Guide Form Specifications
Breaker Protective System (MicroVersaTrip Plus™ and
MicroVersaTrip PM™)
1. Each circuit breaker shall be equipped with a protec
tive trip unit system to protect against overloads, short
circuits (and ground faults) as specified in the following
subparagra phs. The protective trip unit shall consist of a
solid-state, microprocessor-based, programmer: tripping
means; current sensors; power supply and other devices
as required for proper operation.
2. As a minimum, the trip unit shall have the following fea
tures and functions:
1 1 0
a) The housing shall be a metallic enclosure to protect
against magnetic interference, dust and other con
tam inants.
b) The protective system shall have reliable program
mable controls with repetitive accuracy and precise
unit settings.
c) All current sensing shall employ true rms tech nology
for detecting overloads, (short-time overcurrent con
ditions), h i gh-level i nstantaneous overcurrent condi
tions, (and g round-fault conditions).
d) A high-contrast, liquid crystal d isplay - LCD - unit
shall display settings, trip targets, and specified
metering displays. The trip unit shall be equipped with
long-life lithium batteries - with automatic time delay
shut-off features - to provide both programming and
observation of trip targets or other functions when
the breaker is d e-energized.
e) A multi-button keypad to provide local set-up a nd
readout on the LCD of all trip settings.
f) UL Listed, CSA Certified, I EC 947-2 Certified, field-in
stallable, interchangeable rating plugs. It shall not
be necessary to change or remove the trip unit to
change the trip rating. Rating plugs shall contain
rejection features to prevent installation of a plug with
an incorrect current sensor rating.
g) I ntegral test jack for connection of a battery pack or
test kit to the breaker.
h) (When specified) the ground-fault function shall
contai n a memory circuit to integrate low-level arcing
fault currents with time to sum intermittent ground
fault current spikes.
i) A mechanism with provisions for sealing the rating
plug, the trip unit, a nd the " ENTER" key on the protec
tive trip unit to make the installation tamper-resistant.
j) The unit shall be dual-rated for both 50Hz and 60Hz
operation. Noise immunity shall meet the require
ments of ANSI Standard C3 7.90.2
k) The trip unit shall have an integral, resettable trip
counter to record the number of long-time, short
time, instantaneous and ground-fault trips.
I) The trip unit shall display trip targets for long-time,
short-time, instantaneous and ground-fault trips.
3. The trip units for the main and tie breakers shall include
the following protective functions:
a) Adjustable long-time current settings.
b) Adjustable long-time delay with fou r time delay
bands.
c) Long-time pickup warning indicator.
d) Trip targets for long-time. instantaneous (and short
time, when specified). and g round fault (when speci
fied).
e) S ELECT O N E OF THE FOLLOWI N G
1) Adjustable instantaneous pickup.
2) Adjustable short-time pickup and delay, with three
delay bands, and switchable 12t ramp and
adjustable instantaneous picku p.
3) Fixed high-range instantaneous pickup.
f) OPTIONAL: Adj ustable g round-fault pickup and time
delay, with three delay bands and switchable l2t
ramp.
g) OPTIONAL: Zone-selective i nterlocking [SELECT O N E)
(for ground-fault conditions) (for both ground-fault
and short-time conditions).
4. The trip units for feeder breakers shall include the follow
ing protective functions:
a. Adjustable long-time current settin gs
b) Adjustable long-time delay with four time delay
bands.
c) Long-time pickup warning indicator.
d) Tip targets for long-time, instantaneous (and short
time, when specified). and g round fau lt (when speci
fied).
e) S ELECT O N E OF THE FOLLOW I N G
1 1
Adjustable instantaneous pickup.
2) Adjustable short-time pickup and delay, with three
delay bands, and switchable 12t ramp and
adjustable instantaneous pickup.
3) Fixed hig h-range instantaneous pickup.
f.)
OPTIONAL: Adjustable g round-fault pickup and time
delay, with three delay bands and switchable IZt
ramp.
g.) OPTIONAL: Zone-selective interlocking [SELECT O N E)
(for ground-fault conditions) (for both g round-fault
and short-time conditions).
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