IEC Electrical Y2S1 Part 3 Practice Test 2026 - Complete Exam Prep

The type of insulation known for its oil resistance is MTW, which stands for Machine Tool Wire. This type of insulation is specifically designed to withstand harsh conditions, including exposure to oils and solvents commonly found in industrial environments. It is suitable for use in various applications where there may be a risk of contact with oils, making it a preferred choice for powering machinery and tools.

THHN (Thermoplastic High Heat-resistant Nylon-coated) insulation, while versatile and used for a wide range of applications, is not inherently oil-resistant. THW (Thermoplastic High Water-resistant) is designed for wet conditions but does not focus on oil resistance. NM (Non-Metallic Sheathed Cable) is primarily used for residential wiring and is not rated for oil resistance. Thus, MTW stands out as the option specifically engineered for environments with potential oil exposure.