As indestructible as RMC seems it can be eaten up quickly (vaporized) by service conductors faulting inside it.

When I weld I can cut holes through metal as thick as RMC with under 125 amps.

Service conductor may have 1000s of available amps, it is possible that even 2" encasement is not enough.

Don R (A moderator here) got to watch RMC burn back quite a way when service conductors faulted inside.

Bob

Bob Badger
Construction & Maintenance Electrician
Massachusetts