IBM THINKPAD T42 -, Service Manual

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When the drawer power cords are connected to the dc power distribution panel, make sure there is less
than 1 ohm resistance between the drawer frames or the rack frame.
DC Rack Power Cables
The customer provides the power cables from the -48 V dc power source to the dc power distribution
panel. The -48 V dc rack must be connected to a -48 V dc power source that is electrically isolated from
the ac power source. In addition, the -48 V dc power source must be reliably grounded.
The -48 V dc rack may be connected to two separate -48 V dc power sources. When the rack is
connected to two power sources, both power sources must be reliably grounded.
Power cables used in the United States and Canada are listed by Underwriter’s Laboratories (UL) and
certified by the Canadian Standards Association (CSA). These power cables have the following
characteristics:
v Power cables and ground cables must be a minimum of 6 AWG stranded copper (or equivalent) for
lengths up to 50 feet from the power source.
v All connectors must be the copper crimp type (compression). Connector metal must be compatible with
the cable metal.
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7014 Model T00, and Model T42 Service Guide