adjoins the clamping device 20 wherein the clamping device 20 adjoins the short part of the l shaped section the resistor element 40 is formed in the form of a measuring section 41 integrated in the sheet metal element which are indicated by the dashed lines schematically in the figures the measuring section 41 can be understood to mean a region which is shaped so as to be matched specifically to the electrical resistance and is delimited approximately by two voltage measurement points 42 a 42 b in order to increase the electrical resistance within the measuring section 41 recesses 43 a 43 b are provided in the exemplary embodiment shown in fig1 the hollow shaped recesses 43 a 43 b are provided on the edge regions of the sheet metal element 80 as an alternative to this it is also conceivable for a recess 43 c to also be provided within the material in addition to the hollow shaped recesses 43 a 43 b as is shown in the second exemplary embodiment shown in fig2 the recesses 43 a 43 b 43 c are arranged symmetrically with respect to the longitudinal axis of the measuring section 41 and advantageously have rounded off edges the voltage measurement points 42 a 42 b are outside the region lying transversely to the direction of current flow i in which the recesses 43 a 43 b 43 c are located in the case of a current flow through the sheet metal element 80 the current can then be determined via the voltage which is measured at the voltage measurement points 42 a 42 b and the known.