Westell NPTPA1123 Instructions for use

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030-101788 REV D
1123-03D
July 2, 2013
Westell
Fuse Panel
Technical Practice
NPTPA1123
4/4 TPA + 5/5 GMT with Voltage/Current Readout
FEATURES
Compatible with +24V, +48V, -24V or -48V dc input voltages (battery voltages).
3-½ Digit LED display indicating Voltage/Current for either bus.
2 busses per panel (120 Amps/bus maximum).
5 GMT style fuses per bus (20 Amp GMT fuse max, 50 Amps per GMT bus max).
4 TPA style fuses per bus (50 Amp TPA fuse max, 120 Amps per TPA bus max).
Normal and Alarm LEDs for Bus A and Bus B indicate power or fuse failure.
Two sets of “Form C” relay contacts extend alarm conditions for each bus.
Brackets supplied are reversible for both 19” and 23” racks, with flush and offset mounting options.
High current 1/4” stud inputs (1/4”studs on 5/8” centers) for up to 120 Amps/input.
Offset terminal blocks with rear shield provided (standard).
UL Listed

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1. GENERAL DESCRIPTION
1.1. The Westell NPTPA1123 Fuse Panel
provides fused distribution of DC power to
equipment. The panel has 2 buses, each bus
consisting of 5 GMT style fuse positions and 4
TPA style fuse positions. Alarm circuits are
provided to indicate and extend alarm
conditions when faults occur.
1.2. Input wiring is connected to a high current,
2-hole lug input block located at the rear of the
panel. Each bus has its own completely isolated
inputs, allowing the distribution of two battery
voltages through the same panel.
1.3. The power is distributed to the load side
equipment through GMT and TPA style fuses.
There are 5 GMT and 4 TPA style fuses per group
and two groups per panel. Each fuse position is
available for installer connection at the rear of the
panel. 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 a blown fuse (GMT or TPA) within a
given bus. A red fuse alarm LED
!
on the
faceplate will illuminate when a fuse alarm
condition is present. As well, the green Normal
Operation LED will extinguish to signal a fuse
alarm or input power failure and the appropriate
relay contacts will change states. These fuse
panels have 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.
The “Normal” condition of the relay exists when
the panel is powered up without any blown
fuses. The local alarm LEDs are located on the
front of the panel as shown in Figure 1.4.1
LED
SYMBOL
SIGNIFICANCE
GREEN

NORMAL OPERATION
RED
!
BLOWN FUSE
!
!

A
B
V
I
Figure 1.4.1
1.5. These Fuse Panels are made from 0.050"
steel and painted off-white. Single rack height
panels are shipped with universal brackets (1” &
1-1/4” hole spacing) that will fit both 19" and 23"
wide racks and use only one 1.75" panel space.
The panel has a clear L shaped plastic shield to
protect the wiring connections on the back of the
panel.
2. APPLICATION
2.1. The NPTPA1123 Fuse Panel is designed
to be used in the rack level distribution of DC
power. They are rack mount panels that
provide fused DC power through two busses;
each bus has 5 GMT style fuses, and 4 TPA
style fuses per bus.
2.2. The NPGMT family fuse panels are
suitable for installation as part of a Common
Bonding Network (CBN). As well, this family of
fuse panels is suitable for restricted access
locations in Network Telecommunications
Facilities and OSP.
3. CIRCUIT DESCRIPTION
3.1. Power is connected to the panel through
1/4” stud input blocks (see fig 4.4.1). There is
one set of inputs for each bus. These inputs
are high current terminals with a maximum
continuous current of 120 Amps. There is a
Return (RTN) and Battery (BAT) input for each
bus.
3.2. Distribution of current from each bus is
provided by GMT and TPA style fuses. Each
bus has 5 GMT fuses and 4 TPA fuses. Each
fuse position is made available at the rear of the
panel via #6 screw terminal blocks. The GMT
fuses for both bus A and bus B are numbered 5
-53.8

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thru 9. The TPA fuses are numbered 1 thru 4
for bus A and bus B.
3.3. Fuse Alarm circuitry provides 1 set of form
“C”contacts (C, NO and NC) for each bus (Bus A,
and Bus B). In the event of a fuse alarm or loss of
input power, the proper relay will change states,
providing a connection between the Normally
Open “NO” and Common “C” terminals for that
bus. 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 product must be installed within a
RESTRICTED ACCESS LOCATION where
access is through the use of a tool, lock and
key or other means of security, and is
controlled by the authority responsible for
the location. This product must be installed
and maintained by TRAINED SERVICE
PERSONNEL ONLY.
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 Customer Service.
4.2. Once the panel is unpacked, verify that there
are three mounting brackets. The bracket with the
vertical slot is used for both 1” and 1-1/4” hole spacing
applications. There will be two brackets with
horizontal slots, one will fit 1”, and the other 1-1/4”,
hole 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. Please see drawing 1123-19 on
page 6 for mounting bracket configurations.
4.3. Mount the panel on the equipment rack
using the thread forming #12-24 rack mounting
screws and tooth lock washers provided.
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.
19 " MOUNTING
23" MOUNTING
Figure 4.2.1
WARNING: For safety reasons all wiring should
be done with all power sources removed (when
possible).
Note: A readily accessible disconnect device shall
be incorporated in the building installation wiring.

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4.4. Remove the distribution fuse feeding the
input cables that are to be connected to the new
panel. Attach the input cables to the input
terminal block in accordance to the National
Electrical Code, ANSI/NFPA, and Canadian
Electrical code. Hook up the input cables to the
input terminal block on the fuse panel (“BAT” &
“RTN” for each bus). Each high current input
terminal uses a two-hole compression lug (1/4” on
5/8”, torque to 5.5 ft-lbs). A two-hole lug must be
used for proper operation (see fig 4.4.1)
Note: The supply source must be limited to an
instantaneous short-circuit current not to exceed
450 Amps.
9
9
BAT
B
RTN
Figure 4.4.1
4.5. The fused battery outputs (BAT) and
ground returns (RTN) are also located on the
back of the panel. Each fuse holder and
terminal position is individually numbered.
Connect your load side equipment to the fuse
panel, and record which equipment is
connected to which input on the designation
card (supplied).
4.6. All battery return (“RTN”) connections are
also terminated on barrier strips (#6 screw, up to
10awg fork). Note, these returns are isolated from
the chassis frame.
4.7. This panel has Bus A, and Bus B alarm
contacts. Each alarm has a common (C),
normally open (NO) and normally closed (NC)
alarm contact. 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. We recommend you
fuse the alarm battery supply (ABS) to 1A or less
to protect the alarm wiring and circuitry.
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 ground to
the rack via the #12-24 thread forming rack
screws and outside tooth lock washers. In
addition to grounding via the mounting brackets, it
is recommended you ground the chassis using a
ground cable and the two ¼” bolts and locks on
back of chassis (1/4” bolt torque; 5.5ft-lbs or
7.5Nm). Consult the National Electric Code,
ANSI/NFPA, and Canadian Electrical code for
AWG sizes.
4.9. The input wiring feeding this panel should
be protected by a Listed fuse/breaker rated for at
least 60Vdc, with a trip rating of 150 Amps Max.
With input wiring connected and this input fuse
installed, the panel should power up with the
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 Normal Operation
LED should extinguish and the appropriate
alarm extension relay should change states to
extend the alarm.
4.10. Install panel output distribution fuses as
required. Be sure to size fuses to no more than
70% of their rating (14A max for a 20A fuse).
Fuses are not included with this panel. Fuse
ratings should be selected to match the load
equipment ratings. Once the appropriate fuses
have been selected, the fuse information for F1-
F9 on BUS A and F1-F9 on BUS B is to be
recorded at the time of installation. 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.
4.12 Install amperage marking labels as required
below each fuse for identification of circuit rating.
For fuse color codes please see table 4.12.1
below.

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Amps
Color Code
18/100 A
Yellow
2/10 A
Red/Black
1/4 A
Violet
3/8 A
Gray/White
1/2 A
Red
65/100 A
Black
3/4 A
Brown
1 A
Gray
1 1/3 A
White
1 1/2 A
White/Yellow
2 A
Orange
2 1/2 A
White/Orange
3 A
Blue
3 1/2 A
White/Blue
4 A
White/Brown
5 A
Green
7 1/2 A
Black/White
10 A
Red/White
12 A
Yellow/Green
15 A
Red/Blue
20 A
Green/White
Table 4.12.1
Chassis Grounding: Depending on the bus input current being supplied, the chassis bonding
conductor used should meet the minimum requirements. Please note that 120 A is the maximum
allowable bus current rating.
Protective Current
Rating
Minimum AWG
Recommended
Compression Lug
Minimum Wire
Temperature rating
0-40 Amps
10 AWG
Panduit, LCD10-14A
90°C
40-63 Amps
8 AWG
Panduit, LCD8-14A
90°C
63-80 Amps
6 AWG
Panduit, LCD6-14A
90°C
80-100 Amps
4 AWG
Panduit, LCD4-14A
90°C
100-125 Amps
2 AWG
Panduit, LCD2-14A
90°C

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5. SPECIFICATIONS
5.1 Voltage ±24 or ±48 VDC Typical
±22 to ±58 VDC Maximum
5.2 GMT Fuse Size 0.18 to 20 Amps Max*
450A@60VDC I.R.
(Littelfuse Type 481 Series)
5.2. TPA Fuse Size 3 to 50 Amps Max*
(Bussmann TPA style fuse)
5.3. Current/GMT Bus 50 Amps Max**
5.4. Current/TPA Bus 120 Amps Max**
5.5. Current/Input 120 Amps Max
(fuse at 150A)
5.6. Output/Bus 4 TPA & 5 GMT
5.7. Busses/Panel 2 Busses per Panel
5.8. Input Block Two ¼” Studs on 5/8centers
Max std lug is 1 AWG
Max lug width = 0.710”
5.9. GMT Output #22 AWG to 12 AWG wire
Or fork/ring for #6 screw,
10AWG forks/rings will work
5.10. TPA Output #20 AWG to #10 AWG wire
#6 AWG & #8 AWG with
narrow tongue lug (#6 screws)
Max lug width = 0.375”
5.11. Alarm Block 0.045” sq wire wrap pin
5.12. Relay Current 1 Amp/58Vdc max
5.13. Dimensions 1¾ H, 17 W,10½ D
(excluding brackets)
5.14. Rack Mounting 19” and 23” Racks
1” and 1.25” hole spacing
for WECO andEIA style racks
5.15. Weight Approx 10 lbs
5.16. Operating Temp. -40 to +55C (ambient)
(-40 to +131F)
5.17. Color Off-white
5.18. Short Circuit 450A (Max)
Withstand Rating
5.19. Voltage Display 0 to ±60.0 VDC, 0.1V
resolution, ±1%
5.20. Current Display 0 to ±199 ADC,1 A
resolution, ±3%
*We recommend that you size fuses such that they do
not run at more than 70% of their rating. Thus a 20A
fuse should not be run at more than 14 A. TPA fuses
should be sized such that they do not run at more than
70% of their ratings. Thus a 50A fuse should not be
run at more than 35A.
**The sum of the fuse currents must not exceed the
bus rating.
Compatible lugs for Input Block
2 hole compression lugs for 1/4” studs on
5/8” centers (torque 5.5ft-lbs) example;
Panduit® LCD1-14A 1awg wire
LCD2-14A 2awg wire
LCD4-14A 4awg wire
LCD6-14A 6awg wire
LCD8-14A 8awg wire
The Panduit® CT-1700 crimping tool can be
used for securing wire to any of these lugs.
Input wiring should be rated 90°C or better
and fused at 125% of total Bus current (ie:
up to 150 Amps MAX rated input
fuse/breaker)
Output lugs (locking fork recommended):
Ring or fork for #6 screw (up to 10awg).
Torque to 9 in-lbs, use wire rated 90°C or
better.
Or “Narrow Tongue” ring lugs by Burndy, for
the large cable and the TPA blocks:
Burndy# YA8CLNT6 (8 AWG wire)
NOTE: If fuse size is not specified in the
equipment manual, fuses should be selected
such that they do not run at more than 70%
for GMT’s and 70% for TPA’s, of their rating.
When installing fuses, the sum of the fuse
currents installed in each bus should not
exceed the bus current rating (120 Amps) or
input fuse rating.

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6. TECHNICAL SERVICES
6.1 If technical or customer assistance is
required, contact Westell by calling or using
one of the following options:
Voice: [phone]
email: [email protected]
For additional information about Westell, visit
the Westell World Wide Web site at
http://www.Westell.com.
7. WARRANTY & REPAIRS
7.1 Westell warrants this product to be free
of defects at the time of shipment. Westell
also warrants this product to be fully
functional for the time period specified by the
terms and conditions governing the sale of
the product. Any attempt to repair or modify
the equipment by anyone other than an
authorized Westell representative will void
the warranty.
7.2 Westell will repair or replace any
defective Westell equipment without cost
during the warranty period if the unit is
defective for any reason other than abuse,
improper use, or improper installation. To
return defective equipment, first request a
Return Material Authorization (RMA) number
from Westell by calling or using one of the
options shown below. Once an RMA number
is obtained, return the defective unit (freight
prepaid), along with a brief problem
description, to the address we will provide to
you when you contact us.
email: rgm[email protected]
Replacements will be shipped in the fastest
manner consistent with the urgency of the
situation. Westell will continue to repair or
replace faulty equipment beyond the
warranty period for a nominal charge.
Contact Westell for details.

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Noran Tel
Mounting Options

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9
Noran Tel
1234
C
NC
NO
BUS A
C
NC
NO
BUS B
ALARMS
9 8 76 5 9 8 76 5
1234 A
BAT
RTN
TPA TPA
BAT
A
RTN
GMT
98765GMT
9 8 76 5
BAT
B
RTN
B
BAT
RTN
TORQUE 1
4" STUDS TO 5.5 FT-LB
GMT
5 6 7 8 9 GMT
5 6 7 8 9
TPA 1 4 4TPA
1
!
!

BUS A BUS B
A
B
V
I

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