Testing & TroubleshootingQuestion 517 of 521
Two meters are both marked CAT III, but one is rated 600 V and the other 1000 V. What does the voltage number add to the CAT rating?
a.Nothing; only the CAT number matters
b.It is the meter's battery voltage
c.It is the maximum resistance the meter can read
d.It is the maximum working voltage to ground for that category; the meter must meet both the CAT level and the voltage of the circuit
Explanation
The CAT level defines the transient/impulse withstand for a location, and the voltage rating states the maximum working voltage to ground for that category, both must suit the circuit. A CAT III 600 V meter is not appropriate where CAT III 1000 V is required. The number is not battery voltage (b) or a resistance range (c).
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