A coil assembly for a magnetic actuator, the coil assembly comprising: - a tubular coil holder comprising a first and second open distal end ; - the first open distal end comprising an outer circular rim and an inner circular rim separated by a circular groove ; - the second open distal end comprising an outer circular rim ; - a coil formed of a single wire , the coil being arranged in a winding area between the inner circular rim of the first open distal end and the outer circular rim of the second distal end; whereby a first end and a second end of the single wire are arranged in the circular groove; the inner circular rim comprising a longitudinal groove (114.1) to extend the first end and the second end of the single wire from the circular groove to the winding area; - a tubular housing ; the tubular housing having an inner diameter substantially equal to a diameter of the outer circular rim of the first distal end and a diameter of the outer circular rim of the second distal end; - an external connection comprising a first conductor and a second conductor ; whereby an end of the first conductor is electrically connected to the first end of the single wire so as to form a first electrical connection arranged in the circular groove and an end of the second conductor is electrically connected to the second end of the single wire so as to form a second electrical connection in the circular groove and wherein the first and second conductor extend through the outer circular rim via a longitudinal groove (112.1) of the outer circular rim, characterized in that the tubular housing is configured to close the longitudinal groove (112.1) of the outer circular rim and keep the single wire , the first conductor and the second conductor in place. - a tubular coil holder comprising a first and second open distal end ; - the first open distal end comprising an outer circular rim and an inner circular rim separated by a circular groove ; - the second open distal end comprising an outer circular rim ; - the first open distal end comprising an outer circular rim and an inner circular rim separated by a circular groove ; - the second open distal end comprising an outer circular rim ; - a coil formed of a single wire , the coil being arranged in a winding area between the inner circular rim of the first open distal end and the outer circular rim of the second distal end; whereby a first end and a second end of the single wire are arranged in the circular groove; the inner circular rim comprising a longitudinal groove (114.1) to extend the first end and the second end of the single wire from the circular groove to the winding area; - a tubular housing ; the tubular housing having an inner diameter substantially equal to a diameter of the outer circular rim of the first distal end and a diameter of the outer circular rim of the second distal end; - an external connection comprising a first conductor and a second conductor ; whereby an end of the first conductor is electrically connected to the first end of the single wire so as to form a first electrical connection arranged in the circular groove and an end of the second conductor is electrically connected to the second end of the single wire so as to form a second electrical connection in the circular groove and wherein the first and second conductor extend through the outer circular rim via a longitudinal groove (112.1) of the outer circular rim, <EOS>