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Guide To Buying A PAT Tester

Guide to buying a PAT Tester

Buying a PAT Tester can be a confusing business, particularly if it's your first time, so here at we have put together a useful guide to take you through what you should consider before making your purchase.

We have answered some of the most frequently-asked questions about different PAT tester features which should help you choose the right instrument for you.

  1. Video - "A Buyer's Guide To PAT Testers"
  2. What are the minimum requirements of a PAT Tester?
  3. Should I buy a PAC Checker or a PAT Tester?
  4. Should I buy a battery or socket-powered PAT Tester?
  5. Do I need a downloadable PAT Tester?
  6. What is the average battery life of a PAT Tester?
  7. What if I need to test surge-protected extension leads?
  8. Do I need load and run testing?
  9. Do I need flash testing?

We're always happy to help our customers find the right tester for them, so we've put together the video below with a detailed look at some of our entry-level PAT Testers:

What are the minimum requirements of a PAT Tester?

As a minimum, your PAT tester should be able to:

  • Perform earth continuity tests at 200mA with an inbuilt pass limit of <0.2Ω
  • Perform insulation resistance tests with a test voltage of 250V or above (ideally 500V)
  • Test the polarity of extension and IEC leads 

Most modern PAT testers have inbuilt auto-test sequences which are especially useful for novice users.

Should I buy a PAC Checker or a PAT Tester?

A PAC Checker is an instrument that performs earth continuity tests, insulation resistance tests and polarity tests and then provides a PASS/FAIL indication based on pre-set limits contained within the firmware of the checker.

A PAT Tester performs exactly the same tests (as a minimum) but displays actual readings in addition to a PASS/FAIL indication.

PAC Checkers might be a suitable low-cost solution for someone testing only appliances but anyone testing longer extension leads requires a PAT Tester as the extra cable length increases electrical resistance and therefore might result in a FAIL result even when the lead is safe to use. A useful table for working out the maximum resistance limit in cables is located on page 134 of the IET Code of Practice.

PAC checker examples: Seaward Primetest 50, SimplePAT

PAT tester examples: Seaward Primetest 100, Megger PAT320, Metrel SigmaPAT

Should I buy a battery or socket-powered PAT Tester?

Battery-powered testers have the obvious advantage of working wherever the user might need them. This is very useful where a reliable power supply is not readily available, for example on a construction site. However, mains-powered PAT testers often have the advantage of being able to perform flash testing, and test continuity with currents of 10A or 25A. This often makes mains-powered testers the only option when PAT testing heavy-duty factory equipment, production lines and new electrical appliances.

Battery-powered tester examples: Seaward Primetest 100, Megger PAT150, Kewtech KT72

Mains-powered testers: Kewtech KT71, Martindale EasyPAT 1600, Metrel OmegaPAT Plus

Do I need a downloadable PAT Tester?

Downloadable PAT Testers tend to carry a premium price as they automatically log test results in a database contained within the onboard memory of the tester. These memories vary in capacity from 500 results to 50,000 results. Downloadable testers are useful for those with large workloads as they dramatically cut down on paperwork when PAT testing, as well as enabling easier reporting, trend mapping and analysis.

If you have low-volume PAT testing requirements, a PAT Register Book and Certificate Pad can be an ideal low-cost solution when used in conjunction with a non-downloadable PAT tester.

Non-downloadable tester examples: Seaward Primetest 100, Kewtech KT72, Uni-T UT528

Downloadable tester examples: MemoryPAT Blu, Megger PAT410, Seaward Apollo 600

What is the average battery life of a PAT Tester?

It is difficult to accurately predict the battery life of a PAT tester because it is affected by a number of different factors. The most important factor is the test type and test frequency. A PAT tester’s battery might last just one day if used for a particularly intensive testing session. Otherwise, an infrequently-used PAT tester could last for up to six months before needing a replacement battery or charge. To help save the batteries, most testers have an automatic turn-off function which shuts the tester down after a set period of inactivity (often 60 seconds).

Long battery life examples: Seaward Primetest 100

What if I need to test surge-protected extension leads?

Surge-protected extension leads can usually be identified via a red and green neon, an ‘in’ and ‘out’ for a telephone lead, or a lightning strike symbol. When testing these leads, it is important to use a PAT tester that features a 250V insulation resistance test because a standard 500V test will activate the surge protection in the lead and skew the resistance reading.

Surge-protected extension lead tester examples: Megger PAT150, Martindale HandyPAT 600 

Do I need load and run testing?

110V and 230V load and run testing is available on several testers in our range. The run test comprises the earth/touch leakage test and the load test which checks the current being drawn from the wall socket by the appliance. These tests are useful for testing IT equipment and handheld appliances such as kettles and power drills but are not regularly used for standard PAT testing. It is therefore a more useful function for those with large PAT testing workloads. It is important to note that all of our PAT testers, as opposed to PAC checkers, give a reading for earth/touch leakage current so the main additional option on testers with the load and run function is the load test. For more information on load and run testing please take a look at out PAT Knowledge Database.

Load and run PAT tester examples:

Seaward Primetest 250, Fluke 6500-2, Megger PAT420

Do I need flash testing?

Several of our PAT testers can perform flash testing with a range of test voltages starting from 1kV. Flash testing is usually only recommended for new or ‘as new’ appliances and would therefore only be of use to those working in repair workshops or at electrical equipment manufactures. The test is performed to check that an appliance’s insulation is up to scratch but can be destructive so is suitable for batch testing in a production or repair setting. For more information on flash testing please visit our PAT Knowledge Database.

Flash test PAT tester examples: Metrel OmegaPAT Plus, Megger PAT450, Seaward Supernova

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