Use a format that Excel does not recognize as a time:
10 Amps

<<Unfortunately I can't use the tick mark ['10 A] because another vendor's
application is what populates the sheet.

How do you get the data from the vendor? If they are putting it in an Excel
workbook, then you might have to write a macro to change the data after you
open the file. If it is written to a text file, then maybe you could write
a macro to import it and specify "Text" for the format of that column in
the OpenText method.
--
Regards,
Bill Renaud