Why circuit breakers fail

On the othe Recent Posts. Featured products Allen Bradley A3C Allis Chalmers AME. Call Now. Allis Chalmers FAA.

GE BG2. Zinsco HAGF Zinsco HQB Add to cart. Continue Shopping. Proceed to Checkout. A short is caused when the hot wire black wire touches another hot wire or touches a neutral wire white wire. It can also occur if there is a break in a wire in the circuit. Shorts are a little more difficult to identify because they can be caused by the wiring in your home or in something you have plugged into an outlet. To check for a faulty appliance, unplug the fixtures or appliances one by one and check to see if the breaker stays closed when you reset it.

This will identify an appliance that is causing a specific problem. This is when the hot wire, almost always black, touches the ground wire, which is bare copper, or the side of a metal outlet box. John Moore electricians are the best of the best when it comes to getting the job done right and doing it safely.

We want you to be prepared. Educating the community is the first step in our work as licensed Houston area electricians. Having said that, you should remember that the smartest option is always the safest, and that means knowing when to let us take over when times get tough. Give us a call right away if you run into any of the problems above.

Always do plenty of research beforehand and talk to someone experienced to get your breaker on the way to recovery. Overloaded Circuit Remember that time when one of you was heating up some popcorn in the microwave, the other was blending up a smoothie, and then a third person switched on the toaster? Search Submit Clear. About Us. Now, what are the causes of a short circuit?

So, instead of having current go through a motor or heating element, it finds a path around them. This short circuit draws a huge amount of current, immediately tripping the breaker. The breaker does what it is designed to do, interrupting the flow of electrons, before the short circuit damages wiring and other equipment. Therefore, if you receive a complaint about circuit breaker failure, you must check for a short circuit.

Use your multimeter for this, checking all the possible connected appliances. Even something as simple as a loose connector can cause a circuit to overload. Always ensure wires are tightly connected to the breaker and check for similar connection errors on all connected appliances. Loose wires can also cause arcing in circuits.

For high amp equipment, check that wires are tightened to the manufacturer specified torque. Insulated torque screwdrivers have been designed specifically for this purpose. Unless it's malfunctioning or the wires are damaged, it does not need to be replaced unless you see it is burned or if it is hot to touch. You don't have to replace the breaker every time. When in doubt as to the condition of the breaker, it is usually recommended to replace it.

Typically, it is not necessary to replace or change the breaker if it trips, but repeated overload situations or a breaker that randomly trips can be other indicators for replacement. Before resetting the breaker, always ensure the fault that caused the trip has been rectified. Yes, it can definitely happen; a breaker can stop working over time, usually caused by arcing of the contacts when the circuit is disconnected.

Customers sometimes use a circuit breaker as a switch and disconnecting a circuit under load causes arcing of the contacts, which will greatly reduce the lifespan of the breaker. It is essential to check them properly and make a decision whether to replace them or maintain them. An electric short may even cause an explosion if the amperage is high enough. We can see this a runaway current.

With no resistance the current simply cascades, with ever-increasing energy being delivered. To prevent a short circuit from causing damage, the electromagnetic field created by the increasing current is utilized. Part of the circuit breaker consists of an iron core, with wire coiled around it to from an electromagnet. An armature, positioned close to the electromagnet, rotates with the magnetic force, causing the trip bar to open the circuit.

Under normal load, the current passing through the coil does not generate enough magnetic force to move the armature. This happens rapidly, fast enough to break the circuit before the heat generated by the short circuit can cause any harm. When you consider that, within a small circuit breaker, there is so much going on, you should realize how important it is to ensure that these mechanisms function correctly. A circuit breaker should remain reliable for a long time.

But this will depend on the quality of the components and the amount of times the breaker opens and closes. There are other factors too, like heat generated from high loads and arcing. All this will be discussed in more detail as we continue. We know, from discussing how a circuit breaker works, that it will trip when there is too much current flowing through the breaker current overload.

We also know that a circuit breaker will trip in the event of a short circuit. This is the most common reason why a functioning circuit breaker can trip and there can several causes for a current overload.

Lawnmowers, welders, and large power tools may require more current than the circuit is capable of conducting. This is often a result of startup load for inductive motors. A lawnmower with a 1,W electric motor can require as much as 3,W to start, sometimes more. At V, this is 27A. Although the lawnmower will require around 9A when running, the initial inrush current will be much higher.

If you try to use this mower on a 20A circuit, it will trip when you pull the lever to start it. The solution is to use a 30A circuit for the lawnmower or any high-current appliance. Though a common rookie mistake is to simply change the existing breaker for one with a higher amp rating. This is extremely dangerous. A circuit breaker is installed in accordance with the gauge of the wiring it supplies.

A 20A circuit will use a gauge wire to supply the outlets. For a 30A circuit, you need to install guage wire. This should be done by a qualified electrician, knowledgeable in the electric code and local regulations. Sometimes a circuit breaker may trip, seemingly at random. You go reset the breaker, and all is well. Some time later that breaker trips again, so you reset it again. This situation is usually a result of two appliances, requiring a high inrush current, starting simultaneously.

If, for example, you have a refrigerator and an air conditioner running on the same circuit, the combined startup current of both appliances may exceed the amperage that circuit can supply.

Since both these appliances cycle, using a thermostat, you never know when they could start. It is rare, but sometimes both the AC and refrigerator will start at the same time.

Since both require a high startup current up to three times their normal running current , the load will be extremely high. For a brief period, the power required to start both the AC and refrigerator will be 5 — 6 times more than if they were both running. The solution is to sperate the two appliances. A properly wired house will have several circuits in the same room. In other words, different outlets will be supplied by different circuit breakers.

If you switch an appliance on and the circuit trips, you can be sure that the appliance has a fault. This could be damaged insulation, a faulty capacitor, or water in the appliance.

Sometimes, in the case of a water heater or refrigerator, you may not realize it is the appliance that is causing the breaker to trip. This is because these appliances switch on and off automatically. The only way to diagnose automatic appliances is to disconnect each appliance one by one. When you discover the faulty appliance, the circuit will stop tripping. The faulty appliance then needs to be repaired or replaced. If your water heater keeps tripping the breaker, there can be a number of reasons why this is happening.