Scope

Meter marking planning only. It does not select test equipment, authorize energized work, or replace safety procedures and product instructions.

Lookup table

Decode common meter category markings by electrical environment and label-reading context.

Scroll sideways to keep row labels aligned with hidden columns.

Lookup basis summarizes common CAT marking categories used in meter manufacturer safety literature.
CAT ratingCommon contextExposure summaryBoundary
CAT IProtected electronic circuitsLowest transient-energy category in this comparisonNot a building distribution measurement lookup
CAT IIPlug-connected loads and receptacle-connected equipmentLoads connected to fixed wiring through outletsConfirm the meter voltage rating and leads
CAT IIIDistribution panels, feeders, and fixed equipmentHigher-energy building distribution measurementsRequires matching meter, leads, PPE, and work procedure
CAT IVService entrance, utility connection, and outdoor service conductorsHighest transient-energy category in this comparisonUtility/service work needs qualified procedures and equipment
Notes
  • Check table values for preliminary lookup and arithmetic checks only.
  • Confirm equipment ratings, product markings, installation conditions, utility requirements, and the local authority requirements before design or field use.