The most important element of electrical testing is accuracy, and regardless of the environment in which you are carrying out your tests, you need a test instrument that will provide reliable results. For this reason, calibration is essential and a calibration certificate is the means through which this accuracy and reliability can be demonstrated and evidenced.
Understanding what a calibration certificate is
A calibration certificate is an essential tool in quality control and compliance, but it can also be used for more practical purposes. In simple terms, a calibration certificate is a document issued by an accredited calibration laboratory to confirm that a measurement device or test instrument has been calibrated. It effectively demonstrates that the device has been tested against known standards to confirm its accuracy, and that it has successfully met these standards. The user can therefore be assured that the device or instrument is accurate and reliable for ongoing use.
The issuer of a calibration certificate should ensure that it includes details relating to the instrument, how it has been tested and what the results are. So a typical calibration certificate will include details such as:
- ID number – The unique model or serial number of the instrument so that it can be easily identified.
- Standards – The national or international standards used for traceability, and recognised within specific industries or sectors.
- Results – The results of tests on the instrument. These are often recorded as original results before calibration, and then secondary results after calibration and certain adjustments and remedial actions have been made. This allows the user to see how far the instrument drifted out of the acceptable tolerance limits.
- Tolerance – A record of the measurement uncertainty and acceptable tolerances used, so you can see how the instrument performed within these criteria limits.
- Environment – A record of the environment in which the instrument was tested, so this can be factored into any results.
- Remarks – Comments on test findings or any remedial action or adjustments needed on the instrument.
- Accredited lab – Details of the laboratory which carried out the calibration, including their accreditation credentials.
- Date – The date on which the calibration was carried out.
- Recalibration date – The date the next calibration is due and which should not be exceeded. This should also be identified on the instrument itself, so that it can be removed from service until calibration is carried out, as this could invalidate readings and contribute to regulatory non-compliance if the next calibration date is exceeded.
Why is a calibration certificate important?
A calibration certificate is important within a quality system and for demonstrating compliance, as well as to reduce risk in safety situations.
- Verification – A calibration certificate verifies that an instrument has precise measurements and you can rely on the readings.
- Compliance – The certificate provides evidence that an instrument has been calibrated and this is traceable to the required standards. This is essential for many internal quality systems and external regulatory requirements.
- Managing risk – Instruments can easily drift out of acceptable tolerances through everyday wear and tear or due to environmental damage. This can create inaccurate readings and therefore misleading data, possibly leading to incorrect diagnosis and safety risks. A calibration certificate confirms that an instrument is functioning properly and within acceptable tolerances of accuracy, which reduces the possibility of errors and safety risks.
A calibration certificate can be issued as a hard copy or a digital copy, or both. It should be carefully stored so that it can be referred to at all times, such as in audits, but also when there is a concern or question over test instrument results. At Test Instrument Solutions we offer a full calibration service for your test instruments.
Please note that this section is for information purposes only. Anyone using equipment referred to in this section must be suitably qualified and/or experienced within the respective field. If in doubt before use, please consult a qualified electrician or engineer & thoroughly read all instruction booklets.