Cooper Lighting S280-79-10 manual 37

!

SAFETY FOR LIFE

S280-79-10

Grounding on a 3-Wire Uni-Grounded System

Installation of a Form 5 control on a 3-wire uni-ground system must include the following:

•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.

!	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

	Supply Voltage	Form 5 LS Control	Input Terminal Block
Line	Transformer
		AC
to
Line		Neutral
Voltage
			External Ground Lug
ELECTRICAL CONNECTIONS - Dedicated Supply
		Transformer
		Surge
		Arrester	Surge
	Surge		Arrester
	Arrester
			Recloser
		HOT	Head Ground
		NEU
		GND
			Arrester Ground
	Supply
	Voltage
			Recloser
			Control
	Form 5 LS		Cable
	Control
	Input Terminal Block
		AC NEU
	Customer Ground
	Connection
	at External Lug
Control Height must be		Pole
		Ground
3 Meters (10 feet)
minimum above earth

IMPORTANT: In pole-mounted applications, a ground connection must be made between the recloser, transformer, 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 Form 5 control must be routed within 8 inches of their corresponding ground. During a surge, a potential of approximately 1.5kV per foot can develop in the con- ductors. Differences between conductor and ground path lengths can add additional stress to the control components in the event of a power surge.

Figure 31.

Recommended grounding method for the Form 5 Control installed on a 3-wire uni-grounded system.

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