GE AK-15 - Testing and Troubleshooting; Testing; Troubleshooting; False Tripping Breakers Equipped with Ground Fault

False
Tripping
Breakers
Equipped
with
Ground
Fault
When
nuisance
tripping
occurs
on
breakers
equipped
with
the
ground
fault
trip
element
,
a
probable
cause
is
the
existence
of
a
false
“
ground
”
signal
.
Each
phase
sensor
is
connected
to
summing
circuitry
in
the
programmer
.
Under
no
-
fault
condi
-
tions
on
3
-
wire
load
circuits
,
the
currents
add
to
zero
,
and
no
ground
signal
is
developed
.
This
cur
-
rent
sum
will
be
zero
only
if
all
three
sensors
have
the
same
electrical
characteristics
.
If
one
sensor
dif
-
fers
from
the
others
(
i
.
e
.
,
different
rating
or
wrong
tap
setting
)
,
the
circuitry
can
produce
output
suffi
-
cient
to
trip
the
breaker
.
Similarly
,
discontinuity
be
-
tween
any
sensor
and
the
programmer
unit
can
cause
a
false
trip
signal
.
The
sensors
and
their
connections
should
be
closely
examined
if
nuisance
tripping
is
encountered
on
any
breaker
whose
MicroVersaTrip
®
Plus
or
PM
components
have
previously
demonstrated
satisfac
-
tory
performance
.
After
disconnecting
the
breaker
from
all
power
sources
,
perform
the
following
steps
:
Step
1
.
Check
that
all
phase
sensors
are
the
same
type
(
am
-
pere
range
)
.
Step
2
.
Make
sure
that
the
tap
settings
on
all
three
-
phase
sensors
are
identical
.
Step
3
.
Verify
that
the
harness
connections
to
the
sensors
meet
the
polarity
constraints
indicated
by
the
ca
-
bling
diagram
,
Fig
.
8
-
1
.
SECTION
8
TESTING
AND
TROUBLESHOOTING
Once
the
breaker
has
been
converted
,
but
before
it
is
energized
,
it
must
be
tested
.
See
below
for
troubleshooting
details
.
TESTING
Before
installing
a
converted
breaker
back
into
ser
-
vice
,
perform
the
following
steps
:
Step
1
.
Verify
that
the
programmer
is
securely
installed
.
The
phase
sensors
must
not
be
energized
if
they
are
open
-
circuited
.
Step
2
.
Megger
the
breaker
primary
circuit
using
a
1
,
000
-
Volt
Megger
.
Step
3
.
To
verify
that
the
breaker
has
been
properly
retro
-
fitted
,
a
primary
injection
test
should
be
performed
on
each
phase
.
This
test
will
check
the
CTs
,
bus
,
wir
-
ing
harness
,
flux
shifter
,
and
trip
unit
as
a
complete
system
.
A
high
current
,
low
voltage
power
supply
should
be
connected
across
each
line
and
load
ter
-
minal
to
simulate
an
overcurrent
fault
.
The
pro
-
grammer
long
-
time
may
be
set
at
0.5
to
minimize
the
breaker
stress
.
When
ground
fault
is
installed
,
the
test
can
be
performed
by
wiring
two
adjacent
poles
in
series
.
This
will
prevent
the
breaker
from
tripping
due
to
an
unbalance
current
flow
.
Do
not
attempt
to
use
test
kit
Cat
.
No
.
TVTS
1
or
TVRMS
on
this
programmer
.
TROUBLESHOOTING
When
malfunctioning
is
suspected
,
first
examine
the
circuit
breaker
and
its
power
system
for
abnor
-
mal
conditions
such
as
:
1
.
Breaker
not
tripping
in
proper
response
to
overcurrents
or
incipient
ground
faults
.
2
.
Breaker
remaining
in
a
trip
-
free
state
due
to
me
-
chanical
interference
along
its
trip
shaft
.
3
.
Inadvertent
shunt
trip
activations
.
WARNING
:
Do
not
change
taps
on
the
current
sensors
or
adjust
the
trip
unit
settings
while
the
breaker
is
earning
current
.
25
Courtesy of NationalSwitchgear.com