40
Guideform Specifications
(cont.)
Trip devices
Power+™ trip unit
1. Each circuit breaker shall be equipped with a protective trip unit
system to open the breaker for overloads, short circuits <and
ground faults> as specified in the following subparagraphs. The
protective trip unit system shall consist of a solid-state, microproces-
sor-based trip unit, current sensors, trip actuator and interchange-
able rating plugs.
2. As a minimum, the trip unit shall have the following features and
functions:
a. The housing shall be a metallic enclosure to protect against
magnetic interference, dust and other contaminants.
b. The protective system shall have reliable programmable con-
trols with repetitive accuracy and precise unit settings.
Overcurrent characteristics (pickup and delay) shall be selected
via rotary switches with detented settings.
c. All current sensing shall employ true rms technology for detect-
ing overloads, <short time> overcurrent conditions and
<ground fault conditions>.
d. The optional Target Module shall be equipped with long-life
lithium batteries - with automatic time delay shut-off feature - to
provide observation of trip targets. The Target Module and bat-
teries shall not be required for the trip unit to provide its pro-
tective functions.
e. UL listed field installable, 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. Rating plugs shall also be used to provide the trip unit
with ground fault protection. Rating plugs shall be available
with or without ground fault pickup and delay setting switches.
It shall be possible to add ground fault protection to a trip unit
by simply replacing the rating plug.
f. Integral test jack for connection of a battery pack or test kit to
the breaker.
g. (When specified) the ground fault function shall contain a
memory circuit to integrate low level arcing fault currents with
time to sum intermittent ground fault current spikes.
h. A cover with provisions for sealing the rating plug and trip unit
to make the installation tamper-resistant. All trip unit settings,
ratings, and target information shall be capable of being viewed
with the cover in place.
i. The unit shall be dual-rated for both 50Hz and 60Hz operation.
Noise immunity shall meet the requirements of ANSI Standard
C37.90.2
j. The trip unit shall display trip targets for longtime, short time,
instantaneous and ground fault trips (with optional Target
Module)
3. The trip units for the main and tie breakers shall include the fol-
lowing protective functions:
a. Adjustable long time current settings.
b. Adjustable long time delay with four time delay bands.
c. Long time pickup warning indicator (with optional Target
Module).
d. Trip targets for overload, short circuit <and ground fault> (with
optional Target Module).
e. Adjustable short time pickup and delay, with three delay bands,
and switchable I
2
t ramp.
f. SELECT ONE OF THE FOLLOWING IF GROUND FAULT
PROTECTION IS REQUIRED:
1) <Adjustable ground fault pickup and time delay, with three
delay bands, and switchable I
2
t ramp.>
2) <Defeatable ground fault function with adjustable pickup
and time delay, with three delay bands, and switchable I
2
t
ramp.>
4. The trip units for feeder breakers shall include the following pro-
tective functions:
a. Adjustable long time current settings.
b. Adjustable long time delay with four time delay bands.
c. Long time pickup warning indicator (with optional Target
Module).
d. Trip targets for overload, short circuit <and ground fault> (with
optional Target Module).
e. <Adjustable short time pickup and delay, with three delay
bands, and switchable I
2
t ramp> and/or <adjustable instanta-
neous pickup>.
f. SELECT ONE OF THE FOLLOWING IF GROUND FAULT
PROTECTION IS REQUIRED:
1) <Adjustable ground fault pickup and time delay, with three
delay bands, and switchable I
2
t ramp.>
2) <Defeatable ground fault function with adjustable pickup
and time delay, with three delay bands, and switchable I
2
t
ramp.>
5. Current sensors shall be mounted on the breaker frame and shall
use encapsulated construction to protect against damage and mois-
ture. <For ground fault protection of a four-wire power system, a
fourth - neutral current - sensor shall be mounted in the cable
compartment, and shall be compatible with the phase current sen-
sors.>
MicroVersaTrip Plus™ and MicroVersaTrip PM™
1. Each circuit breaker shall be equipped with a protective trip unit
system to open the breaker for overloads, short circuits <and
ground faults> as specified in the following subparagraphs. The
protective trip unit system shall consist of a solid-state, microproces-
sor-based trip unit, current sensors, trip actuator and interchange-
able rating plugs.
2. As a minimum, the trip unit shall have the following features and
functions:
a. The housing shall be a metallic enclosure to protect against
magnetic interference, dust and other contaminants.
b. The protective system shall have reliable programmable con-
trols with repetitive accuracy and precise unit settings.
c. All current sensing shall employ true rms technology for detect-
ing overloads, <short time> overcurrent conditions, <and
ground fault conditions>.
d. A high contrast, liquid crystal display - LCD - unit shall display
settings, trip targets, and the specified metering displays. The
trip unit shall be equipped with long-life lithium batteries - with
automatic time delay shut-off feature - to provide both program-
ming and observation of trip targets or other functions when
the breaker is de-energized.
e. A multi-button keypad to provide local setup and readout on
the LCD of all trip settings, metering values, and trip targets.
f. UL listed field installable, 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. Integral test jack for connection of a battery pack or test kit to
the breaker.
h. (When specified) the ground fault function shall contain a
memory circuit to integrate low level arcing fault currents with
