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D1679-02 – Standard Test Method Technical Guide
🧪 Material Composition and Scope
ASTM D1679-02 specifies a crosslinked synthetic rubber insulating compound engineered for electrical wires and cables. This type of insulation is suitable for continuous operation at conductor temperatures not exceeding 75°C in both dry and wet locations, and for operating voltages not exceeding 2000 V.
⚠️ Low-Temperature Considerations: This insulation may have low-temperature limitations. It is critical to consult the manufacturer for specific recommendations regarding installation or application in cold environments.
The standard specifies that tests be performed on insulated wire or cable solely to determine the properties of the insulation material itself, rather than to evaluate the conductor or completed cable assembly. Whenever two sets of values are presented in different units, the first set is the standard.
⚡ Physical and Electrical Specifications
D1679-02 sets clear benchmarks for insulation performance. The insulation must meet specific thickness requirements and demonstrate robust electrical properties under precise test conditions.
| 📏 Property | 🎯 Requirement | 📐 Standard Reference |
|---|---|---|
| Conductor Temperature (Max) | 75°C | Section 1.2 |
| Operating Voltage (Max) | 2000 V | Section 1.2 |
| Min. Insulation Thickness | 90% of avg (Table 1A, D470) | Section 4.2 |
| AC Withstand Test Voltage | Per Table 1A (D470) for 5 min | Section 5.2 |
| Insulation Resistance Constant | 4000 MΩ-1000 ft (305 m) @ 60°F (15.6°C) | Section 5.3.1 |
💡 Mandatory Test Sequence: When electrical tests are specified, the standard requires a strict order: perform the AC voltage test first, followed by the insulation resistance test, and finally the DC voltage test. The sequence of other testing is not specified.
⚙️ Aging and Durability Conditions
The standard defines specific high-pressure aging protocols to validate long-term material stability under oxidative conditions.
| 🟦 Aging Type | ⚡ Condition (Pressure / Temp) | ⏱️ Duration |
|---|---|---|
| Air Aging | 80 psi (0.55 MPa) / 127°C | 20 hours |
| Oxygen Aging | 300 psi (2.1 MPa) / 80°C | 168 hours |
Insulation resistance values are standardized to a temperature of 60°F (15.6°C). If measurements were taken at a different temperature, they must be corrected using the factors provided in Table 2 of Test Methods D 470, or by applying the specific 1°F coefficient available from the insulation manufacturer.
❓ Frequently Asked Questions
🔍 What is the maximum operating temperature for D1679-02 insulation?
This insulation is designed for continuous operation at conductor temperatures not exceeding 75°C in both dry and wet locations.
💡 What is the maximum voltage rating for this insulation?
The standard covers applications with operating voltages not exceeding 2000 V.
⚡ How is “aging” specifically defined in this specification?
Aging is explicitly defined as exposure to either of the following conditions: air at 80 psi (0.55 MPa) and 127°C for 20 hours, or exposure to oxygen at 300 psi (2.1 MPa) and 80°C for 168 hours.
📌 What is the requirement for insulation thickness?
The required minimum thickness for the insulation is at least 90% of the average thickness specified in Table 1A of Test Methods D 470.