A protection relay connection assembly (10) for connecting a current transformer (14) and/or a voltage transformer (16) of an electrical network (12) to a protection relay (18) is provided. The protection relay connection assembly (10) includes a protection relay data acquisition board (20) and a protection relay connector (22). The protection relay data acquisition board (20) includes a first current mating member (24) connectable to a current measurement sensor (28), the current measurement sensor (28) being connectable in use to the protection relay (18) and/or a first voltage mating member (26) connectable to a voltage measurement sensor (30), the voltage measurement sensor (30) being connectable in use to the protection relay (18). The protection relay connector (22) includes a second current mating member (36) connectable to the current transformer (14) and/or a second voltage mating member (38) connectable to the voltage transformer (16). The first current mating member (24) and the second current mating member (36) are selectively mateable with one another to permit a measured current waveform of the electrical network (12) to be transmitted from the current transformer (14) to the protection relay (18). The first voltage mating member (26) and the second voltage mating member (38) are shaped to be selectively mateable with one another to permit a measured voltage waveform of the electrical network (12) to be transmitted from the voltage transformer (16) to the protection relay (18). Wherein the first current mating member (24) is shaped to prevent mating of the first current mating member (24) with the second voltage mating member (38), and the first voltage mating member (26) is shaped to prevent mating of the first voltage mating member (26) with the second current mating member (36).