Show a dropdown when another field is populated

Hello,

I would really appreciate some excel help on this problem I'm having. I have 2 related columns with one to many relationship, on a tab populated with some data. On another tab I'm referencing these 2 columns. When I populate one column I would like a drop down showing all the related data from the 2nd column of the first tab in the 2nd tab. I'm unable to do a named range as my first column has spaces in its name.
I'm attaching an example of what I'm trying to achieve. Any help would be greatly appreciated.

Thanks,

Could any one help me with this? Please let me know if you need me to clarify my question. Thanks.

Hello
Create the following named ranges:

AC_HV_Swgr = 'Class-Attr realtionship'!$B$14:$B$15

DC_Traction_Swgr = 'Class-Attr realtionship'!$B$12:$B$13

SS = 'Class-Attr realtionship'!$B$2:$B$6

Xfmr = 'Class-Attr realtionship'!$B$7:$B$11

Then apply the Data Validation list in 'Asset Attribute'!C2:C4, using the formula:

=INDIRECT(SUBSTITUTE($B2," ","_"))

Hope this helps.
DBY

One more, see attachment.

Thank you for your response. Let me try this. I'll let you know how it goes.

It works!!!! Great. Thanks so much

Example.xls
I have a follow up question as I stumbled on another issue. You gave me the formula to replace the spaces with an underscore. But I have data in "Asset classifications Abbreviation" columns also staring with a number sometime and some may have parenthesis in them. So the formula to just remove spaces may not work. Can I elaborate the formula to add other types of conditions?

Thanks for help. I'm attaching the spreadsheet with additional data to show you these exceptions I'm encountering(added new rows to the tab Class-Attr relationship)

WHER- How did you create 'myRange'? I'm stuck at this point. Could anyone help?

Could ANYONE respond to this query?

"myrange" is a Named Range, see ctrl+F3 for a list of Names.
In the "Refers To" box you see the formula (based on 'Offset') that defines the range.

=OFFSET('Class-Attr realtionship'!$B$1;MATCH('Asset Attribute'!$B2;'Class-Attr realtionship'!$A$2:$A$15;0);0;COUNTIF('Class-Attr realtionship'!$A$2:$A$15;'Asset Attribute'!$B2);1)

You will probably see the ";" in the formula as ","

Thank You so much. I would have never figured it out. Appreciate your response and help.