What instrument would you use to detect stray voltage before servicing equipment?

What instrument would you use to detect stray voltage before servicing equipment?

• A. A non-contact voltage tester
• B. A multimeter in DC mode only
• C. A current clamp meter
• D. A continuity tester

Answer: (A)

Before servicing equipment, you want a quick, safe way to check for AC voltage on metal surfaces or nearby parts. Stray voltage can be present even when the equipment is off, so you need a tool that can sense voltage without you having to touch anything. A non-contact voltage tester fits that need because it detects the presence of alternating current in or on surfaces without making contact, giving a fast warning if anything is energized. This lets you proceed with caution or confirm it’s de-energized before tools are used. The other instruments aren’t as suitable for this precaution: a multimeter in DC mode won’t reliably detect stray AC voltage, and it requires contact with the circuit to measure anything. A current clamp meter measures current, not voltage, so it won’t tell you if a surface is energized. A continuity tester checks whether a path is complete, not whether voltage is present. Using the non-contact tester gives a safe, quick first check to help prevent shock before you begin work. If voltage is detected, follow proper de-energization procedures and re-check.

Before servicing equipment, you want a quick, safe way to check for AC voltage on metal surfaces or nearby parts. Stray voltage can be present even when the equipment is off, so you need a tool that can sense voltage without you having to touch anything. A non-contact voltage tester fits that need because it detects the presence of alternating current in or on surfaces without making contact, giving a fast warning if anything is energized. This lets you proceed with caution or confirm it’s de-energized before tools are used.

The other instruments aren’t as suitable for this precaution: a multimeter in DC mode won’t reliably detect stray AC voltage, and it requires contact with the circuit to measure anything. A current clamp meter measures current, not voltage, so it won’t tell you if a surface is energized. A continuity tester checks whether a path is complete, not whether voltage is present. Using the non-contact tester gives a safe, quick first check to help prevent shock before you begin work. If voltage is detected, follow proper de-energization procedures and re-check.