Extech CT80 Operating Manual
User Guide
AC Circuit Load Tester
For use on EPD, GFCI, and AFCI Circuits
Model CT80
Introduction
Thank you for selecting the Extech CT80 AC Circuit Load Tester.
This device detects circuit and wiring problems such as: Poor ground impedance, false grounds,
missing ground fault protection, low voltage availability under load, and high ground-to-neutral
voltage. The CT80 can be used reliably on GFCI, EPD, and AFCI circuits.
Circuit and wiring issues listed above can introduce shock hazards (from grounding issues) and can
comprise performance of machinery and equipment (from poor ground impedance, lack of sufficient
voltage under load and/or high ground-to-neutral voltage). In addition, fire can result from the heat
generated by high resistance points in a circuit.
Proper wiring habits have been shown to greatly increase power quality performance.
This device is shipped fully tested and calibrated and, with proper use, will provide years of reliable
service.
Features
True RMS AC measurements
Voltage drop measurements on 12A, 15A, and 20A loads for 120V circuits
Voltage drop measurements on 5A, 8A, and 10A loads for 230V circuits
Voltage measurements: Line, ground-to-neutral, and peak
Measures frequency of the voltage
Measures Hot, Neutral, and Ground conductor impedances
Performs shared Neutral test
Checks 3-wire receptacle configuration
Finds false grounds
Tests GFCI, EPD, and AFCI circuits for proper operation
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Safety
Safety Symbols
This symbol, adjacent to another symbol or terminal, indicates the user must refer
to the manual for further information.
This symbol, adjacent to a terminal, indicates that, under normal use, hazardous
voltages may be present.
Double insulation
WARNING
CAUTION
Safety Information
The CT80 conforms to CE and UL-1436 GFCI and AFCI testing.
Exceeding the specified measurement limits of this device may compromise the device’s
safety protection characteristics.
Always test the CT80 on a known line voltage source to confirm proper operation before and
after performing tests on other circuits.
Do not use the CT80 if it appears damaged or if the operation of the unit is inconsistent with
the supplied user guide instructions.
Voltages above 60VDC, 42.4Vpk, and 30VAC are considered shock hazards; always observe
best practice safety guidelines and precautions when working with such voltages.
Earth Ground
This WARNING symbol indicates a potentially hazardous situation, which if not
avoided, could result in death or serious injury.
This CAUTION symbol indicates a potentially hazardous situation, which if not
avoided, may result damage to the product.
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Description
Meter Description
1. AC power cable connection
2. Test menu
3. Hot-Neutral-Ground coded measurement result
4. Primary reading display
5. Secondary reading display
6. LED test status indicators
7. GFCI test button
8. Down arrow button
9. Right arrow button
10. AFCI test button
(Note: AC Power Cord not pictured)
Display Description
A Amps or Amperes (Current)
V Voltage
Vd Voltage Drop
% Percent Voltage Drop
VL Voltage load
Z Impedance
Hz Hertz (cycles per second)
Ohms (Resistance)
G Ground
N or NEUT Neutral
H Hot
mS Milliseconds
kA, mA kilo-amps and milli-amps
ASCC Available Short Circuit Current
Peak Ground to positive peak measurement
RMS Root Mean Square
GFCI Ground Fault Circuit Interrupter
AFCI Arc Fault Circuit Interrupter
EPD Equipment Protection Device test
OL Overload
m, M, k Unit of measure prefixes: milli, mega, and kilo
‘>’ ‘
Over-temperature alarm (meter operation pauses until cool-down)
AFCI test in progress
Greater than’ symbol
1
2
4
6
89
3
5
7
10
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Operation Overview
The CT80 AC Circuit Load Tester can test outlets or circuits under load in a matter of seconds for
proper wiring, reverse polarity, and the presence of a ground. The CT80 uses a simple menu-driven
display to allow the user to quickly see line voltage, voltage drop under full load, ground-to-neutral
voltage, and line impedance. The GFCI and AFCI testing utility is performed separately per UL1436, disrupting the flow of electricity if a functioning GFCI or AFCI is present.
Notes:
To avoid the buildup of heat during load testing, allow at least 20 seconds to elapse between
tests. In addition to the safety benefits, this will allow the meter to maintain its stated
accuracy during repeated tests. The meter will switch off automatically if an overtemperature condition exists; the meter will automatically switch on when the temperature
cools to an acceptable operational range.
The CT80 is a microprocessor controlled device that prioritizes its tasks; taking a reading
and analyzing the results are its top priorities. This is the reason that the keypad may not
respond immediately to a key-press. The internal computer places a higher priority on
completing a test than on recognizing a keystroke. To minimize this effect, press and hold a
key until the display menu changes.
Warning: To avoid damage to the instrument, do not use this device on the output of a UPS
system, a light dimmer, or a square wave generator.
Interpreting Measurement Results
Measurement Modes
Measurement Results Coding
Warning: Use only the supplied power/test cord with this equipment
There are the four (4) measurement modes available. These are:
1. Voltage (V)
2. Voltage drop (Vd)
3. ASCC (Available short circuit current)
4. Impedance (Z)
These measurement modes are shown on the upper left side of the display. Use the ▼ button to
scroll through the mode list. Measurement results are shown on the main Wiring Configuration icon
located on the upper right of meter display in conjunction with the two LED status indicators located
above the down arrow button. Interpreting the measurement results is covered in the following
sections.
The three circles on the wiring configuration icon in conjunction with the two rectangular LED status
indicators are coded to indicate the test result such as for correct wiring, reverse polarity wiring, and
‘no ground’ condition. The wiring configuration icon and the LEDs change appearance (clear, solid,
flashing) to indicate the measurement results. The test results coding and a legend for interpreting
the codes are provided below.
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