ABSTRACT

The electro-mechanical properties of copper cables produced in Nigeria for electric power distribution were assessed in this study as a precursor to frequent electrical induced fire outbreaks in our residence and work places. The four brands of the cable mostly used for home and work place wiring in southern Nigeria were sampled from industrial markets at Aba, Lagos and Portharcourt and compared with NIS and IEEE specifications. The cable brands include Wesco, Cutix, Scan and Coleman with cross sectional area of 1mm2 to 16mm2 while resistivity, elongation, flame retardant and core diameter/tensile strength constitute the evaluation parameters. The IEEE recommended minimum copper diameter for 1 mm2, 1.5mm2, 2.5mm2, 4mm2, 6mm2, 10mm2 and 16mm2 are 1.15mm, 1.45mm, 1.82mm, 2.2mm, 2.9mm, 3.6mm and 4.6mm respectively. 1mm2 wire gauge of Scan and Wesco cable fall short of set standard for core diameter. In addition, 2.5mm2 wire gauge of the sampled cables did not meet the core diameter specification except Cutix cable. The 1.5mm2, 6mm2, 10mm2, and 16mm2 wire gauge of the four cable brands sampled complied with NIS and IEEE specification. Analysis of the experimental results indicated that all the cable brands met the recommended standard for resistivity and flame retardant. Wesco, Cutix and Coleman cables exhibit low smoke and fume while scan revealed low smoke and halogen free cable burning features. Coleman cable exhibited a linear relationship in the elongation curve while Wesco, Cutix and Scan tend to follow the plasticity profile. Thus, proper care must be taken during installation of Coleman cables to avoid damage to the cable surface.  Although, the tensile strength of all the sampled cable brands falls within the recommended range of 12.5N/mm2 – 25N/mm2 with Cutix cable as the top performer. Cutix cable is the most expensive for all gauges and this can be attributed to the high copper content of their cables as evidenced by the thickness of their conductor material compared to other sampled brands. Hence, the overheating of the cables during service and its consequential high rate of fire outbreak in this country can be attributed to the reduction in the core diameters of some electrical cables used in our house wiring. It is therefore recommended that Nigeria regulatory agencies and cable producers should step up fight against piracy in this sector to save the nation from this fire inducing scourge.