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I have a vacuum that trips the AFCI device of the circuit that services my bedroom.

The vacuum has some age on it, and there is some wear on the motor's commutator. This wear causes electrical arcing which, to the AFCI device, looks to be approaching an unsafe condition. It is not an unsafe condition, however, because the arching is internal to the motor and the wear is part of the motor's design. This knowledge, along with the fact that it sucks dirt really well, leads me to the conclusion that the vacuum is functioning properly.

The AFCI device has been engineered to detect the type of arcing caused by electric motors. Although it occasionally trips when my older vacuum is in use, it does not trip when my neighbor's new vacuum is plugged into the bedroom circuit. The device trips when it senses a potentially dangerous (although not dangerous) arc in my older vacuum, but also is able to distinguish the arc caused by by my neighbor's vacuum as from a motor and not dangerous. This information leads me to beleive that the AFCI device is functioning properly.

Should I get rid of the vacuum? I don't want to do this, because it sucks up dirt really well. Also, if I get a new one, it will wear in a year or two and cause the same problem. Should I get rid of the AFCI device? I don't want to do that, because I want protection from fires and it is required by NEC.

Edwin
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3 Answers3

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Plugging the vacuum into a surge suppressor with EMI filtering, should prevent the vacuum from tripping the breaker. However, if the vacuum is overloading the circuit, no filter will help.

When I run my vacuum sweeper / paper shredder / treadmill / etc. it trips my AFCI.

Eaton’s AFCI has been designed to work with devices with motors that are within the FCC standard for noise. Even though these devices have been manufactured to the FCC’s standards, after frequent use wear within the motor can create noise which trips the AFCI. To mitigate the noise generated by these devices, you may use a surge plug or surge strip

From Eaton AFCI frequently asked questions (pdf)

Community
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Tester101
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Run a 12 gauge extension cord to a non-AFCI circuit. Or really rip your house apart and put in a central vacuum.

Niall C.
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Ecnerwal
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You can have the motor on your vacuum serviced. Either by a professional or by yourself.

Here is a something I found that describes some of the conditions to look for. ( It is chapter one of a general maintenance guide )

Look for obvious brush and brush holder deficiencies:

  • Be sure brushes are properly seated, move freely in the holders and are not too short.
  • The brush spring pressure must be equal on all brushes.
  • Be sure spring pressure is not too light or too high. Large motors with adjustable springs should be set at about 3 to 4 pounds per square inch of brush surface in contact with the commutators.
  • Remove dust that can cause a short between brush holders and frame.
  • Check lead connections to the brush holders. Loose connections cause overheating.

Look for obvious commutator problems:

  • Any condition other than a polished, brown surface under the brushes indicates a problem. Severe sparking causes a rough blackened surface. An oil film, paint spray, chemical contamination and other abnormal conditions can cause a blackened or discolored surface and sparking. Streaking or grooving under only some brushes or flat and burned spots can result from a load mismatch and cause motor electrical problems. Grooved commutators should be removed from service. A brassy appearance shows excessive wear on the surface resulting from low humidity or wrong brush grade.
  • High mica or high or low commutator bars make the brushes jump, causing sparking.
  • Carbon dust, copper foil or other conductive dust in the slots between commutator bars causes shorting and sometimes sparking between bars.

There are more things to check on that page.

You really need to weigh the price to have it serviced ( either in terms of time or cash ), vs the price of a new one.
That is assuming that servicing it would allow it to run without tripping the breaker.

I would say that unless it is a really good vacuum; I would just live with it, replace it, or add a EMI filter as stated in another answer.

Brad Gilbert
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