Starting with the 4th column, I want every third column in the forth row to
say Substation and then the number. I have set a variable that is the max
substation number. I can't get this to output anything. Thanks for the help.

For a = 1 To MaxSubNumber

columnNum = 4 + (a - 1) * 3
Cells(4, columnnum_.Value) = "Substation " & a

Next a