A good purchasing decision begins with the work and its constraints. Use this guide to define those constraints before comparing retailer listings.
Match the category to the environment
CAT ratings describe where a meter can safely face high-energy transients. Work near service entrances, distribution panels, fixed wiring, and receptacle loads presents different exposure. Use the instrument, leads, and probes rated for the location.
Inspect before energizing
Check the case, input jacks, fuse rating, probe guards, and lead insulation. Confirm the lead is in the correct jack before measuring. Prove the meter on a known source before and after testing a circuit that you expect to be dead.
Know when not to measure
If the available fault current, arc-flash boundary, or equipment condition is unknown, stop. A suitable meter does not replace training, lockout procedures, personal protective equipment, or an electrically safe work condition.