Here in NJ, most (but not all) AHJ's allow a "reasonable" amount of UNPROTECTED SE within a structure.
There is no 'black or white' type answer.
As an AHJ, "reasonable" is determined on a case-by-case basis, and I, nor anybody else will commit to a measurement.
Basically, enter at the sill plate, run STRAIGHT down into the panel, and you should be OK. Venture to the right or left, and you get a red sticker. Our utility co's have no jurisdiction past the meter pan, and they usually don't comment on anything past the point of attachment.
Options are exterior disco, or concrete encasement (NOT SEU); choices are left to the EC.
John
