When measuring current, turn off circuit power before connecting the Meter in the circuit.

When measuring current, turn off circuit power before connecting the Meter in the circuit.

• A. False
• B. True
• C. Only for AC
• D. Only for DC

Answer: (B)

Before measuring current, you need to de-energize the circuit. An ammeter is connected in series and presents a low-resistance path; if power is on when you connect it, you can create a short, arc, or overload the meter fuse, and you can expose yourself to shock. Turning off the power keeps the circuit safe while you place the meter in series, then you can restore power to read the current. If you’re using a clamp meter, you can measure current without breaking the circuit, but for a traditional meter that must be inserted in series, power should be off. This safety practice applies to both AC and DC circuits, not just one type.

Before measuring current, you need to de-energize the circuit. An ammeter is connected in series and presents a low-resistance path; if power is on when you connect it, you can create a short, arc, or overload the meter fuse, and you can expose yourself to shock. Turning off the power keeps the circuit safe while you place the meter in series, then you can restore power to read the current.

If you’re using a clamp meter, you can measure current without breaking the circuit, but for a traditional meter that must be inserted in series, power should be off. This safety practice applies to both AC and DC circuits, not just one type.