Fluke T+, T+PRO Service Guide
The NEW Fluke
T+ and T+PRO
Electrical Testers
The first electrical tester had a simple solenoid that
pulled an indicator attached to a spring across a special voltage scale. The higher the voltage applied to
the solenoid, the further the indicator would be pulled
against the spring.
High accuracy is not a big concern when installing
lighting, switches, and other common electrical wiring
and equipment. Often, you just need to differentiate
common voltages from one another.
The problem is, these classic testers are no longer
safe to use by NFPA electrical measurement standards. Many companies have outright barred them
from the field and floor.
Since the basic measurement need was still there,
Fluke developed two new testers that did what electricians needed them to do. The new T+ and T+PRO
ac/dc electrical testers are rated to CAT IV 600 V
and CAT III 1000 V and use light, sound, and vibration
to indicate voltage. They also test for continuity and
GFCI and are low impedance. Additionally, the T+PRO
model has a LCD digital readout screen, a rotary
phase indicator, and resistance.
Application Note
Basic voltage
applications
Before starting any test, touch
the two leads of the T+PRO or
T+ together. All of the LEDs
should light up. That means the
tester is working and has battery
power.
These testers have nine LEDs,
each of which indicates a specific voltage, that illuminate
when the test leads contact
voltage. At the same time, the
testers beep and vibrate strongly
enough that you can feel it when
voltage is detected. For ac voltage, the ac LED lights up and the
beeper makes a chirping sound.
For dc voltage, the dc positive
or negative LED lights up and
the beeper makes a steady tone.
F r o m t h e F l u k e D i g i t a l L i b r a r y @ w w w . f l u k e . c o m / l i b r a r y
And, on the T+PRO, a digital
readout of either measurement
will appear on the LCD. If the
batteries fail, the LEDs will still
light up, so that the user always
has voltage detection capability.
Both testers measure ac and dc
voltage from 12 to 600 volts (the
T+PRO measures down to 10.2 V
on the LCD). For the residential
electrician, the T+ model covers
all of the basic electrical measurements, from voltage entering
the house at the power panel,
to the output of the transformer
powering the doorbell.
One typical use is checking
a 240 V ac outlet for a dryer or
range for correct wiring. Place
the tester’s probes between the
two hot sockets of the outlet. The
tester will automatically come
on, illuminate the LEDs to indicate 240 V ac, beep, vibrate, and
illuminate the hazardous voltage
LED. Next, check for 120 V ac
between each hot and neutral
socket of the outlet.
For industrial techs, check voltage balance between phases—is
it within 2 %—and for voltage
drop across motor contactors
or relays, where voltage drop
should be negligible. Also check
control circuit voltage. To eliminate measurement errors from
ghost or stray voltages, these
testers’ low input impedance
loads the circuit and absorbs any
ghost voltage energy. That gives
you a reliable indication that the
circuit you are testing is truly
dead.
Continuity
One common continuity application is checking switches or
breakers for continuity when they
are closed. With power removed
from the switch, place the tester
probes on the two switch contacts. If the switch is working
properly, the tester will illuminate
the continuity LED and sound
the beeper continuously when
the switch is closed. No need to
power the tester on or select a
function. As long as there is no
voltage present, the tester automatically comes on and selects
the continuity function.
GFCI testing
Both the T+ and the T+PRO
have a GFCI test function. After
installing a GFI protected circuit,
say a kitchen outlet branch circuit for example, apply power to
the circuit by closing the breaker
at the power panel. Go to one
of the kitchen outlets and place
the tester’s black lead into the
ground (not neutral) socket and
the red lead into the hot (small
slot) socket. If the branch circuit
is wired properly, the tester will
immediately illuminate the LEDs
to indicate normal voltage. Next,
press the tester’s GFCI button
and leave tester connected for
seven seconds. While testing, the
dc (+) and dc (-) LEDs will blink
to indicate the GFCI test is active.
If the GFI circuit is operating normally, the GFCI should trip and
remove power from the circuit.
With no power, the tester’s LEDs
should extinguish. Reset the GFCI
circuit and repeat the test from
the next outlet.
Nice-to-haves
When working in dimly-lit locations, use the LED flashlight built
in to the tester to illuminate the
connections and guide your measurement. The light stays on for
five seconds or as long as the
flashlight button is pressed. With
one probe locked into the builtin probe holder, the tester’s light
will illuminate the area where
the probe is pointing.
The Fluke T+ and T+PRO come
with special, extra-heavy-duty
test leads that hold up longer against the wear and tear
of normal use than standard
leads. Both test leads also have
removable probe tips for easy
tip replacement and to allow
alternate probe tip styles. The
test leads themselves can also
be replaced without having to
replace the entire tester.
Additional features of the
T+PRO
The T+PRO Electrical Tester has
additional features tailored to the
electrician working in commercial and industrial installations.
These features include a digital
display with a resolution up to
0.1 volts for readings between
10 V and 50 V, a resistance
function, and a Rotary Field
Direction function.
When measuring ac voltage
between phases of a threephase circuit, the T+PRO tester
indicates the phase relationship between the two test
leads as well as the voltage.
A typical application is connecting a three-phase motor
and testing for proper rotation
direction. Connect the tester’s
leads between two of the phase
conductors. The tester’s display
will indicate a clockwise rotation ( ) when the red test
lead voltage is 120° ahead of the
black lead. You’ll see a counterclockwise indicator ( ) when
the phase between the leads is
reversed. Next, move the red test
lead to the third phase conductor
to see its phase relationship to
the other two conductors. Now
you can connect the conductors to
the motor for the desired rotation.
Press the ohms Ω button to
switch the tester to resistance
mode. Now, you can check resistors in motors, fuses, switches,
relays, or other general resistance applications on dead circuits, up to 9.99 kΩ.
Last but not least, because the
T+PRO can measure down to
10 V with three digits of accuracy, it’s a far more accurate tool
for low-voltage lighting applications. Most standard electrical
testers (solenoid and solid-state)
only measure down to 12 V and
may not be able to see that a
step-down lighting transformer
is only putting out 10.8 volts.
(That’s a 10 % variance from
what the voltage should be.)
Depending upon the set up, the
bulbs may not function properly
(or at all). The farther down the
line you go from the transformer,
the greater the possible voltage
drop—but a standard voltage tester may still read 12 V, leading
you to believe that everything is
fine.
For more information on industrial and HVAC applications, read
the Fluke application note “HVAC
applications for the Fluke T+ and
T+PRO Electrical Testers.”
2 Fluke Corporation The NEW Fluke T+ and T+PRO Electrical Testers
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