Decoding Wiring Schematics in CC Ex Maintenance Manual

[karaka29211]

Trying to decode the text wiring diagrams in the CC diagrams for American Wire Gauge (AWG) sizes in the schematic diagrams- for example say MB7C20O . I think the last letter O (Orange) is a colour code , is the 20 the AWG? Is there a full schematic decode online somewhere?

[Pete D]

I think there is a wire code logic breakdown somewhere, I'll try and locate it.

The basic format is the first two letters are what system;

AB - Avionics Bus
MB - Main Bus
LB - Lighting bus
A - Alternator
P - Power
Various others for avionics like GDU, GMU, BB etc

Second, it is what wire in that system, two digits followed by what segment of that wire (examples; 06A, 05A, 02B etc)

Third is the AWG, 16, 20, 22, 04 etc

and last would be the color of the wire (W, O, B, G etc)

If it is a multi conductor wire there will be a dash and how many conductors it has (-2, -3, -4)

So for example;

P01A04W is a power circuit wire, number 01, segment A, 04 gauge white in color (from the battery (+) to the master solenoid)

MB11B12R is a main bus wire, number 11, segment B, 12 gauge, red in color from the avionics switch to the avionics 1 bus.

[Pete D]

Wire code logic example.jpg