Dell POWEREDGE 2950 - Manual (Page 5)

Cabling Instructions for the –48 VDC Power Supply
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This document describes the requirements and wiring instructions for a –48 VDC power cable and safety
ground wire for systems equipped with a –48 VDC power supply.
CAUTION:
This equipment is designed to permit the connection of the earthed conductor of the DC supply circuit
to the earthing conductor at the equipment. See installation instructions.
This equipment is designed to permit the connection of the earthed conductor of the DC supply circuit to the
earthing conductor at the equipment. If this connection is made, all of the following conditions must be met:
– This equipment shall be connected directly to the DC supply system earthing electrode conductor or to a
bonding jumper from an earthing terminal bar or bus to which the DC supply system earthing electrode
conductor is connected.
– This equipment shall be located in the same immediate area (such as, adjacent cabinets) as any other
equipment that has a connection between the earthed conductor of the same DC supply circuit and the
earthing conductor, and also the point of earthing of the DC system. The DC system shall not be earthed
elsewhere.
– The DC supply source shall be located within the same premises as this equipment.
– Switching or disconnecting devices shall not be in the earthed circuit conductor between the DC source and
the point of connection of the earthing electrode conductor.
CAUTION:
A qualified electrician must perform all connections to DC power and safety grounds. The system
must be safety grounded at the cabinet frame. All electrical wiring must comply with applicable local or national
codes and practices.
CAUTION:
The system chassis must be positively grounded to the rack cabinet frame. Do not attempt to connect
power to the system until grounding cables are connected.
CAUTION:
An energy hazard will exist if the safety ground cable is omitted or disconnected.
Precaution Statements
This product is intended for restricted access locations (dedicated equipment rooms, equipment closet,
or the like) in accordance with the National Electrical Code, American National Standards Institute
(ANSI)/National Fire Protection Association (NFPA) 70.
Wire the unit with copper only, unless otherwise specified, 10 American Wire Gauge (AWG) wire rated
minimum 90ºC in parallel for source and return. Protect the –48 V (1 wire) with a branch circuit
overcurrent protection rated 30-A rated for DC with a high interrupt current rating.
Connect the equipment to a –48 VDC supply source that is electrically isolated from the AC source (reliably
grounded 48 VDC SELV source). Ensure that the –48 VDC source is efficiently secured to earth (ground).
A readily accessible disconnect device that is suitably approved and rated shall be incorporated in the
field wiring.
CAUTION:
When stranded wiring is required, use approved wiring termination, such as closed-loop or
spade-type with upturned lugs. These terminations should be the appropriate size for the wires and must be
double crimped, one on the conductor and one on the insulation.
CAUTION:
When installing the unit, the ground connection must always be made first and disconnected last to
prevent an energy hazard.
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