How to Wire Sub Panel Like a Pro

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Written By Will Dietrich

I love gardening, building, making and fixing things. 





So you want to know about how to wire sub panel? Well you’re in the right place. Lets go over what we need to know.

Service Panel

The service panel is where all of your electrical power comes from and it’s also called main breaker box or fuse box. It has three wires that are connected together with two screws. The first screw connects the black wire which goes into the ground terminal on the back side of the panel. Then there is another screw that connects the white wire which goes into the line terminals on the front side of the panel. Finally there is one more screw that connects the red wire which goes into the load terminals on the front side. This means that if any part of this circuit gets damaged then the entire system will be shut down. So make sure that everything is working properly before turning off the electricity.


A sub-panel is basically just an extension of the service panel. You can have multiple panels wired up inside each other so they form a larger area for distribution. A typical house would only have one sub-panel but some homes may have several. Subpanels usually contain four different types of circuits: Neutral, Ground, Line 1, and Line 2. Each type of circuit contains its own set of breakers. For example, the neutral circuit could have 3 separate sets of breakers while the hot circuit might have 4. If you were to look at the diagram below, you’ll see that I’ve labeled them as such. In reality though, these labels don’t really matter because every single breaker does exactly the same thing.

Amp Breaker

This is used to protect against overloads. When the amp breaker trips, it shuts off the current flowing through the circuit. Amp breakers come in many sizes ranging from 10 amps to 1000 amps. They are rated by their amperage not voltage. Most people use 15 amp breakers when installing new outlets since most appliances draw less than 100 watts. However, if you plan on running large motors or appliances that require higher currents, you should consider using 20 amp breakers instead.

Ground Fault Interrupter

Ground Fault Interrupters are designed to prevent electrocution due to faulty grounding systems. These devices detect small differences between the potential difference across the lines and the earth ground. GFI receptacles are required whenever anyone touches bare metal objects during installation.

Circuit Breaker

Circuit Breakers are used to control the flow of electric current within a home. Circuit breakers are typically installed near the service entrance and are sized based upon the amount of current being drawn by the loads attached to the circuit. There are normally two types of circuit breakers; contactor and thermal. Contactor circuit breakers interrupt the circuit after detecting arcing or excessive heat. Thermal circuit breakers open the circuit once the temperature reaches a certain level.

Hot Wires

Hot Wires are simply those wires that carry direct current throughout the building. Hot wires include both AC and DC cables. All of the wires coming out of the wall outlet must connect to either the neutral or grounded conductor. Any cable without a connection to either of these conductors is considered a “hot” wire.

Grounding Rod

A grounding rod is a device that helps keep dangerous voltages away from buildings. By connecting the negative pole of the generator directly to the grounding rod, we ensure that no harmful voltages get transmitted to our structure. We recommend having at least 6 inches of space between the grounding rods and the foundation walls.

Neutral Wire

The neutral Wire is what allows us to safely switch between live and dead circuits. Without neutrals, we wouldn’t know whether something was plugged into a light socket or a refrigerator. Neutrals are always marked with a yellow stripe and are color coded according to the number of phases they supply.

Ground Wire

 All electrical equipment requires a path back to Earth. This is accomplished via the ground wire which connects all ungrounded conductors together. The ground wire also provides a return path for any electricity generated internally by your appliance. It’s important to note that this wire cannot be connected to anything except another ground wire.

Copper Wire

Copper wire has been around for centuries but only recently have its benefits become widely known. Copper offers superior performance over aluminum because copper conducts electricity better and more efficiently. In addition, copper can withstand high temperatures much longer than aluminum so it will last longer under extreme conditions.

Aluminum Wires

Aluminum wire is an excellent choice for low-voltage applications such as lighting fixtures. Aluminum does not conduct electricity very well compared to copper and therefore won’t work effectively in areas where there may be significant amounts of resistance.

Ground Rod

A Ground Rod is a steel post buried underground that serves as a reference point for locating the center of a property. A properly placed ground rod should extend approximately six feet below grade. If you plan on installing new plumbing pipes, make sure to place them above the location of the ground rod. Plumbing pipe is usually made of galvanized iron and if left exposed to moisture could rust.

GFCI Receptacle

This type of receptacle protects against shock hazards caused by water leakage. They provide protection when someone accidentally contacts a hot line while working inside a wet area. When power enters through the plug, the breaker trips before the load gets energized.

Wiring Diagrams

Diagrams help people understand complicated concepts easily. With diagrams, one can see exactly how things fit together. For example, a diagram shows the relationship between different parts of a house. Another use of diagrams is to show how appliances interact with each other. Electrical diagrams are helpful tools for understanding how electricity works.

Electrical Safety Rules

Safety rules are essential to protect yourself from injury. Here are some safety tips:

  • Never touch bare metal surfaces.
  • Keep children away from outlets.
  • Use extension cords instead of running long distances.
  • Be careful using ladders.
  • Always turn off the main breaker before doing repairs.
  • Don’t overload circuits.
  • Make sure lights aren’t too bright.
  • Turn off unused switches and plugs.
  • Install smoke detectors.
  • Check fuses regularly.

Feeder Breaker

The feeder breaker is used to supply current to the service entrance or meter socket. These breakers are installed at the distribution transformer near the street. Feeder breakers must always remain open unless they’re being tested.

Feeder Cables

Cables connect the service drop wires to the distribution box. There are two types of cable; armored and non-armored. Armored cables are designed to carry large currents safely. Non-armored cables are cheaper and smaller. Both types of cables need to be protected from damage.


To see the step-by-step guide to wire a sub panel, have a look at this video.

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