A brush holder for a motor. The brush holder includes a plastic support structure corresponding incorporating at least a first and a second essentially rigid conducting element connected, respectively, between positive and negative brush or brushes and associated connecting members to form corresponding connecting paths in the brush holder for connecting the brushes to the terminals of an external source of supply voltage. At least one discontinuity is provided in at least one of the connecting paths. A resiliently deformable and electrically conducting strip is connected mechanically and electrically across this discontinuity, with a substantially permanent connection at one end, and with a thermally fusible connection at the other end, the strip having a resilient pre-loading which tends to break the connection at the said other end.