What time will the election be called at?

[Taft]

They'll call it at 11 or thereabouts if they can by then, but not earlier.  As I recall, the media caught hell during one cycle (I forget which one; I'm inclined to think it was either 1980, 1988, or 1996, but it was one of the ones where the winner could have been swept in WA, CA, OR, HI, AK, and NV and still won) for calling the election before the west coast had stopped voting.

For example, in 2008, removing the five 11 PM-or-later states that Obama won (CA, OR, WA, HI), he had 288 EVs.  However, I think you can argue that IN and NC (as well as NE-2) were close enough that calling them too early would have been a bad idea, and NV closed late enough that having it out wasn't untoward.

However, reversing parties, things could get...silly in the event of a hypothetical "comfortable" win, since a Republican isn't going to need CA (which is part of what drags things out for a Democrat...those 55 votes are about 1/5 of the Dems' normal winning coalition these days, and adding in the other states out there gets you to well over 1/4 of it).  The GOP really only has 26 "normal" EVs closing after 9 PM (AR/6, UT/6, NV/6, ID/4, MT/3, AK/3), so in the event that a couple of big swing states become obvious (OH and FL being the biggest ones, as well as VA...all close very early; this is even more true if a big D-leaning swing state or two such as PA or MI somehow went GOP by a sizable margin)...it could get a bit harder to "tapdance" away a clear GOP win until 11 PM without the networks looking like they were just drawing things out.

[Taft]

Whenever a candidate is projected to have 270 or more EVs.

That was simple enough to answer.

Yes and no.  Technically, that is correct, but it is entirely possible for the networks to "drag things out" to avoid irritating people (or because the exit polls misfire, as they did in 2002).