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LEAKAGE CURRENT MEASUREMENT
The leakage current flows when an unintentional electrical
connection occurs between an energized part of the
electrical system and the earth/ground. The desired value of
leakage current should be 0A. Check applicable regulations
and standards for allowable limits of leakage current.
For properly grounded systems, in case of the fault,
leakage current should be conducted via earth conductor
(PE) (Figure 1). We can measure such current directly in a
earth conductor using a leakage clamp meter.
In some cases, specifically when equipment is not properly
grounded, the leakage current may flow through other
paths. Use differential current measurement methods
to verify such current leaks (Figure 2, Figure 3, Figure 4).
Clamp a leakage current meter around all active conductors
(hot and neutrals), but without any earth conductor. An
electromagnetic field around all conductors should cancel
each other if there is no current leak and clamp meter
should read 0A. If there is a leak, there will be imbalance
between electromagnetic fields, and the clamp meter will
read the actual value of that leakage current.
Leakage current measurement process
1. Turn the meter on.
2. Make sure the jaw is closed and the meter is away from
conductors and other sources of electromagnetic fields.
3. Clamp the meter around a earth conductor. The meter
will indicate leakage current in earth conductor.
4. Clamp the meter around all active conductors, hot and
neutrals (but without earth conductors). The meter
will indicate total system leakage current that consists
of earth conductor current as well as any other stray
current leakage.
CAT III 600V
with respect to
earth for the jaw.
Hand Guard Barrier
Do not hold the
meter above the
Barrier
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