Siemens GM-SG

Electrical
Connections
The
ANSI
/
IEEE
requirements
for
bus insulation
in
metal
-
clad
switchgear
are
contained
in
ANSI
/
IEEE
C
37.20
.
2
clause
7.9
,
which reads
as
follows
:
"
This
insulating
covering
is
a
requirement
of
metal
-
clad
switchgear
and is
provided
to
minimize
the
possibility
of
communicating
faults
and
to
prevent
development
of
bus
faults
that would result
if
foreign
objects
momentarily
contacted bare bus
.
This
insulating covering
is
usually only
a
part
of
the
primary
insulation
system
,
and
in
such
cases
the
outer
surface of
this
insulating
covering
will
not
be
at
ground
potential
.
It
should
not
be
assumed
,
therefore
,
that
personnel
can
contact
this
insulating covering
with
complete
safety
.
"
4
,
I
L
2
1
Bus
Joint Insulation
-
Boots
Standard
and
repetitive
bus
bar
joints
are
normally
provided
with
insulation boots installed
at
the
factory
.
See
Figure
21
.
After
they
are
completed
in
the
field
,
bus bar
joints
at
shipping
splits
must
be insulated
as
part
of
the
total insulation
system
.
Normally
,
boots
are
provided
for
field
completed
shipping
split
joints
and
are
shipped
in
the
location where
they
will
finally
be installed
.
See
Figure
22
.
Grommets
are
provided
for
use
with
the boot when the
bus bar
is
smaller than
the
opening
in
the
bus bar
boot
.
When
required
,
these
grommets
are
normally
mounted
along
with
the bus boot
in
the
final
assembly
location
.
Before
removal
of
the boot
to
complete
the
joint
,
observe
the location and orientation
of
the
boot
and hardware
.
This should make reinstallation easier
.
Nylon
nuts
and bolts and
flat
washers
are
used
to
hold
the boot
closed
after
it
is installed
.
Carefully
remove
the
insulation
boot and
save
all hardware
.
After
the bus bar
joint
has been
properly
assembled
,
reinstall the insulation boot
.
Secure
the boot closed
with
the
nylon
nuts
and bolts
.
Completed
boot installation
should be
flush
with
the bus bar
insulation
and
overlap
it
by
at
least
1
-
1
/
2
"
(
38
mm
)
.
In
those
cases
where
the boot
does
not
close
flush
with
the
bus
bar insulation
or
the
overlap
is less than
1
-
1
/
2
"
(
38
mm
)
,
apply
one
layer
of
tape
(
15
-
171
-
987
-
001
)
1
/
2
lapped
,
overlapping
the bar
insulation and boot
by
1
-
1
/
2
"
(
38
mm
)
.
Silver
Plated
Copper
to
Silver
Plated
Copper
Bus Bars
1
.
Cap
screw
2
.
Flat washer
3
.
Nut
4
.
Flat washer
5
.
Lock washer
Figure
20
.
Bus
Bar
Joint
Assembly
Bus
Insulation
Bus
and connections
are
insulated
in
metal
-
clad
switchgear
as
part
of
a
coordinated insulation
system
.
Air
or
creep
distance
plus
bus
insulation
combines
to
provide
the needed
insulation
level
.
BUS INSULATION
IS
NOT
DESIGNED
TO
PREVENT
SHOCK
.
A
DANGER
Hazardous
voltages
.
Will
cause
death
,
serious
personal
injury
,
and
property
damage
.
Do
not contact
energized
conductors
.
De
energize
and
ground
high voltage
conductors
before
working
on or near
them
.
Epoxy
insulation
applied
in
a
fluidized
bed
process
is
normally
furnished
on
the bus bars
.
Bus
joints
are
normally
insulated
with
boots
.
Taping
is
also used
for
bus
joint
insulation
.
26
Courtesy of NationalSwitchgear.com