An electrical load is any device or component in a circuit that consumes electrical energy and converts it into another form of energy, such as heat, light, motion, or sound. Your toaster, ceiling fan, refrigerator, and phone charger are all electrical loads. Without a load, a circuit has no purpose: the load is the reason electricity flows in the first place.
How Electrical Loads Work
Every circuit has three basic parts: a power source, conductors (wires), and a load. The source pushes electrical current through the conductors, and the load uses that current to do something useful. A light bulb converts electrical energy into light and heat. A motor converts it into mechanical motion. A speaker converts it into sound waves.
The size of a load is measured in watts (W), which tells you how much power it draws from the circuit. A small clock radio pulls about 10 watts. A refrigerator uses around 725 watts. A water heater can demand 4,500 to 5,500 watts. The higher the wattage, the more energy the load consumes and the harder the circuit has to work to supply it.
Three Types of Electrical Load
Loads behave differently depending on what’s inside them. The three categories are resistive, inductive, and capacitive, and they differ in how voltage and current relate to each other.
Resistive Loads
Resistive loads convert electricity directly into heat. The voltage and current rise and fall in perfect sync, reaching their peak values at the same time. This gives resistive loads a power factor of 1.0 (sometimes called “unity”), meaning all the power drawn from the circuit is converted into useful work. Common examples include space heaters, incandescent light bulbs, toasters, and electric stove burners.
Inductive Loads
Inductive loads need a magnetic field to operate. Motors, fans, washing machines, transformers, and welding equipment all fall into this category. Creating that magnetic field causes the current to lag behind the voltage by up to 90 degrees, which means some of the power flowing through the circuit isn’t doing useful work. That “missing” power is called reactive power, and it’s why inductive loads have a power factor below 1.0. Factories and commercial buildings with lots of motors often install capacitors specifically to offset this lag, a process called power factor correction, which reduces energy waste and lowers electricity bills.
Capacitive Loads
Capacitive loads are the opposite of inductive ones: current leads the voltage instead of lagging behind it. In practice, pure capacitive loads don’t really exist as standalone devices. Capacitors are more commonly used as correction tools to balance out the reactive power created by inductive loads, rather than serving as loads themselves.
How Load Is Calculated
The basic formula for calculating load in a circuit is straightforward: multiply amps by volts, then multiply by the power factor.
Amps × Volts × Power Factor = Watts
If you skip the power factor, you get a number called “apparent power,” measured in volt-amps (VA). This looks like wattage but overstates how much useful work the load actually performs. For resistive loads with a power factor of 1.0, watts and volt-amps are the same. For inductive loads like motors, the real wattage is always lower than the apparent power.
Common Household Load Values
Understanding how much power your appliances draw helps you avoid overloading circuits and gives you a clearer picture of your electricity use. Here are typical wattage ranges for common household items:
- LED or clock radio: 10 W
- Laptop: 50 W
- Flat screen TV: 120 W
- Clothes washer: 350–500 W
- Refrigerator: 725 W
- Coffee maker: 900–1,200 W
- Microwave: 750–1,100 W
- Hair dryer: 1,200–1,875 W
- Dishwasher: 1,200–2,400 W
- Clothes dryer: 1,800–5,000 W
- Water heater: 4,500–5,500 W
Notice the enormous range. A laptop and a clothes dryer can differ by a factor of 100. This is why high-draw appliances like dryers and water heaters get their own dedicated circuits in your electrical panel.
Base Load vs. Peak Load on the Grid
The concept of load also applies at the scale of entire power grids. Utilities think about load in three tiers. Base load is the minimum level of electricity demand over a given period, the amount of power that’s always needed regardless of time of day. Power plants that run continuously (like nuclear or large natural gas facilities) typically handle this. Peak load refers to short bursts of high demand, often on hot summer afternoons when air conditioning use spikes. Mid-merit power fills the gap between those two extremes.
Electric vehicles are changing these patterns. Research modeling around 200 households found that 100% EV adoption could increase total household electricity consumption by 13% to 19%, while peak load could jump by 15% to 35% depending on when people charge. Simple strategies like limiting charging speed during high-demand hours can significantly reduce those peak surges without meaningfully affecting how people use their cars.
What Happens When a Circuit Is Overloaded
An overloaded circuit is drawing more current than its wiring and breaker are rated to handle safely. This is not a minor inconvenience. According to the National Fire Protection Association, electrical failures cause roughly 47,700 home fires in the U.S. each year, resulting in 418 deaths, 1,570 injuries, and $1.4 billion in property damage. Overloaded circuits are a major contributor.
Warning signs of an overloaded circuit include:
- Flickering or dimming lights
- Frequently tripped breakers or blown fuses
- Warm or discolored wall plates
- Crackling, sizzling, or buzzing sounds from outlets
- A burning smell near receptacles or switches
- A mild tingle or shock when touching an appliance or outlet
If you notice any of these, unplug devices from the affected circuit and redistribute them to other circuits. Persistent problems point to wiring that needs professional attention.
How Residential Load Is Sized
When your home’s electrical service is installed or upgraded, electricians follow the National Electrical Code (NEC) to calculate the total expected load. For a standard single-family home with 120/240-volt service up to 225 amps, the calculation starts with the home’s square footage multiplied by 3 volt-amps per square foot for general lighting. Then it adds 1,500 VA for each small appliance circuit (with a minimum of two) and another 1,500 VA for the laundry circuit.
The first 3,000 VA of this general load is counted at 100%, and everything above that is counted at 35%, reflecting the reality that you’re never running every light and outlet in your home simultaneously. Large appliances like dryers, ranges, and water heaters are added individually based on their nameplate ratings. If you have motors (like a central AC unit), 25% of the largest motor’s load gets tacked on as well. This calculation determines the size of your main breaker panel and the service wires running from the utility to your home, ensuring the system can safely handle your expected demand without overheating.