Panel Upgrades (100A/200A/400A)

Panel Upgrades (100A/200A/400A): A Homeowner and Facility Guide

An electrical panel upgrade is one of the most impactful improvements you can make to a property’s safety and capacity. Panels are designed around a service size—commonly 100A, 200A, or 400A—and that size determines how much electricity the home or building can safely use at once. When the panel is undersized or aging, you may experience tripped breakers, flickering lights, and limited ability to add new equipment.

This guide explains why panel upgrades are needed, how service sizing works, the most common causes of panel problems, and what a professional upgrade typically involves.

What a Panel Upgrade Actually Does

A panel upgrade can include several elements:

• A new breaker panel with modern breakers and improved safety features
• An upgraded service size (for example, 100A to 200A)
• Updated grounding and bonding
• Re‑terminated or replaced feeder conductors
• Improved labeling and circuit organization

Not all upgrades require a service increase. Sometimes the panel itself is outdated or unsafe even if the service size is adequate.

Signs You May Need a Panel Upgrade

Frequent Breaker Trips

Cause: Overloaded circuits or a panel that cannot support current demand.
Solution: Load calculation and, if needed, a service upgrade or additional subpanels.

Flickering or Dimming Lights

Cause: Heavy loads starting (HVAC, well pumps, EV chargers) on a system with limited capacity.
Solution: Rebalance circuits or increase service size.

Limited Space for New Circuits

Cause: An older panel with no room for additional breakers.
Solution: Install a larger panel or add a subpanel if the main service has capacity.

Outdated or Unsafe Panels

Cause: Panels past their service life or with known reliability issues.
Solution: Replace with a modern, code‑compliant panel.

Understanding Service Size (100A vs 200A vs 400A)

Service size represents the maximum current the electrical system can safely deliver.

• 100A service is common in older homes with fewer appliances.
• 200A service is typical for modern homes with multiple high‑draw appliances.
• 400A service is common for large homes, multi‑unit properties, or commercial buildings with heavy loads.

The correct size is determined by a load calculation that accounts for appliances, heating, cooling, and planned additions like EV charging.

Common Causes of Panel‑Related Problems

1) Load Growth Over Time

Homes built decades ago were not designed for modern demand. EV chargers, hot tubs, home offices, and additional appliances increase electrical loads significantly.

2) Aging or Loose Connections

Panel connections can loosen over time due to thermal expansion. This creates resistance, heat, and potential arcing.

3) Corrosion or Moisture

Moisture can enter panel enclosures in basements or poorly sealed areas, leading to corrosion and unreliable performance.

4) Obsolete Equipment

Some older panels lack modern safety features such as AFCI or improved breaker designs. Others may use parts that are no longer supported.

What Problems a Panel Upgrade Solves

• Capacity for new circuits without overloading existing ones
• Reduced nuisance tripping by properly distributing loads
• Improved safety with modern breakers and protective devices
• Cleaner, labeled wiring that is easier to maintain
• Compliance with current code requirements

If you are planning a renovation, a panel upgrade often prevents future delays and rework.

How a Professional Upgrade Is Planned

Load Calculation

An electrician evaluates the existing load and planned additions to determine the required service size. This step prevents under‑sizing and ensures future flexibility.

Equipment Selection

Panel sizing and breaker types are chosen to match the property’s needs. This includes capacity for future circuits and appropriate surge protection options.

Utility Coordination and Permits

Service upgrades often require coordination with the utility and a permit. The upgrade may involve temporary disconnection of power, followed by inspection.

Safety and Code Compliance

Upgrades must meet the Canadian Electrical Code, including clearances, grounding, and bonding requirements. Proper torque values and wire terminations are critical.

Safety Considerations During an Upgrade

Panel upgrades involve live service conductors and should never be done as a DIY project. Safety measures include:

• Utility disconnect and proper lock‑out procedures
• Testing and verification before reconnection
• Inspection and sign‑off by the appropriate authority

These steps are essential for safe operation and legal compliance.

Should You Choose a Subpanel Instead?

A subpanel can be a good option if:

• The main service has adequate capacity
• The goal is to add circuits in a distant area (garage, basement suite)
• The existing panel is modern and safe but full

If the main service is already at capacity, a subpanel alone is not enough.

Planning for Future Electrical Needs

Panel upgrades are easier and more cost‑effective when done proactively. Consider upcoming changes:

• EV chargers
• Heat pumps or electric furnaces
• Hot tubs or spas
• Secondary suites or rental units
• Home office equipment and networking

Planning for these early avoids repeated electrical disruptions later.

A Homeowner Checklist for Panel Readiness

• Breakers trip frequently or unpredictably
• Panel is warm, buzzing, or shows discoloration
• Panel has no room for new circuits
• Service size is smaller than modern needs
• You plan to add high‑load equipment

If two or more of these apply, a professional assessment is recommended.

Closing Thought

A panel upgrade is not just about adding capacity. It is about safety, reliability, and readiness for modern electrical use. When sized correctly and installed properly, an upgraded panel provides decades of safe service and reduces the risk of unexpected outages or hazards.