Measurement category (CAT rating)
Updated 2026-10-27
Data records
- A measurement category is the classification, used in instrument safety standards, of the part of a low-voltage installation on which a measuring instrument and its accessories are designed to be used, graded by the energy of the transient overvoltages that can occur there. The categories rise from receptacle-connected loads, through the fixed distribution installation, to the utility service connection and outdoor conductors, and the voltage rating that accompanies a category ranks instruments only within that category.
- The term is written Measurement category (CAT rating). Value: Measurement category (CAT rating).
- A maker's guide to multimeter safety places single-phase receptacle-connected loads such as appliances and portable tools in CAT II, the distribution level of a building including switchgear, polyphase motors, feeders and commercial lighting in CAT III, and the utility service connection with its meters, primary overcurrent protection and any outdoor conductors in CAT IV. It advises selecting a meter rated for the highest category in which it might ever be used, with a voltage rating that matches or exceeds the circuit.
Sources
- Electrical Testing Reference editorial taxonomy, Electrical Testing Reference editorial taxonomy of test methods, 2026-10 edition, Electrical Testing Reference. Held as: Own observation.
- Fluke learn article, Guide to Digital Multimeter Safety, web page edition, Fluke. Held as: Public page. Publisher page
Changelog (8 entries)
| Date | Revision | Change |
|---|---|---|
| 2026-10-27 | created (gloss.measurement-category.definition) | |
| 2026-10-27 | revised (gloss.measurement-category.definition) | |
| 2026-10-27 | review_status unreviewed -> software_reviewed (gloss.measurement-category.definition) | |
| 2026-10-27 | created (gloss.measurement-category.title) | |
| 2026-10-27 | review_status unreviewed -> software_reviewed (gloss.measurement-category.title) | |
| 2026-10-27 | created (gloss.measurement-category.usage) | |
| 2026-10-27 | revised (gloss.measurement-category.usage) | |
| 2026-10-27 | review_status unreviewed -> software_reviewed (gloss.measurement-category.usage) |
Cite this page
Cite the governing standard for the fact itself; cite this page as the finding aid.
"Measurement category (CAT rating)." Test Instrument Reference. 2026-10-27. https://www.testinstrumentreference.com/glossary/measurement-category/.
Test Instrument Reference, Measurement category (CAT rating) (Oct. 27, 2026), https://www.testinstrumentreference.com/glossary/measurement-category/.
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title = {Measurement category (CAT rating)},
howpublished = {\url{https://www.testinstrumentreference.com/glossary/measurement-category/}},
organization = {Test Instrument Reference},
publisher = {Test Instrument Reference},
year = {2026},
note = {last substantive change 2026-10-27}
}{{cite web |title=Measurement category (CAT rating) |website=Test Instrument Reference |publisher=Test Instrument Reference |url=https://www.testinstrumentreference.com/glossary/measurement-category/ |date=2026-10-27 |access-date=}}