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just stumbled onto this site and crossing my fingers that someone will be able to help.

My problem is the tripping of an AFCI every 3/5 weeks when a 2nd TV is turned on. Sometimes soon afterwards, other times 10/30 minutes later. Besides the two flat screen TVs (one in family room & one in master bedroom) my laptop seems to be another common dominator as problem doesn’t seem to happen if laptop is either unplugged or not in use. On first trip after measuring load and ruling that out, the electrician rewired all switches and outlets from backstabs to screw connections. Problem continued and we had the one circuit split into two.

However that didn't fix the problem either and I believe laptop is the trigger (even though since this started I have replaced both, the power cord and laptop itself). Family room AFCI still tripped upon occasion when family room TV was on and laptop was plugged in but bedroom TV was off. After that happened I ran a cord to plug laptop into bedroom circuit and now the bedroom’s AFCI trips every now and then.

Questions: 1) does code (I live in Orange county FL) require the family room to be on a AFCI? 2) Is there a “filter” that would block any possible electrical surge or whatever the laptop could be creating? 3) Any other thoughts?

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  • When you say you're "unplugging" the laptop, do you mean pulling the low voltage plug from the computer itself, or unplugging the cord from the wall?
    – Tester101
    Commented Sep 23, 2014 at 18:34
  • AFCI's different from a standard breaker. Like a normal breaker, they will break on over current but they will also break if they detect an abnormal arc. I say abnormal because of lot of things arc. Unplug something still drawing power, flip a switch, run a motor, they all cause arcs (plus more). AFCI's are supposed to break if they detect something like a broken conductor in a lamp cord or anything not contacting correctly. You might just have an issue of faulty AFCIs being a little too over protective.
    – diceless
    Commented Sep 24, 2014 at 3:26
  • It's possible that these AFCI's are too sensitive or false tripping, but it's also possible that the laptop cord has a bad connection inside that's resulting in arcing, which is exactly what AFCI's try to prevent.
    – BMitch
    Commented Sep 24, 2014 at 13:05
  • Did the AFCI device itself indicate that it was an arc fault event instead of an over-current event? The device's instructions should tell you how to tell the difference.
    – Edwin
    Commented Oct 1, 2014 at 13:13

2 Answers 2

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1)

According to NEMA Florida has adopted the 2008 version of the National Electrical Code. The 2008 version requires AFCI protection on all 120 volt 15 and 20 ampere circuits supplying

  • Family rooms
  • Dining rooms
  • Living rooms
  • Parlors
  • Libraries
  • Dens
  • Bedrooms
  • Sunrooms
  • Recreation rooms
  • Closets
  • Hallways
  • Or similar rooms and areas

National Electrical Code 2008

Chapter 2 Wiring and Protection

Article 210 Branch Circuits

I. General Provisions

210.12 Arc-Fault Circuit-Interrupter Protection.

(B) Dwelling Units. All 120-volt, single phase, 15- and 20-ampere branch circuits supplying outlets installed in dwelling unit family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, or similar rooms or areas shall be protected by a listed arc-fault circuit interrupter, combination-type, installed to provide protection of the branch circuit.

2)

I'd assume the laptop is not powered directly by line voltage, and that there's some form of electronics between the wall and the laptop. This circuitry should be enough to stop any noise from reaching the breaker. Though it could be something in the circuitry that is causing the problem, if it's not functioning properly.

3)

You didn't mention whether you're unplugging the laptop from the charger, or the charger from the wall. Unplugging the laptop from the charger, should not cause any problems with an AFCI. Unplugging the charger from the wall, could generate a spark (arc) which the AFCI could interpret as dangerous.

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A proper laptop cannot draw enough amperage to trip a 15A circuit breaker (3 amps max) unless the circuit is already running very close to maximum. But a badly wired outlet can easily blow a fuse. If your laptop is plugged into the same outlet every time the breaker trips, maybe that outlet is bad (e.g. shorting out within the outlet, or a loose contact or bare wire that grounds against a metal junction box, etc).

Try using some other small appliance in the same outlet (e.g. a small fan or a 100W lamp), and try moving the laptop to another outlet on the same circuit to see what happens.

You also might want to sum up the power consumptuion of all the appliances that are plugged into that circuit to see what the total load actually is. A small in-line tester (like a "Kill-O-Watt") will reveal how much amperage (or wattage) each appliance consumes. If the summed amperage is nowhere near your circuit's maximum, yet the circuit still trips its breaker, something else is happening (like a bad outlet is shorting out after the wires heat up during use).

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