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.

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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 2:09
  • 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 3 '14 at 22:27

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.

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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 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
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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
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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 1:54
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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! :) diy.stackexchange.com/questions/37277/… – Edwin Dec 29 '13 at 19:49

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