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CAT ratings tell you where a meter can be used safely. Electrical work can be dangerous. Always follow the instructions, use the right safety rating for the job and call a licensed electrician if you are unsure.
Last updated: October 31, 2026.
What CAT Means
CAT is the measurement category and voltage rating. Higher categories are for locations closer to the power source. See our best multimeters.
CAT II, III and IV
CAT II: outlets and appliances. CAT III: distribution panels and building wiring. CAT IV: the service entrance and utility connection.
How to Choose
Choose a meter rated for the highest category you will test and never exceed its voltage rating. Check the rating printed on the meter.
Frequently Asked Questions
Is a cheap meter safe?
Only if it is genuinely rated and certified.
What for home use?
CAT III is common.
Where is the rating?
On the front of the meter.
Bottom Line
Choose the right CAT rating for the job, and when unsure, call an electrician.
