A method and a system for monitoring clamping pressure exerted by a clamping cylinder to an electrode in an electrode slipping device which comprises an upper annular holder ring and a lower annular holder ring, each comprising at least one clamping assembly including a clamping shoe and clamping cylinder arranged in co-operation so that the clamping shoe is forced into pressure contact with the electrode and released from pressure contact with the electrode by the action of the clamping cylinder. The measuring system comprises a force sensor (30) mounted in connection with a pressing piece (22) that transmits the force created by the clamping cylinder to the clamping shoe. The force sensor can be a strain gage (30) mounted in a cavity (25) provided in the pressing piece (22) or a load cell mounted between the pressing piece (22) and the clamping cylinder.