Carbon nanotubes (CNTs) possess the huge potential in becoming a viable replacement for materials in a wide variety of mechanical, electrical and thermal applications. CNT wires (yarns) made of individual CNTs are able to carry power over vast distances, and the amount of power lost from heat or resistivity could be significantly reduced along with the amount of materials needed. CNT wires can be used in satellites, space stations, and other low earth orbit applications. Studying the viability of such applications would require some additional methods to reduce the overall size and weight of the objects being sent into the space. The aim of this study was to investigate the mechanical and electrical properties of CNT wires after post growing of CNTs on 60 plies CNT yarns/wires. The CNTs were grown on the CNT yarn by chemical vapor deposition (CVD) process and it was observed that “fuzzy” CNTs were produced vertically on the CNT wires. The CNTs growth process was simulated and optimized for each test condition. The experimental result showed that some variations of the ultimate tensile strength (UTS) and the tenacity were observed by growing CNTs on the untreated yarns. The CNT yarns have potential in composite materials as the yarn can produce a good interface between the matrix and the yarns.