Quote:
Originally Posted by topman
At build yes, but to ensure they are still accurate they should be tested at regular intervals, every three months. Very rarely out when new but over time they can become less accurate. How old is the certificate?  |
They only need to be tested every 3 - 12 months if in constant use. This is the same with most electronic measurement equipment. Mine are used a couple times in a year and the certificate is about 15 months old.
In any case, the cheap ones such as the one in the boot of my car (which is sold under many different names) have been tested when new and the readings are shall we say inconsistent across samples. But for a wheel nut it serves the purpose.