Comma with 'Who,' 'Which,' 'Whom,' and 'In Which' Clauses
The Comma
Rulebase Summary
Use a comma or commas to set off a dependent clause beginning with 'who,' 'which,' 'whom,' or 'in which' when the clause renames and the renaming is unnecessary to the sentence's core meaning (nonrestrictive). These clauses add extra information but could be removed without changing the essential meaning.
Examples
A. The defendant who had no prior record was released on bail.
A. The defendant, who had no prior record, was released on bail.
Nonrestrictive 'who' clause set off with commas.
A. The report which was filed in March contained several errors.
A. The report, which was filed in March, contained several errors.
'Which' clause adds extra info — commas around it.
Transcript Notes
A nonessential adjective clause can be removed from the sentence and a complete grammatical sentence will remain. If the sentence goes on after the nonessential adjective clause, surround it with commas.
Style Guide References (3)
Morson's
BGGP
BGGP