A check box is exactly that but a calabration check by a certified independent tester helps with insurance indemnity. I hand my tester into an electrical wholesaler for £48 and worth every penny
Calibration centres don’t calculate your test they simply check the accuracy on a fancy check box that has two Digital displays , one will show a none value the try set the second display will show the value on your test if both matches the first display they it a pass . Manufacture’s only recommend that you have your tester calibrated twelve months from date of purchase, the don’t say very twelves months. You are correct you say you don’t agree with calibration annually . It’s an unnecessary money grab . Think about it , you’re fancy flat screen Television is full of resisters and other electronic components do you have to have your television calibrated no you don’t. I have just checked my thirty year old Robin MFT that hasn’t been calibrated since 1992 and it’s is spot on I check it on my Kewtech FC2000 check box which I do once a month along with my other test instruments. The NICEIC only requires that we check the ongoing accuracy at least once a month and keep a whiten record dated for each month.
