On the calibration of ammeters and voltmeters
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A recent safety inspection revealed several old-fashioned ammeters and voltmeters on the control distribution cabinet. The colleagues who conducted the inspection said that these instruments must be checked annually, while others claimed that no such checks are necessary. Who can provide a clear answer? I hope relevant standards and other supporting evidence can be provided.
There is no mandatory requirement; internal verification or external verification can be used.
For measuring instruments, aside from those that are subject to mandatory calibration, enterprises can decide on their own the calibration schedule based on their actual circumstances and in accordance with relevant regulations. As for the calibration methods and intervals, these can also be determined by the enterprises themselves
Please check the requirements of the metrological verification standards and consult the local instrument and meter supervision bureau.
Ammeters and voltmeters are not measuring instruments subject to mandatory calibration; companies can decide on their own the frequency of calibration, with we recommending a calibration every 3 years.
I also checked several relevant regulations and standards. In general, as the people mentioned earlier said, companies that are not on the list of those subject to mandatory inspections can decide for themselves. When we conduct inspections, the municipal work safety supervision agency assigns experts from various industries to form a team for the purpose of conducting these inspections. Since the safety officers in different companies or organizations follow different relevant standards or internal company standards, this leads to discrepancies in opinions. In future inspections, the criteria shall be established based on the industry to which the enterprise being inspected belongs and the regulatory standards it follows.
It can be classified as Category C, requiring only a one-time inspection rather than periodic inspections