A sub-rack mounting bracket (18 40, 60) for mounting an electrical device sub-rack to an electrical device rack, comprising: a first portion (28, 44, 64) extending throughout the length of the mounting bracket for coupling the sub-rack mounting bracket (18, 40, 60) to the rack during use, the first portion (28, 44, 64) being generally planar and arranged in a first plane (46, 66); a second portion (30, 50, 70) extending throughout the length of the mounting bracket for coupling the sub-rack mounting bracket (18, 40, 60) to the sub-rack during use, the second portion (30,50,70) being generally planar and arranged in a second plane (52, 72) at a constant distance from and orientation to the first plane (46, 66) along the length of the mounting bracket (18, 40, 60); the mounting bracket characterized by an intermediate portion (32, 56, 76) extending throughout the length of the mounting bracket and arranged between the first portion (28, 44, 64) and the second portion (34, 46, 58), the intermediate portion (32, 56, 76) being formed of a sheet material shaped so as to reduce the amplitude of vibrations transmitted to the sub-rack through the sub-rack mounting bracket (18, 40, 60) during use, wherein the sub-rack mounting bracket (18, 40, 60) extends lengthwise along a longitudinal axis (24, 42, 62) of the sub-rack mounting bracket (18, 40, 60) and the intermediate portion (32, 56, 76) is formed by a first bend portion, a second bend portion and a third bend portion, or, the intermediate portion (32, 56, 76) comprises a curved portion (88, 98) in the sheet material, the or each bend portion (100, 102, 104) or curved portion (88, 98) being respectively bent in a bend direction (86, 90) or curved in a curve direction (86, 90) perpendicular to the longitudinal axis (24, 42, 62) of the sub-rack mounting bracket (18, 40, 60). a first portion (28, 44, 64) extending throughout the length of the mounting bracket for coupling the sub-rack mounting bracket (18, 40, 60) to the rack during use, the first portion (28, 44, 64) being generally planar and arranged in a first plane (46, 66); a second portion (30, 50, 70) extending throughout the length of the mounting bracket for coupling the sub-rack mounting bracket (18, 40, 60) to the sub-rack during use, the second portion (30,50,70) being generally planar and arranged in a second plane (52, 72) at a constant distance from and orientation to the first plane (46, 66) along the length of the mounting bracket (18, 40, 60); the mounting bracket characterized by an intermediate portion (32, 56, 76) extending throughout the length of the mounting bracket and arranged between the first portion (28, 44, 64) and the second portion (34, 46, 58), the intermediate portion (32, 56, 76) being formed of a sheet material shaped so as to reduce the amplitude of vibrations transmitted to the sub-rack through the sub-rack mounting bracket (18, 40, 60) during use, wherein the sub-rack mounting bracket (18, 40, 60) extends lengthwise along a longitudinal axis (24, 42, 62) of the sub-rack mounting bracket (18, 40, 60) and the intermediate portion (32, 56, 76) is formed by a first bend portion, a second bend portion and a third bend portion, or, the intermediate portion (32, 56, 76) comprises a curved portion (88, 98) in the sheet material, the or each bend portion (100, 102, 104) or curved portion (88, 98) being respectively bent in a bend direction (86, 90) or curved in a curve direction (86, 90) perpendicular to the longitudinal axis (24, 42, 62) of the sub-rack mounting bracket (18, 40, 60).