When most of us think about the electricity in our home, we’re just thankful that we have it! Unless we’re having an issue with our electric power, we rarely give it a second thought. If the lights are going on, the heat or AC is running, and we can cook on the stove or in the microwave, we’re happy.

But have you ever stopped to think about why your toaster works when you plug it in or why blackouts occur during a storm? Or perhaps you’ve recently purchased a home that needs an upgrade to its electrical system, prompting you to stop and think about everything that goes into the successful wiring of a house.

Let’s start with the basics.

You’ve likely heard the word “voltage” plenty of times when discussing the wiring in your home. But do you really know what it means? And how about high voltage vs low voltage? What’s that all about?

What is voltage?

Technically, voltage is the amount of potential energy between two points on a circuit. Got it? Probably not.

Think about it this way. Voltage is like water pressure. Water needs pressure to push it through a hose or pipe. Similarly, electrical current needs some sort of force to make it flow as well. Voltage is the measure of that electric pressure, supplied by a generator or a battery. Electricians use the letter “V” to indicate voltage. For example, you might see a voltage indicator on an item in your house that gives you a number (25, 120, etc.) followed by the letter V.

Different voltage ranges in your house

Homes in Canada and in the U.S. work on what is known as a split-phase system using 3 wires – 2 line wires and 1 ground wire. The power enters your home at 240 V but is then split at the main circuit breaker into two 120 V halves. These halves are run through one of the line wires and the grounded center, providing the electricity you need for small objects like lamps or a blender.

Larger appliances require a higher voltage. So, power for items such as stoves or washers run through both line wires and the grounded wire simultaneously, providing 240 V of power.

Voltage ranges in Canada

So-called “nominal” voltage is the standard voltage that is produced by your utility company. In Canada, it’s 120/240 V. You’ve probably seen voltage markers on various items in your house as well as outside your home marked with these numbers.

In general, low Voltage usually refers to a range that carries a low risk of injury should you encounter it. This is usually under 100 V. If you touched a 100-volt wire with your hands, you won’t likely get electrocuted.

On the other hand, high voltage can be very dangerous and potentially cause harm. You’ve no doubt seen signs that say “Danger: High Voltage” on electrical devices or wiring that you shouldn’t touch. The risk of electrocution is really real when high voltage is involved. Anything above about 600 V is considered high.

Conversely, outdoor landscape lighting usually runs on “very low” voltages. For example, those little path lights you love might operate on just 12 to 24 volts, simply because they will likely be exposed to water from rain or snow and they can easily be damaged by someone with a lawn mower.

So why does my power fluctuate sometimes?

Even though the voltage ranges coming into your home are regulated, power fluctuations do occur now and then for a variety of reasons. This doesn’t mean there’s something wrong with your wiring.

When stable voltage levels are interrupted for any reason, such as a power surge or storm or even the turning on or off of a large household appliance, fluctuations can occur. You might observe them because your lights flicker, become dimmer, or become brighter, depending on what’s affecting the voltage. Usually, there’s no reason for concern and it’s fine to go about your business without contacting anyone.

Sometimes power companies stage brownouts on purpose in order to reduce power levels during peak usage time. If this is going to happen, you’ll likely be warned by your utility supplier

If, however, you have consistent problems with this, contact your electrician to assess the problem. An electrician experienced in residential wiring can diagnose what’s happening inside your home and will make suggestions for fixing the problem so that your household remains safe from any electrical issues that could cause fires or other catastrophic events.