By Miles Nicholson
Block Replacement is available from the Conversion ribbon > Tools panel > 
Block Replacement
You can perform drawing-wide or project-wide block replacements using a user-defined Microsoft Excel spreadsheet and an AutoCAD Electrical-aware symbol library that it references. The spreadsheet performs a lookup for each block name and finds the corresponding new block. Each new block drawing is pulled from the AutoCAD Electrical symbol library and inserted (scaled and rotated as required) in the drawing. The spreadsheet is checked to copy the old attribute values to the appropriate new names on the newly inserted block. This process continues across the drawing, and terminates when no more block names remain. It automatically continues to the next drawing if project-wide mode is selected.
The mapping spreadsheet has two parts: Attribute mapping defaults and Block name mapping. Each section is a sheet within the spreadsheet and must follow a defined column format. The sheets must be in order, where sheet 1 defines the attribute mapping and sheet 2 defines the block mapping.
Attribute mapping defaults
General mapping of old attribute names to new attribute names so that the old values on the blocks can be copied to the swapped AutoCAD Electrical-smart block.
Block name mapping
Maps existing specific or wild-carded block names to the new AutoCAD Electrical block to use during the block instance swap. Each row of this spreadsheet is a mapping record for an old name to a new name swap.
If you have your own library of symbols with attributes, these need to be converted to AutoCAD Electrical symbols before you can perform a Block Replacement
Swap/Update Block is available from the Schematic ribbon > Edit Components panel > 
Swap/Update Block
- Swap Block: Exchanges one block for another, retaining the scale of the old block, rotation, wire connections, attribute values, and attribute positions (if Retain is selected). For example, use the tool to swap out a red standard pilot light with a green one, or drawing-wide, swap out all standard red pilot lights with red press-test pilot lights.
- Update: Updates all instances of a given block with an updated version of the same block. Again, all attribute values and wire connections are retained. For example, an old AutoCAD Electrical project set must be used on a new project but the client likes the limit switches drawn a bit differently. Simply make client-specific versions of the limit switch symbols. Then use the Update option; select any limit switch on the drawing, and then reference the path to the new version of the symbol. AutoCAD Electrical quickly replaces all instances of the symbol it finds on the drawings with the new version of the same symbol. The Library mode works the same way as the Update mode, but swaps out all the blocks on the drawings. This is useful if you wish to change from IEC to JIC as an example or vice-versa.
When you swap or update a block there may be times when you want the values of certain attributes mapped to different attribute names. For example, you may be doing a Library Update and the library symbols you are swapping out do not use standard AutoCAD Electrical attribute names. You want a quick way to update the library symbols, but you do not want to lose information held on the current attributes.