Which wire insulation type is safe for use in direct burial?

The correct choice for wire insulation types suitable for direct burial is that rubber insulation is specifically designed to withstand the conditions encountered underground, such as moisture and soil acidity. Rubber insulation provides excellent water resistance, flexibility, and abrasion resistance, making it ideal for environments where it may come into contact with soil and moisture.

Rubber's properties allow it to maintain its integrity under various environmental stresses, ensuring a longer lifespan and enhanced safety for electrical installations buried underground. This durability is crucial in preventing electrical failures that can arise from moisture infiltration, which is often a risk in direct burial applications.

While other insulation types like thermoplastic, asbestos, and mineral insulated wires have their specific applications, they do not provide the same level of protection and suitability for direct burial that rubber does. For instance, thermoplastic insulation might not withstand extreme conditions as effectively as rubber, and exposure to moisture could degrade its performance over time. Similarly, asbestos is not used for electrical insulation due to health hazards, and mineral insulated cables, while durable, may not be as flexible for installation in direct burial situations compared to rubber-insulated wires.