IDG power phase wire. This is a "one aught" or 1/0 gauge wire..... in other words "big".
The wire had shorted to ground. The Generator Control Unit sensed this as a differential fault and it disconnected the main generator contactor and removed voltage from the excitation field coil of the IDG.
There's a reason it shorted to ground..... When four extra feet are just left flopping inside the pylon! Pretty shitty maintenance if you ask me.
Pylon right. You can see the wire all the way near the top coming through a gap in a cross-member structure area. The other (properly run) wires are behind that opening.