Generally, newer versions of Excel will automatically break text properly between words.
However, when a different space character is used, it will not properly recognize the spaces between words, hence treat the entire text as a single word and break it at fixed widths. (I found this out the hard way, and took quite a bit of time to identify the issue.) When typing text in Excel, the spaces are normally ok (ASCII code 32). However, when copying and pasting text from some other applications, a different character may be used (ASCII code 160, for example, which is equivalent to a space character, except with even parity); Excel treats those differently.
You can use the formula =SUBSTITUTE(," "," ") to reproduce the cell replacing the "bad" space characters, where is the cell in question, the first " " contains the "bad" space character, and the second " " contains a normal space.
And maybe someone else out there has another suggestion on how to strip off the parity bit when copying text.