MN008006EN Manual
Efective March 2021
NOVA LBS Load Break Switch
www.eaton.com/cooperpowerseries
13
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 switch bushings and the supplying
transformer with lightning arresters.
• Grounding of the switch head and tank.
• Grounding of the transformer tank.
• Grounding of the control cabinet.
• Grounding of the SCADA equipment.
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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.
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
CAUTION
Hazardous Voltage. Do not use a shared low-voltage network to power
the switch control unless the network is specifically designed to
withstand maximum ground potential rise. Ground faults on a
highvoltage network can create a rise in ground potential
IMPORTANT
In pole-mounted applications, a ground connection must be made
between the switch, transformer, LBC control, and SCADA equipment
for proper protection of the equipment. An improper ground
connection can cause equipment damage and malfunction. The pole
ground must be sized per local utility practices to minimize the
impedance between the switch 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.
Figure 13.
Recommended grounding method for LBS switches with LBC control and 3-wire system with single ground.
