Characters of exothermic welding: -It has a superior electrical conductivity to the conductors themselves. -It does not corrode, oxidize or degrade with time and is resistant to galvanic coupling. -It is able to withstand repeated electrical discharges. -It never increases its resistance. -It has greater mechanical and squeezing resistance than the conductors themselves. -It does not need extra energy (electrical source or heat source), only needs simple tools and equipment, and has high efficiency of operating. -It is simple to learn how to operate in safe procedure, without professional knowledge and special protection. -It is easy to check the welding quality by visual method -It guarantees all types of common joints. Not only cooper cable unions but also to weld tapes, brass metallic pieces, stainless steel, steel ground rods covered by copper, etc. -It does not produce any contamination and harmless to the environment.