ckspark,
You seemed to be confused and I had difficulty in visualising what you were trying to describe.
I have this afternoon, examined my 2006 x244 Ducato from underneath.
At the RHS of the crossmember, under the intercooler and for about 7cms, (3") under the radiator the battery positive cable to the starter solenoid is protected by a shaped semi-circular metal shield (starter cable shield?) which curves upwards at the RHS end. The starter cable is further protected by a braided plastic mesh, which can clearly be seen where this cable bends backwards towards the solenoid. The other end of the cable can be seen where it terminates at the battery fusebox to the RH rear of the battery.
I think that the braiding on the starter cable is your crumbling braid. The starter cable protector, or shield, will be a steel pressing to give extra protection to the cable. See below.
Again under the intercooler the is a plastic box like cable protector. It is fixed over the starter cable shield and carries the battery negative cable, which runs to the clutch housing close to the starter motor. This same negative cable has a "tee" flag terminal to the main chassis earth point under the front (-ve) end of the battery, before continuing upwards to the battery -ve clamp terminal.
In addition to the previously mentioned heavy cables, there is a split corrugated 16mm plastic conduit which passes all the way under the intercooler (through the plastic "box" protector) and under the radiator. This conduit is only loosely held by oversize cable clips. I am thinking of adding some small cable ties to secure it to the clips.
The conduit carries 3 or 4 thin wires, the purpose of which I have not ascertained.
On the x244 there is no CAL fuse at the battery end of the starter cable, so if the starter cable was shorted to earth, there could be quite a firework display.
In view of the fact that you were carrying out major work in close proximity to the starter cable, I trust that you took the standard precaution of removing the starter battery negative connection before starting work.
Please note that my vehicle does not have aircon, so it is possible that an aircon hose may follow the same route.