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