5 CFR 1655.2 - Eligibility for loans.
A participant can apply for a TSP general purpose or residential loan if:
(a) More than 60 calendar days have elapsed since the participant has repaid in full a TSP loan of the same type.
(b) The participant is in pay status;
(c) The participant is eligible to contribute to the TSP (or would be eligible to contribute but for the suspension of the participant's contributions because he or she obtained a financial hardship in-service withdrawal);