Understanding Electrical Diagrams


By remembering a few simple techniques you should be able to tell which wires are connected and which are not.

In this illustration, Figure A indicates crossing wires are connected by using a small circle.

Figure B shows the wires overlapping or not connected; therefore these are two separate wires.

Figure C also indicates there is no connection. This method is less preferred because a connection could easily be missed and as drawings age, smudging and dirt have a tendency to make it look as though it was a connection. This type of crossed wires designation should be avoided.

Figure D is an example of a termination. Terminals may be shown in many forms, such as squares, triangles, hexagons, and any combination of symbols.

The bottom figure is of a JACK-PLUG, a common connection used in HVACR equipment.

For more information on this and other electrical topics, check the online store at RSES, (Refrigeration Service Engineers Society), the HVACR Training Authority.

This was an excerpt from “Electricity for HVACR Technicians“.


Scroll to Top