Cooper Power Systems NOVA 15 - Grounding on a 3-Wire Uni-Grounded System

Installation on a 3-wire uni-grounded system must include
the following (refer to Figure 13):
• Protection of the recloser bushings and the supplying
transformer with lightning arresters.
• Grounding of the recloser head and tank.
• Grounding of the transformer tank.
• Grounding of the control cabinet.
• Grounding of the SCADA equipment.
S280-42-1
13
!
SAFETY
NOW
!
SAFETY
FIRST
!
SAFETY
FOR YOUR SAKE
!
SAFETY
MAKES SENSE
!
SAFETY
USE IT
!
SAFETY
FOR LIFE
Grounding on a 3-Wire Uni-Grounded System
TRANSFORMER
500 VA SUPPLY MINIMUM
SURGE
ARRESTER
POLE
SUPPLY VOLTAGE
(14 GAUGE MINIMUM)
POLE GROUND
(6 GAUGE MINIMUM)
KYLE
CONTROL
CUSTOMER GROUND
CONNECTION
AT EXTERNAL LUG
NEU
AC
GND
NEU
AC
INPUT
TERMINAL
BLOCK
CONTROL
CABLE(S)
RECLOSER
GROUND
CONNECTOR
NOVA
RECLOSER
ARRESTER
GROUND
SURGE
ARRESTER
ARRESTER
GROUND
SURGE
ARRESTER
Control Height must be
3 Meters (10 feet) min.
above earth.
Figure 13.
Recommended grounding method for NOVA reclosers with Cooper microprocessor-based control on a 3-wire
uni-grounded system.
IMPORTANT: In pole-mounted applications, a ground
connection must be made between the recloser, trans-
former, recloser control, and SCADA equipment for
proper protection of the equipment. The pole ground
must be sized per local utility practices to minimize the
impedance between the recloser and the control.
IMPORTANT: All external inputs to the control must be
routed within 8 inches of their corresponding ground.
During a surge, a potential of approximately 1.5 kV per
foot can develop in the conductors. Differences between
conductor and ground path lengths can add additional
stress to the control components in the event of a power
surge.
WARNING: Hazardous Voltage. Use locally
approved operator safety procedures for proper
insulation when maintaining this equipment. High voltage
step and touch potential is characteristic in uni-ground
systems. Failure to comply can cause death or severe
personal injury. T262.0
CAUTION: Exported Potential. Do not make direct
electrical connections to remote devices. All SCADA
equipment must be mounted locally or connected using
the fiber-optic or radio communication accessory. Direct
connections to remote devices can produce exported
potential causing equipment damage or personal injury.
T263.0
CAUTION: Hazardous Voltage. Do not use a shared
low-voltage network to power the recloser control
unless the network is specifically designed to withstand
maximum ground potential rise. Ground faults on a high-
voltage network can create a rise in ground potential.
T264.0