Application Note

3 Fluke Corporation Leakage current measurement basics
along with the phase conduc-
tors. The measured value will
be any current flowing to
ground. (See Figure 2)
Measuring leakage
current through the
ground conductor
To measure the total leakage
flowing to the intended ground
connection, place the clamp
around the ground conductor.
(See Figure 3)
Measuring leakage
current to ground
via unintentional paths
to ground
Clamping phase/neutral/ground
together identifies imbalance
current that represents leak-
age at an outlet or electrical
panel via unintentional paths
to ground (such as the panel
sitting on a concrete base). If
other electrical bonding con-
nections exist (such as a con-
nection to a water pipe), a
similar imbalance may result.
(See Figure 4)
Tracing the source of
leakage current
This series of measurements
identifies the overall leakage
and the source. The first mea-
surement can be made on the
main conductor to the panel.
Measurements 2, 3, 4, and 5
are made subsequently to iden-
tify circuits carrying the larger
amounts of leakage current.
(See Figure 5)
Summary
Leakage current can be an
indicator of the effectiveness
of insulation on conductors.
High levels of leakage cur-
rent may be present in circuits
where electronic equipment
with filters is used, and can
cause voltages that disrupt nor-
mal operation of equipment. It
is possible to locate the source
of leakage current by using a
low current leakage current
clamp to take methodical mea-
surements as described above.
If necessary, this enables you
to re-distribute loads around
the installation in a more
balanced way.
Load Exposed
Conductive
Parts
mA A
mA
D-H
Figure 3
Load
Leakage current via
unintentional paths
to ground
Phase
Neutral
Ground
Conductor
mA
A
mA
D-H
Figure 4
I
E
I
E
I
E
I
E
Phase
Neutral
Electrical
Panel
Leakage Current I
E
1
2
3
5
4
Figure 5
Fluke Corporation
PO Box 9090, Everett, WA USA 98206
Fluke Europe B.V.
PO Box 1186, 5602 BD
Eindhoven, The Netherlands
For more information call:
In the U.S.A. [phone] or
Fax [phone]
In Europe/M-East/Africa [phone] or
Fax [phone]
In Canada (800)-36-FLUKE or
Fax [phone]
From other countries [phone] or
Fax [phone]
Web access: http://www.fluke.com
©2006 Fluke Corporation. All rights reserved.
Specifications subject to change without notice.
Printed in U.S.A. 11/2006 2788368 A-EN-N Rev A
Fluke. Keeping your world
up and running.™