API-SIEE Exam Dumps : Source Inspector Electrical Equipment

The correct answer isB. Formedium-voltage motor terminal boxes, IEEE 841 requires an added safety provision because these enclosures contain higher-energy terminations and present a more serious shock and arc-flash hazard than standard low-voltage terminal boxes. Apermanent locking mechanismis therefore required for terminal boxes used on motors above1000 V, and also for certain large frame motors at1000 V, to prevent unauthorized or accidental access while the motor is energized. This requirement supports safe operation, maintenance control, and electrical isolation practices.

From an API source-inspection perspective, this falls under verification ofelectrical safety features, enclosure construction, and compliance with the applicable motor standardduring shop inspection and surveillance. The API guide includeselectric motors over 500 HPamong the covered equipment categories and emphasizes checking conformance to applicable codes, referenced standards, drawings, and purchase specifications during manufacture and inspection. A drain fitting may be required on some terminal boxes for moisture control, and grounding provisions are also important, but those are not the specific IEEE 841 requirement identified in this question. The distinctive requirement here is thepermanent locking mechanism.

The correct answer isC, Voltmeter. A voltmeter is the instrument specifically used to measure theelectrical potential difference, or voltage, between two points in a circuit. In electrical inspection and testing, voltage measurement is fundamental for verifying whether circuits, terminals, control panels, and equipment are energized at the correct values required by the design documents and equipment ratings. During source inspection and quality surveillance, understanding the correct use of test instruments is important because inspectors may review or witness electrical tests that confirm compliance with specifications and safe operating conditions.

The other options are not correct for this purpose. Anamp metermeasures current flow, not voltage. AWheatstone bridgeis primarily used for precise resistance measurement. Apotentiometeris generally a variable resistor or a device used in circuit adjustment and comparison methods, but it is not the standard instrument identified for routine measurement of potential difference in a circuit.

Therefore, when the question asks which instrument measures voltage between two points, the technically correct and standard answer isvoltmeter.