A 16mm 5-core PVC/PVC cable in Nigeria is a low-voltage power cable designed for heavy-duty electrical distribution, especially for three-phase systems with neutral and earth.
Description
A 16mm 5-core PVC/PVC cable consists of:
• 5 copper conductors (cores)
• Each core has a cross-sectional area of 16mm2
• PVC insulation (inner layer) on each conductor
• PVC outer sheath (outer layer) for protection
This type is often written as CU/PVC/PVC 5C x 16mm2 cable.
Construction
• Conductor: Stranded annealed copper (for flexibility and conductivity) 
• Number of cores: 5 (typically R, Y, B, Neutral, Earth) 
• Insulation: PVC (heat and flame resistant) 
• Outer sheath: PVC (black, tough and weather-resistant) 
Voltage Rating
• Common rating: 300/500V or 600/1000V depending on type