15
Instructional Leaflet
IL70C1037H05
Effective October 2009
Digitrip models 520, 520i; and 520M, 520Mi,
520MC, 520MCi trip units for use only in
Magnum and Magnum DS circuit breakers
eaton corporation
www.eaton.com
Figurt 11. SNurct GrNund Faulo Stnsing Schtmt fNr 3200A Framt
Figurt 12. SNurct GrNund Faulo Stnsing Schtmt fNr 4000A Framt—DNublt-Widt
10:1 Aux. CTs
Source
Black
Trip
Actuator
Digitrip 520
with GF
Load
a
b
c
Typical Application—Main
a
In this scheme, the residential sensing element R
5
is not used. The ground current is direct true ground current and is sensed directly via element R
4
.
b
A jumper is required on B-6, B-7 (secondary contacts) to program the Digitrip 520 to use element R
4
and input on B-4, B-5 directly for source ground sensing.
c
This scheme is not applicable to four-pole breakers. No secondary contacts (B-4 and B-5) are available on four-pole breakers. Do not jumper B-6, B-7 in four-pole applications.
Ground Return Electrode Conductor
20:1 Aux. CTs
Source
Black
Trip
Actuator
Digitrip 520
with GF
Load
a
b
d
a
In this scheme, the current sensors in the breaker poles are parallel-wired to achieve a 4000A breaker rating. The ground fault is sensed directly via element R
4
.
b
A jumper is required on B-6, B-7 secondary contacts to program the Digitrip 520 to use element R
4
directly for source ground sensing.
c
Source ground sensor input is via B-4, B-5. Source ground current input to secondary contacts is 2A, equivalent to one per unit ground.
d
This scheme is not applicable to four-pole breakers. No secondary contacts (B-4 and B-5) are available on four-pole breakers. Do not jumper B-6, B-7 in four-pole applications.
Ground Return Electrode Conductor
c
