Question 1

What are the requirements for installing parallel conductors, as specified in NEC 310.10( G )?

Accepted Answer

​ 
 The parallel conductors are required to be 1/0 AWG or larger and have the same insulation type. They must also be of the same length and of the same material (copper-copper or aluminum-aluminum). They must be the same size in terms of circular mil area, and be terminated in the same manner. In addition, the raceway or cables are required to have the same electrical characteristics.

Question 2

In the United States, ____ Hz is standard or the fundamental frequency.

Accepted Answer

In the United States, the standard or fundamental frequency for electricity is 60 Hz.

Question 3

Often the load is such that parallel conductors should be considered. This usually occurs with loads over ____ amperes.

Accepted Answer

Parallel conductors are typically considered for loads over 400 amperes to effectively distribute the electrical load and reduce the size of individual conductors needed.

Question 4

What wire and cable options do you have for combating excessive neutral current?

Accepted Answer

The answer of What wire and cable options do you...

Question 5

Feeders are the part of the electrical system that connects the branch-circuit ____ to the electrical service equipment.

Accepted Answer

Feeders are the components in an electrical system that connect the branch-circuit panelboards to the electrical service equipment, ensuring the distribution of power throughout the system.

Question 6

To get accurate current readings where harmonics are involved, ammeters referred to as "____" must be used.

Accepted Answer

True RMS (Root Mean Square) ammeters are designed to accurately measure the current in circuits that contain harmonics, unlike average-reading meters which can give misleading readings in such situations.

Question 7

If the ampacity of a feeder does not match a standard OCPD rating, then ____ be used.

Accepted Answer

According to the National Electrical Code (NEC), if the ampacity of a feeder does not match a standard Overcurrent Protection Device (OCPD) rating, the next higher standard rating may be used, provided it does not exceed the allowable conditions of use for the equipment or conductors.

Question 8

If a lighting load is considered to be continuous, as is the case in commercial buildings, a load factor of ____ percent must be applied.

Accepted Answer

In commercial buildings, continuous lighting loads require a load factor of 125% to account for the continuous operation and ensure the electrical system can handle the demand safely.

Question 9

If the selected OCPD has a rating greater than 100-amperes, the conductors to be installed shall be selected from either the 75 degrees Celsius or ____ degrees Celsius column of NEC Table 310.16 .

Accepted Answer

90 degrees Celsius is the correct choice because NEC Table 310.16 specifies that for overcurrent protection devices (OCPD) rated over 100 amperes, conductors must be sized based on the 75°C or 90°C column ratings.

Question 10

For installations where the nonlinear load is huge, most consulting engineers will specify ____-rated transformers.

Accepted Answer

K-rated transformers are specified for installations with a significant nonlinear load because they are designed to handle the harmonic currents generated by such loads without overheating or suffering from premature failure.

Question 11

____ are multiples of a fundamental frequency.

Accepted Answer

Harmonics are multiples of a fundamental frequency, occurring in electrical systems when non-linear loads distort the current or voltage waveform.

Question 12

Currents of the 3rd harmonic and odd multiples of the 3rd harmonic (9th, 15th, 21st, etc.)add together in the common neutral conductor of a 3-phase system, instead of canceling each other. These odd multiples are referred to as ____.

Accepted Answer

Triplens are the 3rd harmonic and its odd multiples (9th, 15th, 21st, etc.) that add together in the neutral conductor of a 3-phase system, rather than canceling out.

Question 13

When sizing feeder conductors, ____ noncoincident loads (loads unlikely to be operated simultaneously such as the air-conditioning and the heating)need be included.

Accepted Answer

When sizing feeder conductors, only the larger of any noncoincident loads need be included because it is unlikely that both loads (e.g., air-conditioning and heating) will operate at the same time, so only the larger load needs to be accounted for in the sizing.

Question 14

When a smaller conductor is tapped from a larger conductor, the overcurrent protection at the beginning of the tap is ____ the ampacity of the smaller conductor.

Accepted Answer

The overcurrent protection at the beginning of the tap is greater than the ampacity of the smaller conductor. This is because the overcurrent protection device is sized based on the larger conductor to which the smaller one is tapped, allowing for the protection of the system while accommodating the larger conductor's capacity.

Question 15

​What guidelines are given to deal with local energy code regulations?

Accepted Answer

The answer of ​What guidelines are given to deal with...

Question 16

To determine a reasonable minimum size for a neutral conductor, two types of loads must be considered-____.

Accepted Answer

Nonlinear and linear loads must be considered because they have different effects on the neutral conductor. Linear loads have a predictable, sinusoidal current draw, while nonlinear loads can cause harmonic currents that may increase the neutral current beyond the phase currents, affecting the sizing of the neutral conductor.

Question 17

NEC 310.10 ( G )sets forth the requirements for installing ____ conductors. These requirements are intended to ensure the conductors will share the current equally to prevent overloading individual conductors.

Accepted Answer

NEC 310.10 (G) specifically addresses the requirements for installing parallel conductors. The intention behind these requirements is to ensure that all conductors share the current equally, which helps in preventing any individual conductor from being overloaded.

Question 18

On a 3-phase, 4-wire, wye system, ____ reduction is allowed for nonlinear loads.

Accepted Answer

In a 3-phase, 4-wire, wye system, no reduction is allowed for nonlinear loads because these loads can cause significant harmonic distortion, which can affect the system's performance and reliability.

Question 19

What three circuit parameters must be known before feeder component selection can begin?

Accepted Answer

The answer of What three circuit parameters must be known...

Question 20

What are the three conditions of failure that may occur with a 3-phase, 4-wire wye system?

Accepted Answer

The answer of What are the three conditions of failure...

Quiz 8: Feeder Installation and Load Calculation

What are the requirements for installing parallel conductors, as specified in NEC 310.10( G )?

In the United States, ____ Hz is standard or the fundamental frequency.

Often the load is such that parallel conductors should be considered. This usually occurs with loads over ____ amperes.

What wire and cable options do you have for combating excessive neutral current?

Feeders are the part of the electrical system that connects the branch-circuit ____ to the electrical service equipment.

To get accurate current readings where harmonics are involved, ammeters referred to as "____" must be used.

If the ampacity of a feeder does not match a standard OCPD rating, then ____ be used.

If a lighting load is considered to be continuous, as is the case in commercial buildings, a load factor of ____ percent must be applied.

If the selected OCPD has a rating greater than 100-amperes, the conductors to be installed shall be selected from either the 75 degrees Celsius or ____ degrees Celsius column of NEC Table 310.16 .

For installations where the nonlinear load is huge, most consulting engineers will specify ____-rated transformers.

____ are multiples of a fundamental frequency.

Currents of the 3rd harmonic and odd multiples of the 3rd harmonic (9th, 15th, 21st, etc.) add together in the common neutral conductor of a 3-phase system, instead of canceling each other. These odd multiples are referred to as ____.

When sizing feeder conductors, ____ noncoincident loads (loads unlikely to be operated simultaneously such as the air-conditioning and the heating) need be included.

When a smaller conductor is tapped from a larger conductor, the overcurrent protection at the beginning of the tap is ____ the ampacity of the smaller conductor.

What guidelines are given to deal with local energy code regulations?

To determine a reasonable minimum size for a neutral conductor, two types of loads must be considered-____.

NEC 310.10 ( G ) sets forth the requirements for installing ____ conductors. These requirements are intended to ensure the conductors will share the current equally to prevent overloading individual conductors.

On a 3-phase, 4-wire, wye system, ____ reduction is allowed for nonlinear loads.

What three circuit parameters must be known before feeder component selection can begin?

What are the three conditions of failure that may occur with a 3-phase, 4-wire wye system?

Quiz 8: Feeder Installation and Load Calculation

What are the requirements for installing parallel conductors, as specified in NEC 310.10( G )?

In the United States, ____ Hz is standard or the fundamental frequency.

Often the load is such that parallel conductors should be considered. This usually occurs with loads over ____ amperes.

What wire and cable options do you have for combating excessive neutral current?

Feeders are the part of the electrical system that connects the branch-circuit ____ to the electrical service equipment.

To get accurate current readings where harmonics are involved, ammeters referred to as "____" must be used.

If the ampacity of a feeder does not match a standard OCPD rating, then ____ be used.

If a lighting load is considered to be continuous, as is the case in commercial buildings, a load factor of ____ percent must be applied.

If the selected OCPD has a rating greater than 100-amperes, the conductors to be installed shall be selected from either the 75 degrees Celsius or ____ degrees Celsius column of NEC Table 310.16 .

For installations where the nonlinear load is huge, most consulting engineers will specify ____-rated transformers.

____ are multiples of a fundamental frequency.

Currents of the 3rd harmonic and odd multiples of the 3rd harmonic (9th, 15th, 21st, etc.) add together in the common neutral conductor of a 3-phase system, instead of canceling each other. These odd multiples are referred to as ____.

When sizing feeder conductors, ____ noncoincident loads (loads unlikely to be operated simultaneously such as the air-conditioning and the heating) need be included.

When a smaller conductor is tapped from a larger conductor, the overcurrent protection at the beginning of the tap is ____ the ampacity of the smaller conductor.

​What guidelines are given to deal with local energy code regulations?

To determine a reasonable minimum size for a neutral conductor, two types of loads must be considered-____.

NEC 310.10 ( G ) sets forth the requirements for installing ____ conductors. These requirements are intended to ensure the conductors will share the current equally to prevent overloading individual conductors.

On a 3-phase, 4-wire, wye system, ____ reduction is allowed for nonlinear loads.

What three circuit parameters must be known before feeder component selection can begin?

What are the three conditions of failure that may occur with a 3-phase, 4-wire wye system?

What guidelines are given to deal with local energy code regulations?