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STS 300 Series Electronic Indicating Ground Assembly
Installation and Operating Instructions
Special Technical Services Inc • 354 US Highway 46 Suite 1C • Hackettstown, NJ 07840
Phone (609) 259-2626 • Fax (609) 259-0044 • Email info@specialtechnicalservices.com
Installation:
Note: Installation of this equipment should be performed by a
licensed electrician and according to all applicable
requirements of the NEC and local authorities.
Mounting: Four 5/16-18 mounting holes are provided on the
back of the enclosure to secure to Unistrut type rack. Refer to
Figure 1. Optimal height of the installation is eye-level of the
operator. A seal fitting (not included) is required immediately
before the supply conduit enters the top of the enclosure.
After wiring and testing, the seal fitting is required to be filled
with the proper sealing compound. Failure to do so could
result in vapors and liquids being able to enter the enclosure
causing damage, explosion, bodily harm. The (14) 5/16" bolts
that secure the cover should be torqued to 11 ft-lb.
An optional power on/off switch rated for the environmental
conditions can be installed to disconnect power to the unit
while not in use. This will extend the life of the indicating
bulbs.
Electrical Connections: Refer to Figure 2. Supply voltage
should be in accordance with the rating specified on the
nameplate on the front cover. Connect supply voltage to
terminals 1 & 2. There are no connections to terminals 3 &
4. Connect NO and NC closed contacts to interlocking
control contactors to permit operation of pumps etc. when
proper ground is detected. Do not connect these contacts
directly to motor loads.
A permanent ground cable (Type SOOW) must be connected to the
enclosure ground screw and to a grounding bus or rod. Refer to
Figure 3 for details.
R5
Operation and Care:
Attach grounding clamp at the end of ground cable to metal
frame of vehicle, vessel, railcar, barge, etc. The red light
should turn off and the green light should turn on when a
good ground connection is made. At the same time, all
auxiliary contacts will change state, allowing pump, blower,
etc. to operate.
Both ground cables should be inspected regularly to insure
there is no damage to the insulation. Damaged insulation
may impair the proper operation of the grounding device. All
hardware should also be checked to insure proper tightness.
Model
Connection
Nominal Voltage
Connection
G2
120VAC
N
L
G4
240VAC
L
L
G12
12VDC
-
+
G24
24VDC
-
+
Max Voltage
Min Voltage 102VAC 204VAC 9VDC 18VDC
130VAC 240VAC 15VDC 30VDC
12345678910
NC2
NC1
NO2
COM2
NO1
COM1
No Connection
No Connection
DRY CONTACTS
10A 250VAC
*NOTE: NO: NORMALLY OPEN CONTACT THAT CLOSES WHEN GROUND IS ESTABLISHED
NC: NORMALLY CLOSED CONTACT THAT OPENS WHEN GROUND IS ESTABLISHED
Figure 2
R
G
Customer Connections
*Note
*Note
Terminal Block
Mounted Inside
Explosion-Proof
Enclosure
Figure 1
4.500 in
[114.300 mm]
(4) 5/16" – 18
THREADED
MOUNTING
HOLES
½” DEEP
¾” - 14 NPT
CONDUIT
OPENING
11.125 in
[282.575 mm]
13.750 in
[349.25 mm]
4.375 in
[111.125 mm]
5.000 in
[127.000 mm]
3.250 in
[82.550 mm]
Figure 3
CASE GROUND
10-32 3/8" SCREW
WHITE WIRE
SOOW CORD 600V
GROUND ROD
FOR REMOTE
LOCATIONS
BLACK
WIRE
INTEGRITY GROUND
CONNECTIONS STUD
WHERE AVAILABLE, CONNECT
TO PLANT BONDING BUS OR
CABLE. CONNECT EACH WIRE
SEPARATELY
CASE GROUND AND INTRINSIC GROUND
STUD MUST BE CONNECTED SEPARATELY
AT GROUND ROD UNDERS SEPARATE
ACORN CLAMPS.
TO GROUND
CLAMP OR
DEADMAN
CONTROL
WHITE
WIRE
BLACK
WIRE
WHITE WIRE ON
10-32 3/8" SCREW
GROUND CABLE BY
FACTORY
LOCKOUT
(RED) PERMISSIVE
(GREEN)