Circuit Breaker Panel Activity

Construction Context
circuitbreakerpanelThe circuit breaker panel is the control point for the electricity delivered to your home and distributed through multiple circuits throughout your house (see Battery & Bulb activity: http://theselsproject.org/battery-and-bulb-activity/).  All buildings that use electricity (hard to think of one that doesn’t) have at least one control panel for distributing electricity (see video: http://theselsproject.org/electricity/usage/ on this site).  This activity is about understanding the location and function of the circuit breaker panel in your home or school or where you work.

[SAFETY WARNING] While your home circuit breaker panel is usually very accessible, you should not throw any switches or look beyond opening the door to the panel.  Examining the panel further requires someone who understands the operation of the panel and issues of safety.

One reason for learning about electricity in school science or technology classes is because these ideas are directly useful in your life now!  Understanding how electricity is generated, distributed, and used inside a home, school, or work can be of great benefit to you now!  This knowledge can keep you safe, keep things working, and perhaps be knowledge useful in a job, earning you more money.

Materials
Optional Item: Watts Up Pro

Activity Description
As an introduction, view these three short videos:
– Circuit Breaker Panel with the cover on: https://vimeo.com/63018669
– Circuit Breaker Panel with the cover off: https://vimeo.com/63018542
– Circuit Breaker Panel grounding: https://vimeo.com/63018842

Opening the door to a circuit breaker panel reveals a set of switches that control circuits in your house.  Each circuit is numbered, and most panels have been labeled so that you can see which switch controls which circuit in your home.

  1. Find how many circuits go to the kitchen. What does each control?
  1. Note the number on the switch. This indicates how many amps can flow in the circuit before the breaker switches off (or “thrown”) to protect the house from fire (see Grounding & Protection activity: http://theselsproject.org/grounding-and-protection-activity/).
  1. If you have an electric water heater, air conditioner, or oven, compare the circuit breaker for that circuit for others in the box. Use a search of the Web to find out why these breakers are larger than the others.
  1. Under the supervision of a parent or other knowledgeable adult, turn off one of the circuits and then investigate which outlets or lights are not working. You can use a small electric light to detect which outlets are not working.
  1. You cannot see this from the outside of the panel, but panel is connected to the ground by a large copper wire. Walk around the outside of your house and look for a bare, copper wire attached to a large iron steak driven into the ground. This is the return circuit connection back to the generating plant (see Generation video: http://theselsproject.org/electricity/generation/)

Scientific Concepts
Short circuit. Resistance and conversion to heat energy.

Next Generation Science Standards
Scientific and Engineering Practices:
– Planning and carrying out investigations

Crosscutting Concepts:
– Cause and effect: Mechanism and explanation
– Energy and matter: Flows, cycles and conservation

Discussion Questions

  1. Search the Internet to understand how a circuit breaker works.  Two easy places to start are http://www.howstuffworks.com or http://www.wikipedia.org/.  Discuss what are the purposes of the circuit breaker panel?
  1. Look at the main breaker in your home panel to see how many total amps of current can be delivered at one time.  It will probably say something like 200 amps.  Add up the maximum number of amps that all the circuits in the panel can deliver (see the number on the edge of each breaker switch).  How does the total of all circuits compare to the main breaker limit.  Discuss why these two numbers are different and what that means for electrical usage in your home and fire protection.
  1. Talk to the head of maintenance in at your school or where you work to see the circuit breaker panel. It what ways is it different from the one at home?
  1. The circuit breaker panel distributes electricity to your home.  How is electricity distributed to your neighborhood or city?  Ask someone at the power company to come talk to your class at school to explain distribution and protection in your area.

(Download the activity in PDF, Word)