An electrical connector mountable on a printed circuit board and adapted for mating with a complementary connector, comprises an insulative housing and pairs of power contacts. The housing defines a plurality of passageways each having inside walls. Each pair of power contacts includes two separate, opposed power contacts. Each power contact has a contacting portion, a tail portion and an intermediate portion interconnecting the contacting portion and the tail portion. The tail portions of the pair of power contacts are arranged into two rows. One tail portion of one row of tail portions is formed with a protrusion therealong and one tail portion of the other row of tail portions is also formed with a protrusion. The distance between the two tail portions with protrusions located at different rows is larger than any other two tail portions.