Hallo,

teste mal:

Sub SBZ()

Application.ScreenUpdating = False
Range("B2").Select
ActiveWindow.FreezePanes = True
Range("B:B,F:F,H:H").NumberFormat = "dd/mm/yy;@"
Range("C:C,G:G,I:I").NumberFormat = "h:mm:ss;@"
Columns("L:L").Insert Shift:=xlToRight, CopyOrigin:=xlFormatFromLeftOrAbove
Columns("L:L").Insert Shift:=xlToRight, CopyOrigin:=xlFormatFromLeftOrAbove
Range("L2:L" & Cells(Rows.Count, "B").End(xlUp).Row).FormulaR1C1 = "=(RC[-4]+RC[-3]-(RC[-6]+RC[-5]))*24*60"
Columns("L:L").NumberFormat = "General"
Range("L2:L" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions.Add Type:=xlCellValue, Operator:=xlGreater, Formula1:="=30"
Range("L2:L" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions(Range("L2:L" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions.Count).SetFirstPriority
With Range("L2:L" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions(1).Interior
    .PatternColorIndex = xlAutomatic
    .Color = 255
    .TintAndShade = 0
End With
Range("L2:L" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions(1).StopIfTrue = False
Range("L2:L" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions.Add Type:=xlCellValue, Operator:=xlLess, Formula1:="=30"
Range("L2:L" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions(Range("L2:L" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions.Count).SetFirstPriority
With Range("L2:L" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions(1).Interior
    .PatternColorIndex = xlAutomatic
    .Color = 5296274
    .TintAndShade = 0
End With
Range("L2:L" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions(1).StopIfTrue = False
Range("L1") = "Arb.Zeit"
Range("M1") = "SBZ Zeit"
Range("M2:M" & Cells(Rows.Count, "B").End(xlUp).Row).FormulaR1C1 = "=(RC[-5]+RC[-4]-(RC[-11]+RC[-10]))*24*60"
Columns("M:M").NumberFormat = "General"
Range("M2:M" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions.Add Type:=xlCellValue, Operator:=xlGreater, Formula1:="=240"
Range("M2:M" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions(Range("M2:M" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions.Count).SetFirstPriority
With Range("M2:M" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions(1).Interior
    .PatternColorIndex = xlAutomatic
    .Color = 255
    .TintAndShade = 0
End With
Range("M2:M" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions(1).StopIfTrue = False
Range("M2:M" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions.Add Type:=xlCellValue, Operator:=xlLess, Formula1:="=240"
Range("M2:M" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions(Range("M2:M" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions.Count).SetFirstPriority
With Range("M2:M" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions(1).Interior
    .PatternColorIndex = xlAutomatic
    .Color = 5296274
    .TintAndShade = 0
End With
Range("M2:M" & Cells(Rows.Count, "B").End(xlUp).Row).FormatConditions(1).StopIfTrue = False
Cells.Borders(xlDiagonalDown).LineStyle = xlNone
Cells.Borders(xlDiagonalUp).LineStyle = xlNone
With Cells.Borders(xlEdgeLeft)
    .LineStyle = xlContinuous
    .ColorIndex = 0
    .TintAndShade = 0
    .Weight = xlThin
End With
With Cells.Borders(xlEdgeTop)
    .LineStyle = xlContinuous
    .ColorIndex = 0
    .TintAndShade = 0
    .Weight = xlThin
End With
With Cells.Borders(xlEdgeBottom)
    .LineStyle = xlContinuous
    .ColorIndex = 0
    .TintAndShade = 0
    .Weight = xlThin
End With
With Cells.Borders(xlEdgeRight)
    .LineStyle = xlContinuous
    .ColorIndex = 0
    .TintAndShade = 0
    .Weight = xlThin
End With
With Cells.Borders(xlInsideVertical)
    .LineStyle = xlContinuous
    .ColorIndex = 0
    .TintAndShade = 0
    .Weight = xlThin
End With
With Cells.Borders(xlInsideHorizontal)
    .LineStyle = xlContinuous
    .ColorIndex = 0
    .TintAndShade = 0
    .Weight = xlThin
End With
End Sub

Die letzte belegte Zeile ermittle ich in Spalte B. Bis dort wirkt sich dann der Code entsprechend aus. Spalte B dafür nicht passt, müsstest du den Code entsprechend anpassen.

Deine bedingten Formatierungen habe ich auch auf diesen Bereich angepasst. Die wirken sich somit nicht auf die ganze Spalte aus.

Dann noch eine Frage: Willst du tatsächlich die Rahmen um sämtliche Zellen des ganzen Blattes haben, oder nur auf den eigentlichen Datenbereich?

Gruß Werner