I have non-roth funds in the TSP and have separated from the military. I'd like to move this to a public employee sponsered 457(b) so I can begin contributing again. Are there any IRS tax penalties (like the 10% penalty) for doing this?
The first question is: are TSP-to-457(b) rollovers permitted? This helpful chart from the IRS is not definitive but I assume TSP is a pre-tax Qualified Plan, so as long as the 457 has separate accounts (presumably to prevent penalty-free early withdrawals of your TSP money), it appears to be allowed.
Secondly, to answer your main question, there should definitely not be any penalties for this rollover assuming it is completed successfully, because you're not doing an early withdrawal, and you wouldn't pay taxes because you aren't converting money from pre-tax to Roth.
I will ask though, is there a good reason for moving money out of the TSP? It is one of the best retirement plans you can find, with access to funds with extremely low fees. Unless you have a low balance you generally aren't required to move the money even after you can no longer contribute.