View Specials
Schedule Now
Understanding the load calculations for your home electrical system is important. With homeowners adding more electrically driven features to their residences than ever before, the system’s ability to handle the load has become critical. Here is a ground-up look at electrical load terminology and what homeowners should know about load calculations.
Units and Terminology
You will encounter a lot of terminology, and many of the terms involve electrical units. Knowing the following will help you understand the basics of electrical load calculations.
Circuit
A circuit is a path for electricity to follow. Electricity seeks a path. Without encouragement, its preferred path is to the ground. Wires, circuit boards, electrical panels, and similar systems give electricity a useful path so we can harness its energy before it dissipates.
One reason electricity can be dangerous is that it will try to complete a circuit if there isn’t a clear path. Electricity can complete a circuit through you, or it can complete an undesired circuit through a device, potentially damaging it along the way.
Voltage
Voltage refers to the strength of electricity’s tendency to move from one point to another, presuming there is a completed circuit. The more voltage in an electrical line, the more likely it is to follow the path.
It isn’t a perfect analogy, but voltage acts like water pressure. It doesn’t accomplish much if you’ve ever looked at a water hose with little pressure. However, a hose with lots of pressure will emit a kick when you turn it on.
Voltage works similarly, and that electrical kick is handy for starting a cycle in a machine. For example, your dryer needs to get the tumbler spinning to start. A high-voltage kick is an excellent way to get it moving. The machine may then decrease its voltage demand once centripetal motion and a lower voltage are enough to keep the tumbler spinning.
Volts
Volts are the unit of voltage. In America, the power coming out of a typical two- or three-prong outlet is 120 volts. You can also connect high-output systems with a higher-voltage socket. For example, many washers use a 240-volt connection. Modern EV charging stations frequently go even higher.
Amps
We are returning to the water hose analogy. Amps are the flow rate. More amps allow greater flow at the same voltage.
Watts
If you multiply the volts by the amps, you will get the wattage of a system. Watts measure the total output or consumption of the system. We’ll return to the water metaphor once again. Wattage is akin to measuring the number of gallons that come from a hose.
Kilowatt-Hours
Most people have seen kilowatt hours, often styled as kWh, on their electric bills. A kWh is a thousand watts of consumption in use for an hour. The electrical company uses this as a standard consumption unit even if you’re not using a kilowatt each hour. If you used 500 watts over two hours, your bill would reflect one kWh of consumption for those two hours.
Load
Load refers to the power that the electrical system or one of its subsystems can handle at any given instance. This gives you an idea of how much energy you can get from a circuit panel or breaker. It also is a good comparison point for assessing a device’s demands.
Peak Load
Few devices run at full load for their entire operation cycle. For example, your refrigerator will hit its peak load at the beginning of a refrigeration cycle. Peak load is the maximum load a device hits when it asks for all the juice it needs.
Circuit Breaker
A circuit breaker is a safety system in your electrical panel. When the amperage load in a line exceeds the circuit breaker’s rating, the circuit breaker will trip. This shuts the line down, preventing a potential overload at the other end.
For example, a power supply failure in an appliance could cause it to draw more amps than normal. Suppose the appliance is rated for 25 amps and is on a 30-amp circuit breaker. If the buggy power supply starts overloading the appliance, it might try to pull 35 amps. Once it passes that 30-amp threshold, the circuit breaker closes the circuit to prevent the overload.
Understanding Load
Individual devices have specific load requirements. For safety’s sake, you should be concerned about the peak load. The peak load for a typical central air conditioning unit in a house might be between 30 and 50 amps. A conservative way to minimize problems is to add the amperage demands of all the devices in your home and install a panel with that rating.
It is also possible to work backward using your electrical bill to convert kWh into amps by dividing out the days and 120 volts to get a rough approximation of your daily average demand. You can multiply this figure by two to account for peak load needs on the worst days, such as a hot summer day when the AC seems to run constantly. You now have a ballpark figure for your household’s current peak load that includes some overhead, and you can add a projected load to it if you want to incorporate something like a woodshop or an EV charging station.
Remember that load calculations will be made for each circuit. Knowing the demands of a handful of specific devices is critical when considering per-circuit requirements. Take the previous example of a central air conditioner. A 50-amp HVAC unit can’t run on a 30-amp breaker without tripping it.
Also, the demands on a circuit are cumulative if devices run concurrently. A more powerful microwave might have a peak demand of 15 amps. It could also be on the same circuit as a fridge that runs at seven amps. You’d likely need to install a 25-amp circuit breaker for the two to co-exist on the same circuit.
Our electricians generally encourage customers to spread loads out across many circuits. Using a second circuit in your kitchen for your dishwasher and a third for an electric oven is likely safer than loading everything onto a single high-capacity circuit breaker. Few households use all the slots on their electrical panel for circuit breakers. If your household does, installing a bigger electrical panel may be wiser. This approach is also more convenient because you don’t have to worry about a short in the microwave shutting down the breaker for your refrigerator.
Finally, always be aware that the wires have individual loads. You can’t simply pop a 30-amp breaker into a panel without first checking the rating of a wire. If you have a 30-amp circuit breaker connected to a 15-amp wire, the extra load will dissipate as heat through the wire. The net effect will be a melted wire and a fire hazard.
Contact Us Today
Our Palm Springs, CA, electrical company manages many different electrical projects. We provide professional electrical services for indoor and outdoor lighting, electrical panel repairs and replacements, home rewiring, surge protector installations, and more. We are also available 24/7 for emergency service, a BBB-accredited business with an A+ rating, and offer financing on approved credit and online payments. Contact Home Team Electric today to discuss your electrical needs. We offer 24/7 emergency electrical services to make sure you’re always taken care of!
