Bob The Loan Shark !

How many domestic loans can we have in one season?

OK then – I’ll quote PL rules :)

PREMIER LEAGUE RULES: SECTION V
V.5. A “Temporary Transfer” shall mean the transfer of a contract registration effected in accordance with Rules V.6 to V.10.

V.6. Subject to the conditions set out below, a Temporary Transfer shall be permitted:
V.6.1. between Clubs; and
V.6.2. between a Club and a club in membership of the Football League, the
Football Conference, the Northern Premier League, the Isthmian League and
the Southern League.

V.7. The conditions referred to in Rule V.6 are:
V.7.1. a Temporary Transfer to a Club may not take place in the Transfer Window
in which the Transferor Club acquired the Player’s registration;
V.7.2. during the period of the Temporary Transfer of his contract registration a
Player shall not play against the Transferor Club;
V.7.3. if during the period of a Temporary Transfer the Player’s registration is transferred permanently from the Transferor Club to the Transferee Club, the two Clubs may agree in writing (to be copied to the League) that the Player shall not play against the Transferor Club for the remainder of the Season;
V.7.4. subject to any conditions imposed by the Board in the exercise of its discretion under Rule V.4.2, the minimum period of a Temporary Transfer shall be the period between 2 consecutive Transfer Windows and the period of a Temporary Transfer shall not extend beyond 30th June next after it was entered into;
V.7.5. the maximum number of Temporary Transfers to any one Club registrable in the same Season shall be 4 and in no circumstances shall more than 1 be from the same Transferor Club save there shall be excluded from these numbers any Temporary Transfer of the kind described in V.7.6.1 or V.7.6.2;

V.7.6. not more than 2 Temporary Transfers shall be registered by a Club at the same time except that there shall be excluded from that number:
V.7.6.1. any Temporary Transfer which become permanent; and
V.7.6.2. the Temporary Transfer of a goalkeeper which in its absolute
discretion the Board may allow in circumstances it considers to
be exceptional;
V.7.7. a Club may transfer the registration of no more than one of its goalkeepers by way of temporary Transfer to another Club each Season, subject to any further Temporary Transfer of one of its goalkeepers pursuant to Rule V.7.6.2;
V.7.8. any other conditions agreed between the Transferor Club and the Transferee Club or, in the exercise of its discretion, imposed by the Board.
V.8. The Loan Fee payable on a Temporary Transfer shall be such sum (if any) as shall have been agreed between the Transferee Club and the Transferor Club and set out in Football Association Form H.2 or H.3 (as appropriate) or in a supplementary agreement.

OK then – I’ll quote PL rules

PREMIER LEAGUE RULES: SECTION V
V.5. A “Temporary Transfer” shall mean the transfer of a contract registration effected in accordance with Rules V.6 to V.10.

V.6. Subject to the conditions set out below, a Temporary Transfer shall be permitted:
V.6.1. between Clubs; and
V.6.2. between a Club and a club in membership of the Football League, the
Football Conference, the Northern Premier League, the Isthmian League and
the Southern League.

V.7. The conditions referred to in Rule V.6 are:
V.7.1. a Temporary Transfer to a Club may not take place in the Transfer Window
in which the Transferor Club acquired the Player’s registration;
V.7.2. during the period of the Temporary Transfer of his contract registration a
Player shall not play against the Transferor Club;
V.7.3. if during the period of a Temporary Transfer the Player’s registration is transferred permanently from the Transferor Club to the Transferee Club, the two Clubs may agree in writing (to be copied to the League) that the Player shall not play against the Transferor Club for the remainder of the Season;
V.7.4. subject to any conditions imposed by the Board in the exercise of its discretion under Rule V.4.2, the minimum period of a Temporary Transfer shall be the period between 2 consecutive Transfer Windows and the period of a Temporary Transfer shall not extend beyond 30th June next after it was entered into;
V.7.5. the maximum number of Temporary Transfers to any one Club registrable in the same Season shall be 4 and in no circumstances shall more than 1 be from the same Transferor Club save there shall be excluded from these numbers any Temporary Transfer of the kind described in V.7.6.1 or V.7.6.2;

V.7.6. not more than 2 Temporary Transfers shall be registered by a Club at the same time except that there shall be excluded from that number:
V.7.6.1. any Temporary Transfer which become permanent; and
V.7.6.2. the Temporary Transfer of a goalkeeper which in its absolute
discretion the Board may allow in circumstances it considers to
be exceptional;
V.7.7. a Club may transfer the registration of no more than one of its goalkeepers by way of temporary Transfer to another Club each Season, subject to any further Temporary Transfer of one of its goalkeepers pursuant to Rule V.7.6.2;
V.7.8. any other conditions agreed between the Transferor Club and the Transferee Club or, in the exercise of its discretion, imposed by the Board.
V.8. The Loan Fee payable on a Temporary Transfer shall be such sum (if any) as shall have been agreed between the Transferee Club and the Transferor Club and set out in Football Association Form H.2 or H.3 (as appropriate) or in a supplementary agreement.

Understood loud and clear ;)

not more than 2 Temporary Transfers shall be registered by a Club at the same time

Fairly clear. The only exceptions are goalkeepers, and even then it would be invoked if you had no or limited permanent keepers.