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Cisco MGX 8220 Installation and Configuration
Release 5.0, Part Number 78-6430-03 Rev. D0, November 2003
Chapter Rack-Mounting the MGX 8220 Units
Figure7-5 Keyhole Style Bracket
Rack-Mounting the Plenum or Spacer
Either the plenum chamber or the spa cer unit (not both) should be mounte d immediately above the shelf.
The decision of which one to use is depen dent upo n th e configuration of equipment in the rack and how
the air is to be expelled. Th e plenum delivers air to the rea r of the rack and is used in n ormal UL
compliant installations where th e t op o f th e u n it mu s t be covered. The spacer can be used for
installations that hav e equi pmen t mount e d abo v e t he MGX 8220 a ss em bly t ha t act s as th e ne ces sa ry to p
cover. The spacer guarantees the minimum n eces sary air exhaust space of 1.75 inch es , pr ovid in g th e
sides and rear are open and unobstructed. The MGX 8220 shelf might not be UL compliant when the
spacer is used. Further, the plenum supports the attachment of a cable management kit but the spacer
does not. This is an important factor if cable management is to be used for the upper shelf in two shelf
and four shelf configurations.
Insert the selected unit im mediately above the shelf and s ec ur e the unit to the shelf with fo u r, num be r
10-32 machine screws and flat washe r s.
Mounting the Electrostatic Wrist Strap
The MGX 8220 shelf is provided w i th a wrist strap that grounds the use r an d p r ot ec ts t he el ect ro n ic
components from electrostat ic shock. The wrist strap kit consists of a strap, a coiled cor d, and a clip for
holding the strap. (See Figure7-6.)
It is recommended that the wri st s trap b e i nst all ed o n th e l ef t f r ont flange of one of the units at a
convenient height. Use the front mounting screw to secure the ring lug to the flange and front rail. The
other end of the cord is attac hed to the strap with a snap c onnector. Peel the back off the clip to ex pose
Disposable
alignment
screw Disposable
alignment
screw
Spacer
Keyhole-style
holes
Bracket
Rear
chassis
Front
chassis
H10025