Does every device draw its full rated load all the time?

No, a device doesn't always draw its full rated load. A variable-speed fan, for example, may draw less power at a lower setting.

Can a load change when a motor starts?

Yes, a motor can draw more current as it starts than it draws while running. That starting demand may affect how the connected equipment performs.

What can a load calculation reveal about a planned addition?

A load calculation can reveal whether a planned addition fits the available service capacity. It may also show that the service needs an upgrade before equipment is added.

Glossary

What Is an Electrical Load?

An electrical load is the demand placed on an electrical system by equipment that uses power. Lights, appliances, and heating equipment are examples of loads. The term also describes the amount of power those devices draw from a circuit or electrical service during operation.

Local relevance: Indianapolis homes use heating during cold winters and air conditioning during hot summers, so seasonal equipment affects the electrical loads considered in service planning.

Quick Facts About Electrical Load

Category: Electrical demand
Used for: Electrical system planning
Common confusion: Load versus panel capacity
Often discussed with: Electrical Service Upgrade, Electrical Panel Upgrade

Key Takeaways About Electrical Load

Demand changes as equipment switches on and off.
A load calculation helps plan a service upgrade.
Panel capacity and actual demand aren't the same.

How Electrical Load Works

A person uses a screwdriver on an open electrical load box mounted on an exterior wall

Electrical load changes as devices start, run, and stop. A heater adds demand while it runs, but its demand drops when it switches off. Loads on individual circuits add to the demand on the electrical service. Related service: Electrical Service Upgrade.

Related glossary terms: Load Calculation, Electrical Panel, Branch Circuit.

Power is commonly expressed in watts. Current, measured in amps, describes the flow of electricity through a circuit. Equipment labels can show these values, but a label doesn't always describe actual use.

A load calculation estimates demand for a circuit or service. It considers the equipment connected and how the equipment operates. The result helps show whether existing equipment has room for an added load.

Panel capacity describes what a panel is rated to handle. Actual demand can be lower than that rating and can change throughout the day. A calculation helps put those differences in context.

Hands adjust a screwdriver on an electrical panel labeled ELECTRICAL LOAD with colored wires outside in daylight

From the GMB Electric team

When we plan an electrical service upgrade, we review the equipment already connected to the home. We also ask about planned additions, such as an electric vehicle charger. That information helps us choose a service size that fits the home's expected demand.

Electrical Load in Practice: A Real-World Example

A homeowner plans to add an electric vehicle charger during an electrical service upgrade. The load calculation accounts for the charger and the home's existing equipment to help determine the service size.