There was an old discussion on this 7 years ago but it is locked now. In any case there was no definitive answer provided at the time. In years gone by, I would have thought that AVIs and PUs either work or they dont.
But searching online today, Martindale recommend that their AVI's and PU's do need calibrating. This has prompted me to rethink and I note that in GS38 point 30 talks about all test equipment being maintained by a competent person and one of the common errors being failing to verify correct function of illumination (eg indicator/lamp/neon).
If something were to go wrong, and it turns out the AVI and PU were not calibrated within the last 12 months, I can imagine this wording above being used to attribute blame to the person who was undertaking the proving dead.
When we prove the AVI with the PU, we are putting voltage onto the AVI and simply seeing that the lamps light up, but the PU just puts out the max voltage it is capable of, it doesnt step up or down each voltage level individually, so we dont control the level it is proving at.
What's other peoples thoughts? I am considering now that we do need to calibrate these items.
