A system for current measurement in a power grid, comprising: a terminal block comprising: a shunt, a first (1 1a) and a second current terminal (1 1b), a first and a second sensing terminal, a temperature sensor, the system further comprising an Intelligent Electronic Device, IED, and a primary device, wherein a first end of the shunt is connected to the first current terminal (1 1a) and to the first sensing terminal, a second end of the shunt is connected to the second current terminal and to the second sensing terminal, the first current terminal and the second current terminal (1 1b) are configured to be connected to secondary outputs of the primary device, the first sensing terminal and the second sensing terminal are configured to be releasably connected to the IED, and the temperature sensor is configured to measure a temperature of the terminal block; wherein the IED comprises: second IED terminals and/or a wireless receiving unit adapted to receive at least parts of the calibration parameters of the shunt; a voltage measurement unit with inputs connected to the first IED terminals and adapted to be connected via the first IED terminals with the first sensing terminal and second sensing terminal of the terminal block and to measure a voltage drop at the shunt; and a calibration unit that is configured or adapted to calculate, from the calibration parameters of the shunt or the parts of calibration parameters of the shunt and the voltage drop at the shunt, a current flowing through the shunt and/or a primary current of the primary device. a shunt, a first (1 1a) and a second current terminal (1 1b), a first and a second sensing terminal, a temperature sensor, the system further comprising an Intelligent Electronic Device, IED, and a primary device, wherein a first end of the shunt is connected to the first current terminal (1 1a) and to the first sensing terminal, a second end of the shunt is connected to the second current terminal and to the second sensing terminal, the first current terminal and the second current terminal (1 1b) are configured to be connected to secondary outputs of the primary device, the first sensing terminal and the second sensing terminal are configured to be releasably connected to the IED, and the temperature sensor is configured to measure a temperature of the terminal block; wherein the IED comprises: second IED terminals and/or a wireless receiving unit adapted to receive at least parts of the calibration parameters of the shunt; a voltage measurement unit with inputs connected to the first IED terminals and adapted to be connected via the first IED terminals with the first sensing terminal and second sensing terminal of the terminal block and to measure a voltage drop at the shunt; and a calibration unit that is configured or adapted to calculate, from the calibration parameters of the shunt or the parts of calibration parameters of the shunt and the voltage drop at the shunt, a current flowing through the shunt and/or a primary current of the primary device. second IED terminals and/or a wireless receiving unit adapted to receive at least parts of the calibration parameters of the shunt; a voltage measurement unit with inputs connected to the first IED terminals and adapted to be connected via the first IED terminals with the first sensing terminal and second sensing terminal of the terminal block and to measure a voltage drop at the shunt; and a calibration unit that is configured or adapted to calculate, from the calibration parameters of the shunt or the parts of calibration parameters of the shunt and the voltage drop at the shunt, a current flowing through the shunt and/or a primary current of the primary device.