I agree that there is a good chance fuses will not provide protection unless they are rated a lot more like 4800V. Fuses also have an fault current interrupt rating that may be exceeded.
This is for power wiring and is irrelevant for telco. If you are lucky, a service panel surge protector will cause a high enough earth current to blow the fuses on a 4800V line. Surge protectors are usually based on MOVs which work well for short lightning events. But a crossed power line may be long enough time to exceed the energy rating of the MOV.
I don't think a telco protector would be effective against crossed power wiring. The clamping element will be burned out by high sustained current and fuses, if any, will have the same high voltage arc--across problem. Actually my old technology telco protector has fuses in long tubes that might work.
In general, protection can be provided inside a building with plug-in surge protectors which work by clamping, not earthing. (All power and signal wires to a set of equipment need to pass through the surge protector.) For a crossed distribution wire, a plug-in surge protector may be protected by wiring impedance, but may well not.
An excellent guide from the IEEE on surges an surge suppression in general is at:
And a similar one from the NIST:
The IEEE guide was targeted at people who have some (not much) technical background.
I have some doubts how practical it is to protect against power line crosses, which are quite rare. The available energy is likely very high. Depending on what the power line hits, it may stay live. And distribution protection schemes may include reconnecting several times before finally disconnecting.
Gas discharge tubes commonly used in telco protectors and MOVs commonly used in power line surge protectors act like crowbar circuits. Gas discharge tubes, like crowbar circuits, have current limits that could be exceeded by a crossed power line. MOVs can have very high surge current ratings but may be killed by energy - single event or cumulative.
Adding high energy rating MOVs to phone lines may work. Depends on the distribution voltage, circuit impedance and time before the distribution line gets disconnected.
-- bud--