RCDD/TDMM Chapter 9) Power
Distribution Exam 2025 Questions
and Answers 100% Pass
AHJ - ✔✔Authority having jurisdiction
Alternate Current (ac) - ✔✔A current flow that alternates periodically (usually
sinusoidal) in magnitude and direction
Apparent Power - ✔✔The product of the measured voltage and measured
amperage. Expressed in volt amperes
Arc Flash - ✔✔A short circuit through the air. When insulation and isolation
between electrified conductors is breached or can no longer withstand the applied
voltage, an arc flash occurs
AWG - ✔✔American Wire Gauge; the greater the wire diameter, the smaller the
AWG value
Capacitance - ✔✔1) The ability of an electronic component to store electrical energy
2) The opposition to a change in voltage
Delta - ✔✔The difference between two values, symbolized with a triangle
Direct Current (dc) - ✔✔Current flow that has a constant direction. The letters dc are
also used to generically refer to any constant waveform or signal. (EG; a batter
voltage of 3 volts direct current [3Vdc])
COPYRIGHT © 2025 BY EMILLY CHARLOTTE, ALL RIGHTS RESERVED 1
,Frequency - ✔✔The number of cycles that a periodic signal completes in a given
time. If the unit of time is one second, the frequency is stated in hertz (Hz). One Hz is
equal to one cycle per second
Harmonics - ✔✔Multiples of the basic frequency of a sine wave (eg the 3rd harmonic
of 60 Hz power frequency is 180 Hz)
Impedance - ✔✔The total opposition to ac flow, measured in ohms.
Inductance - ✔✔1) The property of an electric force field built around a conductor
when current flows through it. 2) The resistance to change in current
ITE Power - ✔✔Information Technology Equipment Power; the power consumed by
ICT to manage, monitor, control, process, store, and route data within a data center,
excluding all infrastructure technology equipment
LOTO - ✔✔Lockout/ Tagout, a means to protect personnel from the unexpected
startup or re-energization of equipment by ensuring that equipment remains
completely off during routing maintenance and repairs.
LVD - ✔✔Low voltage disconnect; a device that is used to disconnect the battery at a
preset voltage during battery discharge and allow reconnection only when utility
power has been restored. Called a 'no volt release' in the UK
Noise - ✔✔Unwanted electrical signals that were induced onto or superimposed
upon the power line
PDU - ✔✔Power distribution unit; a device that has a transformer, surge
suppression, single point ground, panelboards, and monitoring under a single
enclosure
Phase difference - ✔✔The relationship in time between two waveforms with the
same frequency
Phase configuration - ✔✔The number of phases and the type of connection between
the utility and the user
COPYRIGHT © 2025 BY EMILLY CHARLOTTE, ALL RIGHTS RESERVED 2
, Power - ✔✔1) The rate of transfer or absorption of energy per unit time into a system
2) The energy required to operate an electrical device (EG: Motor, amplifier,
transmitter)
Reactance - ✔✔The opposition to the flow of ac current caused by unductance and
capacitance. Expressed in ohms.
Redundancy - ✔✔Providing secondary components that either become instantly
operational or are continuously operational so that the failure of a primary
component will not result in mission failure
Resistance - ✔✔A measure of opposition a material offers to the flow of direct
current. Measured in ohms.
RPP - ✔✔Remote Power Panel; a power distribution cabinet downstream from a
PDU or UPS, typically containing circuits or breakers, without a transformer located
near the load.
SDS - ✔✔Safety Data Sheet; a document prepared by the manufacturer describing all
known chemical, radiological, and other hazards of a specific product. Formerly
called a material safety data sheet (MSDS)
Short circuit - ✔✔A faulty or accidental connection between two points of different
potential in an electrical circuit, bypassing the load and establishing a path of low
resistance through which an excessive current can flow.
Sine Wave - ✔✔The mathematical representation of an alternating voltage or current
waveform
SPD - ✔✔Surge protection device; a protective device for limiting transient voltages
by diverting or limiting surge current. It has a nonliear voltage-current characteristic
that reduces votages exceeding the normal safe system levels by a rapid increase in
conducted current. Also called a voltage limiter, overvoltage protector, surge
arrestor, or transient voltage surge suppressor (TVSS)
COPYRIGHT © 2025 BY EMILLY CHARLOTTE, ALL RIGHTS RESERVED 3
Distribution Exam 2025 Questions
and Answers 100% Pass
AHJ - ✔✔Authority having jurisdiction
Alternate Current (ac) - ✔✔A current flow that alternates periodically (usually
sinusoidal) in magnitude and direction
Apparent Power - ✔✔The product of the measured voltage and measured
amperage. Expressed in volt amperes
Arc Flash - ✔✔A short circuit through the air. When insulation and isolation
between electrified conductors is breached or can no longer withstand the applied
voltage, an arc flash occurs
AWG - ✔✔American Wire Gauge; the greater the wire diameter, the smaller the
AWG value
Capacitance - ✔✔1) The ability of an electronic component to store electrical energy
2) The opposition to a change in voltage
Delta - ✔✔The difference between two values, symbolized with a triangle
Direct Current (dc) - ✔✔Current flow that has a constant direction. The letters dc are
also used to generically refer to any constant waveform or signal. (EG; a batter
voltage of 3 volts direct current [3Vdc])
COPYRIGHT © 2025 BY EMILLY CHARLOTTE, ALL RIGHTS RESERVED 1
,Frequency - ✔✔The number of cycles that a periodic signal completes in a given
time. If the unit of time is one second, the frequency is stated in hertz (Hz). One Hz is
equal to one cycle per second
Harmonics - ✔✔Multiples of the basic frequency of a sine wave (eg the 3rd harmonic
of 60 Hz power frequency is 180 Hz)
Impedance - ✔✔The total opposition to ac flow, measured in ohms.
Inductance - ✔✔1) The property of an electric force field built around a conductor
when current flows through it. 2) The resistance to change in current
ITE Power - ✔✔Information Technology Equipment Power; the power consumed by
ICT to manage, monitor, control, process, store, and route data within a data center,
excluding all infrastructure technology equipment
LOTO - ✔✔Lockout/ Tagout, a means to protect personnel from the unexpected
startup or re-energization of equipment by ensuring that equipment remains
completely off during routing maintenance and repairs.
LVD - ✔✔Low voltage disconnect; a device that is used to disconnect the battery at a
preset voltage during battery discharge and allow reconnection only when utility
power has been restored. Called a 'no volt release' in the UK
Noise - ✔✔Unwanted electrical signals that were induced onto or superimposed
upon the power line
PDU - ✔✔Power distribution unit; a device that has a transformer, surge
suppression, single point ground, panelboards, and monitoring under a single
enclosure
Phase difference - ✔✔The relationship in time between two waveforms with the
same frequency
Phase configuration - ✔✔The number of phases and the type of connection between
the utility and the user
COPYRIGHT © 2025 BY EMILLY CHARLOTTE, ALL RIGHTS RESERVED 2
, Power - ✔✔1) The rate of transfer or absorption of energy per unit time into a system
2) The energy required to operate an electrical device (EG: Motor, amplifier,
transmitter)
Reactance - ✔✔The opposition to the flow of ac current caused by unductance and
capacitance. Expressed in ohms.
Redundancy - ✔✔Providing secondary components that either become instantly
operational or are continuously operational so that the failure of a primary
component will not result in mission failure
Resistance - ✔✔A measure of opposition a material offers to the flow of direct
current. Measured in ohms.
RPP - ✔✔Remote Power Panel; a power distribution cabinet downstream from a
PDU or UPS, typically containing circuits or breakers, without a transformer located
near the load.
SDS - ✔✔Safety Data Sheet; a document prepared by the manufacturer describing all
known chemical, radiological, and other hazards of a specific product. Formerly
called a material safety data sheet (MSDS)
Short circuit - ✔✔A faulty or accidental connection between two points of different
potential in an electrical circuit, bypassing the load and establishing a path of low
resistance through which an excessive current can flow.
Sine Wave - ✔✔The mathematical representation of an alternating voltage or current
waveform
SPD - ✔✔Surge protection device; a protective device for limiting transient voltages
by diverting or limiting surge current. It has a nonliear voltage-current characteristic
that reduces votages exceeding the normal safe system levels by a rapid increase in
conducted current. Also called a voltage limiter, overvoltage protector, surge
arrestor, or transient voltage surge suppressor (TVSS)
COPYRIGHT © 2025 BY EMILLY CHARLOTTE, ALL RIGHTS RESERVED 3
