Limit to number of "named ranges" in Range method - vba

Question

I am using the following code:
Dim rng As Range
Set rng = Workbooks("import sheet.xls").Sheets("import").Range("project_name,project_author,project_code,project_breaker,default_fault_ac_mcb,default_fault_ac_mccb,default_fault_dc,default_fault_acb,default_rvdrop,default_svdrop,default_eff,default_pfactor,default_ratio,default_freq,default_sfactor_ac,default_spfactor")
For Each cell In rng.Cells
MsgBox cell
Next cell
Now project_name, project_author, etc. are different named ranges in the sheet. The problem is when I add another named range to the above list (already defined), I get a runtime error 1004 ("select method of range class failed").
Is there a limit to the number of named ranges one can add to range object?

Answer 1

I couldn't find anything on why this happens but I am still looking.
However this works. You can combine the range using UNION
Sub Sample()
Dim rng As Range, cell As Range, newRng As Range
Set rng = Sheets("import").Range("project_name,project_author,project_code,project_breaker,default_fault_ac_mcb,default_fault_ac_mccb,default_fault_dc,default_fault_acb,default_rvdrop,default_svdrop,default_eff,default_pfactor,default_ratio,default_freq,default_sfactor_ac,default_spfactor")
Set newRng = Union(rng, Sheets("import").Range("default_sid"))
For Each cell In newRng.Cells
MsgBox cell
Next cell
End Sub
UPDATE: I couldn't find any Microsoft document which describes this behavior, but after some experimentation, I can confirm that the maximum number of named ranges one can add to range object is 16. This behavior can be seen in in Excel 2003, 2007, and 2010.
Strangely this behavior was not replicated in Excel 2011 (MAC). I tested with 19 names and it worked.
MORE UPDATE
After more testing, I discovered that if you name your ranges as Name1, Name2, Name3 etc then I was able to add more named Ranges in Excel 2003-2007-2010. So it has to do something with the naming of the names.
I have filed a bug with Microsoft.
SAMPLE FILE FOR TESTING:
https://skydrive.live.com/redir.aspx?cid=cdd3f8abe20bbe3b&resid=CDD3F8ABE20BBE3B!157&parid=CDD3F8ABE20BBE3B!150&authkey=!ADP_QVBopsqenBA

Answer 2

I have not investigated your problem but the points below may give you and Sid some hints on the possible solution.
If you access Rng.Address there is a limit on the size of the string. I have found comments on the internet claiming the limit is 253 but I do not believe this. Rng.Address is always truncated at the end of a complete sub-range so the string you get back is syntactically correct just incomplete. So the limit depends on the exact string size of the sub-ranges.
I had the opposite problem. I had a sheet with thousands of rows. I used AutoFilter to select the rows of interest and saved the range. But Rng.Address only gave me the first 19 or so ranges of interest. I had to use For Each Cell In Rng and assemble the range string to get the full string.
Your string is 255 characters long. There is clearly no limit on the number of sub-ranges in a union. You could try adding the sub-ranges to the union individually.
Best of luck.
PS If you want my assemble range string routine you are welcome.