A Quick Guide On How To Read An Electrical Panel

The circuit breaker panel is the hub for electricity distribution from the utility company to the electrical circuits within your home. When accessing the panel box, you will encounter a dead front cover or a flat panel with breaker openings. Typically, the panel consists of two vertical rows of breakers, with the main breaker occupying the top position.
The main breaker grants you the ability to shut off all circuits simultaneously. On the other hand, branch circuit breakers are designed to deactivate individual circuits.
Many a time, when you plan to upgrade an electrical panel, the electricians divide them into further groups to easily categorize them:

  • 15-amp circuits, which serve lighting and outlet circuits.
  • Dedicated power outlets in areas such as the kitchen, garage, and other locations where large appliances are utilized require 20-amp breakers.
  • Double-pole breakers with 30, 40, or 50 amps, specifically catering to 240-volt appliances like dryers, ranges, etc.

Let us discuss the circuit breaker panel’s main parts, label decoding, and safety precautions.

Table of Contents

Components Of A Circuit Breaker Panel

The circuit breaker panel, or electrical or breaker box, is typically a metallic box mounted on a wall in utility rooms, basements, or garages. It typically features a hinged door that protects the circuit breakers inside.

A circuit breaker can automatically stop the current flow in an electrical circuit when there is too much current or a short circuit. This crucial device serves to prevent electrical fires and safeguard electrical equipment.

Understanding the functioning of a circuit breaker panel is vital, especially when there is a need to quickly cut off power to a building during emergencies like fires or floods. Additionally, there may be times when access to a tripped circuit breaker is necessary. This is typically due to an overloaded circuit board from the simultaneous use of several appliances. Let us look at the different components in brief.

Main Circuit Breaker

The main breaker is a crucial component of an electric panel as it acts as a safety device and controls the power supply to the entire electrical system. The main breaker, typically the largest circuit breaker in the panel, handles the maximum electrical load the panel can accommodate.

You can turn off the main breaker to disconnect power to the entire electrical system during maintenance or emergencies. Thus, this will protect against overloads and short circuits. However, if you have a tripped breaker, electrical contractors in Calgary prefer to change it to dual-function breakers. This helps protect your home from arcs and ground faults.

Empty Panels

Distribution panels, or load centers, are also known as the basic framework of an electrical panel without any installed circuit breakers. They provide the housing and mounting space for circuit breakers, allowing for electrical power distribution to various circuits within a building.

Empty panels are versatile and can accommodate a range of circuit breakers with different amperage ratings, allowing for customization based on the electrical needs of the building.

Sub Panels

Subpanels are additional electrical panels connected to the main electrical panel. They distribute power to specific areas or circuits within a building far from the main panel. Subpanels help reduce the length of electrical wiring required and make it easier to manage electrical loads in large buildings or multi-story structures.

They typically connect circuit breakers to the main panel through dedicated feeder cables. Subpanels provide localized power distribution, ensuring efficient and safe electrical supply to specific areas or equipment.

Examining The Labels On The Breaker Panel Box

During the initial installation of wiring, circuits are commonly given labels. These labels are next to switches or inside the breaker panel door. Their respective switches assign them numbers corresponding to specific appliances or rooms connected to the circuit.

During emergencies, when power is lost to a specific room or appliance, the labels on an electrical panel breaker box serve as a helpful reference. For example, if the breaker that supplies electricity to the stove or oven trips, you can consult the label to identify the circuit breaker responsible for the oven. Likewise, in emergencies, it may be necessary to deactivate power to certain appliances; in such cases, refer to the labels associated with the appliance and switch off the corresponding breaker.

How To Label The Switches

Label your breaker panel by following these instructions if the circuit breakers are not labeled. The process of circuit labeling simplifies the identification of switches to be toggled on or off in case of a circuit trip or the need to deactivate a specific breaker. Let’s examine them in the words of a knowledgeable Calgary electrical contractor:

  1. Deactivate all the circuits except for one.
  2. Proceed to traverse the premises, testing the functionality of lights and outlets to determine which ones remain operational. Employ a small lamp or electronic device for swift outlet inspection.
  3. Once you have determined the room or rooms associated with the circuit, return to the breaker panel and proceed to affix a label to the corresponding switch.
  4. Repeat this procedure for each switch until they have all been appropriately labeled.

Safety Precautions You Should Take While Working On The Panel

Knowing which circuit breaker controls each appliance and understanding basic problem-solving can save money in the long term. Prioritize safety when working on a circuit breaker panel in a utility room by following these steps:

  1. Shut off the individual circuit breaker or the main breaker.
  2. Read and follow the manufacturer’s instructions.
  3. Wear protective gear.
  4. Avoid overloading circuits.
  5. Disconnect faulty appliances and reset tripped breakers.
  6. Use the correct size breaker or fuse.
  7. Maintain clear access to the circuit breaker panel with a flashlight nearby.

Still, Need Help With The Circuit Breaker Panel?

Identifying and resolving electrical problems may prove more challenging than initially anticipated. In cases where the problem is not readily apparent, it is advisable to rely on the expertise of an electrical contractor in Calgary to diagnose, troubleshoot, and rectify the issue promptly and effectively. Doing so can prevent the situation from escalating or causing further harm to your household.

However, you can also hire Ampt Over Electric to inspect your house before it is too late. They have complete electrical panel services, including installation, upgrade, and replacement, before it causes damage to your property.

Frequently Asked Questions

The numbers on an electrical panel represent circuit breaker slots, corresponding to various areas of your home or building. Each number relates to a specific circuit. It helps identify and manage power distribution and troubleshoot electrical problems within a particular circuit.
The voltage of an electrical panel box varies, commonly at 120 or 240 volts for residential settings in the US. Industrial settings might use 277- or 480-volt panels. The exact voltage can typically be found on the panel's label. The number represents the potential difference, the force driving the electrical current.

When a circuit breaker trips due to overloads, short circuits, or ground fault surges. Overloads happen when too many electrical devices draw power at once. A hot wire touching a neutral wire is what causes short circuits. Ground faults occur when a hot wire touches a grounded or metal box. So, this only explains why it is time to call for an electrical panel upgrade contractor in Calgary, as they will have the skills and the tools to help you repair the problem in no time.

Electrical ratings are read by looking at the volts (V), amps (A), and watts (W) on a device or panel. Volts indicate electrical pressure, amps show the electrical current rate, and watts represent the power consumption. The relationship between these is described by the formula P=IV.
The main circuit breaker at the top or bottom of most panels determines the total amperage of a panel. This breaker has its amp value marked on its handle. The number indicates the maximum amount of current the panel can safely handle.

This post is part of our commitment to transparent, helpful, and informative content for our readers and visitors. For more details on our editorial process and how we ensure accuracy and reliability, please visit our Editorial Process page.


Jorden McCullough,

Master Electrician, CEO of Ampt Over Electric.
Jorden, is a highly skilled Red Seal Master Electrician, with over 20 years of experience serving Calgary’s communities in a commercial and residential electrical capacity. AMPT Over Electric was established in Alberta in 2009 and proudly serves Calgary and surrounding areas. Our goal is, and has always been, to build relationships in business on integrity and respect. Our commitment to our community is to provide safe, high-quality electrical service. In order to guarantee that, we only employ competent Calgary electricians who share the same passion that we do.

Leave a Comment

Your email address will not be published. Required fields are marked *

Get Wired!

Scroll to Top