If you’ve ever studied how electricity works, you know there are enough scientific terms and definitions to drive anyone up a wall. And since you’re an electrician, people probably expect you to be able to explain exactly how the power supply to their lights and appliances works. Whether you were sleeping through Physics 101 or just need some help figuring out how to explain this to the average Joe, here’s a basic refresher on three of the terms every electrician should be able to explain: voltage, amperage, and wattage.

The water analogy

A common analogy that you’ll see used to describe how electricity works is water going through a hose. If you want water to come out of the hose, you need not just water, but also some pressure to force it out of the hose. You can then measure the total amount of water coming out of the hose as well as the rate at which it fills a bucket.

In an electrical circuit, the electrons that carry electricity are like the water in the hose. Voltage is the force pushing the electrons through the circuit. Amperage is the amount of electricity going through the circuit. Wattage multiplies the force and amount to calculate how much total energy is being consumed.

Voltage

If you’re explaining an electrical circuit like a hose, then voltage is like water pressure. Without water pressure, the water will just sit in the hose. Similarly, voltage is the power that pushes electricity through a circuit. The higher the voltage, the more rapidly electricity is being pushed through the wires.

Voltage is determined by the power supplier, and in residential homes in the United States, it’s delivered as 240V, then split in a transformer. Most outlets are connected to one 120V line, but some appliances, like the dryer or stove, may use 220V.

Amperage

An amp is a measure of how much electricity is flowing past a given point. In the water analogy, an amp would measure the amount of water coming out of the hose each second, for example. If your hose is small, less water will come out than if it’s a fire hose with a larger diameter. The pressure is the same, but you get a different amperage depending on the diameter of the hose.

Motors (like vacuums, blenders, etc.) are rated in amperage, but for purposes of lighting, you probably won’t run into amps very often. Just know that it’s the quantity of electricity flowing in a given time frame.

Wattage

To get the wattage, you multiply the volts (force) by the amps (quantity). Watts tell you the total amount of electricity being used over time. In the water analogy, a watt is the rate at which your bucket is filled. If the bucket represents your lightbulb, a watt measures how much electrical power it is using at any given moment.

Since watts measure the total amount of power being used, a 60w lightbulb uses much more energy than a 12w bulb. The type of bulb (incandescent, LED, fluorescent, etc.) will impact how many watts it needs. As a general rule, it’s fine to use a lower wattage bulb in a lighting fixture, but not a higher wattage bulb, as it may damage the fixture.

As a note, wattage is different from lumens. Lumens measure the amount of light a bulb produces, but that is not necessarily related to how many watts the bulb consumes. A 60w incandescent bulb may produce as many lumens as a 12w LED bulb, but the higher wattage means it needs much more power to produce it.

There you go, a simple explanation for a very complicated topic. Do customers ever ask you to explain these terms? Are there others you’d like detailed explanations of?

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