Thermoplastic Sheathed Cable (TPS Cable): What Is Its Service Life?

The service life of a Thermoplastic Sheathed Cable (TPS cable) is not a fixed value; it typically ranges from 15 to 30 years. The exact duration is comprehensively influenced by multiple factors—from the installation environment and material quality to operational load—all of which can significantly alter its actual service cycle. Below are the key influencing factors and recommendations for extending its lifespan:

Core Influencing Factors: 5 Key Determinants of Service Life

The lifespan of a Thermoplastic Sheathed Cable is essentially determined by the aging rate of its thermoplastic insulation layer (e.g., PVC) and sheath material, which is driven by the following factors:

1. Ambient Temperature: The Most Critical Factor Accelerating Aging

Thermoplastic materials (such as PVC) are highly sensitive to temperature. Prolonged exposure to high temperatures accelerates the breaking of molecular chains in the material, causing the sheath to harden, crack, and its insulation performance to deteriorate.

Ideal environment: Indoor spaces with dry conditions, good ventilation, and a long-term stable ambient temperature of -15°C to 40°C (in line with the design parameters of most TPS cables). Under such conditions, the service life can approach 30 years.

Harsh environment: If the cable is continuously exposed to high-temperature areas (e.g., near heaters, boilers, or high-power electrical appliances) or outdoor locations with direct sunlight in summer (without shading), and the ambient temperature frequently exceeds 60°C, its service life may be shortened to 10–15 years or even less.

2. Installation and Operational Load: Avoid "Overloading" and "Physical Damage"

Current load: If the cable operates above its rated current-carrying capacity for a long time (e.g., using a 4mm² cable to power high-power equipment that far exceeds its load capacity), the conductor will generate excessive heat. This heat is transferred to the insulation layer and sheath, accelerating aging. For instance, a cable with frequent overloading may have a service life 30%–50% shorter than one operating under normal load.

Physical damage: During installation, if the cable is crushed, punctured (e.g., by accidental nail gun fire), or subjected to long-term mechanical friction (e.g., near moving parts), the sheath will be damaged. This not only eliminates its protective function but also allows moisture and impurities to seep in, accelerating the aging of the internal insulation layer and directly shortening the service life.

3. Environmental Humidity and Corrosiveness: Accelerate Material Deterioration

High-humidity environments: Areas like bathrooms, basements, and kitchens. If there are tiny gaps in the cable sheath, moisture will slowly seep in, leading to conductor oxidation and moisture-induced breakdown of the insulation layer. The service life in such cases may be shortened to 15–20 years.

Corrosive environments: Locations such as chemical plants, laboratories, and coastal areas (with high salt spray). Corrosive gases or liquids may react chemically with the thermoplastic sheath, causing it to swell and become brittle. The service life here may be only 10–15 years or even shorter (requiring the selection of additional corrosion-resistant cables).

4. Material Quality: The Gap Between Original and Inferior Products

High-quality original cables: Made of standard-compliant high-purity copper conductors (reducing heat generation) and aging-resistant thermoplastic materials (e.g., PVC with antioxidants and UV stabilizers added). Their service life can stably reach 25–30 years.

Inferior cables: Use recycled plastics (prone to sheath cracking) and conductors with high levels of impurities (low current-carrying capacity, prone to overheating). Their service life may be only 8–15 years, and they pose safety hazards (e.g., short circuits, fires).

5. UV Radiation: An "Invisible Killer" for Outdoor Use

The thermoplastic sheath of ordinary TPS cables is not UV-treated. If exposed to direct outdoor sunlight for a long time (e.g., open-air wiring, unprotected exterior wall cables), UV rays will damage the molecular structure of the sheath, causing it to become brittle and peel off rapidly. The service life in such scenarios may be only 5–10 years.

(Note: For outdoor use, dedicated cables with "UV-resistant" sheaths should be selected, or protection measures such as conduit installation or shading should be adopted.)

4 Recommendations for Extending Service Life

1. Match the Usage Scenario: Prioritize conduit protection for cables in humid areas; select UV-resistant models for outdoor use; avoid using ordinary TPS cables in high-temperature/corrosive environments (use armored or temperature-resistant cables instead).

2. Strictly Control Load: Choose cables with an appropriate cross-sectional area based on equipment power (refer to cable current-carrying capacity tables) to avoid long-term overloading.

3. Standardize Installation: Prevent excessive bending, crushing of the cable, or installation near high-temperature/sharp components. Reserve a certain buffer space during wiring to reduce mechanical stress.

4. Regular Inspections: Inspect cables every 3–5 years (especially those in old buildings or harsh environments). Focus on checking for sheath cracking, discoloration, or bulging. Replace defective cables promptly to avoid safety risks.

Summary

Under ideal conditions—indoor dry environment, normal load, high-quality materials, and standardized installation—ordinary thermoplastic sheathed cables (TPS) can have a service life of 25–30 years. However, in harsh conditions such as humidity, high temperatures, outdoor exposure, or overloading, their service life may be shortened to 10–20 years. In practical use, it is necessary to select the appropriate cable based on the scenario and maximize its service life through standardized installation and regular maintenance.