Effective 8/2006
Page 5
I.L. 66A7534H04
1.4 Installing the CH Type-V Current Sensors
The internal components of the circuit breaker, and how
they are wired out to the breaker secondary contacts are
shown in Figures 1.4, 1.5, 1.6 and 2.3. Also refer to the
master connection diagram provided in Appendix C.
1.4.1 Installation Procedure
The CH Type-V Current Sensors/Rating Plug Kit supplied
with this breaker must be installed and wired by the user.
The installation steps are as follows:
a. PRIMARY - Mount one CH Type-V current sensor on the
insulated bushing behind the circuit breaker. The bushing
must be rated for the system Lightning Impulse Withstand
Voltage (LIWV), and the ground (earth) shield terminal or
ground (earth) shield surface must be connected to the
ground (earth) bus. Confirm that the polarity mark (red dot)
on the front of the current sensor faces the circuit breaker.
b. SECONDARY - Connect secondary terminals of the
current sensor to the correct terminals in the switchgear
control circuit using #14 AWG Type SIS wire. Terminal X1
is the one nearest to the polarity mark. Refer to Appendix
C for distinction between Fixed and Drawout variations.
Consult manufacturer if length of wire to device exceeds 12
feet (3.7m).
c. Use ring terminals on current sensor terminals. Use
AMP #66598-2 female sockets to connect to breaker’s
secondary connector.
d. Ground (Earth) the non polarity terminal of each sensor.
Also Ground the bushing shield surfaces.
e. Install rating plug into the Digitrip 520V and 520MCV trip
units for the matching CH Type-V current sensors. Also
attach the additional rating plug label to the circuit breaker
enclosure as a future reference indicating which CH Type-V
current sensors used in this application.
1.4.2 CH Type-V Current Sensor Functionality
The three CH Type-V current sensors are installed external
to the circuit breaker over the main circuit conductors by
means of bushings equipped with a ground shield. The
current sensor rating defines the breaker rating (
I
n)... i.e.
1200A:1A sensors are used on a 1200A rated breaker.
There are four auxiliary current transformers with a ratio of
10:1 which further step down the rated current to 100 milli-
amperes, which is equivalent to 100% (
I
n) to the Digitrip.
The primary current sensors produce an output signal
proportional to the load current and furnish the Digitrip trip
units with the information and energy required to trip the
circuit breaker when functional protection settings are
exceeded.
If the CH Type-V current sensors and circuit breaker
enclosure label are changed to a different ratio, the rating
plug must also be changed. The associated rating plug
must match the current sensors installed and as specified
on the circuit breaker enclosure label. Refer to Figure 2.3
for CH Type-V current sensors available.
1.5 Plexiglass Cover
A clear, tamper-proof, plexiglass door sits on the breaker
cover. This door allows the settings to be viewed but not
changed, except by authorized personnel. The plexiglass
cover meets applicable tamper-proof requirements. The
cover is held in place by two screws. Security is insured
by the insertion of a standard meter seal through the holes
in both of the cover retention screws. The plexiglass cover
has an access hole for the
Reset/Battery Test
push
button.
1.6 Ground Alarm/Power Supply Module (520MCV
Models Only)
The Ground Alarm/Power Supply Module
(See Figure 1.7)
is a required accessory to enable communications on the
Digitrip 520MCV model. The module can be installed
beneath the metal mounting plate of the trip unit in the
Magnum Circuit Breaker. The module covers the following
input voltage ratings: 120 VAC (7802C83G11), 230 VAC
(7802C83G12), 24-48 VDC (7802C82G12) and 125VDC
(7802C8213). The burden of the Power/Relay Module is
10VA.
Figure 1.4 CH Type-V Current Sensor Installation
