Device support for mounting an electrical installation device on a line guidance duct, comprising: - a base part, comprising a base, side parts and mounting elements, for receiving the electrical installation device, - at least two lateral, opposing and elastic clamping arms, which are formed on the base part, for fastening the electrical installation device, characterized in that the clamping arms, for mounting the electrical installation device in the mounted state, can be tensioned outwards against the tensioning force which is directed inwards in the direction of the centre of the base, and a guide web and also a clamping strip, which is arranged above the said guide web and runs parallel to the guide web, are arranged at the head end of each of the clamping arms, wherein the guide web and the clamping strip form a guide slot into which the electrical installation device or a mounting part of the said electrical installation device can be inserted, wherein the clamping arms, which are pretensioned in the mounted state, are pressed inwards in order to change over to the locking state, as a result of which the electrical installation device or the mounting part is held on account of the tensioning force which is directed inwards in the direction of the centre of the base, wherein a mounting profile is formed on the guide web of the clamping arm, the said mounting profile comprising at least one lateral retaining hook which is formed on the guide web and, in the mounted state of the pretensioned clamping arms, engages into a slot which is formed at the head end of a mounting element, and wherein a sliding lug is additionally formed on the mounting element. - a base part, comprising a base, side parts and mounting elements, for receiving the electrical installation device, - at least two lateral, opposing and elastic clamping arms, which are formed on the base part, for fastening the electrical installation device, characterized in that the clamping arms, for mounting the electrical installation device in the mounted state, can be tensioned outwards against the tensioning force which is directed inwards in the direction of the centre of the base, and a guide web and also a clamping strip, which is arranged above the said guide web and runs parallel to the guide web, are arranged at the head end of each of the clamping arms, wherein the guide web and the clamping strip form a guide slot into which the electrical installation device or a mounting part of the said electrical installation device can be inserted, wherein the clamping arms, which are pretensioned in the mounted state, are pressed inwards in order to change over to the locking state, as a result of which the electrical installation device or the mounting part is held on account of the tensioning force which is directed inwards in the direction of the centre of the base, wherein a mounting profile is formed on the guide web of the clamping arm, the said mounting profile comprising at least one lateral retaining hook which is formed on the guide web and, in the mounted state of the pretensioned clamping arms, engages into a slot which is formed at the head end of a mounting element, and wherein a sliding lug is additionally formed on the mounting element.