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What Is a Short Circuit?

an outlet

Many people know that a short circuit is a sign that something isn’t working properly in their electrical system, but aren’t sure exactly what happens or what it is. A short circuit is a condition in an electrical circuit where the electrical current does not follow the correct path but unintentionally finds a different pathway. Within your home, your light sockets and outlets are part of the circuit. Under normal conditions, outlets and sockets use electricity to power lights or appliances but don’t break the circuit.

Most household wiring is made of copper because it conducts electricity efficiently. Not all metals conduct electricity as well, but they will conduct better than other household materials. Sometimes, a short circuit can happen through a less-ideal material if something has disrupted the main circuit.

Short Circuit Causes

Several things can cause a short circuit in your home. Typical short circuit causes that homeowners encounter include the following:

  • Damaged or old electrical devices, sockets, outlets and switches
  • Broken or chewed wires from pest activity
  • Damaged or deteriorated wire sheathing
  • Power surges
  • Water or fluids coming into contact with wiring
  • Loose or damaged electrical box connections

Another common short circuit cause is when homeowners or contractors place nails or screws in the wall that come into contact with an electrical wire.

Short circuits can damage your home and wiring by scorching the area where the circuit is shorting or even causing a fire. There are several signs to look for that indicate you have a short circuit. If you see scorch marks or sparks near an outlet, notice a burning smell or hear a popping or buzzing sound, you should contact a licensed electrician sooner rather than later.

a living room

Fuse Box Versus Circuit Breaker

Even the most careful homeowners can experience short circuits. You may not realize you have a pest problem until a licensed electrician investigates a short circuit. Lightning could strike during a storm, causing a surge of power. Most homes have built-in safeguards that help reduce the chances of a short circuit. Fuse boxes and circuit breakers can disrupt a short circuit before it damages your home. Although they are both helpful safety devices, they are not the same.

What Is a Fuse Box?

A fuse box is a metal box that contains multiple fuses. Inside each fuse is a wire or strip of metal that melts when too much electrical current passes through it. When this happens, the circuit is broken. However, while fuses and fuse boxes function similarly, they are not the same as a circuit breaker. Fuses come with a rating that indicates the amount of overcurrent or excess electricity they can handle. Once a fuse blows—when the wire or strip melts—you can no longer use it. It can be tempting to replace a blown fuse with a higher-rated one, but that can allow more current to flow through than your electrical system can handle.

Fuse boxes and fuses are increasingly rare. Since the 1960s, home builders have moved from using fuse boxes to using circuit breakers in new construction. Building codes in many places now prohibit installing fuse boxes or require upgrading old ones. If your home is older and still has a fuse box, modern appliances and electricity use could draw more electricity than the fuse box can safely handle.

a circuit breaker

What Is a Circuit Breaker?

Circuit breakers, pictured above, are switches. When an electrical surge happens, it triggers the magnetic switch to move from “on” to “off.” When a circuit breaker switches to “off,” it breaks the connection and can prevent a short circuit. You cannot reuse a fuse once it has blown, but you can reuse circuit breakers many times by resetting them to “on.” If your licensed electrician needs to work on a particular area of your home wiring, circuit breakers make it easy to turn the electricity off in that area without shutting down the entire home system.

Avoiding Short Circuits With Fuses or Circuit Breakers

Fuses can respond slightly faster to a surge and are often less expensive than circuit breakers. But most homeowners draw far more power than older home fuse boxes can handle. In addition, fuses protect your electrical system from overload but may not prevent a short circuit.

But is there a big difference between a fuse box and a circuit breaker? Unlike fuses, you can reset circuit breakers. Some circuit breakers can detect electrical leakage and will immediately switch off to prevent a short circuit in moist or wet areas like the bathroom or kitchen. Other circuit breakers, like arc fault circuit interrupters, respond to sparking and overload. You can also turn circuit breakers off and on at the electrical panel.

It’s a good idea to talk to an electrician if you have an older fuse box or even an older electrical panel with circuit breakers. Most modern families use more appliances and draw much more power than fuse boxes and older circuit breakers can handle. Upgrading your electrical components is a complex process, so be sure to contact a licensed electrician.

a circuit breaker

What Causes a Circuit Breaker to Trip?

You may have a circuit breaker trip occasionally or after a bad storm. Likely, it is simply doing its job, and you can reset it. However, it helps to know what causes a circuit breaker to trip so you can troubleshoot. If you are resetting a circuit breaker often, don’t ignore it. Frequent tripping of a circuit breaker can mean an issue is happening that needs professional attention.

There are three reasons why your circuit breaker keeps tripping, including:

  • Ground faults
  • Overloads
  • Short circuits

A ground fault happens when electricity unexpectedly makes a path to the ground. The current increases and then causes the breaker to trip. A ground fault can be the result of damaged appliances, incorrect wiring or worn wire insulation.

Overloads happen when too many items draw power on the same circuit. Every appliance uses a certain amount of amps to operate. If you have a circuit that can handle 20 amps but use two devices that draw 30 amps, you can trip the circuit breaker.

Short circuits happen when a hot wire touches a neutral, ground or another hot wire. When there is a short circuit, the electricity takes the shortest route as opposed to the route it’s supposed to take. This electrical shortcut can cause fires or shocks.

In most cases, overload is the culprit when a circuit breaker trips. Once the breaker trips, you won’t be able to operate the things you have plugged in. To troubleshoot, begin by unplugging some electrical devices or appliances, and reset the circuit breaker. However, if you plug some of those appliances back in and the breaker trips again, it’s time to call a licensed electrician.

Get Electrical Help From Specialists

With a good understanding of what is a short circuit and how it happens, you see how reliable electricity is an integral part of our lives. When things go wrong, it’s crucial to contact an expert who can assess your problems and deliver professional work. Instead of getting bogged down in a never-ending list of home repairs, contact a licensed electrical so you can enjoy your home again.

ABC Can Protect Your Home From Electrical Problems

If you want to protect your home, contact ABC Home & Commercial Services. Our licensed electricians can perform a host of electrical services throughout your home. Whether you’re wondering if you should upgrade your electrical panel or you just have questions, we can help with your electrical needs.

Tom Riggs

Tom Riggs is the Division Manager for Mechanical Services, overseeing sales and operations for HVAC, Plumbing, Electrical, Appliance Repair and Water Quality for all ABC Austin branches. He joined ABC in 2014. Before ABC, he was an HVAC Service Technician, HVAC Comfort Advisor/Sales and Operations Manager. Tom attended Universal Technical Institute. He's an avid outdoorsman and enjoys country living with his wife and two sons.

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