Procedure · SOP-24
Electrical Calibration
DC and low-frequency calibration of multimeters, calibrators and process instruments.
Purpose
To define the method for calibrating DC and low-frequency AC electrical measuring instruments and sources against a multifunction calibrator and a reference multimeter, with uncertainty evaluated per SOP-16 and reporting per SOP-18.
What is inside
10 sections, about 4 pages when printed.
- 1. Purpose
- 2. Scope
- 3. References
- 4. Definitions
- 5. Responsibilities
- 6. Procedure
- Records generated by this procedure
- Monitoring and performance indicators
- Assessment readiness notes
- Related documents
Records it generates
Applying this procedure produces the following records, which are the evidence an assessor samples.
- –Calibration worksheet with raw data, environment, equipment and calculations
- –Instrument / logger data files
- –Job uncertainty evaluation
- –Certificate and review checklist
- –QC / check standard results
What an assessor looks for
The document closes with these points, so you can check your own practice before someone else does.
- –Asking how the reference's drift contribution is justified and whether its certificate corrections are applied.
- –Checking the specification edition and confidence level used for conformity statements.
- –Reviewing the AC points and frequencies against the scope.
- –Witnessing warm-up, settling and the pre-use check.
Before you use it
- Replace every square-bracket token, starting with [LABORATORY NAME], [ADDRESS] and [EFFECTIVE DATE]. The full token list is in GD-01 Read Me First.
- Have the content technically reviewed against how your laboratory actually works, then approved by the responsible manager before it becomes a controlled document.
- Update the Word fields after editing so the table of contents and page numbers are correct: select all, then press F9.
- Record the document in your own document register and set its review date.
- Delete the assessment readiness notes if you do not want them in your controlled version; they are guidance for you, not requirements.
Related documents
- QM-01
Quality Manual
Top-level description of the management system against every clause of ISO/IEC 17025:2017.
- SOP-13
Selection, Verification and Validation of Methods
Choosing appropriate methods, verifying standard methods, validating non-standard and laboratory-developed methods.
- SOP-16
Evaluation of Measurement Uncertainty
GUM-based uncertainty evaluation, budgets, CMC consistency and reporting, aligned with UKAS M3003 principles.
- SOP-21
Temperature Calibration
Comparison calibration of thermometers, PRTs, thermocouples, indicators and data loggers in baths, dry blocks and chambers.
- SOP-22
Humidity Calibration
Calibration of hygrometers, RH probes and loggers against a reference hygrometer in a humidity generator or chamber.
- SOP-23
Pressure Calibration
Calibration of gauges, transducers and indicators against pressure balances and reference transducers.
- SOP-25
Dimensional Calibration
Calibration of callipers, micrometers, gauge blocks, dial indicators and rules by comparison to reference standards.
- SOP-26
Mass and Balance Calibration
Calibration of weights and non-automatic weighing instruments, aligned with EURAMET cg-18 principles.