The National Electrical Manufacturers Association.  NEMA is a guide of practical information containing instructions for the safe and proper application of ground fault protective devices (GFP devices). GFP devices include current sensing devices, relaying equipment, or combinations.
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The Delaware County electrician.

A wiring diagram should be a simplified pictorial map of an electrical circuit. It should show the components of the circuit as simplified shapes and legend. The power and lines connecting between the devices should be easy to follow. A wiring diagram usually gives more information about the relative position and arrangement of devices and terminals on the devices, as an aid in construction the device. This is unlike a schematic diagram where the arrangement of the components interconnections on the diagram does not correspond to their physical locations in the finished device. A pictorial diagram would show more detail of the physical appearance, whereas a wiring diagram uses a more symbolic notation to emphasize interconnections over physical appearance. A wiring diagram is used to troubleshoot problems and to make sure that all the connections have been made and that everything is present.