Retirement tax questions

Thank you for a quick response.  My understanding is that I can't contribute to a SEP IRA for my side consulting job because that would put me over the 415(c) limit for a 403(b) which the IRS states is not the same as a 410K but I assumed a nondeductible IRA would be okay since it is after tax dollars so it does not add to the 415 (c) limit.  Or am I incorrect about a Sep IRA?