Page 2-1
FPU-32 Feeder Protection Unit
Rev.
2-A-103014
Installation
2. I
NSTALLATION
2.1 G
ENERAL
A basic system consists of an FPU-32, an MPU-CIM,
and three 1-A- or 5-A-secondary line-current transformers.
Earth-fault protection can be provided from a core-balance
CT or from phase CT’s. A core-balance CT (1-A, 5-A, or
EFCT series) is recommended. A single PTC/RTD input is
provided on the FPU-32.
The FPU-32 switch-mode power supply is rated 65 to
265 Vac and 80 to 275 Vdc.
All modules can be mounted in any orientation.
2.2 FPU-32 F
EEDER
P
ROTECTION
U
NIT
Outline and details for FPU-32 panel-mounting are
shown in Fig. 2.1. The FPU-32 mounts in a 92-mm
(3.62”), ¼ DIN, square cutout and is secured by a
panel-mount clamp. Insert the FPU-32 through the panel
cutout and slip the panel-mount clamp over the FPU-32
body. Slide the clamp forward until the latch tabs snap
into the mating holes. Lock the unit in place by
tightening the four clamp screws against the panel.
C
AUTION:
Do not over tighten the clamp screws as this
may deform the clamp and release the latch tabs.
Outline and details for FPU-32 surface-mounting are
shown in Fig. 2.2. Ensure that the L/S switch is set before
installing surface-mounting brackets. See Section 3.2.1.4
for switch positions. A detailed installation instruction
sheet is included with the MPU-32-SMK Surface-
Mounting Hardware Kit.
2.3 MPU-CIM C
URRENT
I
NPUT
M
ODULE
The MPU-CIM can be surface or DIN-rail mounted.
Outline and mounting details are shown in Fig. 2.3. To
minimize CT-lead burden, an MPU-CIM can be located
close to the CT’s. The MPU-CIM terminates phase- and
earth-fault-CT secondaries
shorting blocks are not
required for MPU-CIM outputs.
2.4 E
ARTH-
F
AULT
CT’
S
Outline and mounting details for the EFCT-1, EFCT-2,
and EFCT-26 are shown in Figs. 2.4, 2.5 and 2.6.
2.5 FPU-32/FPU-16 C
OMPATIBILITY
The FPU-32 is hardware compatible with existing
FPU-16 installations, except that it has a temperature
sensor input and does not include an operations counter.
An FPU-32 can replace an FPU-16 with minimal wiring
changes. I/O connections to FPU-16 terminals 13 to 16
and 21 to 24 are identical to those on the FPU-32 and
should be transferred to the plug-in terminal blocks
supplied with the FPU-32. If a switch was connected to
the FPU-16 program-enable terminal 21 and a hard-wired
program enable is required, it can be implemented using
digital-input terminals 25 and 26 as outlined in Section
4.2.6. A hard-wired program enable is often not required
since the FPU-32 set points are password protected. If the
FPU-16 analog output was used, ensure that the FPU-32
analog output switch is set to the ‘S’ (Self Powered)
position.
Although FPU-32 terminals 1 to 12 have been
rearranged to provide a third relay output (terminals 1, 4,
and 9), the FPU-16 lower terminal block can be safely
plugged into the equivalent FPU-32 terminal locations.
C
AUTION:
The keying plug installed in position 9 of the
FPU-16 lower terminal block must be removed before the
terminal block can be plugged into an FPU-32. Use a
dental pick, awl, or similar pointed tool to remove the
keying plug. If the keying plug is difficult to remove, use
the terminal blocks supplied with the FPU-32.
A TERMINAL BLOCK WITH A KEYING PLUG WILL
DAMAGE THE FPU-32.
If the FPU-32 does not power up, ensure that L1 is
connected to terminal 2 (not terminal 1) and L2/N is
connected to terminal 3 (not terminal 4). If the duplicate
L1 and L2 terminals on the FPU-16 are used to power
another device, disconnect the outgoing L1 and L2 leads
and power the next device directly from the power source.
This change is in compliance with current codes that do
not permit daisy chaining power connections at plug-in
terminals. FPU-32 default relay assignment is the same
as the FPU-16 trip- and alarm-relay configuration.
For additional information see www.littelfuse.com/
relayscontrols and refer to Technical Note FP-02
Replacing an FPU-16 with an FPU-32.
