I have reviewed both the NEC and the UL "White Book." Neither specifically address the issue- it appears that no one considered it. Type USE is severely limited in its' indoor applications, but there is no such limit on SE.
Since it is not specifically prohibited, I would say it is allowed- especially if there is a desire for additional mechanical protection. However, I would consider the issue of de-rating, as is done with Romex. While there is no official temperature rating for the assembly (unlike Romex, which is 60 degrees), it seem reasonable to treat SE in a like manner.
I looked in the '02 NEC at Article 352 Sect 352.22 and it seens to say no- SER installed in RNMC would not be a code compliant installation because SER is not specifically identified for use in a raceway. Some cables are identified as being acceptable when installed in a raceway: Fire alarm cable (760.54) NM cable for short sections (334.15 (B)) Class 2 & 3 cables (725.55(C)). I do not see that kind of wording for SER or SE cables.
Now if you go to the '05 code Article 352 Section 352.22 is worded diffeently and it might change things. Now why anyone would want to install a raceway system and then pull in SER or SE cable is beyond me. The chance of overfilling the raceway or damaging the cable is very high.
I came across the same situation: SER in 21/2" pvc #80 outside od house. 50' run,2-90% and 1-LB then to meter main. Cable tech. drill a hole in the conduit and shorted out the feed. I told them that I needed to replace the conduit and install the correct cable (THHN). What you had was a violation. They said prove it. I opened up the code book and look & look, but could not find any thing to support my statement. It would seem that SER in such a run of pvc would be wrong. Maybe ampacity,number of conductors in conduit would play out in the code? Would that large of SER 200amp size bent in a LB a violation. That must have been someting to install. Or my last one was "not completing conduit run before installing cable". ????
George, what about 338.10(B)(4)? This says for interior runs of SE, you use the part I and II rules for NM cable. But the NM rules only seem to get you a physical protection run of conduit and not necessarily a complete conduit system.