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Circuit breakers can often trip when a light bulb fails just at the point when you switch on the light. The reason it happens is that, in normal use, the bulb's filament gets thinner and thinner and more and more brittle over time.

Eventually it is about to fail - also known as "burn out" - but it doesn't usually do it whilst it is still burning because it's resistance is at its highest when it is hot and "lit", so it is taking the least amount of current whilst it is "on".

But then, if you switch that bulb off as normal, when you next come to switch it on its filament will be cold and its resistance will be lower than when it was hot. At the point of switching it on it draws a higher starting current for the last time but then, as the filament finally "snaps", the "flying ends" of the snapped filament can sometimes momentarily short-out the hot and neutral filament feed wires, taking a very high current which trips the circuit breaker!

Any incandescent light bulb will draw a higher starting current when you first switch it on because, when cold, the filament resistance is at its lowest point. The bulb soon heats up to its normal running temperature at which point the current settles to its normal running current which is lower than its cold starting current.

But in the case of a bulb that has been used for near to - or more than - its designed number of hours, then it is much more likely to fail in a way that causes the circuit breaker to trip, as has been described above.

Provided they have not been "knocked or dropped" at some time during their life - which would significantly shorten their actual expected "life" because of mechanical damage to the filament - ordinary incandescent bulbs are rated for only about 1000 hours of actual use. More expensive "long-life bulbs are available that are rated at 2000 hours.

A different answer

If your home is new and has the new type of arc-fault breakers, this occurs from time to time when the filament in the bulb blows because the failing bulb causes an arc and the breaker does what it was designed to do: stop the arc.

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โˆ™ 2011-05-15 10:08:11
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Q: What is wrong with an electrical circuit that pops the 15A breaker each time a light bulb fails?
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Related questions

What do I do if there is no circuit breaker for outdoor light?

If you have a light that is not being powered through a circuit breaker or fuse, you should call a qualified electrician to remove this circuit from the panel's bus and install a circuit breaker for it. Without an overcurrent protective device (circuit breaker or fuse) you have a potential fire hazard.

What size amp circuit breaker should be used for a pool light?

The pool light is usually on a 15 amp circuit. The breaker feeding this circuit must have a GFCI rating.

Can you use a 20 amp circuit breaker for a light circuit?

As long as the light circuit isn't over 20 amps.

What happens to a parallel circuit if one light fails?

A parellel circuit does not fail if one light dies. In a series circuit, it's broken if one light fails (like the old style Christmas lights). See link for example...

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It is a relay or switch problem. A circuit breaker or fuse won't keep a light on.

If a light bulb is missing in a series circuit will the bulb light?

If one light bulb in a series circuit fails, all the other light bulbs will go out, until the failed bulb is replaced and the series circuit is completed again.If one light bulb in a parallel circuit fails, all the other light bulbs will still work.

What are the parts of a simple electrical circuit?

power source, protection device (fuse, circuit breaker, etc.), control device (switch), load [whatever you want to power (light bulb)], and conductors to connect them.

What might cause a breaker to trip when switching on a light when resetting the breaker and checking the fuse doesn't restore power to one circuit?

Overloaded circuit, short in circuit, or defective switch.

What happens if you put a 15 amp circuit breaker in a light circuit?

The circuit should be protected by a 15 A breaker.CLARIFICATION:If the wires and other components are capable of handling 15 amps (14 Ga wire or larger), you can safely protect the circuit with a 15 amp breaker. If the circuit is a non-standard lighting device for something other than typical residential application, you should contact an electrical engineer to help you determine the proper wiring and breakers.

What does electrical receiver mean?

An electrical receiver is the part in a complete circuit that receives the electrical energy, if in a build circuit the receiver will be the light bulb

Why does the light switch pop the circuit breaker after a period of time?

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If the electrical conductivity in an electrical circuit decreases then the brightness of the light bulb does what?

Then the brightness of the light buld increases.

What is a part of a circuit that closes or opens the circuit?

Generally a circuit breaker (like a light switch) But I guess you could use a resistor of the right resistance If you are talking about the circuit breaker there is an electromagnetic coil in it which get magnetized on a specific amount of current and breaks the circuit

If the electrical conductivity in an electrical circuit decreases then the birghtness of the light bulb does what?

It decreases

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A conductor carries the voltage potential from the source to the load, i.e. the wires from a circuit breaker to a light.

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What is the function of bulb in an electric circuit?

The function of a light bulb in an electric circuit is that it turns electrical energy into light.

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Why do you use a lightbulb? because you need light. Why do you use it in a circuit? because all electrical devices are in a circuit.

How can you find out a defective light bulb in a parallel circuit?

In a parallel circuit, the defective light bulb is the one that fails to glow when the power source is energized.

What does the light bulb do in a circuit?

Bulbs convert an electrical energy to produce light

What are the four parts of any electrical circuit?

The three essential parts of any electrical circuit are: a power source (like a battery or generator), a load(like a light bulb or motor) and connectors (wires) to join them together.A fourth part, that is always a very important thing to have in most circuits, is a control device such as a switch, circuit breaker or fuse.

What is a simple electrical circuit?

A simple electrical circuit has one path for electrical current (electrons) to flow. A simple circuit has a power supply, switch/push button, and a load (light, bell, etc).

What happens when the circuit is complete and the switches are closed?

*Look at the simple circuit illustrated in Figure A-2. What will happen when only switch S1 is closed? Correct Answer= "Nothing will happen-the light bulb won't light up." <<>> If there is a load in the circuit the load will operate. If there is no load in the circuit and it is complete then a short circuit will occur and something in the circuit will burn open. If the circuit is complete and there is a fuse or breaker in the circuit, then the fuse or breaker will open the circuit.

Where is the circuit breaker for 1979 Chevy truck headlights?

It is built into the head light switch.

Why do lights in a series circuit go out when one goes out?

In a series circuit each light completes its part of the circuit and connects to the next light. So, if one light fails, the circuit is broken and the flow of current to all lights must stop.