23
Instruction Leaflet
IL01301051E
effective September 2013
Operating Manual for Series NRX
Trip Units - Digitrip™ 520/520M
EATON
www.eaton.com
Section 6: Rating plugs
The rating plug defines the rated current (In) for the trip unit and is the
basis for the trip unit current settings:
1. The instantaneous and ground current setting (if provided) are
multiples of (I
n
)
2. The long delay current setting, (I
r
), is a fractional multiple of (I
n
):
L
ong
D
elay current setting = (I
r
) = LD x (I
n
)
3. The short delay current setting is a multiple of (Ir):
S
hort
D
elay current setting = SD x (I
r
) = SD x [LD x (I
n
)]
A rating plug value, (I
n
), that is less than the breakers maximum
continuous current rating (as listed on the nameplate of the breaker I
u
)
may be chosen to be the basis for the coordination of the protection
function of the circuit breaker without affecting its short-circuit current
capability.
Generally, ratings plugs are defined per customer breaker selection
upon ordering and are installed in the factory. Field-installable kits are
also available as defined in
Tables 9
and
10
.
•
WARNING
THE RATED CURRENT VALUE OF A RATING PLUG MUST NOT EXCEED
THE MAXIMUM CURRENT FRAME RATING AS LISTED ON THE BREAKER
NAMEPLATE.
For the Series NRX-NF frame, there are three groupings of rating plugs
available: Group A, Group B, Group C (
Table 9
). It is important to select
the proper group when choosing another replacement rating plug for
a particular circuit breaker application. The identification label on the
cover of the circuit breaker will identify the proper group rating plug
required.
For the Series NRX-RF frame, there are four groupings of rating
plugs available: Group D, Group E, Group F and Group G (
Table 10
).
The identification label on the cover of the circuit breaker will identify
the proper group rating plug required if a replacement rating plug is
desired.
Table 9. Series NRX NF Frame Raoing Plugs
Group A
Group B
Group C
Frame Size
630A
800A
1000A
1200A
1250A
1600A
RP
I
n
Catalog Number
Catalog Number
Catalog Number
400
x
x
NA400T
IZMX_RP40A-400
x
x
x
NB400T
IZMX_RP40B-400
-
-
500
x
x
NA500T
IZMX_RP40A-500
x
x
x
NB500T
IZMX_RP40B-500
-
-
600
x
x
NA600T
IZMX_RP40A-600
x
x
x
NB600T
IZMX_RP40B-600
-
-
630
x
x
NA630T
IZMX_RP40A-630
x
x
x
NB630T
IZMX_RP40B-630
-
-
800
-
x
NA800T
IZMX_RP40A-800
x
x
x
NB800T
IZMX_RP40B-800
x
NC800T
IZMX_RP40C-800
1000
-
-
-
x
x
x
NB1000T
IZMX_RP40B-1000
x
NC1000T
IZMX_RP40C-1000
1200
-
-
-
-
x
x
NB1200T
IZMX_RP40B-1200
x
NC1200T
IZMX_RP40C-1200
1250
-
-
-
-
-
x
NB1250T
IZMX_RP40B-1250
x
NC1250T
IZMX_RP40C-1250
1600
-
-
-
-
-
-
-
x
NC1600T
IZMX_RP40C-1600
IEC Only - (not UL Listed)