A CABLE CONNECTION UNION HAVING ONE PROTECTION BOX

A power cable joint box is provided to minimize usage of waterproof material between an inner side pipe and an outer side pipe by covering an outer side pipe on an inner side pipe. A power cable joint box(100) includes a connection joint(110), a protection box(120), and waterproof material(130). The connection joint connects end parts of two cable conductors(2). The protection box covers an outer part of the connection joint. The waterproof material is filled between the connection joint and the protection box. The protection box includes an inner side pipe(121) of metal material and an outer side pipe(122) of reinforced plastic material. The inner side pipe covers an outer part of the connection joint. The outer side pipe covers an outer surface of the inner side pipe. A ground terminal(140) is formed in one side of the outer side pipe, and is connected to the inner side pipe. An inlet port(123) is formed in one side of the protection box. The waterproof material is injected inside the inner side pipe through the inlet port.