Electrical Load In Electricity: The Basics

Aug 13

Even experienced facility managers can benefit from revisiting the basics of electrical load and related terminology. Understanding how electrical loads affect overall energy consumption and implementing intelligent consumption reductions can lead to significant cost savings on operating expenses, especially in energy-intensive industrial facilities.

What Is Load in Electricity?

An electrical load is any component of a circuit that consumes electricity. That includes everything from light bulbs to appliances to industrial machinery. The load of any circuit is inversely proportional to the electrical flow; a bigger load lowers the current within the circuit. The term load can be used relatively broadly to refer to several components of a circuit, including:

Equipment that uses energy.
The amount of energy required to meet demand within a circuit.
The current of energy passing through a line.

Types of Electrical Load

Different types of loads use energy differently. It’s often useful to define types of load by how they use energy, which makes it easy to determine that load’s most likely application.

Resistive Load

In most cases, any load that includes a heating element is considered a resistive load. Resistive loads restrict or slow the current and convert electricity into thermal energy. Incandescent lamps, space heaters, and hair dryers are examples of resistive loads in everyday life.

Inductive Load

Inductive loads require a magnet to do most of the work. Examples of inductive loads include transformers, generators, or electric motors.

Capacitive Load

Capacitive loads are considered leading, which means the current wave leads the voltage wage. Capacitive loads always require another type of load. By themselves, they are typically used to control large power circuits rather than consume energy.

It’s important to note that most modern electrical circuits include some combination of resistive, inductive, and capacitive loads.

Electrical Load Calculation: Crunching the Numbers

Calculating electrical load allows facility managers and engineers to right-size power supplies and optimize system performance. You won’t need to calculate electrical load often, but there are scenarios that demand a fresh assessment. In commercial and industrial applications, you’ll need to evaluate load whenever you add new appliances, machinery, or any energy-intensive systems, including on-site data storage or server towers.

Remember to account for several factors, including the three most important.

Demand factor - Not all equipment will be running at full capacity all the time. Track energy uses over daily, weekly, and quarterly periods and note average, high, and low demand periods.

Diversity factor - Account for the varying types of loads' overall effects on the system, and remember that resistive (thermal) loads require more energy than others.

Continuous and non-continuous loads - Continuous loads include any electric devices that run for three hours or more at a time, while non-continuous loads run for shorter periods.

Here’s a quick look at the load calculation. Electrical systems are complex, so we’ve simplified it to the basics.

P=VI

In this formula, P is power, V is voltage, and I is current.

For power, multiply the amperage by volts. For example, 5 amps at 120 volts is 600 watts for a single load. Repeat this process for all loads within the circuit; many industrial systems complete this multiplication step automatically and in real-time.

Add up the wattage of each load to determine the total amount of electricity the building consumes.

The Most Common Types of Commercial Electric Loads

There are dozens of potential loads in a commercial or industry facility. Some of the most energy-intensive loads are from basic operations, including:

Lighting
HVAC
Office equipment and technology
Appliances and machinery
Motors

Electrical Line vs. Load

Load may also refer to a specific wire. In most circuits, line and load in electrical describe two wires that connect to a device.

Line wire - Also known as a source wire, line wires carry electricity from the power source to the device.

Load wire - Also known as a hot wire, carries electricity from the devices forward in the circuit.

It’s useful to think of line wires as “incoming” electricity and load wires as “outgoing” electricity.

The Benefits of Electrical Load Calculations

Knowing your facilities’ electrical requirements can help identify inefficient machines and equipment that may need to be repaired or replaced and inform load-shedding strategies. Especially in facilities with on-site electrical generation or energy storage, identifying peak load demand provides an opportunity to utilize low-cost electricity during high-demand periods and reduce utility costs.

Get Expert Insight With Keen Technical Solutions

We’ve helped hundreds of Michigan businesses calculate load demand and improve operating efficiencies. The Keen team brings diverse industry experience to improve HVAC, lighting, and electrical system performance to provide lasting energy savings. See what Keen Technical Solutions can do for your organization - speak with a representative today.

Cody Sovis