I N S TA L L AT I O N , O P ER AT I O N S A N D M A I N T EN A N C E M A N UA L
21
—
16
Standard section
with main bus
—
16
—
17
—
17
Plenum arc-resistant
top view
—
18
—
18
Top view of Plenum
design for arc-resistant
Cable entry for arc-resistant motor control center
After a motor control center is in place and the
sections are joined together, conduits for cable
entry can be brought into the top of sections as
required. Note: Only the front side of the top
section can be used for cable entry.
For arc-resistant design, the Equipment is
guaranteed to maximize protection to surrounding
if an arc instance occurred inside the equipment
except for designated gas release locations.
Customers need to identify the front side of the
section using the help of the main bus channel.
Figure 16 show a section with a top main bus.
For a plenum arc-resistant design there is no
restriction on using a certain brand for hubs,
however it is recommended to use water-gas tight.
The end piece of the plenum should be routed to
proper gas relief environments due to the toxicity
of the gases. Also 48 inches of space at the end
piece is needed as a safe zone.
The plenum design can vary in height, depth and
width, see table 1. It is used on the flap covers on
the top of the section. The frontal fap cover of the
section is the only one to be removed.
When the plenum is installed users can cut
anywhere in the top of the plenum for incoming
cables with the exception for the outside of the
frame perimeter. Figure 18 shows the perimeter of
the frame for the top plenum for the section.
To release the exhaust gases of the arc-resistant
equipment the sections are sold in two different
types with and without a plenum.
Arc-resistant plenum equipment
Plenum equipment that is ventilated with ducts can
be identified for the hinges that are on the top of
the section. See Figure 17 for a top view of an arc-
resistant plenum equipment, only the flap cover
from the top side can be removed for conduit
hub areas.
Height
Width
Depth
6 in
20 in
20 in
12 in
24 in
30 in
-
30 in
-
-
36 in
-
Table 1: Plenum sizes for arc-resistant design
Front side
Main bus
and channel
Rear side
Rear cover
Flap cover hinges
Main bus channel
Flap cover
1 in
1.2 in
1 in
1.2 in
