When it appears to the Secretary that the loan applicant is able to obtain a loan for part of his credit needs from a responsible cooperative or other credit source at reasonable rates and terms consistent with the loan applicant’s ability to pay and the achievement of this chapter’s objectives, he may request the loan applicant to apply for and accept such a loan concurrently with an insured loan, subject, however, to full use being made by the Secretary of the funds made available hereunder for such insured loans under this subchapter. The Secretary may not request any applicant for an electric loan under this chapter to apply for and accept a loan in an amount exceeding 30 percent of the credit needs of the applicant.