3.75Kv PAT

One of the largest hire companies supplying to the construction industry sent a crew of chaps to be trained in flash testing at 3.75KV. Apparently they carry out the test on every item of electrical equipment returned from hire. Methinks madness but they have been doing this for years and are required under some international group standard to perform the test under a specified regime. 

  • Methinks insurance company overexcitement due to the nature of the risk. I received a letter from one of my insurance companies stating (you/your/activities/machinary) is unfortunately now outside of risk appetite for (no specified named company)

    The brackets represent specific terms and names withheld.

  • When I first got involved at a place that took PAT seriously, the University of York in the early 1990s, testing originally recreated the full set of manufacturing tests, including hi-pot insulation tests like this.  Within a few years the tests got relaxed to a basic 500V DC test, as there were concerns, at least in the elecronics dept, of the risk  that the new tests were causing failures in equipment that would otherwise have gone on for years. There is no sense in over stressing things !!


  • Due to noise suppression and with some wiring arrangements of wiring, it's also possible to damage motors of some Class II equipment (meeting the requirements of appropriate product standards) with repeated "flash" test.

    The "flash" test is used in standards:

    (a) as a "one-off" type-test during initial product testing and certification of a standard, usually at the longer time of 60 sec

    (b) as a production line test, where the test is applied for 1 second, once only, for each appliance (or components - some components are tested separately) ... a much lower time than the 60 sec.

    I can see an argument that, after certain repairs, a production-line test is carried out, but would NOT advocate this on a regular basis unless a manufacturer specified it in their maintenance and repair instructions.

    If the products can't stand the environment, are they selected correctly under PUWER and EAWR?