Gorman-Rupp Pumps S3A1 460V 3P All serial numbers Control Box - Manual (Page 12)

OM−05169 CONTROL BOXES
PAGE B − 6 INSTALLATION
ELECTRICAL CONNECTIONS
Obtain the services of a qualified elec-
trician to make all electrical connec-
tions and to service the control box.
The electrical power used in this control
box is high enough to cause injury or
death. Make certain that the control box
is properly grounded after installation.
Make certain that the power source
phase and voltage matches the data on
the control box. Complete all electrical
connections before connecting the
power supply to the control box. Make
certain to ground the appropriate lead
of the power source before connecting
power to the control. Make certain that
the control box is properly grounded af-
ter installation.
Grounding Methods
Electrically ground the installation before connect-
ing the field wiring to the control box. Install a
grounding terminal to the enclosure and connect it
to a properly embedded electrode.
The material used for the electrode must be an ex-
cellent conductor of electricity, such as copper. If
iron or steel is used, it must be galvanized or other-
wise metal plated to resist corrosion. Do not coat
the electrode with any material of poor conductiv-
ity, such as paint or plastic.
The electrode must conform to the recommenda-
tions of N.E.C. ARTICLE 250. Follow all installation
requirements of the N.E.C., and all applicable
codes. See Figure B−2 for some suggested
grounding methods.
ROCK
8 FEET
(2,4 M)
3/4 INCH (19,1
MM) NOMINAL
DIAMETER
(MINIMUM)
SOIL SOIL SOIL
1/4 INCH STEEL
PLATE 2 SQ. FEET
(1858,1 SQ. CM)
SURFACE AREA
(MINIMUM)
a) PLATE ELECTRODE b) DRIVEN ELECTRODE c) BURIED ELECTRODE
3/4 INCH (19,1 MM)
NOMINAL DIAMETER
(MINIMUM) 8 FEET
(2,4 M) LONG
Figure B−2. Suggested Grounding Methods
a. Plate Electrode: An iron or steel plate, 1/4
inch (6,4 mm) thick, completely impeded in
the ground. The plate must present a surface
area of at least 2 square feet (1858,1 sq. cm).
b. Driven Electrode: A rod or pipe, 3/4 inch
(19,1 mm) in diameter minimum, 8 feet (2,4 m)
long, completely driven into the ground.
c. Buried electrode: If rock or stone prevents
embedding the full 8 foot (2,4 m) length of the
ground rod, bury it horizontally in a trench.
Space the ground rod or plates at least 6 feet
(1,8 m) from any other electrode or ground
rod, such as those used for signal circuits, ra-
dio grounds, lightning rods, etc.
The earth surrounding the ground rod or plate
must contain enough moisture to make a
good electrical connection. In dry or sandy ar-
eas, pour water around the rod, or consult
qualified personnel to devise a method of im-
proving the connection.