The meter contains an arrangement for optionally connecting its voltage circuit (L) to a current path (5) or to a calibration system. The arrangement comprises an opening (2), provided in the housing of the meter, for introducing a contact member (3) connected to the calibration system and a pivoting lever (H) which, when the contact member (3) is introduced into the said opening (2), can be adjusted from an operating position connecting the voltage circuit (L) to the current path (5) to a calibration position which connects the voltage circuit (L) to the calibration system. As a result, the arrangement can be switched between the operating position and the calibration position with the least possible complexity. <IMAGE>