Tag your entities, manage your drawing.
Create scenes for each layer and hide entities based on what layer they are on.
Medeek Electrical is a SketchUp Extension that provides a simple interface for creating accurate 2D and 3D electrical geometry within SketchUp.
Visualise a Ray of Light + Solar Data
The UL SPOT app for Sketchup is an add-in that enables Sketchup users to access product data from UL SPOT (spot.ul.com) and assign it directly to their project.
Parametric Modeling for SketchUp