Krishnakumar, I really appreciate your help!

I changed that segment that you posted, and now the code properly implements the comma that was missing before. I added more arrays and For Next statements and now I am running into the problem of not getting the correct output from the for next statement. I think this is because the way that you showed me only cosiders a scenerio with two arrays.

An example would be for UL 489. When the code looks for this it should see that its in the power distributions array, and output power distributions in the N column. Instead, the code is outputing ITE, Consumer Electronics, Power Distribution, Security & Signal in the N column. In one case I found with multiple entries in the M column, it didn't even output Power Distribution when UL 489 was present. Here is the code that I have now. I cut out most of the array section, as that has been entered correctly. What do I need to do from here?

Sub kTest()
Dim a, i As Long, x, y, c As Long, iteAry, applAry, wirAry, conAry, insAry, firAry, comAry, hvaAry, iceAry, ligAry, _
medAry, gasAry, ppeAry, pfdAry, powAry, sigAry, watAry, hazAry

iteAry = Array("UL 60950", "UL 60950-1", "UL 1459", "UL 497", "UL 497A", "UL 497B", "UL 497C", _
            "UL 1863", "UL 1310", "UL 1012", "UL 61965", "UL 60601-1", "UL 60601A-1", "UL 60601B-1", _
            "UL 60601C-1", "UL 1863")

a = Range("n8", Range("m" & Rows.Count).End(xlUp))
ReDim w(1 To UBound(a, 1), 1 To 1)

For i = 1 To UBound(a, 1)
    x = Split(a(i, 1), ",")
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), iteAry, 0)
        If Not IsError(y) Then w(i, 1) = "ITE": Exit For
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), applAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "Appliances"
            Else
                w(i, 1) = "Appliances": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), wirAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "Wire & Cable"
            Else
                w(i, 1) = "Wire & Cable": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), conAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "Consumer Electronics"
            Else
                w(i, 1) = "Consumer Electronics": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), insAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "Insulating Materials"
            Else
                w(i, 1) = "Insulating Materials": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), firAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "Fire"
            Else
                w(i, 1) = "Fire": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), comAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "Components"
            Else
                w(i, 1) = "Components": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), hvaAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "HVAC"
            Else
                w(i, 1) = "HVAC": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), iceAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "ICE"
            Else
                w(i, 1) = "ICE": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), ligAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "Lighting"
            Else
                w(i, 1) = "Lighting": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), medAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "Medical & Dental"
            Else
                w(i, 1) = "Medical & Dental": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), gasAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "Gas & Oil"
            Else
                w(i, 1) = "Gas & Oil": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), ppeAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "PPE"
            Else
                w(i, 1) = "PPE": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), pfdAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "PFD"
            Else
                w(i, 1) = "PFD": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), powAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "Power Distribution"
            Else
                w(i, 1) = "Power Distribution": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), sigAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "Security & Signal"
            Else
                w(i, 1) = "Security & Signal": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), watAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "Water"
            Else
                w(i, 1) = "Water": Exit For
                End If
            End If
    Next
    
    For c = 0 To UBound(x)
        y = Application.Match(Trim(x(c)), hazAry, 0)
        If Not IsError(y) Then
            If Not IsEmpty(w(i, 1)) Then
                w(i, 1) = w(i, 1) & ", " & "Hazardous Location"
            Else
                w(i, 1) = "Hazardous Location": Exit For
                End If
            End If
    Next
Next

With Range("n8")
    .Resize(i - 1).Value = w
End With
End Sub