Here "Aux" means additional. You may also consider measuring the current in the "Aux" power supply line with an additional CT connected to the "Aux" power supply.
similarly, if you have an additional single-phase load and want to measure the current for that, then that also can be done using 5th CT/PT
5th CT is normally used to measure earth leakage current or residual current. If you have an additional CT installed to measure earth leakage current then the second of that CT may be connected to the 5th CT input of this meter.
If there is no additional CT installed then you may follow the wiring described in the user manual for "Residual Current measurement" (page 22 in the User Manual).
Kindly note, in the installation guide it is mentioned as "Aux" because if you want to do an additional current measurement (other than normal
I1, I2, I3, and N), then it can be done using this input.
similarly, if you have an additional single-phase load and want to measure the current for that, then that also can be done using 5th CT/PT
5th CT is normally used to measure earth leakage current or residual current. If you have an additional CT installed to measure earth leakage current then the second of that CT may be connected to the 5th CT input of this meter.
If there is no additional CT installed then you may follow the wiring described in the user manual for "Residual Current measurement" (page 22 in the User Manual).
Kindly note, in the installation guide it is mentioned as "Aux" because if you want to do an additional current measurement (other than normal
I1, I2, I3, and N), then it can be done using this input.