The Low Voltage Device Blocks commands allow you to customize the list of blocks available to be used for low voltage devices in the project and master schedules.
See the Block Creation section for more information about creating new blocks.
See the General Customization Commands section for more information about how the Edit Project List, Edit Master List, Copy Project List to Master, and Copy Master List to Project commands work.
To edit the low voltage device blocks project list, go to
Ribbon: DME: Customization->Project Customization-> 
Low Voltage Device Blocks
Pulldown Menu: DM Electrical->Customization->Low Voltage Devie Blocks->Edit Project List
To edit the low voltage device blocks master list, go to
Ribbon: DME: Customization->Master & Standards Customization-> 
Low Voltage Device Blocks
Pulldown Menu: DM Electrical->Customization->Low Voltage Device Blocks->Edit Master List
Low Voltage Device Blocks Dialog Box
Sort: Press this button to sort the list of blocks alphabetically by the Description column.
Move Up: Press this button to move the selected block up in the list of blocks.
Move Down: Press this button to move the selected block down in the list of blocks.
New: Press this button to create a new block.
Delete: Press this button to delete the selected block. If the block is currently used by a record in the schedule, you will be asked if you want to replace the block in the schedule with another block.
For most low voltage devices, To Scale should not be checked and Can Rotate should be checked. See the Common Block Information section for more information about these values and others that can be specified for low voltage device blocks.