Example: If one accidently fell asleep at night while reading a story to his children and woke up some time later must he wash hands? Do all the restrictions apply prior to doing so? Likewise if one took a nap at night, or took a nap during the day and woke up at night, do the above restrictions apply?
The law: If one slept for [over] sixty breaths at night then the spirit of impurity resides on him and he is required to wash his hands in the same way as he does in the morning. He is to follow all the restrictions of washing until he does so. This applies even if one only slept a “temporary sleep” [i.e. nap] of 60 breaths. If one slept for less than sixty breaths then he is not required to wash hands and the restrictions do not apply.
One who slept at night, even for a short nap, is to wash his hands upon awakening. He is to guard all the restrictions until he does so. A blessing is only to be recited on this washing if he slept for more than thirty minutes and it is past midnight.
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 Siddur; Kama 4/4; Admur there does not differentiate between sleeping in the beginning of the night or later on, so long as he slept for 60 breaths.
Other Opinions: Some write that the evil spirit only resides on one’s body if he is sleeping during midnight. Hence if he awoke before midnight or went to sleep after midnight the below mentioned restrictions would not apply. [Divrei Shalom 48, grandson of Rashash in name of Rashash, brought in Kaf Hachaim 4/4; Shulchan Hatahor 4/10] Practically the Poskim do not differentiate in this matter and the restrictions apply in all cases that one slept at night. [Piskeiy Teshuvos 1/6]
 Siddur. However in Kama 4/4 Admur simply writes 60 breaths.
 One is to be stringent in this regard to consider it 3 minutes. [See Ketzos Hashulchan 2 footnote 1; Chapter 4 Halacha 17 Q&A]
 Kama 4/4; Siddur
 Siddur: “One who sleeps for 60 breaths, even a temporary sleep, must wash three times inconsecutively”; Kama 4/4 which does not differentiate between a temporary and permanent sleep so long as one slept for 60 breaths.
Does the spirit of impurity definitely reside on one’s hands if he slept a temporary sleep? It is implied from Admur [Kama 4/14 and Siddur] that it is a doubt whether the spirit of impurity resides when one sleeps a temporary sleep of 60 breaths and only if one slept a set sleep of 60 breaths does the spirit of impurity definitely reside. This is implied from the wording there “even if one went to sleep a set sleep in which case the spirit of impurity definitely resides.”
Regarding the definition of a temporary sleep-see Chapter 4 Halacha 17 Q&A!