A power connector (1) includes an insulative housing (10), a number of conductive contacts (20) received in the insulative housing, a first shell (30) enclosing the insulative housing and a second shell (40) enclosing the first shell. The insulative housing includes a base portion (101) and a tongue portion (103) extending forwardly from the base portion. The cross-section of each of the first and the second shells consists of a pair of straight sections (308, 408) parallel to each other and a pair of arcuate sections (308′, 408′) each connecting with the pair of straight sections.