verstapp wrote:Perhaps its because my tester doesn't have a 'special mains cable socket' or even a 'special mains lead' but only the plain ordinary ones supplied
Now, when you say this, do you mean you were trying to use the 13A plug to IEC C13 lead to supply mains power to the PT300, via the IEC C14 inlet?
If that's the case, you're onto a non-starter.
The IEC inlet is only used for testing mains leads/extensions with the earth bond, insulation resistance and polarity tests.
It certainly won't provide power into the PT300 for any of the powered tests (touch current, PE current, RCD & loop test).
The 'special mains socket' is shown as reference 7 on figure 2, page 3 of the PT300 manual.
You should have a corresponding power lead which fits into this connector. If you don't, then all the powered tests are out of your grasp until you source a replacement lead.
or I'm sure Seaward could supply one.