Recently I was posed an interesting requirement. A client wanted the ability to change the linetype properties of selected blocks in a schematic to represent that this device or devices are external.
AutoCAD Electrical defaults to the SYMS layer for symbols and a linetype of CONTINUOUS.
However I came across a post on www.autolisp.com that fitted the exact requirement.
In notepad, copy the text below and save the file as LTCHANGE.LSP in one of your support directories e.g. C:\Program Files\Autodesk\AutoCAD 2014\Support.
Type APPLOAD at the AutoCAD command line and add the LSP to the Start-Up > Contents
To initialise the command type LTCHANGE
Type the name of the layer you want e.g. HIDDEN2 (must be a loaded layer in LINETYPES and within the current drawing)
Pick the blocks you wish to change.