GE AV-Line - Installation Details and Operational Guidelines; Bolting and Electrical Clearances; Ambient Temperatures and Short Circuits; Switchboard Maintenance

GROUND
FAULT
PROTECTION
When
ground
fault
protection
is
furnished
,
it
is
important
that
all
field
connections
shall
be
made
correctly
so
that the
ground
fault
protection
system
will
function
properly
.
Observe
the
following
rules
,
illustrated
in
Figs
.
12
,
13
.
ELECTRICAL
CLEARANCES
BOLTING
The
following
minimum
clearances
should
be
maintained
except
at
terminals
of
circuit breakers
and
switches
:
AV
-
Line
switchboards
are
furnished
with
medium
carbon
steel
hardware
having
a
high
tensile
strength
.
V
4
"
to
Vs
"
bolts
have
a
tensile
strength
of
120
,
000
psi
,
and
W
to
5
/
s
"
bolts
have
a
strength
of
60
,
000
psi
.
Similar
hardware should
be
used
for
any
additional
bolting
.
The
use
of
a
torque
wrench
is
recommended
to
assure
the
following
torques
.
These
torques
apply
to
alumi
-
num
or
copper
connections
.
When
torquing
bolts
the
following
values
are
nominal
:
0
-
125
V
126
-
250
V
251
-
600
V
Between
live
parts
of
opposite
polarity
:
Through
air
Over
surface
Between
live
parts
and
grounded
metal
through
air
or
over
surface
GROUNDING
Where
required
,
the
ground
bus is
bolted
to
the
uprights
of
the
rear
frame
structure
.
It
is
arranged
so
that
connections
to
the station
ground
can
be
made
in
any
unit
.
A
ground lug
is
included
in
each
complete equipment
for
tying
the
switchboard
to
the
station
ground
.
IT
IS
VERY
IMPORTANT
THAT THE
EQUIPMENT
BE
ADEQUATELY
GROUNDED
,
TO
INSURE
THAT ALL
PARTS
OF
THE
EQUIPMENT
,
OTHER
THAN LIVE
PARTS
,
ARE
AT
GROUND
POTENTIAL
.
Ground
sensor
relays
are
recommended
for
protection
of
the switchboard
.
V
2
"
3
/
4
"
1
"
2
"
3
/
4
"
11
/
4
"
8
-
10
lb
.
ft
.
16
-
19
lb
.
ft
.
23
-
27
lb
.
ft
.
35
-
40
lb
.
ft
.
45
-
50
lb
.
ft
.
1
/
4
"
—
20
bolts
5
/
i
6
w
—
18
bolts
—
16
bolts
1
/
2
"
—
13
bolts
s
/
s
"
—
16
bolts
Flat
washers
and
spring
washers should
be
used
for
all
connec
-
tions
.
Washers
should
not
be
included
under
the heads
of
car
-
riage
bolts
.
V
2
"
V
2
"
1
"
Switchboard
Maintenance
CAUTION
!
De
-
energize
this
equipment
before
performing
any
work
.
A
periodic
maintenance
schedule should be established
to
ob
-
tain the best service
from
the
switchboard
.
An
annual
check and
overall maintenance
procedure
for
the switchboard
devices
and
all
connections
,
should
be
followed
as a
minimum
requirement
.
Equipment
subject
to
highly
repetitive operation
may
require
more
frequent
maintenance
.
A
permanent
record
of
all
maintenance work should
be
kept
.
The
record should
include
a
list
of
periodic
checks and
tests
made
,
the date
they
were
made
,
the condition
of
the
equipment
,
and
any
repairs
or
adjustments
that
were
performed
.
Maintenance
employees
should
follow
all
recognized
safety
practices
,
such
as
those
contained
in
the
National Electrical
Code
,
OSHA
and
in
company
or
other
safety
regulations during
maintenance
.
For
specific
information
regarding
the
maintenance
of
devices
,
such
as
circuit
breakers
,
relays
,
meters
,
etc
.
,
refer
to
the
sepa
-
rate
instruction
book
furnished for
each device
.
1
.
Periodically
inspect
switchboard
,
while under
load
to
deter
-
mine
if
there
is
any
indication
of
overheating
.
If
overheating
or
any
other
unsatisfactory
condition is
found
,
completely
de
-
energize
switchboard
and
investigate
.
Particularly
look
for
loose bolts
and
connections
,
or
overloading
.
Remove
any
accumulation
of
dirt
or
other
foreign
matter
in
enclosure
.
Do
not
touch live
parts
while
switchboard
is
energized
.
2
.
Plated
parts
may
become dark
over
a
period
of
time
due
to
oxidation
.
Do
NOT
remove
this discoloration
,
as
it
will
reduce
the thickness
of
the
plating
.
3
.
Retighten
lugs
and
joints
to
eliminate
possible
heating
points
.
Transmittal
of
vibration
through
building
structure
and conduit
to
switchboard
may
loosen
lugs
and
joints
.
Turning
load
off
and
on
causes
expansion
and
contraction
between
lug
and
cable
tending
to
loosen
lug
.
4
.
Do
not
open
sealed
breaker
or
trip
units
as
calibration
may
be
disturbed
.
Return
to
factory
for
any
replacement
.
AMBIENT
TEMPERATURES
AND
CIRCUIT
LOADING
Switchboards
are
designed
for
installation where
average
ambi
-
ent
temperature
will
not
exceed
40
°
C
(
104
°
F
)
.
For
higher
tem
-
peratures
,
derating
may
be
required
.
The
conductor
temperatures
within
the enclosure
may
be
as
high
as
80
°
C
(
176
°
F
)
.
Some
parts
of
breakers
,
switches
and
fuses
may
run
hotter
.
In
accordance
with
NEC
Art
.
384
-
16
(
c
)
it
is recommended
that thermal
-
magnetic
molded
-
case
breakers
in
switchboards
not
be loaded
in
excess
of
80
%
of
rating
where load
will
continue
for
three hours
or more
,
even
with
ambient
-
compensated
breakers
.
SHORT CIRCUITS
Normally
,
the
overcurrent
protective
device
on
the
circuit
will
prevent
any
electrical
damage
except
at
the
actual
point
of
short
-
circuit
.
A
thorough
inspection
of
the
entire
system
after
any
large
fault
current
should be made
to
insure that
there
has
been
no
mechanical
damage
to
conductors
,
insulation
or
equipment
.
In
addition
,
the
individual
overcurrent
protective
device
or
de
-
vices
which
performed
the short
-
circuit
interruption
must
be
in
-
spected
for
possible
arcing
damage
to
contacts
,
arc
chutes
and
/
or
insulation
.
Do
not
open
sealed devices
such
as
breaker
trip
units
or
150
A
frame
breakers
.
If
there is
any
possibility
that
sealed
units
may
have
been
damaged
,
they
should
be
replaced
.
For
additional
details
on
the
particular
device involved
,
refer
to
the
applicable
individual
instruction
book
.
ARCING
DAMAGE
TO
INSULATION
Some
organic
insulating
materials
carbonize
when
subjected
to
the
heat
of
an
electrical
arc
and lose
their
insulating
qualities
.
Any
insulation
found
to
be carbon
-
tracked
must
be
replaced
before
applying
power
.
(
Continued
on
Page
12
)
11
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