Switchgear and Busway Inspection Flashcards
7 cards from real NETA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Switchgear and Busway Inspection flashcards as text
Which document does NETA reference as the standard for determining arc flash incident energy during switchgear maintenance?
Answer: IEEE 1584
IEEE 1584 provides the methodology for calculating arc flash incident energy and is the primary reference used in conjunction with NETA for arc flash hazard assessment.
A draw-out breaker's secondary (control) disconnect plug shows signs of overheating on several pins. What is the most likely cause?
Answer: High resistance contacts due to oxidation, dirt, or misalignment in the secondary plug
Overheating of secondary disconnect pins is most commonly caused by high contact resistance from oxidation, contamination, or physical misalignment of the plug pins.
When inspecting indoor distribution switchgear, which environmental condition is most likely to accelerate bus bar insulation degradation?
Answer: High humidity combined with airborne conductive dust
High humidity combined with conductive dust creates a conductive path on insulation surfaces, promoting tracking and leakage current that degrades insulation over time.
What does a NETA technician verify when performing a 'contact resistance' test (also called a 'Ductor' or micro-ohmmeter test) on a circuit breaker?
Answer: The resistance across the main current-carrying contacts in the closed position
A contact resistance test measures the milliohm or microohm resistance across the breaker's main contacts when closed, verifying low-resistance current paths and detecting pitting or oxidation.
What is the function of the 'cell switch' (also called a 'racking interlock switch' or 'position switch') in a draw-out switchgear compartment?
Answer: Signals the control circuit the breaker's position (connected, test, or disconnected) for interlocking and indication
The cell switch provides position feedback signals to the control and protection circuits indicating whether the breaker is in the connected, test, or disconnected (withdrawn) position.
During acceptance testing of a new busway installation, NETA requires that the conductor-to-conductor and conductor-to-ground insulation resistance tests be performed under which condition?
Answer: With the busway de-energized and all tap-off units removed or open
Insulation resistance tests on busway must be performed de-energized with all plug-in tap-off units removed or switched open to test only the busway insulation without parallel paths.
A switchgear bus bar has been properly torqued to the manufacturer's specification using a calibrated torque wrench. According to NETA best practices, what should be done to verify connection quality?
Answer: Apply a torque-seal (witness mark) to allow future visual detection of loosening
Torque-seal (torque stripe) is applied across the bolt and nut after final torquing to provide a visual indicator if the fastener subsequently loosens.