I had a call this week from a past candidate that had purchased some PAT adapters for 415V and assumed the adapter was wired incorrectly.

This I thought would be a good blog entry in case anyone else is wondering why their adapter looks like it might be wired wrong.

PAT Adapters are exactly that, they are adapters that allow connection to a PAT tester to allow you to do ‘dead tests’ with your machine and your associated appliance be that 110V, 230V, and 415V.

We buy all of our adapters in from manufacturers, we really don’t have time to sit and make PAT adapters and to be honest I wouldn’t want to.

Also this allows us to use businesses that have controlled production and test procedures in place for the construction of these adapters.

When you have PAT testing adapters it is important that these are only used by trained individuals, in the wrong hands they could be misused.

With most PAT adapters particularly when danger may occur the first thing that happens is the live (brown) is snipped inside the adapter, then the earth is connected and the Neutral into first phase connection, each subsequent phase is then looped together into the first.


By cutting the live inside the adapter this prevents an ‘ordinary person’ plugin the adapter into mains and sending power to the appliance.

A PAT adapter configured this way will allow for Earth continuity testing (if needed) and insulation resistance testing as the PAT tester joins the L+N inside the tester.

This also prevents accidental powering of the appliance!

Here is a quick snippet from Jim Wallace, Associate Director, Seaward Product and Technology

“but the requirement will be to test the protective earth and the insulation resistance. The insulation resistance can be tested using an adaptor with no live connection provided the live conductors (3P + N if present) are commoned together as most appliance testers put the insulation test voltage out on both the line and neutral terminal i.e. the voltage on the neutral is then applied to all live conductors.

The polarity must also be checked but this can be performed as part of the formal visual inspection”.

Source: https://www.seaward.co.uk/forum/viewtopic.php?f=3&t=55677&p=56430&hilit=415V#p56430

So there is method in the madness, they are specialist adapters that should:

  • Only be used for PAT testing
  • Kept away from potential use by an ‘ordinary person’
  • Appreciate the fact they are solely for ‘dead testing’ Earth and Insulation
  • Don’t make them yourself