This paper presents a three-dimensional thermal model of an electric fuse mounted on its fuse holder. The proposed model can be used in steady-state conditions but also during transient operating conditions. A comparison at the same ambient temperature and load current, between the thermal model of the fuse with and without its fuse holder, has been performed. In the case of load current and ambient temperature variation, a thermal analysis at different voltage drop values on the fuse contacts has been done. For different thermal load on fuse contacts and current variation, the temperature distribution along the fuse link, has been investigated. The experimental tests led to the validation of the proposed three-dimensional thermal model of the fuse mounted on its fuse holder.