Rating Plug; Current Sensors; Figure 34 . Digitrip Rms 1150 Programmable Trip Unit; Figure 35. Hand Held Tester - Eaton SBN-508 Instructions For Installation, Operation And Maintenance

Instructional Leaflet
Effective March 2012

Rating Plug

All Magnum SB circuit breaker trip units use a fixed type
rating plug . The current rating of the rating plug must match
the current rating of the integrally mounted current sensors
(Figures 6 and 34 and Table 6) . The rating plug performs
several functions:
1 It tells the trip unit what the rating is of the current sensors .
A label on the front of the rating plug clearly indicates that
the rating plug and sensors must have the same rating .
2 It determines the maximum instantaneous setting which is
a function of the current sensor rating .
3 The National Electrical Code (NEC) requires that the
maximum ground fault pickup value not exceed 1200
amperes . A properly matched rating plug accomplishes this
requirement for higher ampere sensors by incorporating
circuitry to identify that level by sensor rating .
If the rating plug is removed from the trip unit, the circuit
breaker will trip if it is carrying current . Make certain the rating
plug is secured in position with its retaining screw . Do not
torque the retaining screw beyond 15 In-Oz .
Refer to Table 6 for a tabulation of the available rating plugs .

Current Sensors

Three toroidally wound current sensors are installed at the
rear of the circuit breaker on the lower terminals (Figure 36) .
The sensors produce an output current proportional to the load
current . Under preselected conditions of current magnitude
and time, the sensors furnish the trip unit with a signal and the
energy required to trip the circuit breaker .
Neutral current sensors are available for customer installation .
The additional sensor is not supplied with the circuit breaker
and must be ordered separately . They are wired to the trip unit
through the secondary contacts of the circuit breaker .
Refer to Table 6 for a tabulation of the available current sensor
ratings .
26 EATON CORPORATION www.eaton.com
IB2C12063H03
Instructions for Installation, Operation and
Maintenance of Magnum SB Insulated Case
Low Voltage Power Circuit Breakers
Figure 34. Digitrip RMS 1150 Programmable Trip Unit Installed in
Magnum SB Circuit Breaker

Figure 35. Hand Held Tester

Pop Out Trip
Flag
Auxiliary Power
Module Port
Rating Plug
Test
Receptacle