Westell NPGMT1122 Instructions for use

530-101080 REV F
1122-03F
March 11, 2013
Westell
FUSE PANEL
Technical Practice
NPGMT1122
10 Position GMT Front Access
FEATURES
¾1 bus of 10 GMT fuses (Accepts up to15 Amp GMT fuses).
¾Polarity insensitive (+/- 24 or +/- 48 Vdc) battery voltage.
¾This panel can operate at 70 Amps of output current per panel.
¾Barrier terminal strips for fused outputs and isolated returns (grounds).
¾Form C relay contacts are provided to extend alarms.
¾Front access design has all terminations on front of panel, (1RU panel, 1.75”H).
¾Mounting brackets are supplied for 1” & 1-3/4” spacing and are universal for 19” and 23” racks, with flush
and offset mounting options.
¾RoHS Compliant.
¾UL Listed
__________________________________________________________________________________________

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1. GENERAL DESCRIPTION
1.1. The NPGMT1122 Fuse Panel provides up
to 10 circuits for the distribution of DC power to
equipment. Each of the 10 circuits is
individually protected by a GMT style
telecommunication fuse located on the panel's
faceplate. Alarm circuits are provided to
indicate and extend alarm conditions when
faults occur. Normal Operation LEDs are
provided to indicate the status of each bus in
the panel.
1.2. Input wiring is connected to a high current,
2-hole lug input block located on the front of the
panel.
1.3. The power is distributed to the load side
equipment through GMT style fuses. There are
a total of 10 fuses per panel. (See Figure 3.2.1)
Each fuse position is available for installer
connection on the front of the panel. (See
Figure 4.5.1) A designation card is provided for
keeping records of which position is connected
to which equipment and what amperage is to
be used.
1.4. Alarm circuits are provided to alert service
personnel of fault conditions. A fuse alarm is
caused when any of the GMT distribution fuses
opens. A red fuse alarm !LED on the
faceplate will illuminate and the green Normal
Operation 9 LED will extinguish to signal a
fuse alarm and also the appropriate relay
contacts will change states. (See Figure 3.2.1)
The fuse panel has common (C), normally
open (NO) and normally closed (NC) terminals
for alarms. Note, the use of the alarm
contacts is optional, if you do not wish to
extend the alarms, you don’t have to do
anything with the alarm pins. (See Figure
4.7.1)
The “Normal” condition of the relay exists when
the panel is powered up without any blown
fuses.
If input power is lost the 9 LED will extinguish
and the alarm relay will indicate an alarm.
1.5. The NPGMT1122 fuse panel is made from
0.050" steel and painted off white. This panel is
shipped universal brackets that will fit both 19"
and 23" wide racks and uses only one 1.75"
panel spaces. The panel has two clear L
shaped shields to protect the wiring
connections on the front of the panel. (See
Figure 1.6.1)
Figure 1.6.1
2. APPLICATION
2.1. The NPGMT1122 Fuse Panel is designed
to be used in the distribution of DC power.
They are rack mount panels that can provide
fused DC power to up to 10 individual circuits.
3. CIRCUIT DESCRIPTION
3.1. Power is connected to the fuse panel via
¼” studs on 5/8” centers located on the front of
the panel (Torque 36 in-lbs). This input is a
high current stud block that supplies current to
the fuse panel. Connect the battery return
cable to the stud input that is labeled “RTN”
and the Battery supply cable is connected to
the terminals labeled “BAT”.
3.2. Distribution of current is provided by GMT
style fuses. Each panel has 10 fuse holders for
distribution, the fuses are labeled 1 to 10.
(See Figure 3.2.1) Each fuse position is made
available on the front of the fuse panel.
Maximum output current of each fused position
is 10.5 Amps for a 15 Amp fuse. The input
must be fused at the BDFB at 100Amps max.
Load current should not exceed 70% of the
fuse capacity. Fuses should be sized at at
least 1.5 times the maximum current draw of
the equipment.

Page 3
4
3
1259
8
6710
9
!

MAX FUSE SIZE 15AMPS
Figure 3.2.1
3.3. Alarm circuitry provides 1 set of form “C”
contacts (C, NO and NC). In the event of a fuse
alarm or input power failure, the relay will
change states, providing a connection between
the Normally Open “NO” and Common “C”
terminals. The normally closed “NC” terminal
will open to high impedance.
4. INSTALLATION
Please read completely before beginning.
WARNING: Installation should only be
performed by an experienced Installer familiar
with DC power distribution systems.
This equipment is intended to be installed
in RESTRICTED ACCESS LOCATIONS by
TRAINED PERSONNEL ONLY.
CAUTION: For continued protection against
fire, replace only with the same manufacturer
make and model number fuse. Please read the
specifications carefully to ensure the panel’s
maximum ratings are not exceeded.
NOTE: The DC Short Circuit rating for the
Panel’s input bus and output fuse position, 450
Amps maximum.
4.1. Unpack and inspect the Fuse Panel for
possible damage incurred during shipping. If
damage is found, file a claim immediately with
the carrier, and notify the customer service
department.
4.2. Once the panel is unpacked, verify that
there are three mounting brackets. The
bracket with the vertical slot is used on both 1”
and 1-3/4” spacing. There will be two brackets
with horizontal slots, these will fit 1” or 1-3/4”
spacing. All three brackets are universal for
19” and 23” rack mount spacing (see figure
4.2.1) and can be mounted so the panel can be
installed for a flush mounting or 5” offset.
Adjust the position and orientation of the
correct mounting brackets on the fuse panel,
such that it will fit the rack you wish to mount
the panel in.
Rack Mount Instructions:
Elevated Operating Ambient - For closed or
multi-unit rack assemblies, the operating ambient
may be greater than room ambient. Take care to
install the equipment in an environment
compatible with the maximum ambient
temperature (Tma) specified by the
manufacturer.
Reduced air flow - Installation of the equipment
in a rack should be such that the amount of air
flow required for safe operation is not
compromised.
Mechanical Loading - Mounting of the
equipment in the rack should be such that a
hazardous condition is not achieved due to
uneven mechanical loading.
Circuit Overloading - Consideration should be
given to the connection of the equipment to the
supply circuit and the effect that overloading of
the circuits might have on overcurrent protection
and supply wiring. Appropriate consideration of
equipment nameplate ratings should be used
when addressing this concern.
Reliable earthing - Reliable earthing of rack-
mounted equipment should be maintained.
Particular attention should be given to supply
connections other than direct connections to the
branch circuit.

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19" Mounting Position
23" Mounting Position
Figure 4.2.1
4.3. Mount the fuse panel on the equipment
rack using the thread forming #12-24 rack
mounting screws and tooth lock washers
provided.
WARNING: For safety reasons all wiring
should be done with the power source removed
(when possible). A readily accessible
disconnect is to be provided in the end use
installation.
Note: The input to the unit is intended to be
supplied by an Earthed DC Mains Source
4.4. Remove the distribution fuse feeding the
input cables that are to be connected to the
new panel. Using input cables specified by the
Job Engineer, hook up the input cables to the
input terminal block on the fuse panel (“BAT” &
“RTN” for each panel). Please use a minimum
of 1 AWG (Ø7.35mm), 90C (or higher temp)
copper wire to connect this panel to its DC
supply. Each high current input terminal uses a
two hole compression lug (1/4” on 5/8”, torque
to 36 in-lbs). A two hole lug must be used for
proper operation. (See Figure 4.4.1)
123
BAT
RTN
BAT RTN
MAX TORQ
36 IN-LB
Figure 4.4.1
4.5. The battery outputs (“BAT”) are available
at the terminal blocks (#6 screw, up to 10awg
fork (Ø2.59mm wire)) on the front of the panel.
Each fuse position is numbered and that circuit
is available at the terminal block position with
the same number. (See Figure 4.5.1)
12345
BAT
RTN
MAX TORQ
36 IN-LB
Figure 4.5.1
CAUTION: Wiring protected by GMT fuses
shall be at least one size larger than the
minimum required wire based on the National
Electric Code, NFPA 70 ampacity tables.
4.6. All battery return (“RTN”) connections are
also terminated on barrier strips (#6 screw, up
to 10awg (Ø2.59mm) fork). Note, these returns
are isolated from the chassis frame. (See
Figure 4.5.1)
4.7. This panel has one set of alarms. Each
panels alarm has common (C), normally open
(NO) and normally closed (NC) alarm contacts
(as shown in figure 4.7.1). In an alarm, the
“C” contact will short to the “NO” contact, and
the “NC” will open. Wire-wrap the alarm
connections as per your alarm system
requirements. Its recommended you fuse the
alarm battery supply (ABS) to 1A or less to
protect the alarm wiring and circuitry.
9
87 10
COM
NC
NO
ALARM
Figure 4.7.1

Page 5
4.8. CHASSIS GROUND; For safety reasons,
and as recommended by NEBS, the chassis
should be electrically connected to the rack
ground. From step 4.3. the panel should
already be grounded to the rack via the #12-24
thread forming rack screws and outside tooth
lock washers. In addition to grounding via the
mounting brackets, you must also ground the
chassis using a separate ground cable that is a
minimum 6 AWG (Ø4.11mm), 90C, copper
cable. Please use an appropriate UL® listed
ring terminal for a #10 screw, such as a
Panduit PV6-10R or P6-10R. Fasten the lug to
the #10 bolt and locks on the front of the
chassis (#10 screw torque; 2 ft-lbs or 2.7Nm)
See Figure 4.8.1
Figure 4.8.1
4.9. Power up the panel by installing the
distribution fuse (or breaker) supplying the
panel. Select an appropriate protection device
to limit the input current to 100 Amps max (ie
use a Maximum 100A battery supply fuse.)
The panel should power up with the
9 Normal Operation LED illuminated and
without any red !LEDs illuminated, and
the relays should be in the “Normal” state (“C”
connected to “NC”).
4.10. If you wish to verify the fuse alarm circuit,
you can insert a blown fuse into one of the
empty fuse holders. The red !Fuse Alarm
LED should light and the 9 Normal Operation
LED should extinguish and the appropriate
alarm extension relay should change states to
extend the alarm.
4.11. Install panel output distribution GMT
fuses, with fuse covers on each, as required.
Use the provided designation card to keep a
record of which equipment is connected to
which circuit and what the fuse rating is. Be
careful not to overload the panel bus or BDFB
fuse position rating supplying the panel.
NOTE: If fuse size is not specified in the
equipment manual, fuses should be selected
with a rating of at least 150% of the maximum
current draw of the equipment on that circuit.
Thank You.