Extron Electronics HRU 109 - Manual (Page 2)

HRB 109 and HRU 109 • Installation Guide (Continued)
Underwriters Laboratories Guidelines for Rack Mounting
The following Underwriters Laboratories (UL) guidelines are relevant to the safe
installation of products in a rack:
Elevated operating ambient temperature — If a unit is installed in a closed or multi-unit
rack assembly, the operating ambient temperature of the rack environment may be greater
than room ambient temperature. Therefore, install the equipment in an environment
compatible with the maximum ambient temperature specified by Extron.
Reduced air flow — Install the equipment in the rack so that the equipment gets adequate
air flow for safe operation.
Mechanical loading — Mount the equipment in the rack so that uneven mechanical
loading does not create a hazardous condition.
Circuit overloading — Connect the equipment to the supply circuit and consider the effect
that circuit overloading might have on overcurrent protection and supply wiring. Give
appropriate consideration to the equipment nameplate ratings when addressing this
concern.
Reliable earthing (grounding) — Maintain reliable grounding of rack-mounted equipment.
Pay particular attention to supply connections other than direct connections to the branch
circuit (such as the use of power strips).
Secure Devices to the Shelf
TIP: It is easier to secure devices to the shelf before attaching the shelf to the rack.
All rack-mountable Extron devices have two
threaded holes in diagonally opposite corners of
the base plate for mounting onto the shelf.
CAUTION: Some products have hexagonal
holes in their base, which anchor
stand-offs for internal circuit boards
(see the figure to the right). Using these
holes will damage the product and will
not provide secure mounting.
Before securing a device to the shelf, decide where it will be placed. If multiple smaller
devices are to be placed on a single shelf they can be placed at the front of the rack or the
back. Ensure that adequate space remains for running cables.
To mount the device to the shelf, follow these instructions and see figure 2 on the opposite
page:
1. If the device has rubber feet attached, remove them.
2. Place the device on the rack so that the rack mounting holes are aligned with two holes
in the rack.
3. Secure the device to the shelf, using two of the provided 4-40 x 3/16 inch screws.
4. Repeat steps 1 to 3 to install other devices, as desired.
#4-40 Thread for
Rack Mounting Hexagonal Stand-off
(for mounting
circuit board)
2