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We recently had our main electric service panel upgraded (from a 50 year old 100 AMP panel to a 200 AMP panel).

As part of the upgrade, the electrician installed an arc fault breaker on the bedroom circuit (15 amp). I've noticed that when the Vacuum is running and plugged in on that circuit for extended periods of time (say, 5-10 minutes), it triggers the breaker. This only happens when the vacuum is on and occurs regardless of what else is running on the circuit. We've tried turning everything else off and it still occurs.

Is this indicative of some major electrical issues? We have a variety of other electronic devices on the circuit (PCs, Piano Keyboard, TV, etc). This only happens when the vacuum is on.

This didn't happen before when the vacuum was running on that same circuit using a "normal" breaker.

Mike B
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    How old is the vacuum? Is the vacuum in good repair? Is the cord in good repair? Does the plug fit snuggly in the receptacle? Do the breakers indicate the reason for the trip, or do they simply trip? What is the HP and\or amp rating of the vacuum? – Tester101 Dec 27 '13 at 23:10
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    The vacuum is a Dyson DC14 (about 4 years old). The cord is in good shape. It plugs sniggly in the receptacle. I'm not sure what to check for to determine the reason for the trip - can you please elaborate? The vacuum is rated for 12 Amps. – Mike B Dec 27 '13 at 23:26
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    There are instructions that come with the AFCI. The electrician may have stuck a sticker to your breaker box. For my Murray AFCI, there is a yellow light. After the breaker trips and you switch it to the on position, if there is a yellow light, it was an arc fault that caused the trip. If there is no light, it was over-current that caused the trip. – Edwin Dec 28 '13 at 02:09
  • Vacuums tend to use Universal Motors. Universal motors have a field winding and commutated rotor windings. The brushes that ride on the commutator arc as the rotor spins. AFCI circuit breakers are designed to detect arc hash in broken lamp cords, etc. – Fiasco Labs Nov 03 '14 at 22:27

1 Answers1

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The arc fault breaker detects arcing between wires in appliance cords or house wiring which could cause fires. Unfortunately, such similar arcing also occurs in electric motors as a part of normal operation. The Arc Fault breakers are supposed know the difference between the two, but often trip anyway. In my experience, they trip most often when the vacuum turns on or off.

The vacuum tripping the arc fault breaker, by itself, is not an indication of an electrical issue.

Edwin
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  • And welcome to "Why I'm not planning to refit MY house with AFCI's, thank you very much AFCI pushers sitting on the NFPA committees." Unfortunately common sense does not have big lobbying dollars to set people on the committees, but companies with crap to sell do. So now folks will use fire-hazard extension cords to run things they can no longer run on their "safe" AFCI circuits - clev-er. – Ecnerwal Dec 27 '13 at 21:13
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    The same thing happened when GFCI breakers came out. It took a while for the bugs to work out. Until then it will be a pain. Sorrowfully I have to agree with Ecnerwal. Electricians on the jobsite made the same statement. – Jack Dec 27 '13 at 22:02
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    You can try changing brands of AFCI breakers, as each vendor has different software. Or switch that AFCI out for a GFCI and be happy. However: if those are two wire K&T circuits I do recommend an AFCI (See http://diy.stackexchange.com/a/20279/5960). In that case could you install a new 3 prong outlet in the hall for the vacuum? – Bryce Dec 27 '13 at 22:05
  • Can you cite sources or point to studies that support your position? How can you definitively blame the AFCI device, without knowing the make, model, age, and condition of the vacuum? AFCI devices have had problems in the past, but in my experience modern devices are much more accurate. It sounds like you are blindly propagating outdated, and potentially inaccurate information. – Tester101 Dec 27 '13 at 23:05
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    @tester101 I have an AFCI device installed on a new circuit that trips occasionally when I turn on my vacuum. It's from my own experience, and the experience of others, along with a simple understanding of how electric motors and AFCI devices work. The OP did not ask "Do all AFCI devices trip when any vacuum is turned on?", he just asked is it normal that a vacuum trips an AFCI device. The answer is yes. It's normal. I'm not propagating any false info. – Edwin Dec 27 '13 at 23:42
  • @Edwin It is not "normal" for AFCI devices to be tripped by properly functioning electrical devices. – Tester101 Dec 28 '13 at 01:08
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    @Tester101 It is normal for AFCI breakers to trip when there is an arc between the line and the neutral. Guess what; universal motors all have brushes which cause arcs during proper operation. About the only way to make absolutely sure that type of motor won't trip AFCI device is to use a common mode choke or an isolation transformer. – Brad Gilbert Dec 28 '13 at 01:54
  • @BradGilbert AFCI devices have software that analyze each arc event, and can differentiate between a dangerous arc and a normal arc. In older models they were not so smart, and often tripped incorrectly. Newer models are more accurate, and nuisance trip much less often. So... Do AFCI devices occasionally trip due to vacuums, yes. Is it "normal" for an AFCI device to trip due to a vacuum, no. – Tester101 Dec 28 '13 at 14:02
  • @Tester101 I am aware of that. If there is some wear on the commutator, it will seem more like the kind of arcing that an AFCI should trip for. Even though the motor is fine. So a motor will become more likely to set off an AFCI over time. So either replace the motor every few years (even if it would continue to work for decades), take it apart and service the motor, or put some sort of filtering to reduce the signal that the AFCI "sees". I would like to point out that having a professional service the motor would probably be more expensive than replacement of the whole vacuum. – Brad Gilbert Dec 28 '13 at 15:57
  • @BradGilbert Which is exactly what I'm saying... It's not a problem with the AFCI device, but with the vacuum. If you have a poorly designed vacuum, you have to replace or repair it more often. – Tester101 Dec 29 '13 at 13:16
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    The OP just wants to know if his wiring is safe. I created a separate question to settle this AFCI vacuum debate once and for all! :) http://diy.stackexchange.com/questions/37277/what-should-i-do-if-my-vacuum-trips-my-afci-device – Edwin Dec 29 '13 at 19:49
  • I know this is old, but I am having the same problem. GFCI breaker circuits trip when using my vacuum or my laser printer. Guessing this is normal. My vacuum is old but works fine. Laser printer---5amps trips it? I have Square D breakers. There's no light or other indicator I can see. The big black throw switch trips halfway. – dex3703 Jul 18 '17 at 19:22