FLUKE 377 FC Clamp Meter User Manual

FLUKE 377 FC Clamp Meter

LIMITED WARRANTY AND LIMITATION OF LIABILITY

Each Fluke product is warranted to be free from defects in material and workmanship under normal use and service. The warranty period is three years and begins on the date of shipment. Parts, product repairs, and services are warranted for 90 days. This warranty extends only to the original buyer or end-user customer of a Fluke authorized reseller and does not apply to fuses, disposable batteries, or to any product which, in Fluke’s opinion, has been misused, altered, neglected, contaminated, or damaged by an accident or abnormal conditions of operation or handling. Fluke warrants that software will operate substantially in accordance with its functional specifications for 90 days and that it has been properly recorded on non-defective media. Fluke does not warrant that software will be error-free or operate without interruption.
Fluke authorized resellers shall extend this warranty on new and unused products to end-user customers only but have no authority to extend a greater or different warranty on behalf of Fluke. Warranty support is available only if the product is purchased through a Fluke authorized sales outlet or the Buyer has paid the applicable international price. Fluke reserves the right to invoice the Buyer for importation costs of repair/replacement parts when a product purchased in one country is submitted for repair in another country.
Fluke’s warranty obligation is limited, at Fluke’s option, to refund of the purchase price, free of charge repair, or replacement of a defective product which is returned to a Fluke authorized service center within the warranty period.
To obtain warranty service, contact your nearest Fluke authorized service center to obtain return authorization information, then send the product to that service center, with a description of the difficulty, postage and insurance prepaid (FOB Destination). Fluke assumes no risk for damage in transit. Following warranty repair, the product will be returned to Buyer, transportation prepaid (FOB Destination). If Fluke determines that failure was caused by neglect, misuse, contamination, alteration, accident, or abnormal condition of operation or handling, including overvoltage failures caused by use outside the product’s specified rating, or normal wear and tear of mechanical components, Fluke will provide an estimate of repair costs and obtain authorization before commencing the work. Following repair, the product will be returned to the Buyer transportation prepaid and the Buyer will be billed for the repair and return transportation charges (FOB Shipping Point).
THIS WARRANTY IS THE BUYER’S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. FLUKE SHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES OR LOSSES, INCLUDING LOSS OF DATA, ARISING FROM ANY CAUSE OR THEORY.
Since some countries or states do not allow limitation of the term of an implied warranty, or exclusion or limitation of incidental or consequential damages, the limitations and exclusions of this warranty may not apply to every buyer. If any provision of this Warranty is held invalid or unenforceable by a court or other decision-maker of competent jurisdiction, such holding will not affect the validity or enforceability of any other provision.

Fluke Corporation
P.O. Box 9090 Everett, WA 98206-9090 U.S.A.

Fluke Europe B. V. P.O. Box 1186 5602 BD Eindhoven The Netherlands

Introduction

The Fluke 377, 377 FC, 378, and 378 FC Current Clamp (the Clamp or Product) provides:

• display with two simultaneous measurements (current and voltage)
• grounding with a single lead
• live measurements with no circuit downtime
• non-contact voltage measurement with Power Quality Indicator
• wireless connectivity to smartphone for work-orders and reporting integration with Fluke Connect™ app

The Clamp measures true-rms ac current and voltage, dc current and voltage, inrush current, resistance, capacitance, frequency, and dc millivolts.
The included iFlex (detachable, flexible current-probe) expands the measurement range to 2500 A ac. The iFlex allows measurements of awkward-sized conductors and improved wire access.
The illustrations in this manual show the 378 FC.
Table 1 is a list of features available for each model.

Table 1. Features by Model

Contact Fluke

Fluke Corporation operates worldwide. For local contact information, go to our website: www.fluke.com.
To register your product, view, print, or download the latest manual or manual supplement, go to our website.

Fluke Corporation
P.O. Box 9090
Everett, WA 98206-9090
+1-425-446-5500
[email protected]

Safety Information

General safety information is in the printed Safety Information document that ships with the Product and at www.fluke.com. More specific safety information is listed where applicable.

Specifications

Complete specifications are at www.fluke.com. See the 377/377 FC / 378/378 FC Product Specifications.

Before You Start
Table 2 is a list of items included with the Product. Use Table 3 to order additional accessories.

Table 2. Standard Equipment

Table 3. Accessories

Terms to Know
Use this section to familiarize yourself with these terms that are unique to this Product.
FieldSense™ Technology/Non-contact voltage (NCV) Measurement. Voltage measurements by capacitive sensing technology that completes galvanic isolation. This technology uses capacitive sensors for measuring AC voltages through non-galvanic contact, coupled with a Hall Effect jaw that allows simultaneous current measurements. It enables minimizing voltage probes connections, therefore reducing hazardous situations and saving setup-up time, and circuit or machine downtime. Fluke-developed icon for FieldSense technology is U.
L1-L2-L3. L1, L2, and L3 (or Line 1, Line 2, and Line 3) is a common naming convention for the wires in three-phase alternating current (ac) systems. The Clamp features a sequential line-to-ground measurement that results in a calculated line-to-line voltage measurement. This voltage measurement is an indication that the three-phase system is, or is not, working as expected.
Power Factor. Power factor (PF) is the ratio of working power, measured in kilowatts (kW), to apparent power, measured in kilovolt amperes (kVA). PF expresses the ratio of true power used in a circuit to the apparent power delivered to the circuit.
Fluke Connect™App. Fluke Connect is a system that wirelessly connects your Clamp with an app on your smartphone or tablet.
THD. The total harmonic distortion is a measurement of the harmonic distortion present in a signal and is defined as the ratio of the sum of the powers of all harmonic components to the power of the fundamental frequency.

Fluke Connect™ (377 FC/378 FC)
Fluke Connect™ software (may not be available in all regions) supports the Clamp to wirelessly connect to a mobile app. The app shows the measurements and other data on your smartphone or tablet display. You can share this data with your team and save collected measurements and calculations to the Fluke Connect Cloud.
Fluke Connect uses low-power 802.15.4 wireless radio technology to connect the Clamp with an app on your smartphone or tablet. The wireless radio does not cause interference with Clamp measurements.

Radio Frequency Data
Note
Changes or modifications to the wireless 2.4 GHz radio not expressly approved by Fluke Corporation could void the user’s authority to operate the equipment.

For complete information about radiofrequency data, go to www.fluke.com/manuals and search for “Radio Frequency Data Class A”.
SIMPLIFIED EU DECLARATION OF CONFORMITY
Hereby, Fluke declares that the radio equipment contained in this Product is in compliance with Directive 2014/53/EU. The full text of the EU declaration is available at the following internet address: www.fluke.com/declaration-of- conformity

Fluke Connect™ Mobile App
The Fluke Connect™ app works with Apple and Android mobile products. The app is available for download to your smart device from the Apple App Store and Google Play.
To use the Fluke Connect app:

1. Open the Fluke Connect app on your device.
2. Turn on the Clamp.
3. Push F to activate the radio on the Clamp. E shows on the display.
4. On your smartphone, go to Settings > Bluetooth.
5. Verify that Bluetooth is turned on.
6. Go to the Fluke Connect App and in the list of connected Fluke tools, select 377 FC/378 FC.
   You can now take, save, and share measurements with the app. Go to www.flukeconnect.com for more information about how to use the app.

Battery

Warning
To prevent personal injury and for safe operation of the Product:

• The battery door must be closed and locked before you operate the Product.

• Remove all probes, test leads, and accessories before the battery door is opened.

• Replace the batteries when the low battery indicator shows to prevent incorrect measurements.

• When batteries are changed, ensure that the calibration seal in the battery compartment is not damaged. If damaged, the Product may not be safe to use. Return the Product to Fluke for replacement of the seal.
  Caution
  To prevent damage to the battery:

• Repair the Product before use if the battery leaks.

• Do not expose battery to heat sources or high-temperature environments such as an unattended vehicle in the sun.

• Always operate in the specified temperature range.

• Do not incinerate the Product and/or battery.

The Product ships with the batteries installed. To replace batteries, see Figure 1.

Figure 1. Batteries

Features/Controls

Table 4 is a list of features and controls.

Table 4. Feature/Control Descriptions

Display

Table 5 is a list of the display annunciators.

Table 5. Display

Power
Two AA batteries supply power to the Clamp:

• To turn on the Clamp, rotate the control knob to a function.
• To turn off the Clamp, rotate the control knob to OFF.

Auto Power Off
The Clamp automatically powers off after 20 minutes of no use. If the Clamp automatically powers off, turn the control knob to OFF and then to a function to resume operation.
To disable auto power-off, see Power-On Options.
Note
Auto power off is always disabled when you use the Min/Max/Avg function.

Backlight
The display on the Clamp includes a backlight that improves the readability in dim work areas.
FC models:

• Hold B for >2 seconds to turn on the backlight.
• Hold B for >2 seconds to turn off the backlight.

Non-FC models:

• Push to toggle on/toggle off the backlight.
  The backlight has an auto-off feature that turns off the backlight after 2 minutes of no use. To disable the auto-off backlight feature, see Power-On Options.

Power-On Options
Power-on options allow you to customize the controls:

• Turn off/turn on audible beeper
• Turn off/turn on auto backlight
• Turn on/turn off auto power shutoff
• Clear Logging Memory
• Set PQ Sensitivity Level

To select a power-on option:

1. Turn off the Clamp.

2. Push and hold e as you turn the control knob to V.
   The Clamp goes into the option mode.
   Note
   Anytime you release the Clamp exits the option mode but retains any changes to the settings.

3. Push B to go through the options.

4. Push M to change a setting.
   Option| Display
   ---|---
   Beeper Enabled| bEEP On
   Beeper Disabled| bEEP OFF
   Auto Backlight On

(Backlight turns off after 2 minutes of no use)

| 8CLt On
Auto Backlight Off (Backlight stays on)| 8CLt OFF
Auto Power On

(Clamp powers off after 20 minutes of no use)

| AUtO On
Auto Power Off

(Auto Power Off is disabled)

| AUtO OFF
Clear Logging Memory| CLr
PQ Sensitivity| LEU HI

LEU nmEd LEU L0

5. Release e to exit the options mode.
   All power-on options are canceled when you turn off the Clamp with the exception of PQ Sensitivity setting.

Basic Measurements

Warning
To prevent possible electrical shock, fire, or personal injury:

• Hold the Product behind the tactile barrier.
• Do not measure current while the test leads are in the input jacks.

Note
Exposure to severe mechanical shock may cause the readings of the Product to not meet the specifications.
If the published accuracy is required, the Product should be calibrated to verify proper operation after such an event. See Service.
Hazardous Voltage Indicator
When the Clamp senses a voltage ±30 V or a voltage overload (OL), Z shows on the display to tell you a hazardous voltage is at the Clamp input.
FieldSense™ Measurement
FieldSense measurement, or non-contact voltage (NCV) measurement, is ac voltage, current, and frequency measurement with no electrical contact to live voltage. The Clamp display shows the voltage and current measurements at the same time.
Note
All FieldSense measurements require a ground lead connection.
FieldSense AC Current, Voltage, and Frequency

To make the measurement:

1. Insert the ground lead into the COM input and attach the alligator clip to ground.

2. Rotate the control knob to U.
   The display shows the U icon.

3. Use the jaw release to open the jaw and position the Clamp around the conductor. Close the jaw and make sure the wire position is correct. See Figure 2.

Figure 2. Wire Placement

The display shows C to indicate that the measurement is from the jaw. When the current measurement is <0.5 A, the center dot in the icon flashes. For current measurements >0.5 A, the center dot in the icon is steady. The Aac display shows – – – when a measurement is <1 A.
Note
Use B to toggle on/toggle off the Amps Hz function shown in yellow at the control knob position.
FieldSense technology is not intended to measure the output of a variable- frequency drive (VFD) motor controller. Use the V or Kcontrol knob position for this application.

L1-L2-L3
Three-phase alternating current (ac) systems are universally used to distribute electrical power and to supply electricity directly to high-power equipment. Use the Clamp to make sequential line-to-ground measurements that result in calculated line-to-line voltage measurements. These voltage measurements are an indication that the three-phase system is, or is not, working as
expected.
When you use the Fluke Connect mobile app, the Clamp also indicates the phase rotation as 1-2-3 or 3-2-1 in the three-phase system.
To setup:

1. Turn the control knob to U.
2. Connect the Clamp to ground with the ground lead.
3. Push M for >2 seconds. The Clamp is in the line-to-line mode and x-y-z shows on the display.

To test:

1. Position the Clamp jaw around the first conductor.
   Wait for the measurement on the display to settle. You will hear a beep and x shows on the display.

2. Move the Clamp jaw to the second conductor within 10 seconds.
   Wait for the measurement on the display to settle. You will hear a beep and y shows on the display.

3. Move the Clamp jaw to the next conductor within 10 seconds.
   Wait for the measurement on the display to settle. You will hear a beep and z shows on the display.

When the x-y-z measurements are complete, use the Clamp to calculate the total voltage between each pair of conductors:

1. Push M. The displays shows the total voltage between
   L1 and L2.

2. Push M again to show the total voltage between
   L2 and L3.

3. Push M again to show the total voltage between L3 and L1.

While in the line-to-line mode, you can review each line-to-ground measurement:

1. Push M again to show the L1 measurement.
2. Push M again to show the L2 measurement.
3. Push M again to show the L3 measurement.
   To review L1-L2-L3 measurements, continue to push M and scroll through the measurements.
   To exit the line-to-line mode, push M for >2 seconds.

Power Quality Indicator (378/378 FC)
The Power Quality indicator shows that the ratio of the real power compared to the apparent power or harmonic distortion is outside the optimal range.
To setup:

1. Turn the control knob to U.
2. Connect the Clamp to ground with the ground lead.
   If the total harmonic distortion or the power factor is outside the optimal range, the related indicator shows on the display:Fluke Connect software supports the Power Quality indicator.
   The Power Quality indicator sensitivity is adjustable:

Function

| Sensitivity
---|---
High| Medium| Low
PQ-Amps| 10 % THD| 25 % THD| 50 % THD
PQ-Volts| 8 % THD| 10 % THD| 15 % THD
PQ-PF| 0.9| 0.75| 0.6

For information about how to set the sensitivity, see Power-On Options.

AC/DC Voltage Measurement with Test Leads

To measure ac or dc voltage:

1. Turn control knob to V or N.
2. Connect the black test lead to the COM terminal and the red test lead to the VX terminal.
3. Touch the probes to the test points of the circuit.
   The display shows the measurement.
   Note
   Use B to toggle on/toggle off the mV function shown in yellow at the control knob position.

Resistance/Continuity
To measure resistance or continuity:

1. Turn the control knob to D.
2. Remove power from the circuit to test.
3. Connect the black test lead to the COM terminal and the red test lead to the VX terminal.
4. Touch the probes to the test points of the circuit.
   The display shows the measurement.
   If the resistance is <30 Ω, the beeper sounds continuously to indicate continuity. If the display shows OL, the circuit is open.
   To disable the beeper, see Power-On Options.

Capacitance

The Clamp determines capacitance by charging a capacitor with a known current, measuring the resulting voltage, then calculating the capacitance.
Note
A good capacitor stores an electrical charge and may remain energized after power is removed. Before you touch the capacitor or make a measurement, turn all power OFF, use the Clamp to confirm that power is OFF, and carefully discharge the capacitor by connecting a resistor across the leads. Be sure to wear appropriate personal protective equipment.

To test capacitance:

1. Turn the control knob to D.
2. Push B to shift to the t function.
3. Remove the capacitor from the circuit and discharge the capacitor.
4. Connect the black test lead to the COM terminal and the red test lead to the VX terminal.
5. Touch the probes to the capacitor leads.
   The display shows the measurement.
   indicates the capacitor is faulty or the capacitance value is higher then the measurement range. diSc indicates the capacitor does not properly discharge.

DC Current
To measure dc current:

1. Turn control knob to Y.
2. Push B to compensate for outside influences.
   The display shows C to indicate that the measurement is from the jaw. When the current measurement is <0.5 A, the center dot in the icon flashes. For current measurements >0.5 A, the center dot in the icon is steady. iFlex Probe

Warning
To avoid electrical shock, do not apply or remove from live hazardous conductors.
The high-performance AC Flexible Current Probe uses the Rogowski principle for accurate, non-intrusive measurement of sinusoidal, pulsed, and other complex waveforms. The flexible and
lightweight measuring head allows quick and easy installation in hard-to-reach areas and works well with large conductors.

To use the iFlex Probe:

1. Connect the iFlex Probe to the Clamp. See Figure 3.

2. Connect the flexible part of the iFlex Probe around the conductor. If you open the end of the iFlex Probe to make the connection, make sure that you close and latch the coupling.
   See the detail in Figure 3. You should be able to hear and feel the lock snap into place.
   Note
   When you measure current, center the conductor in the iFlex Probe. Avoid measurements close to other current-carrying conductors.

3. Keep the probe coupling >2.5 cm (1 inch) away from the conductor.

4. Turn the control knob to K.
   The display shows J to indicate that the measurements are from the iFlex Probe. When the current measurement is <0.5 A, the center dot in the icon flashes. For current measurements >0.5 A, the center dot is steady.
   The display shows the measurement.

If the iFlex Probe does not work as expected:

• Make sure that the coupling system is connected and closed correctly or look for any damage. If any foreign material is present, the coupling system will not close properly.
• Inspect the cable between the iFlex Probe and the Clamp for any damage.
• Check that the control knob is in the correct position

Figure 3. iFlex Probe Setup

Measurement Features

This section is about the Clamp features you can use for measurements.

Warning
To prevent possible electrical shock, fire, or personal injury:

• Do not use the HOLD function to measure unknown potentials. When HOLD is turned on, the display does not change when a different potential is measured.
• Disconnect power and discharge all high-voltage capacitors before you measure resistance, continuity, capacitance, or a diode junction.

Display Hold
To capture and hold the display reading, push e. The display freezes and blinks. The Clamp periodically beeps to remind you that the measurement is not live. When in HOLD mode, if the
Clamp senses a voltage ±30 V or a voltage overload (OL), Z shows on the display to tell you a hazardous voltage is at the Clamp input.
When in HOLD mode, push e again to resume normal operation with live readings.

MIN/MAX/AVG Measurements
Min Max Avg mode captures the minimum, maximum, and average readings of a given output signal over an extended time.
The Clamp beeps when it senses a new high value or new low value.
This function works in current, voltage, and frequency modes:

1. Push M to enter the Min/Max/Avg mode.
   The maximum reading shows on the display.

2. Continue to push M to select between the maximum, minimum, average, and live readings.
   The cycle continues each time you push M.

3. To exit Min/Max/Avg mode, push and hold M for >2 s.
   Note
   Auto Power Off is always disabled when you use the Min Max Avg function.
   Inrush Current
   Inrush Current is surge current that occurs when an electrical device is first powered on. The Clamp can capture this surge current reading. Current spikes from motor drives are one example of such an event. The Inrush function takes samples over a 100 ms period and calculates the starting current envelope.

To measure inrush current:

1. Select the measurement function (ac current, dc current, or iFlex ac current).
2. Center the Jaw or iFlex Probe around the live wire on the device.
3. Push I.
   Dashes show on the display until the Clamp detects the inrush current. When the inrush current is detected, the measurement shows on the display.

Data Logging (377 FC/378 FC)
The Fluke Connect™ app enables you to log the data measurements. This app shows measurements from the connected Clamp on your smartphone or tablet display. The app also saves the measurements to the Fluke Connect Cloud™ storage and shares the information with your team.
Note
The logging interval is set in the Fluke Connect app.
Logging is not available for the inrush and line-to-line measurement modes.

To log measurements:

1. On the Clamp, push I for >2 s.
   The memory icon indicates how much memory is available.

2. On the Clamp, push I for >2 s to stop logging.

Clear Memory (377 FC/378 FC)
See Power-On Options.

Firmware Update (377 FC/378 FC)
Firmware updates are available for Clamps that have the
Fluke Connect™ feature. The Fluke Connect mobile app shows a notification if a firmware update is available when the unit is connected to the app.

To update:

1. Make sure the Product has at least 50 % battery power available.
2. Make sure you download all the logged data before you update the firmware.
3. In the app, tap Update to start the firmware update to the Product.

Firmware Version
The firmware version for the Clamp is found in the Maintenance Mode.
To enter Maintenance Mode:

1. Turn off the Clamp.

2. Push and hold e as you turn the control knob to V.
   The Clamp goes into the option mode.

3. Push B until nmAt nm0d shows on the display.

4. Push M.
   All LCD segments turn on.

5. Releasee.
   All LCD segments continue to show on the display.

6. Press e again to show the firmware version.

Maintenance

The Product does not require routine maintenance.

Warning
To prevent possible electrical shock, fire, or personal injury:

• Remove the input signals before you clean the Product.
• Repair the Product before use if the battery leaks. Battery leakage may create a shock hazard or damage the Product.
• Use only specified replacement parts.
• Have an approved technician repair the Product.
• Remove the batteries if the Product is not used for an extended period of time, or if stored in temperatures above 50 °C. If the batteries are not removed, battery leakage may result.
  How to Clean the Case Wipe the case with a damp cloth and mild detergent.

Caution
Do not use abrasives, isopropyl alcohol, or solvents to clean the case or lens/window.

Environmental
This Product has electronic printed circuit boards. These components must be disposed of specifically when the Product is at the end of its use.
The manufacturer offers to take back the Product from the customer to ensure that the Product is disposed of in an environmentally-friendly manner when it is at the end of its use.
See Contact Fluke for more information.

Service
An authorized Fluke Calibration service center should service the
Product at two-year intervals to maintain optimum performance.
Contact your equipment distributor or authorized Fluke Calibration Service Center for any equipment performance failure or to schedule regular maintenance service. See Contact Fluke for more information.
Table 6 is a list of replacement parts.

Table 6. Replacement Parts

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