GE AV-Line - Field Connections, Testing, and Operation; Ground-Fault Protection Systems; Fuse Selection and System Testing

Installing
The
AV
-
Line
Switchboard
3
-
PHASE
4
WIRE
SUPPLY
N
G
.
V
1
2
3
©
L
©
SERVICE
ENTRANCE
MAIN
BREAKER
)
)
)
FIELD
CONNECTIONS
AND
TESTING
OF
GROUND
-
FAULT
PROTECTION
SYSTEMS
(
7
)
In
the
service
-
entrance
section
,
the
neutral
conductor
shall
be
bonded
to
the
switchboard
ground
bus
by
a
“
main
bonding
jumper
”
(
ground
strap
)
(
NEC
250
-
5
;
UL
-
891
,
Para
.
23.8
and
23.12
)
.
This
grounding
point
on
the
neutral
conductor
shall
be
located
on
the
supply
side
of
any
ground
-
fault
sensors
in
-
volving
the
neutral
conductor
(
UL
-
891
,
Para
.
15.4
and
15.5
)
.
Grounding
connections
shall
not
be
made
to
the
neutral
con
-
ductor
on
the
load
side
of
the
service
disconnecting
means
(
NEC
250
-
23
a
;
UL
-
891
,
Para
.
15.4
)
.
(
?
)
On
load
feeders
,
run
all
phase
conductors
(
and
neutral
if
used
)
through
the
sensor
window
(
s
)
,
with
all
in
the
same
direction
with
respect
to
sensor
polarity
.
(
J
)
Do
not
run
equipment
ground
conductors
through
ground
-
fault
sensors
.
Connect
them
directly
to
the
switchboard
ground
bus
(
not
to
the
neutral
bus
)
(
UL
-
891
,
Para
.
38.39
)
.
(
71
)
Connect
the
service
grounding
electrode
(
water
pipe
,
etc
.
)
to
the
lug
provided
on
the
switchboard
ground
bus
for
this
pur
-
pose
(
NEC
250
-
26
c
;
UL
-
891
,
Para
.
23.6
)
.
(
J
)
Whenever
a
service
is
derived
from
a
grounded
neutral
sup
-
ply
,
the
grounded
neutral
conductor
must
be
brought
into
the
service
-
entrance
equipment
,
even
if
the
grounded
conductor
is
not
needed
for
the
load
supplied
by
the
service
(
NEC
250
-
23
b
)
.
This
is
required
to
provide
a
low
-
impedance
ground
-
fault
current
return
path
to
the
neutral
to
assure
operation
of
the
overcurrent
device
,
for
safety
to
personnel
and
property
.
(
&
)
Refer
to
GEI
-
48907
for
instructions
for
conducting
perfor
-
mance
tests
of
new
installations
of
ground
-
fault
protection
systems
,
as
required
by
NEC
230
-
95
(
c
)
.
4
WIRE
IGF
NEUTRAL
-
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)
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)
)
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¥
1
FDR
#
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-
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IGF
=
INTEGRAL
GROUND
FAULT
PROTECTION
3
WIRE
IGF
GHD
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|
3
PHASE
—
3
WIRELOAD
~
~
|
|
3
-
PHASE
—
4
WIRE
LOAD
|
TYPICAL
SINGLE
-
SOURCE
GROUND
FAULT
PROTECTION
USING
INTEGRAL
GROUND
FAULT
TRIPS
FIGURE
13
FUSE
SELECTION
The
proper
fuses
for
each
circuit
should
be
selected
based
on
load
characteristics
(
see
Ambient
Temperatures
and
Circuit
Loading
)
and
available
short
-
circuit
current
at
the
line
terminals
of
the
switchboard
.
Select
a
fuse
for
which
the
rating
of
the
combination
fuse
and
switch
equals
or
exceeds
the
available
short
-
circuit
current
.
Removable
link
-
type
fuses
are
not
recommended
.
TESTING
AND
INSPECTION
After
the
equipment
has
been
installed
and
all
connections
made
,
it
should
be
tested
and
inspected
BEFORE
ENERGIZING
.
Although
the
equipment
and
devices
have
been
inspected
at
the
factory
,
a
final
field
test
should
be
made
to
be
certain
that
the
equipment
has
been
properly
installed
and
that
all
connections
are
correct
and
have
not
become
loose
in
transportation
.
It
is
recommended
that
the
switchboard
be
completely
wire
checked
,
and
all
bolts
and
terminals
double
checked
for
tightness
.
Check
all
Kirk
key
interlocking
schemes
to
insure
desired
performance
.
The
incoming
line
should
be
completely
de
-
energized
while
the
tests
are
in
progress
.
In
addition
to
these
mechanical
checks
the
switchboard
should
be
meggered
.
Meggering
should
be
performed
with
all
switchboard
devices
in
the
open
position
and
all
instrumentation
and
control
fuses
removed
.
A
megger
(
megohmmeter
)
developing
500
volts
should
be
used
.
As
a
guide
switchboards
tested
when
leaving
the
factory
have
shown
typical
minimum
values
of
100
megohms
.
Any
switchboards
job
tested
under
the
above
conditions
showing
values
considerably
below
this
should
be
inspected
for
possible
tracking
on
insulation
or
insulation
breakdown
.
All
scraps
of
wire
,
plaster
,
dust
and
other
foreign
material
must
be
removed
.
Vacuum
cleaning
is
the
recommended
method
of
removal
.
After
thorough
cleaning
and
inspection
,
if
the
megger
reading
is
still
low
,
it
may
still
be
safe
to
energize
the
equipment
.
When
restoring
flooded
or
wet
equipment
to
service
,
for
example
,
it
is
accepted
maintenance
prac
-
tice
to
require
a
minimum
of
one
megohm
before
energizing
.
Under
damp
or
humid
conditions
it
is
considered
good
practice
to
operate
the
equipment
at
lower
-
than
-
rated
voltage
for
a
short
time
,
if
possible
,
to
improve
the
low
megger
reading
.
Instructions
for
inspection
and
testing
of
low
voltage
power
circuit
\
breakers
are
given
in
the
applicable
individual
instruction
book
.
Direc
-
tions
for
testing
devices
such
as
relays
,
instruments
and
meters
are
given
in
the
instruction
book
furnished
for
each
device
.
Protective
relays
must
be
coordinated
with
other
relays
in
the
system
,
therefore
these
relays
are
to
be
set
by
the
purchaser
.
General
instructions
on
setting
the
relays
are
given
in
the
relay
instruction
books
.
3
-
PHASE
4
WIRE
SUPPLY
1
2
3
N
G
ALTERNATE
SENSOR
ARRANGEMENTS
I
t
2
3
N
I
ALTERNATE
SENSORS
FOR
MAIN
BREAKER
GFP
c
X
>
t
©
I
ZERO
SEQUENCE
GROUND
RETURN
SENSOR
)
)
SERVICE
ENTRANCE
MAIN
BREAKER
12
3
N
GFR
I
x
>
-
(
(
I
I
ZERO
-
SEQUENCE
OR
RESIDUAL
SENSOR
RESIDUAL
2
3
N
NEUTRAL
N
BUS
(
X X X
^
I
RESIDUAL
1
!
>
~
Epl
)
)
>
-
-
)
)
)
GFR
-
GROUND
FAULT
RELAY
FDR
01
GFR
FDR
02
GRD
c
sus
©
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1
2
3
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2
3
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©
©
L
1
1
1
1
2
3
N
G
I
I
I
I
I
1
2
3
G
I
I
I
I
|
3
PHASE
—
4
WIRE
LQAD
~
~
|
|
3
PHASE
—
3
WIRE
LOAD
|
TYPICAL
SINGLE
-
SOURCE
GROUND
FAULT
PROTECTION
USING
GROUND
FAULT
RELAYS
FIGURE
12
10
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