Dim a as range, b as range, c as range, d as range, rngAll as range

'...set the ranges a-d

Set rngAll = Application.union(a, b, c, d) '<< limited to 30 ranges

'...but no limit with this incremental method
Set rngAll = Application.union(a, b)
Set rngAll = Application.union(rngAll, c)
Set rngAll = Application.union(rngAll, d)