Cabling & Wiring; Cooling Air; Mounting Requirements - Garmin GMC 7 Series Installation Manual

2.4 Cabling & Wiring
Use AWG #24 or larger wire for all connections unless otherwise specified by the aircraft manufacturer
or Garmin. The standard pin contacts supplied in the connector kit are compatible with up to AWG #22
wire. In cases where some installations have more than one unit sharing a common circuit breaker, sizing
and wire gauge is based on aircraft circuit breaker layout, length of wiring, current draw of units, and
internal unit protection characteristics. Do not attempt to combine more than one unit on the same circuit
breaker unless it is specified on aircraft manufacturer approved drawings.
In these cases, a larger gauge wire such as AWG #16, #18, or #20 may be needed for power connections.
Special thin-wall heat shrink tubing is also provided to insulate the extended barrels inside the backshell.
If using AWG #16 or #18 barrel contacts, ensure that no two contacts are mounted directly adjacent to
each other. This minimizes the risk of contacts touching and shorting to adjacent pins and to ground.
Ensure that routing of the wiring does not come in contact with sources of heat, RF or EMI interference.
Check that there is ample space for the cabling and mating connectors. Avoid sharp bends in cabling and
routing near aircraft control cables.
2.5

Cooling Air

Cooling is not required for the GMC 7XX. Refer to the G1000 System Installation manual, Garmin part
number 190-00303-00, for information on cooling requirements.
2.6

Mounting Requirements

The GDU 1040 mounting hardware is used in the installation of the GMC 7XX. The locking socket (see
Figure 2-1) can be attached by using a rivet or screw. If using rivets, the rivet should be 1/8" flat head
100° countersunk solid rivet. If using screws, the screw should be #4-40 flat head 100° countersunk
screws with standard hex nuts on the back. If screws are used, thread locking compound (Loctite or
equivalent) or a self locking nut with a nylon locking feature should be used. The specified screws and
rivets are designed to provide a flush front surface. See Figure A-1 for the GMC Panel Cutout.
Page 2-2
Revision F
Figure 2-1. GMC 7XX Locking Socket
GMC 7XX Installation Manual
190-00303-70