As the 'Roche limit' is defined the distance within which the gravitational field of a large body is strong enough to prevent any smaller body from being held together by gravity. So, my thought was that, since we suppose that crossing the event horizon leads (at first at least) to extreme spaghettification, perhaps it would not be false to oppose that the Roche limit identifies to the event horizon when talking about black holes.
I hope my description makes my thought path clear enough. Thank you
No, in general, the Roche limit is distinct from the radius of a black hole. One reason being that ``spaghettification doesn't occur, inevitably, as a body crosses the horizon (in fact nothing happens as the body crosses the horizon itself).
``Spaghettification'' is due to tidal forces, that are proportional to the curvature and, for sufficiently large black holes, the curvature ``at the horizon'' can be ``small''. (It's crucial to keep in mind the difference between ``event horizon'' as the space-like surface of the collapsed star and ``event horizon'' as a spacetime surface; in spacetime, the event horizon is a light-like surface).
Nope, it's two totally different concepts.
The Roche limit (which applies to all kinds of 2-body systems, not necessarily one where the larger body happens to be a black hole), also depends also on the properties of the smaller body - its geometry, density, etc.
The event horizon designates the limit at which the escape velocity becomes equal to the speed of light, and it's fully independent of anything else but the properties (mass) of the black hole.
Interesting question! Since others have already answered it, I will complement their answers by appending a reference which may provide more insights on this topic:
Article Roche Accretion of stars close to massive black holes
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