VBA to Add carriage return in cell after x number of character

I looking for vb at will format cells in a column, at 27 characters it should insert a carriage return, however this return should not be in the middle of a word, if the break were to fall in the middle of a word it would go to the previous space.


So for example :

This is just a sample line of text to show how I would like it formatted

would change to the following :

This is just a sample line
of text to show how I would
like it formatted

Appreciate any help, I can get it to insert a return after x characters but only on the first occurance and cant work out to allow for not breaking words.

Steve.