Klein Tools RT390 is a circuit analyzer that tests the wiring condition
at an electrical outlet, displays AC line voltage, inspects GFCI and AFCI
devices with time to trip device, and performs voltage drop tests at
12A, 15A and 20A current loads. The tester is designed for use with
North American 120V AC 3-wire electrical outlets.
• Environment: Indoor. Do NOT expose to moisture rain or snow.
To ensure safe operation and service of the tester, follow these
instructions. Failure to observe these warnings can result in
severe injury or death.
• RT390 is designed for use with North American 3-wire grounded
120V electrical outlets. DO NOT connect to higher voltage
electrical supplies.
• Only use the tester with the supplied NEMA-rated cord.
• Prior to use, always verify tester operation by testing on a known
live and correctly wired electrical outlet.
• DO NOT attempt an AFCI testing event on a circuit with powered
ON equipment or devices.Remove or power OFF prior to testing.
• DO NOT use if the tester appears damaged in any way.
• The tester is intended for indoor use only.
• To reduce the possibility of erroneous readings:
• All appliances or equipment on the circuit being tested should
be disconnected.
• Turn off or move away from equipment which cause
electromagnetic interference.
• DO NOT attempt AFCI, GFCI, 30mA ground fault testing, or
load testing on an incorrectly wired outlet. Consult a qualified
electrician to resolve wiring problems.
• This tester only detects common wiring problems. ALWAYS consult
a qualified electrician to resolve wiring problems. The device:
• Will not indicate quality of ground.
• Will not indicate two hot wires in a circuit.
• Will not detect a combination of multiple wiring faults.
• Will not indicate reversed ground and neutral.
• AFCI indicators produce characteristics that mimic some
forms of arcing. Because of this the indicator may give a false
indication that the AFCI is not functioning properly. If this occurs,
recheck the operation of the AFCI.
SYMBOLS ON TESTER
Risk of danger. Important information: It is important that
users of this tester read, understand, and follow all warnings,
cautions, safety information, and instructions in this manual
before operating or servicing this tester. Failure to follow
instructions could result in death or serious injury.
RT390 is designed for use with North American 3-wire grounded 120V
electrical outlets. DO NOT connect to higher voltage electrical supplies.
Prior to use, always verify tester operation by testing on a known
live and correctly wired electrical outlet.
POWER ON/OFF
Press and hold the Power/Reset button 1 for two seconds to power ON/
OFF the tester. When the tester is powered ON and not connected to a circuit,
2
the LCD
automatically power OFF after 5 minutes of inactivity to conserve battery life.
will display "OOO", "Open Hot" condition.
NOTE: The tester will
NOTE: Auto-Power Off is disabled if tester is plugged into an energized circuit.
WIRING CONDITION
With the tester powered ON and inserted in the outlet, the "ENERGIZED"
3
Indicator
at the top of the LCD if voltage is detected. The tester will display the wiring
condition
outlet, the tester holds the information on the LCD for 10 seconds and the
Hold Indicator
Indicator
circuit, or, if no voltage is detected, the Wiring Condition Indicator
will illuminate, and the Circuit Energized Indicator B will appear
E
and the line voltage D on the LCD. If removed from the
L
will be displayed. During this time, the Wiring Condition
E
will blink. The LCD will reset once it is plugged into another
E
will
blink during the time-out period.
If the tester indicates that the outlet is not wired correctly,
consult a quali ed electrician.
NOTE: Conditions NOT indicated include, but are not limited to, quality of
ground, multiple hot wires, reversal of neutral and ground conductors,
and combinations of defects other than dual open neutral and ground.
NOTE: All appliances or equipment on the circuit being tested should be
unplugged to help reduce the possibility of erroneous readings.
LCD WILL DISPLAY
VOLTAGE*
Neutral
(White)
Hot
(Black)
Ground (Green)
"CORRECT WIRING"
"OPEN GROUND"
"OPEN NEUTRAL"
"OPEN HOT"
"HOT & GRD REVERSED"
"HOT & NEU REVERSED"
"OPEN GROUND OPEN NEUTRAL"
LINE VOLTAGE
NO VOLTAGE
WIRED CORRECTLY
OPEN GROUND
OPEN NEUTRAL
OPEN HOT
DUAL OPEN (NEUTRAL & GROUND)
REVERSED HOT/GROUND
REVERSED HOT/NEUTRAL
WIRING CONDITION
>30V VOLTAGE
*Expected voltage reading on LCD based on the indicated wiring condition.
NOTE: If the detected voltage is either low (30–85V AC) or high (135–150V AC),
the voltage displayed on the LCD will change from white to red. It is possible to
have the voltage displaying in red (indicating low or high voltage) and the green
OPERATING INSTRUCTIONS
GFCI, AFCI, AND 30mA GROUND FAULT FUNCTIONS
NOTE:
Refer to the GFCI, AFCI, or 30mA Ground Fault devices’ user
manual for information on installation and operation prior to using
this tester.
Power ON the tester and plug into the outlet to be tested, noting
the wiring conditions. The wiring conditions
"CORRECT WIRING", the "ENERGIZED" Indicator
illuminated, and the Circuit Energized Indicator
E
should indicate
3
should be
B
should appear at
the top of the LCD.
If the tester indicates that the outlet is not wired correctly,
DO NOT attempt to initiate an electrical testing event. Consult a
quali ed electrician.
Press the following buttons to initiate an electrical fault:
4
• The GFCI button
will create 6mA to 9mA ground fault to trip the
GFCI device.
5
• The AFCI button
device.
• 30mA Ground Fault Test button
trip a 30mA GFCI device.
will simulate a parallel arc condition to trip the AFCI
6
will create a 30mA ground fault to
NOTE: 30mA ground fault protection is not inherent in all models of GFCI
circuit breakers.
If the Circuit Not Energized IndicatorK is displayed on LCD, and
"ENERGIZED" Indicator
the
or 30mA Ground Fault device by pressing its reset button. After
reset, the wiring conditions
"ENERGIZED" Indicator
the
Energized Indicator
3
is not illuminated, reset the AFCI, GFCI,
E
should indicate "CORRECT WIRING",
3
should be illuminated, and the Circuit
B
should appear at the top of the LCD.
If the circuit remains Energized, or any other condition is indicated
other than Not Energized, the device being tested may be
miswired, may not be installed correctly, or may not be functioning
appropriately.
NOTE: The GFCI
deactivated if the wiring is not correct. An error message
Consult a quali ed electrician.
4
, AFCI5, and 30mA6 buttons will be
N
will
appear on the LCD.
NOTE: Allow 20 seconds between successive AFCI testing events.
NOTE: In AFCI testing, an error message that the tester needs to cool
J
may appear on the LCD. A successive AFCI test cannot be
down
initiated until the unit cools down and the message is off the LCD.
NOTE: Some models of AFCI devices may not trip if the cable run
from test location to breaker is longer than 100 ft. (30.48 m).
NOTE: If the test is successful, the AFCI test fails to trip, the RT390
will perform a Load Test in the background to determine if high line
impedance may be the reason for the failed trip. An error message
will appear on the LCD.
Power On the tester and plug into the outlet to be tested, noting the
wiring conditions. The wiring condition
WIRING", the
Circuit Energized Indicator
"ENERGIZED" Indicator
B
should be displayed.
E
should indicate "CORRECT
3
should be illuminated, and the
If the tester indicates that the outlet is not wired correctly, DO NOT
attempt to initiate an electrical testing event. Consult a quali ed
electrician.
Press the Load Test button7, and the 12A, 15A, and 20A test load
voltage and percentage voltage drop will appear on the screen.
NOTE:
If
the voltage drop is greater than 5%, the background color will change
to red to indicate a large voltage drop.
NOTE: The Load Test button7 will be deactivated if the tester
detects that the electrical outlet is not wired correctly.
NOTE: During a Load test, a message may display that the tester
needs to cool down
J
. A successive Load test cannot be initiated
until the unit cools down and the message is no longer displayed.
BATTERY REPLACEMENT
When the Battery Life IndicatorC turns red, the batteries must be
replaced.
1. Loosen screw from battery cover8.
2. Replace 3 x AAA batteries (note proper polarity).
3. Replace battery door and fasten securely with screw.
T
o avoid risk of electric shock, unplug from any voltage source
before removing battery door.
To avoid risk of electric shock, do not operate tester while
battery door is removed.
CLEANING
Be sure tester is turned off and wipe with a clean, dry lint-free
Do not use abrasive cleaners or solvents.
cloth.
STORAGE
Remove the batteries when tester is not in use for a prolonged period
of time. Do not expose to high temperatures or humidity. After a period
of storage in extreme conditions exceeding the limits mentioned in
the General Specifications section, allow the tester to return to normal
operating conditions before using.
WARRANTY
DISPOSAL / RECYCLE
Do not place equipment and its accessories in the trash. Items must
be properly disposed of in accordance with local regulations. Please
see www.epa.gov/recycle for additional information.