How to Wire a Main Breaker Box | Hunker Electricity is one of the most dangerous parts of construction. A new project requires a licensed electrician to pass city inspections. However, knowing how to wire a main breaker box can help a homeowner determine issues that may be stemming from the electrical wiring. Circuit Breaker Wiring Diagrams - Do-it-yourself-help This page contains wiring diagrams for a service panel breaker box and circuit breakers including: 15amp, 20amp, 30amp, and 50amp as well as a GFCI breaker and an isolated ground circuit. Circuit Breaker Panel Box Wiring Diagram. This diagram illustrates some of the most common circuits found in a typical 200 amp circuit breaker service panel box. Square D Breaker Box Wiring Diagram | Free Wiring Diagram Variety of square d breaker box wiring diagram. A wiring diagram is a streamlined standard pictorial depiction of an electric circuit. It shows the components of the circuit as simplified shapes, and the power as well as signal connections between the devices.