NM ES-3 Test (New Mexico Low
Voltage Journeyman) Complete Study
Guide
This comprehensive study guide is designed to help you prepare for
the New Mexico ES-3 Low Voltage Journeyman licensing examination.
The exam is administered by PSI and consists of 50 open-book
questions to be completed in 145 minutes, requiring a passing score
of 75%.
License Scope: The ES-3 license permits work on interior and exterior
special systems operating at 50 volts or less, including
telecommunications, fire alarm, CATV, audio/visual, security systems,
and access control.
SECTION 1: WIRING & INSTALLATION
REQUIREMENTS
Question 1
What is the minimum clearance to the edge of a wood stud for a wire
hole?
A) 1/2 inch
B) 3/4 inch
C) 1 inch
D) 1 1/4 inches
,Answer: D
Rationale: The minimum clearance to the edge of a wood stud for a
wire hole is 1 1/4 inches. This requirement ensures that nails or
screws driven into the stud will not contact and damage the wiring.
Question 2
Electrical conduit buried 18 inches below grade shall have a warning
tape at how many inches above the conduit?
A) 6 inches
B) 8 inches
C) 10 inches
D) 12 inches
Answer: D
Rationale: Warning tape must be placed 12 inches above buried
conduit that is installed 18 inches below grade. The tape provides a
visual alert for future excavation work.
Question 3
A phase converter is an electrical device that ______?
A) Converts AC to DC power
B) Converts single-phase power to three-phase power
C) Steps voltage up or down
D) Regulates current flow
Answer: B
,Rationale: A phase converter is an electrical device that converts
single-phase electrical power to three-phase electrical power. This is
commonly used when three-phase equipment must operate on
single-phase power sources.
Question 4
A rotary phase converter has a nameplate rating of 28 full load input
amps. What is the minimum ampacity required for the conductor
supplying the phase converter?
A) 28 amps
B) 30 amps
C) 35 amps
D) 40 amps
Answer: C
Rationale: The minimum ampacity required is 35 amps. The conductor
must be sized at 125% of the full load input amp rating (28 × 1.25 =
35).
Question 5
According to the NEC, electrical equipment may NOT be mounted to
concrete, cinder block, or brick walls with which of the following?
A) Expansion anchors
B) Wooden plugs
C) Toggle bolts
D) Masonry screws
Answer: B
, Rationale: Wooden plugs are prohibited for mounting electrical
equipment to concrete, cinder block, or brick walls. Wooden plugs can
rot, shrink, or become loose over time, compromising the security of
the installation.
Question 6
If a cable is being installed in an area that is above a suspended
ceiling that contains completely enclosed air ducts, what term
identifies this location?
A) Plenum
B) Accessible
C) Concealed
D) Exposed
Answer: B
Rationale: This location is defined as "accessible," meaning it can be
approached or entered for maintenance without damaging the
building structure. The presence of enclosed air ducts above the
ceiling does not make the space a plenum.
Question 7
What percentage of fill is allowed in a conduit with three conductors?
A) 30%
B) 35%
C) 40%
D) 50%
Answer: C
Voltage Journeyman) Complete Study
Guide
This comprehensive study guide is designed to help you prepare for
the New Mexico ES-3 Low Voltage Journeyman licensing examination.
The exam is administered by PSI and consists of 50 open-book
questions to be completed in 145 minutes, requiring a passing score
of 75%.
License Scope: The ES-3 license permits work on interior and exterior
special systems operating at 50 volts or less, including
telecommunications, fire alarm, CATV, audio/visual, security systems,
and access control.
SECTION 1: WIRING & INSTALLATION
REQUIREMENTS
Question 1
What is the minimum clearance to the edge of a wood stud for a wire
hole?
A) 1/2 inch
B) 3/4 inch
C) 1 inch
D) 1 1/4 inches
,Answer: D
Rationale: The minimum clearance to the edge of a wood stud for a
wire hole is 1 1/4 inches. This requirement ensures that nails or
screws driven into the stud will not contact and damage the wiring.
Question 2
Electrical conduit buried 18 inches below grade shall have a warning
tape at how many inches above the conduit?
A) 6 inches
B) 8 inches
C) 10 inches
D) 12 inches
Answer: D
Rationale: Warning tape must be placed 12 inches above buried
conduit that is installed 18 inches below grade. The tape provides a
visual alert for future excavation work.
Question 3
A phase converter is an electrical device that ______?
A) Converts AC to DC power
B) Converts single-phase power to three-phase power
C) Steps voltage up or down
D) Regulates current flow
Answer: B
,Rationale: A phase converter is an electrical device that converts
single-phase electrical power to three-phase electrical power. This is
commonly used when three-phase equipment must operate on
single-phase power sources.
Question 4
A rotary phase converter has a nameplate rating of 28 full load input
amps. What is the minimum ampacity required for the conductor
supplying the phase converter?
A) 28 amps
B) 30 amps
C) 35 amps
D) 40 amps
Answer: C
Rationale: The minimum ampacity required is 35 amps. The conductor
must be sized at 125% of the full load input amp rating (28 × 1.25 =
35).
Question 5
According to the NEC, electrical equipment may NOT be mounted to
concrete, cinder block, or brick walls with which of the following?
A) Expansion anchors
B) Wooden plugs
C) Toggle bolts
D) Masonry screws
Answer: B
, Rationale: Wooden plugs are prohibited for mounting electrical
equipment to concrete, cinder block, or brick walls. Wooden plugs can
rot, shrink, or become loose over time, compromising the security of
the installation.
Question 6
If a cable is being installed in an area that is above a suspended
ceiling that contains completely enclosed air ducts, what term
identifies this location?
A) Plenum
B) Accessible
C) Concealed
D) Exposed
Answer: B
Rationale: This location is defined as "accessible," meaning it can be
approached or entered for maintenance without damaging the
building structure. The presence of enclosed air ducts above the
ceiling does not make the space a plenum.
Question 7
What percentage of fill is allowed in a conduit with three conductors?
A) 30%
B) 35%
C) 40%
D) 50%
Answer: C
