NETA - InterNational Electrical Testing Association Certified Technicians Switchgear and Busway Inspection Questions and Answers

Question 1

During a visual and mechanical inspection of a medium-voltage, metal-clad switchgear lineup, which of the following findings represents the most severe and immediate safety hazard?

Accepted Answer

A defeated or malfunctioning mechanical interlock between a circuit breaker and its cell.

Answer

A malfunctioning position indicator light (on/off/trip) on a draw-out circuit breaker.

Answer

Minor surface rust noted on the exterior of a non-ventilated enclosure door.

Answer

An outdated maintenance sticker on the front panel from the previous inspection cycle.

Question 2

A NETA technician is inspecting the silver-plated copper busbars within a 480V switchboard and observes a dark, dull discoloration concentrated at several bolted connection points. What is the most likely cause of this condition?

Accepted Answer

A high-resistance connection causing excessive localized heat.

Answer

Corona discharge from the busbars to ground due to high humidity.

Answer

Normal oxidation of the silver plating over an extended period.

Answer

Over-application of conductive grease during the initial installation.

Question 3

When performing a maintenance inspection on a 480V plug-in busway, a technician finds evidence of water staining and minor corrosion on the exterior of a single section. What is the MOST appropriate initial diagnostic step to assess the integrity of the busway?

Accepted Answer

Perform an insulation resistance test on the affected section of busway.

Answer

Immediately open and visually inspect the interior of the affected section.

Answer

Use a calibrated torque wrench to check all bus stab connections in the area.

Answer

Clean the exterior housing and recommend installing a drip shield.

Question 4

According to NETA MTS, when performing a routine mechanical inspection of accessible bolted electrical connections on a switchgear bus where manufacturer's data is unavailable, what is the standard procedure?

Accepted Answer

Verify the tightness of a representative sample of connections using a calibrated torque wrench and NETA Table 100.12.

Answer

Re-torque 100% of the bolted connections to the values listed in NETA Table 100.12.

Answer

Visually inspect all connections for discoloration but do not apply a torque wrench.

Answer

Measure the contact resistance of all connections and compare them to each other.

Question 5

Per NETA standards, what is the recommended DC voltage for performing an insulation-resistance test on a 600V rated switchgear bus assembly?

Accepted Answer

1000 VDC

Answer

5000 VDC

Answer

500 VDC

Answer

2500 VDC

Question 6

When inspecting the interior of a low-voltage switchgear enclosure located in an industrial facility, which of the following contaminants presents the greatest risk for causing an insulation flashover?

Accepted Answer

An accumulation of conductive dust, such as carbon or metallic particles.

Answer

A light, uniform layer of dry, non-conductive process dust.

Answer

A small amount of construction debris, like wood shavings, on the enclosure floor.

Answer

An expired desiccant pack that is no longer absorbing moisture.