×
Follow Us
Page 4 of 5 FirstFirst ... 2345 LastLast
Results 31 to 40 of 44

Remembered NETA 2 Questions Help

 Jump to latest post
Page 4 of 5 FirstFirst ... 2345 LastLast
    #31
  1. Join Date
    Feb 2015
    Location
    Red Oak TX
    Posts
    26
    Reputation

    multimeter connection

    Quote Originally Posted by Izeldeen View Post
    5.) A Multimeter is device that:

    a.) is connected in series, low impedance
    b.) is connected in series, high impedance
    c.) is connected parallel, low impedance
    d.) is connected parallel, high impedance
    answer is d
    I agree that the answer is D and would answer the question that way too, but not to forget that most DMMs are rated to be used at 10 amps in series with the circuit.
    That would be more handy in an electronics circuit where accuracy would be a great concern, but it is an option, so the question is misleading since the DMM can technically be used in series and parallel.

  2. #32
  3. Join Date
    Feb 2015
    Location
    Red Oak TX
    Posts
    26
    Reputation
    6.) What is the highest pickup for a low voltage-480 system ground?

    a.) 600 A
    b.) 800 A
    c.) 1000 A
    d.) 1200 A

    Ground Fault protection can never exceed 1200 amps.
    Even if the breaker is 4000 amps or larger and the dial for GF setting would reach 1200 amps on the first few notches of settings, once the setting reaches 1200 amp, the settings above that point will not go any higher than 1200 amps.

  4. #33
  5. Join Date
    Feb 2015
    Location
    Red Oak TX
    Posts
    26
    Reputation

    downstream bonding test

    7.) Why do an insulation test between neutral and ground?

    I read this and was confused on the wording. Are you talking service entrance or non service entrance? The question did not specify! Come on NETA. Killin me smalls....


    We typically perform GF test for new installations. We typically remove neutral and/or neutral to ground bond to test for downstream bonding. This test can be performed with an ohm meter, but recently, we have had city inspectors require an insulation test (AKA Megger test) be performed to check for downstream bonding.
    I agree that it is overkill, but the inspector gets what the inspector wants.

  6. #34
  7. Join Date
    Feb 2015
    Location
    Red Oak TX
    Posts
    26
    Reputation
    8.) Interlock on MV MCC between switch and contactor. Why?


    My experience has been with a slow-close disconnect that was interlocked with the door/cover and the contactor.
    The disconnect only closed/opened as fast as you moved your hand.
    My thought was that the contactor had to be opened before operating the disconnect, that way the disconnect is not operated under load.
    In this case, the contactor mechanism malfunctioned and stuck in a position, which also damaged the main disconnect linkage due to repeated attempts to operate the disconnect.

  8. #35
  9. Join Date
    Feb 2015
    Location
    Red Oak TX
    Posts
    26
    Reputation

    VFD for speed of motor

    9.) What is the role of a VFD?

    Watch for this one. The wording in the answers was VERY confusing.


    VFD Variable Frequency Drive (also known as Variable Speed Drive) controls the speed of a motor by varying the frequency of voltage that is delivered to motor. The VFD rectifies the AC to DC, then DC is inverted to AC, but when the DC is inverted to AC, the frequency can be varied by the speed of switching in by PWM (Pulse Width Modulation).
    This rapid switching comes at a price. To create a varied frequency, this switching can distort the sinewave, and/or cause excess vibration in the motor. The motor needs to be rated for use with a VFD or the motor may be short lived.

    A VFD can also be used as a form of soft-start, but the main reason is to control the speed of the motor since starting and stopping a motor is harder on the motor than running it at a reduced speed.

  10. #36
  11. Join Date
    Feb 2015
    Location
    Red Oak TX
    Posts
    26
    Reputation

    Outdoor panel rating

    14.) What is the outdoor panel class?

    a.) Class 2
    b.) Class 3
    c.) Class 3R
    4.) Class 4


    Outdoor panel rating would be NEMA 3R. R for raintight. This does not mean it is submersible, it only means that rain that runs down the panel, will not makes its way into the enclosure due to how the lips of cover overlap or divert rain away from panel.
    Typically a dry-type transformer is a NEMA 2 but can but can be converted to a 3R with additional rain guards over vents.

  12. #37
  13. Kalbi_Rob's Avatar
    Kalbi_Rob is offline Experienced Member Pro Subscriber
    Join Date
    Feb 2018
    Location
    Jacksonville, NC
    Posts
    284
    Reputation
    Quote Originally Posted by BruceG400 View Post
    7.) Why do an insulation test between neutral and ground?

    I read this and was confused on the wording. Are you talking service entrance or non service entrance? The question did not specify! Come on NETA. Killin me smalls....


    We typically perform GF test for new installations. We typically remove neutral and/or neutral to ground bond to test for downstream bonding. This test can be performed with an ohm meter, but recently, we have had city inspectors require an insulation test (AKA Megger test) be performed to check for downstream bonding.
    I agree that it is overkill, but the inspector gets what the inspector wants.
    I would disagree as NETA ATS 7.14.2 states: Measure the system neutral-to-ground insulation resistance with the neutral disconnect link temporarily removed. Replace the neutral disconnect link after testing.

    Definition of insulation resistance test is performed with active voltage applied. Resistance of a system can be checked using an ohmmeter, but insulation can only be tested via potential. I would agree with the City Inspector. I've always tested with ohmmeter prior to applying voltage as most systems are <1 ohm, and require additional work.

  14. #38
  15. Join Date
    Feb 2015
    Location
    Red Oak TX
    Posts
    26
    Reputation
    Quote Originally Posted by Kalbi_Rob View Post
    I would disagree as NETA ATS 7.14.2 states: Measure the system neutral-to-ground insulation resistance with the neutral disconnect link temporarily removed. Replace the neutral disconnect link after testing.

    Definition of insulation resistance test is performed with active voltage applied. Resistance of a system can be checked using an ohmmeter, but insulation can only be tested via potential. I would agree with the City Inspector. I've always tested with ohmmeter prior to applying voltage as most systems are <1 ohm, and require additional work.
    Since you agree with the inspector, are you saying you normally take a resistance reading for downstream bonding with an insulation resistance tester?
    I agree that downstream bonding needs to be tested while any neutral to ground reference on line-side needs to be removed. We have always used an ohm-meter in the past to run this test with bonding jumper removed, but have only recently been required to use an insulation resistance tester.

  16. #39
  17. Join Date
    Sep 2021
    Posts
    3
    Reputation
    Quote Originally Posted by BruceG400 View Post
    I agree that the answer is D and would answer the question that way too, but not to forget that most DMMs are rated to be used at 10 amps in series with the circuit.
    That would be more handy in an electronics circuit where accuracy would be a great concern, but it is an option, so the question is misleading since the DMM can technically be used in series and parallel.
    On the test I took about a month ago the question actually asked something along the lines of

    "A DMM used to measure voltage is connected:" or
    "A DMM used to measure current is connected:"

    It was in no way ambiguous as to what answer they were looking for.

  18. #40
  19. Kalbi_Rob's Avatar
    Kalbi_Rob is offline Experienced Member Pro Subscriber
    Join Date
    Feb 2018
    Location
    Jacksonville, NC
    Posts
    284
    Reputation
    Quote Originally Posted by BruceG400 View Post
    Since you agree with the inspector, are you saying you normally take a resistance reading for downstream bonding with an insulation resistance tester?
    I agree that downstream bonding needs to be tested while any neutral to ground reference on line-side needs to be removed. We have always used an ohm-meter in the past to run this test with bonding jumper removed, but have only recently been required to use an insulation resistance tester.
    I've always taken my Megger MIT/420 and used the ohmmeter to verify Neutral and ground are clear with the neutral disconnect link removed. On New Construction (which for whatever reason the East Coast Mid-Atlantic region doesn't require NEC 230.95 test), I will take and perform a insulation resistance test. I don't perform it on maintenance test because of potential of downstream devices. So, for an inspector on new construction, yes per every procedure I have seen it is written as perform an insulation resistance test.

Page 4 of 5 FirstFirst ... 2345 LastLast
Subscribe

Login or register to leave a reply!


Share this thread

Related Topics

  1. NETA 4 Exam Questions 7/2018
    By MartyCoyne in forum NETA Level 4 Exam
    Replies: 29
    Last Post: June 22, 2022, 10:46 PM
  2. NETA 4 exam questions I am unsure about
    By mmacdonell in forum NETA Level 4 Exam
    Replies: 2
    Last Post: August 6, 2021, 07:15 AM
  3. Why so few questions for NETA 4 exam?
    By mmacdonell in forum NETA Level 4 Exam
    Replies: 3
    Last Post: February 10, 2020, 12:14 PM
  4. Challenging NETA questions after the test
    By adamstraub in forum NETA Level 3 Exam
    Replies: 1
    Last Post: October 24, 2019, 07:38 AM
  5. Couple NETA III Questions
    By jaycee91 in forum NETA Level 3 Exam
    Replies: 1
    Last Post: January 23, 2019, 01:14 PM

Tags for this Thread

Follow us


Explore TestGuy


NETA Certification Training


NICET Electrical Power Testing


Help and Support