SECTION 74 IPC - Indian Penal Code - Limit of solitary confinement

In executing a sentence of solitary confinement, such confinement shall in no case exceed fourteen days at a time, with intervals between the periods of solitary confinement of not less duration than such periods;
and when the imprisonment awarded shall exceed three months, the solitary confinement shall not exceed seven days in any one month of the whole imprisonment awarded, with intervals between the periods of solitary confinement of not less duration than such periods.

IPC 74 in Simple Words

In simple words, when imposing solitary confinement as part of a sentence, it cannot exceed 14 days at a time, with breaks between the periods of solitary confinement lasting at least as long as the confinement itself, and if the overall imprisonment is longer than three months, the total solitary confinement in any one month should not exceed seven days.