Installation
13
Note: Before energizing the breaker, install a proper rat-
ing plug. Refer to
Section 2.7, Inserting and
Removing the Rating Plug
.
Note: Take care not to pinch any wires when replacing the
front cover of the breaker.
2.7
Inserting and Removing the Rating
Plug
The trip unit executes its overcurrent protection functions
based on the rating plug value and the setting of the current
adjustments. Therefore, care should be taken to make proper
selections and settings. All pick-up values, except ground
fault, are multiples of the rating plug value, I
n
. Ground fault
pick-up is a multiple of the Max ampere rating, up to a maxi-
mum of 1200 amperes. All pick-up settings are expressed in
RMS amperes.
Field interchangeable rating plugs are used to set the effective
ampere rating of the circuit breaker. Available rating plugs for
each frame ampere rating appear in the following table. Note
that the maximum rating plug value for a particular trip unit is
equal to the Max ampere rating. A rejection scheme is built into
the rating plugs and trip units to prevent the insertion of a rat-
ing plug into a trip unit for which it is not intended.
Follow these steps to install the rating plug.
Note: Prior to inserting or removing a rating plug, check to
see that the circuit breaker is in the “Open” position.
The circuit breaker should always be in the “Open”
position when a rating plug is not in the trip unit.
Take precautions to prevent damage to equipment
protected by the breaker prior to opening the
circuit.
1.
Check the label on the rating plug.
Before attempting to insert the rating plug, check the label on
the rating plug to verify that it is a proper plug for the trip unit. If
it is not a proper plug, the pins on the plug will not mate with
the connector in the trip unit.
2.
Remove the plexiglass shield.
Inserting and removing the rating plug requires removal of the
clear plexiglass shield. To remove the shield, remove the two
screws that hold it in place.
Table 2.2
Available Rating Plugs
Max Ampere Rating
Rating Plug Ampere Values, I
n
400
200, 225, 250, 300, 350, 400
800
400, 450, 500, 600, 700, 800
1200
600, 700, 800, 1000, 1200
1600
800, 1000, 1200, 1600
2000
1000, 1200, 1600, 2000
2500
1600, 2000, 2500
3200
1600, 2000, 2500, 3000, 3200
4000
2000, 2500, 3000, 3200, 4000
5000
2500, 3000, 3200, 4000, 5000
Cat No
.
Use With
Type
SB
Trip Unit Rated
Rating Plug
I
r
= 2000 A
