P
AGE
11
OF
26
DGF100
reference
manual, rev 1, Feb 22, 2022
Ground
Fault
Systems
B.V.
4.
C
ONNECTIONS
AND
PRECAUTIONS
Please consult the following checklist when applying the DGF100.
1.
for typical field connections.
2.
If the DGF100 is used for alarming only purposes, or if the G/F Trip Delay Time is set to 1 s or
higher, verify that the DGF100 cannot be subjected to conditions exceeding its Thermal Withstand
Capability (see
3.
Place the DGF100 in a clean dry enclosure. Locate the unit in the vicinity of the isolating device
(circuit breaker or contactor) that is protecting the circuit being monitored.
4.
Provide maximum clearance between the DGF100 (plus the external CS if used) and any strong
magnetic flux producing devices such as power transformers, autotransformers, control
transformers, reactors, high power conductors, contactors and other buswork.
5.
Lead the power conductors of the circuit being monitored, (including Neutral if any and excluding
the ground wire) through the internal OR external CS’s opening. WARNING: Never lead conductors
through both the internal and the external CS at the same time.
6.
All connections to the DGF100 are by means of screw clamp pull-apart terminals rated 10 A, 300 V.
Terminals will accept 0,5-2,5 mm
2
, (20-14 AWG) solid or stranded conductors. The user may want to
identify the following terminals:
T1 and T2 for connecting an external CS, use 2-2,5 mm
2
, 14 AWG stranded wire.
R1 and R2 for connecting an external momentary, N.O., voltage free, pushbutton.
FB
for providing an absolute ground reference to the system (refer to
), use
2-2,5 mm
2
, 14 AWG stranded wire.
L+
for connecting ac or dc Control Voltage’s ‘hot’ side.
N-
for connecting ac or dc Control Voltage’s ‘cold’ side.
11 and 12 for access to the normally closed (N.C.) contact of the relay.
13 and 14 for access to the normally open (N.O.) contact of the relay.
7.
In order to meet the Electromagnetic Compatibility (EMC) requirements a firm and short connection
is required between terminal FB and the chassis ground point. The chassis ground must not be more
than 50 mm away from the unit.
8.
If the DGF100 is mounted on a 35 mm DIN rail, a ‘DIN rail ground terminal block’ can be installed
beside the unit to act as the chassis ground point.
9.
For good EMC behaviour it is important (as in any installation) to run all wiring, especially if
unshielded, close along the chassis or in metal ducts, avoiding excess lengths and coiled up wires.
10.
Integrate the relay contacts into the control circuit. Apply appropriate fusing to protect the contacts
(13 A maximum).
11.
If an external CS is being used, connect the two secondary terminals of the CS to terminals T1 and
T2 of the DGF100 using 2 mm
2
(14 AWG) shielded twisted pair cable. Connect the shield to chassis
ground by means of a clamp, close to the DGF100 (where the FB terminal is bonded to chassis
ground as well). From the clamp to terminals T1 and T2 the wires can be left unshielded. Please
note that terminal T2/R2 is internally connected to terminal FB of the DGF100. Since terminal FB
must be grounded, it means that the external CS will be grounded automatically. If separate
grounding is required by electrical regulations, the external CS terminal connected to T2 should be
connected to the same grounding point as terminal FB of the DGF100. This will avoid ground loops
and nuisance tripping.
12.
Secure the unit to the DIN rail ensuring the white release latch at the bottom of the unit engages
the rail. If the unit is to be mounted in any other position take appropriate steps to prevent the unit
from becoming disengaged from the DIN rail.
