Ch 3 Flashcards
In a parallel circuit, the total power is equal to what?
The sum of the branches’ powers
What can happen if the neutral conductor of a multi-wire circuit is interrupted (opened)? Why?
Fire or destruction of equipment, because it can cause overvoltage or undervoltage of the electrical equipment.
The current flowing in the neutral conductor of a multi-wire circuit is called:
Unbalanced Current
The neutral conductor of a 3-wire, 120/208V or 277/480V circuit from a 4-wire, three phase system will ______ carry neutral current
Always
In a parallel circuit, the resistance total is _____ than the smallest individual resistance
Less
This type of circuit is also called “Open-loop system”
Parallel
What is the formula for the Product-Over-Sum Method?
Rt = (R1 x R2) / (R1 + R2)
This conductor is also called a “grounded conductor”
Neutral
In a series circuit, what does the sum of the power consumed by all the resistors equal?
The total power consumed by the circuit
(Series or Parallel) Total power is equal to the sum of the branches’ powers
Parallel
The _______ conductor or a solidly grounded system is required to be grounded.
Neutral
(Series or Parallel) Total resistance is less than the smallest individual resistance
Parallel
Term for “connected to the Earth”
Grounded
Because of the dangers of an open neutral conductor, what does the NEC require in a multi-wire circuit?
That the neutral be spliced and brought out to the device. This way if the device is removed, it does not result in an open neutral conductor.
Circuit consisting of two or more ungrounded conductors that have a voltage between them, and an equal voltage between each ungrounded conductor
Multi-wire Circuit
Current is identical through all circuit elements in this type of circuit
Series
In a 3-wire 120/240V, single-phase circuit, the current flowing on the neutral will be what?
The difference between the current on the ungrounded conductors
When power supplies are connected in series, the voltage of the power supply will be ________
Additive
(Series or Parallel) The sum of the currents through each path is equal to the total current that flows from the source
Parallel
In a parallel circuit, voltage is ____ across each component of the parallel circuit?
The same
In a parallel circuit, the sum of the currents through each path is equal to what?
The total current that flows from the power source
In a multi-wire branch circuit, what could cause the neutral to become overloaded with current and damage the insulation?
Not terminating the ungrounded conductors to separate phases
(Series or Parallel) Current is constant
Series
(Series or Parallel) Total resistance of a series circuit is equal to the sum of all of the resistances of the circuit
Series
What is the formula for the Reciprocal Mehtod?
Rt = 1 /(1 /R1, + 1/R2, + 1/R3……)
If the circuit is balanced and the current flow on each line of the circuit is the same, how much current will the neutral conductor carry?
0 Amps
(Series or Parallel) Has two or more paths for current to flow through
Parallel
In a 2-wire circuit, the _____ flowing on the neutral will be the same as the ______ on the ungrounded conductors.
Current, Current
This type of circuit is also called a “closed-loop system”
Series
In a series circuit, what does the sum of the voltages equal?
Voltage of the power source
In a series circuit, what is the value of the current through all the resistances?
The same
In a 2-wire circuit, is it required to pigtail the conductors?
No
In a series circuit, what is the total resistance equal to?
The sum of all the resistances in the circuit
(Series or Parallel) The sum of the voltage drop of all resistors must equal the voltage of the source
Series
(Series or Parallel) Voltage is the same across each component of the circuit
Parallel
When power supplies are connected in parallel, what remains the same and what will be increased?
Voltage remains the same and current or amp-hour capacity will be increased
(Series or Parallel) The sum of the power consumed by all resistors equals the total power of the circuit
Series
Will opening the ungrounded or neutral conductors in a 2-wire circuit during replacement of a device cause a safety hazard?
No
What are the three main advantages to a multi-wire branch circuit
Less conductors
Smaller Raceway
Lower conductor voltage drop
What is the formula for the Equal Resistance Method?
Resistance of one element / total number of resistors
When will the neutral conductor of a 4-wire, 120/208V or 277/480V circuit carry current?
When the load on the ungrounded conductors is not identical
