Fluke 374 User manual

PN 3608883
July 2010 Rev. 1, 3/23
© 2010-2013 Fluke Corporation. All rights reserved. Specifications are subject to change without notice.
All product names are trademarks of their respective companies.
374/375
376/376-II
Clamp Meter

LIMITED WARRANTY AND LIMITATION OF LIABILITY
The Fluke 374/375/376 products will be free from defects in material and workmanship
for 3 years from the date of purchase. The Fluke 376-II product will be free from
defects in material and workmanship for 5 years from the date of purchase. This
warranty does not cover fuses, disposable batteries, or damage from accident,
neglect, misuse, alteration, contamination, or abnormal conditions of operation or
handling. Resellers are not authorized to extend any other warranty on Fluke’s behalf.
To obtain service during the warranty period, 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 problem.
THIS WARRANTY IS YOUR ONLY REMEDY. NO OTHER WARRANTIES, SUCH AS
FITNESS FOR A PARTICULAR PURPOSE, ARE EXPRESSED OR IMPLIED. FLUKE
IS NOT LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR
CONSEQUENTIAL DAMAGES OR LOSSES, ARISING FROM ANY CAUSE OR
THEORY. Since some states or countries do not allow the exclusion or limitation of an
implied warranty or of incidental or consequential damages, this limitation of liability
may not apply to you.
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
11/99

i
Table of Contents
Title Page
Introduction ............................................................................................................. 1
Contact Fluke .......................................................................................................... 2
Safety Information ................................................................................................... 2
The Meter................................................................................................................ 8
Specifications .......................................................................................................... 18
General Specifications......................................................................................... 18
Accuracy Specifications....................................................................................... 20

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1
Introduction
Warning
Read "Safety Information" before you use the Meter.
The Fluke 374/375/376/376-II (the Meter) measure true-rms ac current and voltage, dc current
and voltage, inrush current, resistance, and capacitance. The 375/376/376-II also measure
frequency and dc millivolts. The detachable iFlex (Flexible Current Probe) that is included with the
376/376-II (optional with the 374/375) expands the measurement range to 2500 A ac. The
Flexible Current Probe provides increased display flexibility and allows measurements of
awkward sized conductors and improved wire access. The illustrations in this manual show the
376.

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2
Contact Fluke
Fluke Corporation operates worldwide. For local contact information, go to our website:
www.fluke.com
To register your product, or to view, print, or download the latest manual or manual supplement,
go to our website: www.fluke.com/productinfo.
[phone] fluke-[email protected]
Safety Information
A Warning identifies conditions and actions that pose hazard(s) to the user. A Caution identifies
conditions and procedures that could cause Meter damage, equipment under test damage, or
permanent loss of data.
Symbols used on the Meter and in this manual are explained in Table 1.

Clamp Meters
Safety Information
3
Warning
To prevent possible electrical shock or personal injury, follow these guidelines:
•Use the Meter only asspecified in this manual or the protection provided by the
Meter can becompromised.
•Examine the case before you use the Meter. Look for cracks or missing plastic.
Carefully look at the insulation around the connectors.
•Never measure current while the test leads are inserted into the input jacks.
•Make sure the battery door is closed and latched before operating the Meter.
•Remove the test leads from the Meter before the battery door is opened.
•Examine the test leads for damaged insulation orexposed metal. Check test lead
continuity. Replace damaged test leads before usingthe Meter.
•Do not use the Meter if itoperates incorrectly. Protection can be compromised.
When indoubt, have the Meter serviced.
•Do not use the Meter around explosive gas, vapor orindamp or wet
environments.
•Use only type AA batteries, properly installed in the Meter case,topower the
Meter.
•When measuring current with the Jaw, keep fingers behind the Tactile Barrier.
See "The Meter"  .
•Measure a known voltage to verify product operation.

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•Do not use in CAT III or CAT IV environments without the protective cap of test probe.
The protective cap decreases the expose probe metal <4 mm. This decreases the
possibility of arc flash from short circuits.
•To avoid false readings that can lead to electrical shock and injury, replace the
batteries as soon as the low battery indicator () appears.
•When batteries are changed, ensure that the calibration seal in the battery
compartment is not damaged. If damaged, the Meter may not be safe to use. Return
the Meter to Fluke for replacement of the seal.
•When servicing the Meter, use only specified replacement parts.
•Have the Meter serviced only by qualified service personnel.
•Be careful around voltages >30 V ac rms, 42 V ac peak, or 60 V dc. Such voltages
pose a shock hazard.
•Do not apply more than the rated voltage, as marked on the Meter, between the
terminals or between any terminal and earth ground.
•When using the probes, keep fingers behind the finger guards on the probes.
•Connect the common test lead before connecting the live test lead. When
disconnecting test leads, disconnect the live test lead first.
•Do not work alone so assistance can be rendered in an emergency.
•Use extreme caution when working around bare conductors or bus bars. Contact
with the conductor could result in electric shock.

Clamp Meters
Safety Information
5
•Adhere to local and national safety codes. Individual protective equipment must
be used to prevent shock and arc blast injury where hazardous live conductors
are exposed.
•Disconnect circuit power and discharge all high-voltage capacitors before you
measure resistance, continuity, or capacitance.
•For the 374 and 375, do not measure ac/dc current in circuits carrying more than
1000 V or 600 A with the Meter Jaw.
•For the 376/376-II, do not measure ac/dc current in circuits carrying more than
1000 V or 1000 A with the Meter Jaw.
•Never operate the Meter with the back cover removed or the case open.
•Do not measure ac current in circuits carrying more than 1000 V or 2500 A with
the Flexible Current Probe.
•Do not apply the Flexible Current Probe around or remove from HAZARDOUS
LIVE conductors.
•Do not use the flexible current sensor if the inner contrasting insulation color is
showing.
•Take special care during fitting and removal of the Flexible Current Probe. De-
energize the installation under test or wear suitable protective clothing.

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Caution
To avoid possible damage to the Meter or to equipment under test:
•Use the proper jacks, function, and range for the measurement application.
•Clean the case and accessories with a damp cloth and mild detergent only.
Do not use abrasives or solvents.
Table 1. Symbols
Symbol Definition Symbol Definition

Consult user documentation.  WARNING. RISK OF DANGER.
WARNING. HAZARDOUS
VOLTAGE. Risk of electric shock.

Conforms to European Union
directives.

DC (Direct Current)

AC (Alternating Current)

Earth

Double Insulated

Application around and removal
from uninsulated hazardous live
conductors is permitted.

Battery. Low battery when shown on
display.

Clamp Meters
Safety Information
7
Symbol Definition
Do not apply around or remove from uninsulated hazardous live conductors without
taking additional protective measures.
Measurement Category II is applicable to test and measuring circuits connected
directly to utilization points (socket outlets and similar points) of the low-voltage
MAINS installation.
Measurement Category III is applicable to test and measuring circuits connected to
the distribution part of the building’s low-voltage MAINS installation.
Measurement Category IV is applicable to test and measuring circuits connected at
the source of the building’s low-voltage MAINS installation.

This product complies with the WEEE Directive and its marking requirements. The
affixed label indicates that you must not discard this electrical/electronic product in
domestic household waste. Do not dispose of this product as unsorted municipal
waste. For information about take-back and recycling programs available in your
country, see the Fluke website.
Note
The Measurement Category (CAT) and voltage rating of any combination of test probe,
test probe accessory, current clamp accessory, and the Meter is the LOWEST rating of
any individual component.

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The Meter
Clamp Meter
fig01.eps

Clamp Meters
The Meter
9
20
ON
ON
Auto Power Off Backlight
fig02_3.eps

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Display Hold MIN MAX AVG
1x
=
2x
=
3x
=
2 sec = Exit
fig04_5.eps

Clamp Meters
The Meter
11
Flexible Current Probe
<0.5 A >0.5 A
fig06.eps

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Users Manual
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7Jaw Hz
(375/376/376-II)
<0.5 A >0.5 A
Fig07.eps

Clamp Meters
The Meter
13
7
<0.5 A
Fig08.eps

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dc (375/376/376-II)
fig09_10.eps

Clamp Meters
The Meter
15
ON
<30
Fig15.eps

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On
100 ms
Off
1
4
2
3
fig13_14.eps