Understanding Your Electrical Panel: A Homeowner's Guide

The Quick Answer

Your electrical panel is the central distribution point for all electricity in your home. It receives power from the utility, divides it into individual circuits through circuit breakers, and protects your home from overloads and short circuits. Understanding how your panel works helps you make informed decisions about maintenance, upgrades, and safety.

How Your Electrical Panel Works

The Basics

Electricity flows from the utility through your meter into the main panel. Inside the panel:

1. Main breaker: Controls all power entering your home and establishes your service amperage (typically 100 or 200 amps)
2. Bus bars: Two metal bars that distribute power from the main breaker to individual circuit breakers
3. Circuit breakers: Each breaker controls one circuit in your home and trips (shuts off) when the circuit is overloaded or shorted
4. Neutral and ground bars: Complete the electrical circuits and provide safety grounding

Single-Pole vs. Double-Pole Breakers

• Single-pole breakers (120V): Standard 15 or 20-amp breakers for most outlets, lights, and small appliances
• Double-pole breakers (240V): Larger breakers (typically 30-50 amps) for high-demand appliances like dryers, ranges, water heaters, AC units, and EV chargers

GFCI and AFCI Breakers

• GFCI breakers: Detect current leaking to ground (like through water or a person) and trip in milliseconds — required for wet locations
• AFCI breakers: Detect dangerous electrical arcing (sparking) that can start fires — required in bedrooms and most living spaces under current code
• Dual-function breakers: Combine both GFCI and AFCI protection in a single breaker

100 Amp vs. 200 Amp Service

100-Amp Service

Common in homes built before 1990. Provides approximately 24,000 watts of power.

Adequate for:

• Smaller homes (under 1,500 sq ft) with gas heating and gas appliances
• Homes without central air conditioning
• Basic electrical needs without high-draw additions

Likely insufficient for:

• Central air conditioning plus electric dryer plus electric water heater
• EV charger installation (40-50 amps is half your total capacity)
• Home additions or major appliance upgrades
• Hot tubs, saunas, or workshop equipment

200-Amp Service

Standard for homes built after 1990. Provides approximately 48,000 watts of power.

Handles:

• Central AC, electric dryer, electric water heater, and EV charger simultaneously
• Home additions, workshops, and outbuildings
• Multiple high-draw appliances without load management concerns
• Future electrical needs as technology demands increase

When to Upgrade

Consider upgrading from 100 to 200 amps when:

• You're adding an EV charger, hot tub, or workshop
• Breakers trip frequently under normal use
• You're planning a kitchen or bathroom renovation
• Your home insurance company recommends or requires it
• You're adding a home addition

Common Panel Issues

Dangerous Panel Brands

Certain manufacturers produced panels with known safety defects:

• Federal Pacific Electric (FPE) Stab-Lok: Independent testing found these breakers fail to trip during overloads at rates far exceeding industry standards, significantly increasing fire risk. If your home has an FPE panel, replacement is strongly recommended.
• Zinsco/GTE-Sylvania: Breakers can fuse to the bus bar, preventing them from tripping. The result: uncontrolled current flow generating extreme heat.
• Pushmatic: Older design with push-button breakers. Parts are scarce and the technology is obsolete.
• Certain Challenger models: Some have exhibited similar failure patterns to FPE panels.

Warning Signs of Panel Problems

• Burning smell: Indicates overheating — this is an emergency
• Buzzing or crackling sounds: Suggests loose connections or arcing
• Warm panel cover: The panel door should never feel warm to the touch
• Discoloration or scorching: Evidence of past overheating events
• Rust or corrosion: Moisture intrusion that degrades connections and increases resistance
• Frequent breaker trips: May indicate overloaded circuits or failing breakers
• Breakers that won't stay reset: Could indicate a short circuit or ground fault in the wiring

Panel Maintenance

Electrical panels require minimal but important maintenance:

• Annual visual inspection: Look for rust, discoloration, or signs of water intrusion on the panel exterior (never remove the cover yourself)
• Exercise breakers: Once a year, turn each breaker off and back on to prevent contacts from seizing — but not if you suspect any panel issues
• Test GFCI and AFCI breakers monthly: Press the test button to verify they trip, then reset
• Keep the panel area clear: Maintain 36 inches of clearance in front of the panel per code
• Professional inspection every 5-10 years: Especially for panels over 20 years old

What a Panel Upgrade Involves

If you need a panel upgrade, here's what to expect:

1. Evaluation: Electrician assesses current panel, load requirements, and service entrance
2. Permit: Required in Wisconsin for panel replacement
3. Utility coordination: The utility disconnects power at the meter (electrician coordinates this)
4. Installation: New panel is mounted, circuits are transferred, and connections are made
5. Inspection: Municipal inspector verifies the work meets code
6. Reconnection: Utility reconnects power at the meter

A typical panel upgrade takes 6-10 hours and is usually completed in one day.

Frequently Asked Questions

Q: What is the difference between 100 amp and 200 amp service?

100-amp service provides about 24,000 watts — adequate for basic needs in smaller homes with gas appliances. 200-amp service provides about 48,000 watts — enough for modern homes with central AC, electric dryers, EV chargers, and multiple high-draw appliances. Most homes built after 1990 have 200-amp service.

Q: How long does an electrical panel last?

Most panels function properly for 25-40 years. Federal Pacific and Zinsco panels should be replaced regardless of age due to known safety defects. If your panel is over 25 years old, a professional evaluation is worthwhile.

Q: Can I replace a circuit breaker myself?

While technically possible, it's not recommended. The bus bars inside your panel remain energized at lethal voltage even when the main breaker is off. A licensed electrician can replace a breaker safely and evaluate whether the tripping indicates a larger problem.

Get Your Panel Evaluated

Not sure if your panel needs attention? A professional evaluation takes less than an hour and gives you a clear picture of your electrical system's condition. Call Couillard Electric at (262) 618-2851 for a free estimate.

Serving Sheboygan, Mequon, Port Washington, Grafton, Cedarburg, West Bend, Plymouth, Kohler, and surrounding Wisconsin communities.