NETA level II exam
At what current level does ventricular fibrillation occur?
-60 to 100mA in AC systems -300 to 500mA in DC systems
What is the minimum oxygen level before entering a transformer?
23.5% by volume
Class 00 rubber gloves what is the AC retest voltage?
2500 VAC
SAE grade 5 Bolt
3 lines on head Tensile strength 105 KSI
The most accurate method for a ground test is?
3-point (fall - of - potential) method
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
Class 3 rubber gloves what is the AC retest voltage?
30,000 VAC
Class 4 rubber gloves what is the AC retest voltage?
40,000 VAC
Class 1 rubber gloves what is the DC retest voltage?
40,000 VDC
SAE grade 7 Bolt
5 lines on head Tensile strength 133 KSI
Class 0 rubber gloves what is the AC retest voltage?
5,000 VAC
What is the maximum deviation between resistance measurements on bolted connections?
50% of the lowest value (MTS 7.20.3.1)
Class 2 rubber gloves what is the DC retest voltage?
50,000 VDC
SAE grade 8 Bolt
6 lines on head Tensile strength 150 KSI
Resistance grounding is used for voltages:
6.6kV and greater
Class 3 rubber gloves what is the DC retest voltage?
60,000 VDC
Class 4 rubber gloves what is the DC retest voltage?
70,000 VDC
Arc Flash Hazard
A dangerous condition associated with the possible release of energy caused by an electric arc
NEC defines CONTINUOUS LOAD as
A load where the maximum current is expected to continue for 3 hours or more.
What two conditions must be met for a protective relay device 67 to cause tripping?
A-C Directional Overcurrent Relay Functions on a desired value of a-c over-current flowing in a predetermined direction.
What instructions govern the performance of a Coordination STUDY?
ANSI/IEEE STANDARD 399 ANSI/IEEE STANDARD 242 NFPA 70 (NATIONAL ELECTRIC CODE) protective devices
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 is the description of the THIRD letter designator for the cooling class of transformers listed here: A
Air
Meter Sockets and meter disconnect switches should be connected on the load side of a service disconnecting means.
FALSE (NEC Article 230.82)
Contactor coils are present in manual motor starters: True or False
FAlse
A downstream 30A fuse will always blow before an upstream 100A fuse.
False
Storage batteries for emergency lighting must maintain 85% of charge for 90 minutes.
False
The field of a three-phase, squirrel-cage induction motor is located in the rotor.
False
PCB spills of any quantity must be reported to the EPA. True or false
False. spill exceeds 10 pounds of PCBs by weight
What is the LET-GO current threshold?
For a 70kg body 75mA DC 15mA AC
What is the description of the FOURTH letter designator for the cooling class of transformers listed here: F
Forced Circulation
What is the description of the SECOND letter designator for the cooling class of transformers listed here: D
Forced circulation through cooling equipment, directed flow in man windings
What is the description of the SECOND letter designator for the cooling class of transformers listed here: F
Forced circulation through cooling equipment, natural convection in windings
Buchholz relays are ____ actuated.
Gas or Oil actuated
What is the description of the first letter designator for the cooling class of transformers listed here: K
Liquid with flash point greater than 300*C
The breaking capacity of a circuit breaker is usually expressed in:
MVA
Class 0 rubber gloves what is the AC / DC max use voltage?
Max use = 1000VAC / 1500VDC
Class 2 rubber gloves what is the AC / DC max use voltage?
Max use = 17,000VAC / 25,500VDC
Class 3 rubber gloves what is the AC / DC max use voltage?
Max use = 26,500VAC / 39,750VDC
Class 4 rubber gloves what is the AC / DC max use voltage?
Max use = 36,000VAC / 54,000VDC
Class 00 rubber gloves what is the AC / DC max use voltage?
Max use = 500VAC / 750VDC
Class 1 rubber gloves what is the AC / DC max use voltage?
Max use = 7500VAC / 11,250VDC
Which standard addresses equipment grounding?
NFPA 70 (National Electric Code)
What is the description of the FOURTH letter designator for the cooling class of transformers listed here: N
Natural convection
What is the description of the SECOND letter designator for the cooling class of transformers listed here: N
Natural convection through cooling equipment and windings.
SAE grade 1 & 2 Bolt
No lines on head Tensile strength 64KSI
A moving iron meter operates by applying _____ current to the coil.
Operating current ( can be AC or DC)
Which of the following tests would you perform to verify the integrity of a fiber optic cable?
Optical Time domain reflectomer (OTDR) ?
Class 4 rubber gloves what is the glove color?
Orange
Hydrogen clings to the positive plate in primary cell and thus effectively reduces the effective surface of this plate resulting in reduction in the EMF of the cell. This phenomenon is known as:
Polarization
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.
A ________ is used when cables fed from the bottom of a switchboard need to be routed to the top of the switchboard.
Pull Section
Class 0 rubber gloves what is the glove color?
RED
The minimum operating time of a Buchholz relay is:
The minimum operating time of the relay is 0.1 seconds.
Winding resistance measurements can be made by using a:
Transformer winding resistance measurements are obtained by passing a known DC current through the winding under test and measuring the voltage drop across each terminal (Ohm's Law). Modern test equipment for this purposes utilizes a Kelvin bridge to achieve results; you might think of a winding resistance test set as a very large low-resistance ohmmeter (DLRO).
Cells are connected in parallel to give strong current when the external resistance is very low in comparison to the internal resistance of the cells.
True
Overhead service conductors are not permitted to be readily accessible for services not over 600V nominal. True or False
True
Schematic diagrams should be arranged without regard for the actual physical location of any components. True or False
True
"Oxygen deficient atmosphere" means
an atmosphere containing less than 19.5 percent oxygen by volume.
"Oxygen enriched atmosphere" means
an atmosphere containing more than 23.5 percent oxygen by volume.
A given 1500kVA transformer has a 4.16kV delta primary winding, a 480Y/277V secondary winding, and an impedance of 5.75%; what is the maximum secondary fault current of this transformer?
answer=31,377 Amps Fault Current = Full Load Amps (FLA) / % Impedance (Z) FLA = (KVA x 1000)/(line to line voltage x 1.732)
Arc Flash Boundary
is established where incident energy levels have decreased to 1.2 cal/cm^2
Second degree burn
is possible by an exposure of unprotected skin to an electric arc flash above 1.2 cal/cm^2. Therefore all exposed skin must be protected from arc flash at incident energy levels energy levels greater than 1.2 cal/cm^2.
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).
Low-voltage is defined by NETA as
less than 1,000 volts
What is the description of the first letter designator for the cooling class of transformers listed here: L
liquid with no measurable flash point
Class 2 rubber gloves what is the AC retest voltage?
20,000 VAC
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 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 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.
Class 0 rubber gloves what is the DC retest Voltage?
20,000 VDC
Class 1 rubber gloves what is the AC retest voltage?
10,000 VAC
Class 00 rubber gloves what is the DC retest voltage?
10,000 VDC
Class 00 rubber gloves what is the glove color?
Beige
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.
What does an Inverter do?
Changes direct current (DC) to Alternating Current (AC).
What does a Rectifier do?
Converts an Alternating Current (AC) to a Direct Current (DC).
Class 3 rubber gloves what is the glove color?
Green
If you have your ground conductor running through your zero-sequence CT with your current carrying conductors, what will happen?
Ground fault protection won't function
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
Ammeter
Identify the electrical symbol shown:
Removable / Drawout circuit breaker Normally 5kV or above
Identify the electrical symbol shown:
Incident Energy
Is the amount of thermal energy released during the arc flash and is measured at a certain distance from the source; typically expressed in calories per square centimeter (cal/cm^2)
Which of the following protective functions requires the most energy to trip a circuit breaker? L S I or G
L long time function
What is the description of the first letter designator for the cooling class of transformers listed here: O
Liquid with a flash point less than or equal to 300*C
Which is the equipment through which power enters a building?
Service drop conductors and underground lateral conductors
What is the purpose of a line trap?
Substation Communication -Line Traps prevent transmission of these high frequency signals to unwanted directions without loss of energy at power frequency.
The grounded conductor is one of the two conductors through which normal circuit current flows. True or False
TRUE
A primary cell is one in which the chemical action is irreversible:
TRUE A cell or battery designed to deliver its rated capacity once and then be discarded; it is not designed to be recharged. Primary batteries include alkaline, heavy-duty and general-purpose batteries.
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.
What is the description of the THIRD letterdesignator for the cooling class of transformers listed here: W
Water
SAE 5, 105K
What is the minimum tensile strength (lbf/in2) of the bolt pictured above?
What is used to measure resistance?
Wheatstone bridge, Kelvin double Bridge is used to measure very low resistances (typically less than 1/10 of an ohm).
When using a hydrometer, where is the specific gravity of a cell taken?
When using a hydrometer, the specific gravity of a cell should be taken a third of the way down the side of the cell.
Class 1 rubber gloves what is the glove color ?
White
Class 2 rubber gloves what is the glove color?
Yellow
All approved voltage detectors:
alarms in the proximity of electric fields, it is not necessary to make physical contact with the equipment being checked. Because it is made of non-conductive materials, it will not conduct electricity and not cause an arc flash even if contact with energized equipment is made.
Medium-voltage is defined by NETA as
greater than 1,000 volts and less than 100,000 volts
High-voltage and Extra-High voltage is defined by NETA as
greater than 100kV and less than 1,000kV
Surge arresters are _____ devices used to protect electrical insulation in a power system.
voltage limiting