Meter loss by the wiring method

QWhy is the measurement value different depending on the wiring to the power meter?

A

There are two wiring methods for the power meter to input the current directly.
According to the voltage and current being measure, please use the appropriate wiring method from the following.

1) Connecting the current terminals to the load side
This method measures the power including the loss of the input resistance on the current input terminal.
This method minimizes meter loss when the voltage is high and the current is low.

2) Connecting the voltage terminals to the load side
This method measures the power including the loss of input resistance of the voltage input terminal.
This method minimizes meter loss when the voltage is low and the current is high