Emerson FPC user manual System Grounding, Equipment Grounding

Installation Instructions

Figure 10 Low voltage control junction box connections, typical

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Building

Interface

Relay

Factory-supplied low-voltage control cable

Figure 11 Main input junction box connections, typical

	A
	B
	C
Customer input	N
power connection
3-phase, 3-wire + GND
for units with transformer	G
3-phase, 4-wire + GND
for units without transformer

Factory-supplied input power cable assemby

NOTE: Parallel cables are used on units with higher-ampacity

Neutral busbar and wire furnished on units without transformer

1.3.3System Grounding

The performance and safety of any power conditioning system depend on proper grounding. Figure 12 shows the typical grounding arrangements for the Liebert FPC.

Equipment Grounding

Equipment grounding is primarily for safety. Correct implementation of grounding also enhances equipment performance. All power feeders must include equipment grounding means as required by the NEC and local codes.

An insulated ground conductor is recommended to be run in each feeder conduit. Ground conductors must be at least the minimum size per NEC Table 250-66. Larger wire sizes may be used for increased system performance.

If the input power feeder conduit is used as a grounding conductor, adequate electrical continuity must be maintained at all conduit connections.

! CAUTION

Using isolating bushings in a metal conduit run can be a safety hazard and is not recommended.

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