How to Test & Tag an Extension Lead

Extension leads are one of the most common electrical items you’ll come across when testing and tagging.

The process starts with a thorough visual inspection, followed by electrical testing to check the earth connection, insulation and polarity of the lead.

In the video below, we demonstrate how to test an extension lead using a Metrel DeltaPAT 3309 appliance tester.

Start With a Visual Inspection

Before connecting the extension lead to the tester, check it carefully for obvious signs of damage.

Look for things such as:

• cuts, splits or damage to the cable
• exposed conductors
• damaged or cracked plugs and sockets
• bent or damaged pins
• signs of overheating or discolouration
• loose connections or components 

The vast majority of failures do in fact appear at the visual inspection stage, before it's even tested. 

See our complete Test & Tag Visual Inspection Checklist for more information.

Run the Electrical Tests

After completing the visual inspection, the extension lead is connected to the DeltaPAT 3309, with the supplied IEC lead plugged into the tester’s IEC socket to complete the circuit.

We then select IEC Lead Test from the Simple Test menu and work through the test sequence:.

• Earth continuity - this checks that there is continuous protective earth through the lead
• Insulation resistance - checks integrity of the insulation
• Polarity - checks the active, neutral and earth conductors are connected correctly

Once the sequence is complete, the PAT tester displays the results.

Record and Tag the Extension Lead

If the extension lead passes the required tests, the result can then be recorded and the appropriate test tag applied with the person who tested it, the test date and when the next test is due. 

If it fails any part of the inspection or testing process, it should not be passed or returned to normal use. In this case, you'll need to use a failed test tag so it's clearly identified.

The exact process and menu options can vary between portable appliance testers, so always follow the appropriate procedure for the tester being used.

Learn How to Test Electrical Equipment Properly

Testing an extension lead is one of the practical skills covered during our nationally recognised Test & Tag course.

Students get hands-on experience using portable appliance testers and testing a range of common electrical equipment.

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