How to Troubleshoot a Tripped Breaker
Most of the time a, circuit breaker trips people simple go to their electrical panel find the offending breaker and reset it. But what happens when the breaker does not reset, or trips often, you can troubleshoot the problem yourself and depending on the problem, repair it or hire an electrician to do the repair for you. Circuit breakers are designed to trip, unlike older fuses in a fuse box that are designed to melt a thin metal strip, and turn off power whenever the following potentially dangerous situations occur:
• Overloaded Circuit
• Short Circuit
• Ground Fault
Types of Breakers
There are three types of residential circuit breakers; magnetic circuit breaker, thermal circuit breaker, and thermal magnetic circuit breaker.
Magnetic circuit breakers are equipped with an electromagnet that gets increasingly strong as the flow of electricity increases. The magnet activates a cutoff switch when too much power enters the circuit. Thermal circuit breakers employ metallic strips that bend and activate a cutoff switch when temperatures get too high. Thermal magnetic circuit breaker employs both methods and protects against electrical current surges with a thermal breaker, and against a complete short-circuit, by a magnetic trip feature.
Internal components of a circuit breaker
(Source: www.IAEI.org)
Circuit Overload
The most common cause for a breaker trip is when a circuit has more connected electrical load than it is supposed to have. When more current runs through the circuit than the circuit was intended to take, the circuit breaker is designed to trip to break the electrical connection.
Circuit breakers come in different amperage ratings that determine how much current that can safely flow through the circuit. If a typical 15 Amp circuit breaker is protecting a series of receptacles and you have a hair dryer, a computer, television, and fan plugged into various receptacles on the circuit, the circuit breaker trips to prevent overheating which can cause a fire. The size of the wire also relates to the amperage of the circuit breaker, but we will go over that in a little while.
It is also important to understand that the size of the breaker, whether it’s 15 or 20 amps, is a nominal size. Breakers are designed to trip above 80 percent of the rated load; this is why vacuum cleaners or circular saws state that they are 12 amps. Most residential circuits are 15 amps, and 80% of 15 is 12. Now you know.
Correcting an Overloaded Circuit
Too many devices plugged into one outlet or multiple outlets connected in a circuit.
• Relocate lamps, heaters, irons, hair dryers and other high load devices to a different circuit with less load.
• Turn off some of the devices on the circuit to reduce the load.
• Inspect the plugs and cords of the electrical devices connected to the circuit. Damaged plugs and twisted or pinched cords can develop a short after they have been in use for a while and trip the breaker.
Tip: Another way to tell if a circuit is nearly overloaded is to touch the knuckle of your index finger to the surface of the circuit breaker to see how warm it is. All electrical wires heat up when current passes through them, so they can be slightly warm, but if you have a breaker that is hot or substantially warmer than the rest, you may have to have a electrician increase the gauge of wire to the circuit or increase the breaker size.
Short Circuit
A Short Circuit is a very serious problem which can cause breaker tripping. A short circuit happens when the hot wire (black) touches another hot wire or touches a neutral wire (white). A break in the circuit wiring can also cause a short. These can be difficult to troubleshoot since the cause can be the wiring in your home or in something you have plugged into an outlet.
Short Circuit Inspection
• Confirm that power is off to the outlets.
• Inspect your power cords for damage or a melted appearance. Space heaters which are on for long periods of time can cause the neutral side (the longer of the two slots) of the outlet to overheat and begin to discolor or even melt.
• Check your outlets and plugs for the smell of burning or brown or black discoloration.
• Remove the receptacle cover and check the insulation on the wires. Make sure it is not brittle and cracked and touching another wire, the ground wire, or the box if it is metal.
• Inspect all the outlets and switches in the circuit.
• If ceiling light fixtures are connected to the same circuit, remove the fixture and inspect the wiring inside.
• If you can’t find a problem, contact an electrician as soon as possible.
You can also purchase a receptacle tester to check if receptacles are wired properly.
Receptacle Tester
To narrow down if the short circuit is a device or the house wiring, follow this procedure:
• Unplug all devices connected to the circuit.
• Turn off all light fixtures on the circuit.
• Go to the electrical panel and reset the breaker.
• If it trips immediately, the short is in the wiring of the circuit.
• If the breaker does not trip, turn on any light fixtures connected to the circuit.
• If the breaker holds, the short circuit is being caused by something plugged into the outlet.
• It is better to purchase a continuity tester for a few dollars and follow the instructions for testing the appliances or devices. Otherwise, plug each item into an outlet and turn it on to find the faulty appliance or lamp and then have it repaired.
Note: Each time a breaker trips you can damage it and it may have to be replaced.
Continuity Tester
Other causes for repeated breaker trips can be due to loose load terminal connections on the breaker. If you can’t find the cause for circuit breaker tripping, hire an electrician an have him check the electrical service panel and all the connections inside the panelboard.
4 comments
Need some help troubleshooting a tripping Breaker located at my service box down at the boat dock. I have an electrical line run from the house to the dock. The breaker at the house is fine and does not trip. However, the line runs into a box with has a 20amp circuit breaker in it with a GFCI test button on it. In the box, load line connects to the block terminal for the breaker, Neutral connects to the neutral bus bar, and Ground to the ground bus bar. All outlets from this point have been disconnected. As soon as I connect the Panel Neutral pig tail from the breaker to the Neutral bus bar the breaker trips instantly. There is nothing hooked up to the circuit and all wires are disconnected for the circuit breaker. Ideas??
Point well taken. A hot wire on a ground is a short circuit, but this will still trip the breaker which is the point of the article. I will adjust the article and remove the ground fault terminology to clear up any confusion. Thanks.
Maybe I'm being picky but what Daniel is describing as a "Ground Fault" is really a "Short Circuit." A Ground Fault does not occur between the black hot wire and the bare copper grounding wire but occurs when the white, neutral conductor makes electrical contact with the bare copper grounding wire of some other grounded surface, Regular circuit breaker, neither thermal or magnetic, detect and respond to a true ground fault condition because the neutral conductor is also a grounded conductor. The neutral conductor is connected to the system ground at the service panel. . A special circuit breaker, a GFCI circuit breaker is required. A GFCI circuit breaker contains a solid state differential amplifier built in that compares the current flowing in both the hot wire and the neutral. When these two currents differs by more than 0.005 Amperes, the amplifier sends a signal to a solenoid that trips the breaker open.. There is a change in current flow because electric currents always seek the path of least resistance to ground and that path is always through what ever completes the ground fault. The path of least resistance to ground would be you if the neutral wire made electrical contact with the metal case of a small appliance and you touched the appliance and a good ground like a water faucet at the same time. The purpose of the two types of breakers differ considerable. the standard thermal or magnetic circuit breaker was designed to protect equipment and property against short circuits and circuit overloads, they were not designed to protect human beings against ground fault conditions. Because they did not protect people against ground fault condition, the Ground Fault Circuit Interrupter became part of the National Electrical Code with the Codes 1971 Revision and went into effect on January 1, 1973.
Need some help troubleshooting a tripping Breaker located at my service box down at the boat dock. I have an electrical line run from the house to the dock. The breaker at the house is fine and does not trip. However, the line runs into a box with has a 20amp circuit breaker in it with a GFCI test button on it. In the box, load line connects to the block terminal for the breaker, Neutral connects to the neutral bus bar, and Ground to the ground bus bar. All outlets from this point have been disconnected. As soon as I connect the Panel Neutral pig tail from the breaker to the Neutral bus bar the breaker trips instantly. There is nothing hooked up to the circuit and all wires are disconnected for the circuit breaker. Ideas??