The Importance of Accurate PAT Testing

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PAT stands for portable appliance testing. As you might guess, the term refers to testing electrical equipment to ensure safety, condition, and functionality. It is a routine process in Australia, New Zealand, the Republic of Ireland, and the United Kingdom.

Accurate PAT testing is crucial for businesses hoping to meet and maintain solid electricity safety standards, keeping your employees and customers safe. It is also a legal requirement in many areas.

This article will dive into what PAT testing is, the different kinds of testers available, and how you can ensure your testing devices remain accurate year-round.

What is PAT testing?

In Australia, PAT testing is commonly known as ‘Test & Tag’. The full terminology, as defined by the IET/IEE standard, is ‘In-service Inspection & Testing of Electrical Equipment’.

Some devices you might use a PAT to test include detachable leads and plugs, home appliances, computers, printers, and more.

Testing usually involves visual inspection followed by checks for:


  • Grounding or earthing continuity,
  • Insulation quality,
  • The presence of exposed metal.


There are formal limits for determining whether a piece of electrical gear has passed or failed a PAT inspection, depending on the type of equipment.

To ensure safety, it’s essential to test devices at regular intervals. The regularity of testing will depend on the appliance type and the environment it’s used in.

Types of PAT tester devices

There are several different kinds of PAT testers available today. The most common varieties include:


  • Pass/fail PAT testers
  • Advanced PAT testers
  • RCD testers
  • Computerised PAT testers


Pass/fail PAT testers are the most common variety thanks to their simplicity and affordability. When you carry out a test, the device will present a reading of either ‘PASS’ or ‘FAIL’. Some will also show polarity, insulation resistance, and earth continuity.

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Advanced PAT testers display more detailed information, including:


  • Earth continuity resistance
  • Insulation resistance
  • Touch current measurement (i.e. earth leakage tests)
  • Fuse tests
  • Lead polarity

RCD testers are similar to standard PAT testers, but can also test residual current devices or RCDs.

Finally, computerised PAT testers can connect to a computer, sending information back and forth via Bluetooth or a data cable. These devices make recording pass-and-fail data much easier.

Why accurate PAT testing matters

Accurate PAT testing is crucial in determining whether an electrical device is safe, functional, and in line with industry standards. Inaccurate measurement directly impacts the health and safety of your employees and customers.

The best way to ensure accuracy is to calibrate your tester regularly. Calibration involves internally trimming the tester to match its original specification. The process involves:


  • Ensuring an accurate resistance readout and correcting drift,
  • Calibrating the unit to its national standards—it’s best to have the product manufacturer or an accredited laboratory do this,
  • Conducting a safety test if the device is mains powered,
  • Issuing a calibration certificate.


Accurate PAT testing plays a central role in maintaining electrical safety standards within your workplace. That’s why investing in high-quality testers and regularly calibrating them is crucial.

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