How to Check a 3-Phase Extension Lead
To check a 3-phase lead we need to perform an earth resistance test and a leakage/insulation
test. Polarity can be checked with a basic multimeter.
• Make sure the TPL is NOT plugged into mains.
• Plug one end of the extension lead into the TPL.
• Plug your IEC lead from your appliance tester into the IEC socket on the side of the TPL.
• With your earth probe/clamp probe inside the earth terminal on the other end of the
extension lead.
• Perform the earth resistance test.
• Disconnect the IEC lead from the TPL and remove your probe from the end of the extension
lead.
• Plug the TPL into the appropriate mains socket.
• Leave one end of the extension lead plugged into the TPL and the other end not connected
to anything.
• With the mains applied turn on the TPL and take a measurement by pressing the test button.
In this case we are “powering” a lead which is not connected to anything to check the quality
of the insulation.
• Note the leakage reading in mA.
• Perform polarity test with basic multimeter.
Calibration
To ensure accurate measurement the unit shall be calibrated every 12 months. Please return
the unit to Appliance Testing Supplies or calibration agency for re-calibration.
Specifications
Mains Ratings:
20A, 32A, 40A, 50A (depending on model)
500V, 50Hz
Display
Reading rate time: 2-3 readings per second
Range: 0 - 19.99 mA AC
Accuracy @ 5mA AC: +⁄ -1%, 23 D⁄-5 Degrees Celsius,<80%RH
