To meet the goals of its Sustainability and Climate Action Plan (S/CAP), the City of Palo Alto Utilities (CPAU) is taking actions to support driving electric and shifting away from natural gas use. For many CPAU customers, this may require an electric panel upgrade. This page helps you understand how to determine whether or not your project will require an electric panel upgrade and the best way to proceed. 


Will my project require an electric panel upgrade?

Whether or not your project requires an electric panel upgrade depends on the amount of current (measured in amps) that your existing electric panel can handle, as well as the amps that will be required by your new appliance(s). The majority of older (built before 2000) homes in Palo Alto have 100 amp electric panels. These 100 amp panels are usually fine when it comes to handling the baseline electrical requirements of the home – existing lighting and appliances – which typically require about 60 to 80 amps when operating together. However, if a homeowner wants to install an electric vehicle (EV) charger as well as electric appliances, an electric panel upgrade may be needed. 


What are typical sizes for residential electric panels?

Electric panels are rated according to the amount of electric current they can handle, also referred to as the amp capacity, measured in amps (A). Standard sizes for electric panels in residential applications are 100, 200 or 400 A.In most cases, 200 A is more than sufficient. However, we are seeing an increase in the number of requests for upgrades to 400 A panels. A factor to consider – reflected in what is referred to as the diversity factor – is that not all electric appliances will be running simultaneously. A diversity factor of 1.2, which is often applied in practice, reflects a situation in which the total current requirements of all appliances connected to an electric panel can be up to 20% higher than the panel capacity. For a 200 A panel, this would mean that 240 A of current requirement could be connected. Electricians are familiar with taking these considerations into account when sizing an electric panel. Have a licensed electrician assess the panel capacity needed for your home.


Projects that may require an electric panel upgrade:

Project  Example Product Description  Estimated Required Amps* 
 Electric Vehicle Charger  Level 2 30-40
 Heat pump water heater  80 gallons 15-30
 Heat pump space heater / Air conditioner 30K-60K Btu heating load, mini-split unit 15-45
 Induction cooktop 4-5 burner cooktop 40-50
 Heat pump clothes dryer 4-7 cubic feet drum capacity 15-30
 Solar 5kW DC Consult with your electrician**
 Battery storage 7 kW peak power 30

*Depends on specific model of equipment selected.

**The number of available breakers on your electric panel may also be a limiting factor for projects that add to your home’s electrical load. In some circumstances, breakers can be added to an existing panel, but in other cases increasing the number of breakers may result in the need for a panel upgrade. A licensed electrician can assess whether your panel has enough available breakers to accommodate added electric loads.

How much will a panel upgrade cost?

The cost of upgrading your electric panel depends on several factors. For example, since for safety reasons upgraded panels must comply with existing code requirements, if your existing panel's location does not meet code requirements then the cost of a panel upgrade will include costs associated with relocating the panel. For information about permits, fees and requirements, refer to our electric panel upgrade Permits and Requirements page. Always be sure you understand fees of contractors and electricians prior to enlisting their services.

Still have questions? Check out these additional resources: