How to perform a high current ZE measurement using the Seaward PowerTest 1557?

When testing circuits which are not RCD protected and where the earth loop impedance is low, for example    when measuring ZE, performing a high current loop test can give improved accuracy and repeatability.

The line impedance (L-N) test can be used to perform a high current ZE measurement as shown below:

Method a) 3 wire measurement

1. Connect the red test probe to the line conductor.

2. Connect both the green and black test probes to the earth conductor.

3. Select the loop test Zs on the rotary switch.

4. Select a high current line impedance test by pressing the F1 key until L-N is shown on the LCD display.

5. Press the TEST key to make a measurement.

Method b) 2 wire measurement

1. Connect the red test probe to the line conductor.

2. Connect the combined green/black test probe to the earth conductor.

3. Select the loop test Zs on the rotary switch.

4. Select a high current line impedance test by pressing the F1 key until L-N is shown on the LCD display.

5. Press the TEST key to make a measurement.