NETA level II exam questions & answers 2023

NETA level II exam questions & answers 2023 What is the preferred method of performing primary-injection testing on a low voltage circuit breaker with ground fault protection? Use of the manufacturer's test kit or rewiring the neutral CT input is the preferred method of primary-injection testing on a low voltage circuit breaker with ground fault protection, otherwise two poles can be connected in series to provide balanced secondary currents to the trip unit. At what current level does ventricular fibrillation occur? -60 to 100mA in AC systems -300 to 500mA in DC systems What is the LET-GO current threshold? For a 70kg body 75mA DC 15mA AC Meter Sockets and meter disconnect switches should be connected on the load side of a service disconnecting means. FALSE (NEC Article 230.82) Which standard addresses equipment grounding? NFPA 70 (National Electric Code) A moving iron meter operates by applying _____ current to the coil. Operating current ( can be AC or DC) What is the maximum deviation between resistance measurements on bolted connections? 50% of the lowest value (MTS 7.20.3.1) Removable / Drawout circuit breaker Normally 5kV or above Identify the electrical symbol shown: Resistance grounding is used for voltages: 6.6kV and greater Medium-voltage motor starters use blowout coils. What do these do? Blowout coils may be used to extinguish the arc by means of a magnetic blast. The arc created when the contacts open is subjected to the action of a magnetic field set up by coils connected in series with the circuit being interrupted. These coils are called blowout coils because they help blow out the arc magnetically. The arc is magnetically blown into arc chutes where the arc is lengthened, cooled, and extinguished. Medium voltage air circuit breakers use PUFFER TUBES. What do these do? Puffer tubes incorporate the operating mechanism to blow a puff of air through a tube and nozzle to each contact assembly when the breaker is opened. The air helps quench the arc by pushing it up into the arc-chute. Ammeter Identify the electrical symbol shown: SAE grade 1 & 2 Bolt No lines on head Tensile strength 64KSI SAE grade 5 Bolt 3 lines on head Tensile strength 105 KSI SAE grade 7 Bolt 5 lines on head Tensile strength 133 KSI SAE grade 8 Bolt 6 lines on head Tensile strength 150 KSI NFPA 70B 11.27.3 Decal color code RED (Non-serviceable) - Device has a problem detrimental to its proper electrical or mechanical operation such as no trip on one or more phases or high contact resistance readings. This device should not be placed back into service. NFPA 70B 11.27.3 Decal color code yellow (Limited Service) - Device has a minor problem that does not impact equipment serviceability but should be fixed as soon as possible. Some examples of minor problems include slightly lower than acceptable insulation resistance readings or chipped arc chutes. NFPA 70B 11.27.3 Decal color code white (Servicable) - Device is electrically and mechanically sound and suitable for service but may still have minor defects such as slight corrosion or incorrect circuit ID. What instructions govern the performance of a SHORT CIRCUIT STUDY? ANSI/IEEE standard 399 Step by step procedures outlined in the short circuit calculation chapters of IEEE standard 141 and ANSI/IEEE 242. What instructions govern the performance of a Coordination STUDY? ANSI/IEEE STANDARD 399 ANSI/IEEE STANDARD 242 NFPA 70 (NATIONAL ELECTRIC CODE) protective devices Two standards are typically used for the interconnection of smart devices in a substation environment. One is an IEC standard, the other is an IEEE standard. What are the two standards? IEEE C37.1 IEC 61850 Time travel analysis is commonly performed on: is used on medium and high-voltage circuit breakers and provides information as to whether the breaker's operating mechanism is operating properly (NFPA 70B). Which of the following is not a standard dc power source voltage? 1. 24VDC 2. 48VDC 3. 96VDC 4. 125VDC 5. 250VDC 3. 96 VDC Medium-voltage is defined by NETA as greater than 1,000 volts and less than 100,000 volts Low-voltage is defined by NETA as less than 1,000 volts