When PAT testing offices and retail environments, it is highly likely that you will be PAT testing computers and other PC-type devices.

As computers and other IT equipment are electrical devices, they must be PAT tested; however, there are crucial rules and safety precautions that you must follow when testing such devices, to avoid damage being caused to the equipment or yourself from suffering harm.

Test the Power Cable

The first step when PAT testing computers is to assess the power cable: this test is independent of PAT testing the actual computer unit.

This test is very standardised and separated into four distinct steps:

  1. Visual inspection – via inspecting the cable yourself, you should look for faults such as a broken plug, damage to the plug flex, breaks in the wiring or any exposed internal wiring
  2. Earth continuity test
  3. Insulation test (at 500V DC)
  4. Polarity test

If you are completely satisfied with the results of the test and that the power cable is still fit for purpose, you are now safe to use the cable when PAT testing the computer.

PAT Testing the Computer

Please note: when PAT testing a computer, please only use a PAT tester that can conduct the earth continuity test with a current of no more than 200mA – if you use a higher current, you could potentially damage the motherboard of the computer.

Firstly, you must conduct a visual inspection computer. Your visual inspection should include the main body of the computer (often called a tower) and external equipment. Should you have any doubts stemming from the visual inspection regarding the tower or external equipment, mark it down as a fail and give the findings and recommendations to the relevant authority of the business (here’s what to do in case of a PAT test fail). 

Should you be satisfied that the computer and its peripherals are competent, according to the visual inspection, you can use the power cable from earlier to conduct the PAT test on the computer.

Before conducting any of the regular PAT testing procedures, you should conduct a bare metal test (such as on USB ports) by using the earth bond lead to detect if there are any unsafe electricity leaks that have the potential to shock people.

Once you are satisfied with the results from the bare metal test, you may begin the PAT testing of the computer proper:

  1. Conduct the earth continuity test at 100-200mA – do not use more than 200mA as this may cause damage to the computer or its components
  2. Move on to the insulation test at 500V DC for newer computers, or a leakage test for older models

Following all of these steps and granting a pass rating will ensure that the computer is usable, ideally until the next PAT test is due.

Extra: PAT Testing A Computer Monitor

Often overlooked, you must also PAT test a computer’s monitor. The majority of computer monitors in use are class 1 items, often containing exposed metal parts – such as the USB ports – meaning that, much like other IT equipment, you should PAT test computer monitors to assess their safety.

Cardinal Fire Protection’s Computer PAT Testing Services

Cardinal Fire Protection assists companies who are looking to improve their fire safety and awareness, or those businesses who have fallen short in their fire safety obligations.

We will assist in your day-to-day fire safety obligations by providing direct and succinct fire safety training, assessment and services, including regular PAT Testing of computers and other equipment.

Was this computer PAT testing guide helpful? Check out some more useful PAT testing resources belowWho can PAT Test? | Beginner’s guide to PAT Testing | All about PAT Testing Classes | BS5839 Alarm Guide