 200 | Silicone resin or PTFE |
| V | Inorganic (fibrous glass) | 200 | Silicone elastomer |
| VI | Inorganic (fibrous glass) | 155 | Epoxies, polyesters, acrylics |
| VII | Inorganic (fibrous glass) | 180 | Impregnated or coated |
⚡ Dielectric and Temperature Performance
Performance is determined by dielectric breakdown voltage and temperature index. Grades are identified by minimum average dielectric breakdown voltage as shown in Table 1 of the standard. The temperature index reflects maximum continuous operating capability, with Types IV and V rated for 200°C.
💡 Tip: Select a sleeving type with a temperature index exceeding your maximum operating temperature to ensure insulation reliability.
Test methods for dielectric and thermal properties are referenced in ASTM D350.
📏 Sizing and Ordering Specifications
Sleeving sizes are based on the diameter of round conductors that fit snugly without distortion, as listed in Table 2 of the standard. Orders must include type, color, and grade per Section 5.1.
⚠️ Warning: Incorrect sizing can cause insulation failure. Always consult Table 2 for proper dimensions.
Referenced documents include ASTM D1711 for terminology and ASTM D4088 for shipment preparation.
❓ Frequently Asked Questions
🔍 What is the scope of ASTM D372-00? It covers flexible insulating sleeving for lead wires and connections in electrical apparatus such as motors, transformers, and switch gears.
💡 How are types classified? Types are classified by base fiber material (organic or inorganic) and temperature index, ranging from Type I (105°C) to Type VII (180°C).
⚡ What is the temperature index? It is a measure of the sleeving’s ability to withstand continuous high-temperature operation without degradation.
📌 What information is required for ordering? Orders must specify type, color, grade, and size as defined in the standard.