Specifications

Audio International, Inc. A/V-9691-01(-02)-x Installation & Operation Manual
Document # 540250, Rev D, 07/2004
Page 13 of 33
3.4 Wiring Requirements
The installing agency shall supply and fabricate all external cables and
connectors. The length and routing of external cables should be carefully
studied and planned before attempting installation of the equipment.
Allow adequate space for installation of cable and connectors.
3.4.1 Power Wires
All power and ground connections of P7 must be 20 AWG,
MINIMUM. Power and ground connections to P13 must be
16 AWG MINIMUM. Audio International recommends that all other
power and ground wires be 22 AWG minimum.
The chassis shall be electrically bonded to the airframe structure by
a conductive mounting point with <0.1 Ω resistance using <50 Ω
impedance cable. Aluminum wool, nylon webbing impregnated
with aluminum oxide abrasive or fiber bristle brushes are the
approved tools for removing anodized surfaces at mounting point
where the bonding wire is attached. Power and Ground wires shall
be in accordance with NEMA WC 27500 or equivalent. Protect
power wires with circuit breakers or fuses located close to the
electrical power source bus. A stud is provided on the front of each
amplifier for grounding of the unit. A minimum of 10 AWG wiring is
recommended. This connection should be made to aircraft
structure no more than 12 inches from the unit.
3.4.2 Audio Lines
To reduce the opportunity for electrically-induced ground-loop
noise, Audio International recommends that all analog audio wire
connections be twisted shielded cable with the shield properly
grounded at the source (ideal practice) and floating at the load end.
If shield cannot be grounded at the source, then ground at the load
end with the source end floating. The shield for each cable length
shall be terminated at one end only. Terminating both ends of a
shield is NOT recommended, and highly increases the likelihood of
creating unwanted electrically-induced ground-loop noise into the
analog audio signal. Twisted shielded cable shall be 22 AWG
(minimum) for low-level audio signals or 16 AWG (minimum) for
speaker-level audio signals and shall be in accordance with NEMA
WC 27500 or equivalent. Individual conductor wire gauge in each
twisted shielded cable assembly shall increase accordingly with
analog audio signal type and any significant increases in cable
routing.